Sodium Cell Charging and Discharging Analysis, Hardware Compatibility. Future or Niche product?

Summary

The video explores sodium ion batteries, testing their charge/discharge curves, voltage ranges, capacity, and compatibility with existing lithium hardware. It finds sodium batteries have very different charge behavior, with more linear discharge but lower usable capacity. Charging to 3.95V yields 1.3Ah capacity. Discharge plateau occurs around 2.6V, optimal cutoff is 2V. Inverter voltage ranges may only allow 80% sodium battery use. More testing is needed, but hardware changes seem necessary for full sodium support, challenging their drop-in claims.

Takeaways

• 😀 The video tests and compares sodium ion and lithium ion phosphate batteries
• 🔋 Sodium batteries have very different charge/discharge curves from lithium batteries
• ⚡ Sodium batteries can be charged from -10°C to 45°C unlike lithium batteries
• 🔋 The sodium battery voltage range is huge - from 1.5V to 3.95V per cell
• ⏱ A 1.3Ah sodium cell takes about 1.5 hours to charge/discharge at 0.5C
• 😕 Existing inverters can only use a portion of sodium battery capacity due to voltage limits
• 🤔 Not clear what the optimal sodium battery charge/discharge depths are for longevity
• 🛠 BMS parameters can be configured for sodium batteries, but hardware changes may be needed
• 🔬 More sodium battery testing needed - capacity, longevity, safety, overcharge tolerance
• ⏳ Overall sodium battery tech seems early stage and far from replacing lithium batteries

Q & A

What type of batteries are being tested in the video?

The batteries being tested are sodium-ion batteries, which use sodium instead of lithium as the charge carrying ion.

How do the dimensions and appearance of the sodium-ion 18650 cells compare to normal lithium-ion cells?

The sodium-ion 18650 cells have the exact same dimensions and look identical on the outside to standard lithium-ion 18650 cells. The only difference is they have a blue heat shrink wrap to denote the negative terminal.

What is the charging voltage and charging protocol used for the sodium cells?

The sodium cells are charged to 3.95 volts at a rate of 0.5C with a cutoff current of 0.05C.

What are the key differences between the discharge curves of sodium-ion and lithium-ion phosphate cells?

The sodium cell discharge curve is much more linear overall. It has a plateau region from 2.9-3V but lacks the steep voltage drop-off at the end that lithium-ion phosphate cells have.

Can existing lithium-ion phosphate BMS systems be reconfigured for use with sodium-ion batteries?

Yes, the JK BMS tested in the video was configurable for the different voltage and current parameters needed for sodium-ion batteries.

What inverter challenges exist when trying to use sodium-ion batteries?

Many inverters have tighter voltage cut-off thresholds that would prevent the full charge/discharge capacity of sodium cells from being utilized.

What is the typical shipping voltage for sodium cell prototypes?

The manufacturer specifications indicate the cells are typically shipped with a 20-30% state of charge, not at 0 volts.

What further testing does the presenter want to conduct on the sodium cells?

Additional tests proposed are overcharging to see if the cells will explode/catch fire since they are supposedly safe, and discharging fully to 0V to see if additional capacity can be obtained.

What open questions remain about best practices for sodium-ion battery usage?

Optimal depth of discharge, impact of extreme charge/discharge on cycle life, and other usage recommendations are still yet to be determined.

Does the presenter think sodium-ion batteries will replace lithium-ion batteries anytime soon?

No, he believes lithium-ion phosphate chemistry is currently very good and sees challenges around hardware compatibility with sodium-ion batteries being adopted.

Outlines

00:00

📽️ Introducing sodium batteries and testing plans

The video introduces sodium ion batteries that will be tested and compared to lithium iron phosphate batteries. Testing will look at charging, discharging, capacity, charge/discharge curves, suitable equipment like inverters and BMS, and safety. A 12V 50Ah sodium ion battery will also be tested.

05:00

📃 Specifications for the sodium ion cells

The key specifications for the 18650 sodium ion cells are provided, including capacity, voltages, charge/discharge rates, temperature ranges, cycle life, safety tests, and more. There is some confusion on whether the capacity is 1.3Ah or 1.5Ah.

10:02

💻 Software setup and initial charge test

The EB tester software and hardware are set up to test the sodium ion cell. An initial charge test is performed to 3.95V with 0.1A cutoff to analyze the charge curve and capacity.

15:04

🔋 Discharge test and analysis of curve

The cell is discharged at 0.5C down to 1.5V to get the full discharge curve. Capacity measures 1.3Ah. The curve shape is analyzed, showing a plateau region around 2.7V. 2V seems a reasonable discharge cutoff.

20:05

⚡️ Charge test and discussion of usage

The cell is charged back up at 0.5C, measuring 1.31Ah capacity. The charge curve is fairly linear. There are no usage guidelines on state of charge limits, unlike lithium batteries.

25:05

🔧 Testing compatibility with BMS and inverter

A JK BMS can be programmed for sodium ion batteries. Testing shows multiplus inverters can only use 86% of a 16S sodium pack due to voltage limits. So hardware changes may be needed to support sodium batteries.

30:07

😕 Challenges integrating sodium batteries

Even though BMS programming seems possible, inverter voltage ranges severely limit capacity usage of sodium batteries. Significant hardware changes may be needed for adoption. Lithium iron phosphate systems have no such issues currently.

35:09

🤔 Future sodium battery testing ideas

Further sodium battery testing ideas are proposed, like discharge to 0V, overcharge testing, and more capacity measurements. The differences to lithium batteries are highlighted.

Keywords

💡sodium batteries

Sodium batteries are a new battery chemistry using sodium ions rather than lithium ions. They are presented in the video as an alternative to the popular lithium iron phosphate batteries. The video tests sodium battery characteristics like charge/discharge curves, capacity, compatibility with equipment, etc. to evaluate if they can replace lithium batteries.

💡charge/discharge curves

The charge and discharge curves show how a battery's voltage changes during charging and discharging. The video analyzes the curves for sodium batteries to understand their behavior and compare to lithium batteries. For example, sodium batteries have a more linear discharge while lithium batteries plateau and then drop rapidly.

💡cut-off voltage

The cut-off voltage is the minimum or maximum voltage at which charging or discharging is stopped to prevent damage. For sodium batteries, the charge cut-off is 3.95V while discharge is 1.5V, very different from lithium batteries. This affects compatibility with equipment.

💡C-rate

The C-rate defines the charge or discharge current rate in relation to the battery capacity. For example, the video charges and discharges the sodium cells at 0.5C and 2C, meaning a 1.5Ah cell uses 0.75A and 3A current.

💡state of charge

State of charge (SOC) refers to the battery charge level, typically from 0 to 100%. The video observes that sodium battery voltage correlates well with SOC, allowing SOC estimation from voltage measurement.

💡battery management system (BMS)

A BMS manages charging, discharging and protection of battery packs. The video checks if a lithium BMS can be reconfigured for sodium batteries - parameters like voltage limits are adjustable but hardware compatibility needs more testing.

💡battery inverter

An inverter converts DC from batteries to AC for appliances. Inverters have voltage limits that may only utilize a portion of sodium battery capacity. For example, only 80% of a 48V sodium pack works with a Victron inverter.

💡constant current charging

Constant current charging method charges at a steady predefined current value, used in the video for analyzing sodium battery behavior. The voltage rises until it reaches the set maximum voltage.

💡depth of discharge

Depth of discharge (DOD) indicates how deeply a battery is discharged, from 0% (empty) to 100% (full). The lack of guidelines for sodium batteries raises questions on optimal DOD to maximize cycles while protecting health.

💡safety testing

As a new chemistry, verifying sodium battery safety is critical before mainstream use. The video references safety tests showing no fire/explosion concerns, but additional real-world testing may be needed for performance assurance.

Highlights

Testing lithium and sodium batteries to explore questions about sodium batteries

Sodium battery dimensions and look identical to normal 18650 lithium cells

Sodium battery charge voltage is 3.95V, discharge cutoff is 1.5V - very different from lithium batteries

Can charge sodium batteries from -10°C to 45°C unlike lithium batteries

Discharge capacity at high and low temps is 85-98% of capacity at 25°C

Sodium batteries lose ~5% capacity per month when stored fully charged

Safety tests show no fire/explosion with sodium batteries after abuse tests

Discharge curve is very linear initially, then plateaus from 2.7-2.6V before dropping off

2V seems a good minimum discharge voltage based on the curve

Charge curve also quite linear, with rapid initial voltage increase

Can likely use existing BMS by programming limits for sodium chemistry

Inverters have very limited input voltage range - may only use 50-80% of sodium battery capacity

May need new inverter and BMS hardware designed for sodium chemistry

Lithium iron phosphate chemistry already mature, questions if sodium batteries will achieve breakthrough

More sodium battery testing videos coming on the channel

Transcripts

[Music]

[Music]

[Music]

guys welcome back to the offut garage

here in super super sunny and very very

hot Australia we have like uh 80 amps

outside at the moment and know I'm

already on 66% and it is 11:00 in the

morning I've got all the time to fully

charge this battery slowly today very

slowly because there will be Sunshine

until 5:30 or

so well guys what can I say you have

seen it in the intro we are going to

test

lithium we are going to test sodium

batteries na+ or salt batteries I tell

you there are a ton of questions about

sodium batteries out there and I'm going

to explore them all we will measure the

heck out of these sodium batteries doing

all the charge discharge test find out

how to charge how not to charge them we

will do capacity tests in both

directions have a comprehensive and

detailed look at the charge and

discharge curve of these batteries how

do they absorb do they need float mode

what equipment can be used with sodium

batteries the same inverter the same BMS

do we still need active balancers so we

will do the whole comparison between

sodium batteries and lithium iron

phosphate batteries we know lithium iron

phosphate batteries very very well we

have done a ton of testing here on the

channel discovered every angle of these

batteries but now slowly these sodium

batteries are sneaking into the market

and we want to see how far they actually

are can we replace lithium iron

phosphate with sodium batteries already

so these are just the questions I came

up while talking to the camera now I'm

sure you've got a million other

questions as well so without further

Ado let's get

[Music]

started so there you go sodium batteries

no lithium anymore huh so I bought these

four 18650 cells well this one is not

one of them this is actually a lithium

ion 18650

but if I mix them up you can't tell so

of course exactly the same d dimensions

and look as a normal 18650 cell and

these ones have a capacity of 1.5 amp

hours and a nominal voltage of 3.1 volts

and they come with the usual blue heat

rink negative on one side and the usual

positive terminal on the other side so

nothing special you cannot tell from the

outside that these are sodium batteries

and I bought four of them because I

wanted to build a 12vt battery but is

this actually possible with four of them

or do we need only three or do we need 5

um we don't know yet well to start with

let's have a look at the data sheet they

provided with these cells it's very

interesting so here's the document they

provided for these cells specification

for sodium iron rechargeable cell I

don't know exactly what kind of brand

that is I couldn't find the name of the

manufacturer of these cells here and

there was also a bit of confusion from

the beginning because these cells were

offered as 1.3 a hour batteries and it

says 1, 300 here in the specification as

well but here on the heat ring it says

1,500 so I guess we will find out so we

want to have a look at the definitions

before we start going deeper into the

specifications here so we've got a

capacity of 1.3 or 1.5 amp hours at 25°

we've got an end voltage of 1.5 volts we

can charge these batteries to 3.95 volts

with a constant current of5 C and then

we have the usual drop off of

0.05c at 3.95 discharging with a

constant current of

0.5c down to 1.5 volts so 1.5 volts is

our low limit and 3.95 is our high limit

so this is very different to our

well-known lithium ion phosphate

batteries so here are the

dimensions nominal voltage 3.1 volts

charge voltage up to 3.95 volt

discharge cut off is 1.5 internal

resistance is smaller than 20 milliohms

they claim an energy density of 118 wat

hours per kilogram and here's another

main difference to lithium iron

phosphate batteries we can charge these

batteries down to -10° C yeah only with

2 C but we can still charge these

batteries this would be a nogo for

lithium and from 0 to 45° we can charge

these cells with to 1 C if the battery

getss hotter than 45° we cannot charge

it anymore lithium phosphate goes to 55°

we can discharge these batteries down to

-30° C 0.2c again from 0 to

45° 3 C and I'm sure we will test this

in one of the upcoming videos and even

above 45° up to 60° we can still pull 05

C from this battery cell so as we have

seen already the maximum constant charge

current is 1 C up to 3.95 volts and then

at 0.05 C we consider the battery to be

fully charged we can discharge the cell

with up to 3 C down to 1.5 volts very

interesting okay charge and discharge

curves of sodium cells we're not looking

at that we will make our own charge and

discharge Curves in this video here so

here we have the usage conditions again

so we can charge this battery from -10

to + 45° and we can discharge from 30

to+ 60° C so that's a bit of a

difference to lithium ion phosphate so

here we have the test conditions

explained at 25° we are constant current

constant voltage charging this battery

to 3.95 volts with

0.5c and with a cut off of 0.05 c as

seen before the discharge constant

current down to 1.5 volts we're

discharging with 1 C 2C and 3C and

getting different results with the Capac

capacity so even at 3C they're claiming

we are still getting 98% of the capacity

but I'm not 100% sure how they mean this

here is this like a discharge capacity

at 1 C divided by discharge capacity at

0.5c and this gives you more than 99% of

the

capacity I don't know ah yeah I think so

so the cycle life is at 25° again the

same conditions to charge the battery

and discharging with 0 5c down to 1.5

and then we have a discharge capacity at

3,000 Cycles divided by a nominal

capacity gives us more than 80% I guess

this is how it works and here again the

capacity calculation for high and low

temperature this is always in relation

to 25° so discharging the battery at

very low temperatures gives you 85% of

the capacity discharging the battery at

very high temperatures gives you 98% %

of the

capacity then charging the battery at

25° to 3.95 volts with

0.05c cut off and storing the battery

for one month in these conditions and

then do a discharge test it gives you

95% of the capacity so it looks like

they are losing around 5% of their

capacity if you store them for one month

and then they have done all the safety

tests with them viberation test no

explosion no fire thermal abuse no

explosion no fire so they heated up the

battery to 130° C short current was also

no explosion no fire they overcharged

the battery with 1 C for 1 hour no

explosion no fire and they discharged

the battery with one C for 1.5 hours

there was also no explosion and no fire

they also did an impact test and there

was no explosion and no fire and then

there come the usual warning so don't

use these batteries in water don't put

them in fire so I will link this

document on our website as well as the

test results we are doing today so if

you want to have a closer look at at all

these specifications for these cells

here so I'm pretty confident we can

finish all the tests today charging and

discharging with taking the curves and

analyzing everything because I'm going

to discharge and charge this battery

with 0.5 C usually we use only 2 of a c

but then charging and discharging would

take 5 hours so here for a first look

and taking the curves 5c it will be so

for this test I'm using one of the

standard 18650 holders here it's a four

four battery holder but we using only

one slot here for one

battery and then I have already set up

the EBC a20 tester which we will use

connected to our computer to take the

curve and we will connect the positive

directly to this terminal and the

negative directly to this one over here

so we should have a voltage reading

already 3 5 six I just got a bit scary

at the moment because I thought this

battery is so full but now it's a sodium

battery it's not lithium ion phosphate

so 3.5 volts totally fine all right then

we are starting the EB tester software

ah I tell you what it feels so good we

want to actually connect this this com 7

yes it is okay so we've got now the

voltage here of our battery cell on the

Monitor and we want to constant voltage

charging with

um yeah well is this a 1.5 it doesn't

matter

0.75 amps to

3.95 volts and the cutoff current good

old calculator 1 5 0 *

0.05 cut of current is 75 milliamps

0.075 is that correct so just checking

again charging to 3.95 volts with 75

amps and and then we have a cut off at

75 milliamps all right let's uh fully

charge this battery and then we do the

full discharge with

05c I'm not sure how long this will take

here should be ready in about 20 minutes

or so all right see you then I guess I

will say this a lot of times in this

video

oh okay I think the cut off current is

.1 amps this is the minimum I can go

okay we go with that we're charging

we've got current and we've got voltage

which is rising all right see you in a

couple of

minutes oh we just pass the magical 3.65

volt

Mark and we keep charging oh

God while this uh battery is charging

here I have also a brand new 12vt 50 a

hour sodium ion battery here so this is

like a drop in 12vt battery and her

Miller from Miller energy in Sydney here

was so kind to donate this battery to me

um he bought actually a couple of them

to test them out they are prototypes and

he said he's not very happy with them so

he donated one to the offcut garage here

for me to test and the good thing with

this battery is we can also open the lid

here and have a look inside what kind of

BMS they have used what kind of cells

how the battery is being built so we

will do all this in a later video as

well having a look at this um 12vt 50

amp hour battery Tre uh just having a

quick look at these specifications here

so we've got a charge voltage here of

9.2 to 15.6 volts that is insane

standard charging 10 amps standard

discharging 10 amps maximum is 50 for

both so this will be very interesting to

test out the voltages are so different

wow

caution only use 15.6 volt charger to

avoid the risk of fire or explosion can

sodium batteries actually catch fire or

explode I thought they are so

safe all right we are charging now for

20 minutes or so we have reached the

3.95 volts the the current is tapering

off and we already down to 2

amps there are so tiny currents

unbelievable so I guess the cell is now

absorbing and before we start our

discharge test I also want to take the

temperature of this cell 33.5 de this is

at full charge now I'm not expecting the

battery gets too warm during discharging

but who knows so here in the cycle test

tab I have already programmed the

sequence so we're going to fully charge

the battery again to 3.95 volts and this

is only to get a common start point for

our discharge I will do this with all

the other cells as well and once we have

reach that we do the discharge and this

measures then the capacity and also

takes the discharge curve cve all right

charging has now stopped voltage is

dropping just a little

bit okay we start this test so it's

charging again to 3.9 5 volts 0.1 amp

cut off all right discharge has now

commenced yep discharging with

0.5c we've got the current up here

constant current and this is our voltage

curve all right I would say see you in

uh 2 hours 2 hours and then we have a

look at this discharge curve of a sodium

battery I'm very excited I'm literally

very excited this will be so different

okay we are now discharging for 15

minutes with um 75 amps voltage has gone

down from 3.95 to

3.5 and we can see a pretty linear

discharge curve so far it is very

lightly curved but very very different

to lithium ion phosphate okay I just

wanted to share this during the test

because I think this is a very

interesting well you find this

interesting as well otherwise you

wouldn't watch

this all right see you in a bit all

right and we are back in the garage

after 1 hour and 46 minutes and 20

seconds we've got the result we

discharged the cell from 3.95 volts down

to 1.5 with 7 50 milliamp of discharge

current and we got a capacity of 1.3 to9

amp hour so I'm not sure if these are

1.5 a hour batteries or 1.3 a hour

batteries still undecided here it could

be the large discharge current as well I

have a quick look at the

temperature this is 35° so 2° more than

before we started that's fine that could

be the ambient temperature here as

well so I will repeat this test with 2C

discharge and see if there's any gain in

capacity but I think these are 1.3 amp

hour batteries and not 1.5 as it says on

the heat shrink so here I can present

you the discharge curve of the sodium

battery and it looks very very different

to lithium iron phosphate very different

so this is where we started 3.95 volts

discharging and the curve is going down

very linear from here I would say to

this point here this is a very linear

discharge almost flat it's a bit banded

here at the top roughly until here but

then it goes very very linear down until

here at 2.7 volts obviously there

something happening with the Sodium

battery we have discharged

851 amp hour so far so that is 64% of

the capacity already used and then the

curve suddenly plateaus out a bit yeah

probably roughly until here 2.62 volts

and this where we have discharged around

1 amp hour so around 75% of the capacity

so and from here it goes downhill but we

still have 25% of the capacity there so

the voltage is going down further and

further we are at 2 volts

here here so here's exactly 2 volts and

we have discharged 1.25 1 amp hours

which is just over 95 4% of the measured

capacity then the voltage goes further

down there's another bit of a kink here

in the curve at around 1.7 volts but

then we have already discharged 1.31 amp

hours so we are close to 99% discharged

energy now so I would

say if you discharge them down to 2

volts and leave 5% in the battery that

would be fine this is probably like 3

volts with lithium ion phosphate

batteries then you've got like five six

or 7% still in the battery and usually

we stop discharging at 3 volts and I

would say the same here 2 volts should

be your lowest discharge of these

batteries so there is a bit of a jump in

voltage at the beginning when you fully

charge this battery to 3.95 volts but

then again do you charge to 3.95 volts

all the time you know this is like 3.65

with our lithium iron phosphate we

usually don't go that far do you leave a

buffer of 5% at the top and five at the

bottom and honestly I'm not even sure if

this is necessary with sodium batteries

so we are really missing out on these

important and significant points on this

discharge curve here like with lithium

ion phosphate where we have this steep

incline of voltage at the end and a

steep incline at the beginning and then

it plateaus out in the middle but here

it's a very

linear discharge curve bit of plateauing

then here and then it goes further down

and we know if sodium batteries are

getting getting stressed as well as the

lithium batteries so you keep actually a

buffer at the top and at the bottom well

we just don't know I guess we will do

some more testing in the future with

this battery here and see how far we

actually should charge maybe it's enough

if we charge to 3.7 volts and then

absorb here and it gives us almost full

capacity anyway watch this space well

here at the bottom I would say 2 volts

is a good number 95% of the capacity

should be fine to stop discharging

technically

we can actually discharge this battery

down to 0.0 volts right this is one of

the marketing Arguments for sodium

batteries you can discharge them to zero

volts and they don't take any harm but

from what I can see here I mean we are

down to 1.5 volts and the and the curve

goes really steep already I don't think

there's any capacity left between 1.5

and 0 volts so this is not the reason to

discharge them to zero volts the only

reason could be because of Transport the

this is what you can read everywhere you

discharge the batteries to zero volts to

transport them

safely well I have never heard of an

accident somewhere where they

transported lithium iron phosphate

batteries with about 30 to 40% state of

charge and they got into an accident and

because the cells were still charged to

30 or

40% it got really

bad I never heard of any incident

worldwide so

far if so I'm not sure if this

discharging to zero volt is not really

just a marketing trick hang on where was

this ah here here it says here in the

specification sheet as well single cells

are shipped with nominal capacity of 20

to 30% or according to customer

requirements so even here they're saying

the batteries will be shipped with 20 or

30% state of charge not with 0% state of

charge or zero volts okay I think this

is very very interesting to see this

discharge curve here and we now do the

reverse we are now charging this battery

up again to 3.95 volts take the full

charge curve talk about it analyze it

and see how far we should charge this

battery okay I have now programmed the

next task sequence here so we're going

to discharge this battery down to 1.5

volts again to get our zero point and

then from there on we take the curve and

charge it all the way up to 3.95 volts

with 75 amps and then when we hit 0.1

amps cut off weall it that's it that's

our capacity test for the charging and

we will have a look at the curve then of

course I have saved the discharge curve

and the data as well this will be all

available on my website I'll talk about

this again at the end of the video okay

there we

go we hit the task

sequence discharging

again okay and here we are charging

voltage is rising

steep obviously the charge current is

constant and voltage is rising very fast

we already at over two volts here after

a few seconds 2.1 volts Rising very

quickly all right I guess this is

another 1 hour and 40 minutes so we will

see us again

at at around 4:00 hey that's almost b:

right okay see you

then I'm back it is 4 30 1 hour and 44

minutes we have just reached the 3.95

volts you can see the voltage is now

being kept constant while the charge

current is going down very very quickly

we already down to 370 milliamps and at

100 milliamps that's fully charged then

so far we have charged

1,36 Mah hours into this battery so

pretty much the same as we have

discharged I really believe these are

1.3 amp per hour cells not 1.5 unless

the quality is so bad and they have just

less capacity as stated on the heat

shink we can take another temperature

measurement 35° stable at this uh

temperature so the tester has just

turned off voltage is now declining a

bit we have charged

1317 amp hours into this little cell

starting from 1.5 and finishing at 3.95

cut off 0.1 amps a fairly linear charge

curve so here's 1.5 volts and the next

measurement is already 2 volts so

voltage Rises very quickly at the

beginning I mean we have charged 1

milliamp hour into this battery and the

voltage has already jumped from 1.5 to 2

volts incredible and then we see a

fairly linear

increase a bit of a bow and then we've

got this Plateau here again in even in

the charge curve so roughly starting

from 2.9

volts and finishing probably here

somewhere at close to 3 volts the

incline is a bit flatter and then we see

a very very linear increase in voltage

and capacity right until we hit the 3.95

volts there's a bit of a Bend from maybe

from here all the way up but this is so

small so looking at the discharge curve

and now the charge curve here that means

you can actually measure the voltage of

this sodium battery and can determine

the state of charge of it just by

measuring the voltage so if you measure

3.44 volts this is roughly 50% of state

of

charge so and now let's determine so

we've got

1,317 at 1,2

51 so does it make sense to charge these

batteries to 95% only is this good for

the health well we don't know we've got

no information about this right and the

same with the discharge does it make

sense to stop discharging at 2 volts or

should we go all the way down to 1.5

will the sodium battery last longer if

we use it between 10 and 90% state of

charge we don't know so far there's no

recommendation there's no data there's

nothing out there

nothing so obviously they achieve the

3,000 Cycles by discharging the battery

from 3.95 volts down to 1.5

volts and here under cell usage

condition there's only the temperature

stated but there's no recommendation

about state of charge while lithium iron

phosphate manufacturers they actually

stayed use the battery between 10 and

90% but here I cannot read anything here

we've got our charge and discharge curve

again so it looks very similar to what

we achieved just looking through all the

specifications here again and there's

nothing in here so that is pretty

interesting before we have a quick

discussion about this I will save all

these information the curve and the data

for it as a CSV file on my website the

link is down under the video you can

download the EB tester software for free

you can import these CSV files I have

here created and have the exact curve

for voltage and current on your computer

you can then use the right Mouse click

to get all the data see it tells you it

tells you the voltage the current the

Amper hours and the wat hours for this

specific moment and you can drag your

mouse along the curve all the

information is there free of charge it's

free

um

actually uh let me go

into this BMS the JK BMS here this is

one of the new PB inverter

bms's and we put in the password and

let's see if I would be able to program

this BMS here for sodium batteries so

the cell over voltage protection at 3.95

volts set okay okay it has it has it has

accepted it we can set the requested

charge voltage to 3.9 Volts for example

yeah it would do it we would also reset

the um BMS to 100% at 3.9 n needs to be

lower come on JK 8 9 9 1 molt lower yep

and the cell over voltage protection

recovery I want to have at 3.8 volts

okay this was this is actually possible

to program what about the

1.45

volts okay accepted the under voltage

protection is at at 1.5

Vol accepted we are at zero at

1.55

Vols and the recovery would be at

1.75 Vol for example okay so obviously

we can use the JK BMS with sodium

batteries all the parameters can be

programmed for this type of chemistry

that's cool so what about your inverter

let's have a look at the victron multi

plus 2 so we have to make a decision

here what kind of battery are we going

to build a 48 volt battery obviously a

48 volt system how many of these sodium

batteries do we need to put in series to

get 55 57 volts so 57 volts divided by

3.95 14 so you're building a 14s system

can we build a 15s system 15

3.95 Vol is 9.28 so this will be in the

specifications for charging right so if

we go in here somewhere it should tell

us yeah the maximum the multipl plusus 2

can charge is 64 volts and if you put 15

of these sodium batteries in series

we've got 59.2 5 volts so we could

actually go one cell more and do a 16s

3.95 which would be 63.2 volts this

would still be in the spefic ifications

for the multi plus 2 so we could charge

a 16s sodium battery to 63.2 volts with

a multi plus 2 okay now we have to look

at the other side if we have a 16s

battery 16 * 1.5 because this is how far

we can discharge that would be holy

that would be 24 volts so let's have a

look in the inverter for the charger to

still be operational is 37.2 volts so

here uh

37.2 ided by

16 is 2.3 volts this is the maximum or

this is the minimum I can discharge the

batteries to otherwise my inverter would

shut down due to a low voltage

disconnect so here's our discharge curve

again and we have calculated

2325 volts 2.3

25 um 2.32 five there a come on

there there so this would be

1,151 amp hours milliamp hours out of

1,329 which is which is um 86% state of

charge so we could use the multi plusus

2 to fully charge this battery to 3.95

volts and then discharge it down to 2.3

something volts which gives us

86% 86.6% % of the capacity of a sodium

battery but this is the absolute maximum

the inverter can do it goes almost to

the maximum of 64 volts and it goes down

to the absolute bare minimum of 37.2

volts so we cannot use more capacity of

these sodium batteries with this

inverter how about other

inverters so I just did the calculation

here if we have a 12vt system

considering of a 4S sodium battery this

could be a voltage between 6 volts at

the very low end to 15.8 volts an 8A

system for a 24v battery lowest voltage

is 12 volts for a 24 volt system really

maximum voltage here 31.6 volts and a 48

volt as we have seen could be 24 volt to

63.2 volts so the voltage Delta is huge

with these sodium

cells and here let me turn on this

screen recorder again and here I have

the instructions for the fch for the for

the peder inverter the voltage range

goes to 10.5 to 15 volts the 24 volt

version goes from 20 to 30 volt and we

have 12 to 31 so we can only use a

porion of the battery and the 48 volt

version of the peder inverter goes from

40 volt to 60 volts let's go quickly

back into our discharge

curve this is

so you would be able to use only 80% of

your sodium battery ah actually no I'm

I'm incorrect here because the manual

says because it says the maximum voltage

is 60 volts not 63 we have to go into

the charge

curve over

here so charging the battery to 60 volts

only would leave us with 12% at the top

which we cannot use with this inverter

and what was the what was the other

number I can't remember I put this all

on the screen here so you will be very

limited what you actually can use from

this battery with the Peter inverter for

example and you can have a look in the

manual of your inverter you are using

and put these information down in the

video description what is the minimum

and maximum input voltage for your

inverter and then we can have a look in

the curve and can figure out how much

capacity would your inverter be able to

use from a from a sodium battery a 16s

sodium battery and to be honest this is

only one aspect we are looking at now

the voltage range from minimum to

maximum and the existing equipment on

the market and I'm sure they cannot just

output a new software update for your

inverter and then it will be sodium

ready because the hardware in your

inverter needs to run stable as well at

1.5 volt per cell for a 12vt system the

inverter still needs to run at 6 volts

or a bit over 6 volts so as you can see

this is already where the problem with

the Sodium batteries start we have

literally no Hardware to support this

sort of chemistry the jkbm seems to be

fine we can also have a look at other

bms's see if we can program the step

loss BMS for example for such a battery

or the pace BMS but the inverter side

seems to be far more difficult to match

the sodium chemistry and because this

cell number one is now fully charged

here I want to take the opportunity to

do another discharge test here with 2C

and see if I get more capacity out of

this battery yeah guys I guess so far

this video from this afternoon fully

charging fully discharging this sodium

battery very very interesting and very

different charge and discharge curves

right and with all the hype about sodium

batteries I'm not sure if these

batteries will always have a

breakthrough like the lithium iron

phosphate batteries and we see these

batteries here in cars in vehicles and

tools and or in ebike batteries and all

kind of stuff I mean this is one of the

first generations of um sodium batteries

here and they may put other goop inside

at some stage to have have a flatter

voltage curve then but imagine they have

to make new hardware like new inverters

and new um new bms's and new balancers

just because everyone wants some sodium

batteries now I think the lithium iron

phosphate battery chemistry is very very

good at the moment Top Notch Works a

treat and there are no issues with it

there are no safety issues there are no

hardware issues there are no battery

issues yeah all right guys I think we

are doing more testing with the Sodium

batteries if you want to see specific

tests please leave them down in the

comment section of this video here as

well I'll have a look and pick some of

them unfortunately the EC a20 tester

goes only down to 1 volts so we cannot

really discharge this battery to zero

volts here and measure their overall

capacity and see if there's any gain

from 1.5 to 0 volts that would be a test

I would be interested in and we don't

have any information how long we can

keep this battery on zero volts is that

good or bad for the battery why do we

stop at 1.5 volt then what is the

recommended depth of discharge for this

battery 90% 80% less 95 who knows well

and you have seen on the 12vt battery it

also States we can charge the battery to

15.6 volts while 15.8 volt would be the

maximum so I assume this is a 4S battery

inside as well and when we discharge it

it goes down to 6 Volts for 12vt battery

that is insane so we will do a lot more

testing with these batteries here in the

next couple of videos analyze the sodium

batteries in terms of charging and

discharging and um because these um

sodium cells are supposedly so safe now

what happens if we overcharge them if we

charge them to 5 volts or something what

happens are they exploding are they

start burning are they just gasing who

knows I guess we have to try that

somehow no please don't leave any of

these comments under the video here I'm

not able to do any short circuit test

here or overcharging test to five or six

volts or something until the battery

goes in Goes Up in Flames or explodes or

whatever I have I don't have the

equipment for here and it's far too

dangerous to do at home and I certainly

don't want to be in the news with these

new batteries but we will see we will do

some more testing and we'll see how much

capacity we actually get out of these

batteries so stay tuned for that as

always guys thank you so much for

watching thanks for all your amazing

support here on the channel and until

the next video guys you stay charged

stay safe and thanks again for watching

see you then

bye-bye ah before I forget I will um I

will of course link these batteries down

in the video description as well I think

I paid about 27 Australian dollars for

four of them well I'll link them down

below they also have bigger Prismatic

cells 230 whatever it says here on the

screen they have already offered me but

I don't really see the point to buy

bigger capacity cells because we are not

going to use them in a production

environment as of yet maybe in a couple

of years but who knows maybe they are

not coming to Market at all maybe they

are more suitable for very cold climates

where you have to charge your battery

and negative temperatures but we have to

wait and see it is all speculation right

now so let me know what you think about

these batteries I'm Keen to read your

comments I'm sure there will be lots all

right guys thanks again see you in the

next

video