Dual BMS Problem for Sodium Ion Battery - Fixed

Using two BMSs (LiFePO4 and NMC) with a sodium ion battery is not without its problems. One such problem is overheating MOSFETs.
Sodium ion cells from: www.evpromax.com

[@hugegamer5988]

“Because you don’t normally point a thermal imager at things”. Whoah there buddy, I point a thermal imager at everything, how else do I know my pan is an even temp to make breakfast?

[@panospapadimitriou3498]

i love bulb experements . especialy in winter!!! you got some inevidable warming situation and its kind of free!!!

[@JulianIlett]

Yes I agree :)

[@-Graham]

Are configurable bms modules not a thing? How does the module get it's thresholds? Is it a chip or resistor set? Would be interesting and maybe useful to play with

[@BeefIngot]

How much do these bad boys cost, weigh, store, and discharge/charge at and where does a normal mortal get just a handful? The better question is is there a link to the datasheet and a purchase link?

[@JackRussell021]

I have a half a mind to play with some of this myself, but i think i will wait for a better BMS solution.

[@lezbriddon]

I only use jk BMS but there for bigger packs, ebikes and above.

[@d.t.4523]

A real sodium ion BMS is available. I don't know why he didn't use one, but they are out here.

[@lezbriddon]

cant you parallel more diodes across the mosfets, this wont affect the boards operation and will distribute the current/heating? or just use a larger bms...

[@PietroZambon]

The voltage drop across the diodes will remain the same even if more in parallel so you will have a lot of energy loss. It's better to short out the unused MOSFETs as he did so they're essentially removed from the circuit.

[@lezbriddon]

@@PietroZambon agreed, but having more in parallel will stop them burning up. I have 6 on the output of my charger otherwise the charger becomes a load when the AC fails discharging my batteries. I charge at 20a but use 5 10a diodes to get 50a and they run cooler. If you want to reduce the voltage drop then you need a different diode material. Or use an 'ideal diode' in parallel built from more MOSFETs. For this problem shorting them out was the quick solution but I'm just thinking of other ways

[@chilllytube]

I wonder how long before we see a BMS for the sodium cells that don't have these fudge factors?

[@JulianIlett]

Soon, very soon ;)

[@solarute5486]

Maybe these sodium batteries dont need a BMS. Charge to 4 x 3.8V and I'd reckon it'd right. Check and balance occasionally. Discharge not really a problem.

[@Sylvan_dB]

Sounds like a very poor BMS design. Without having finished the video, are you going to short the "off" FETs? Both BMS are the same design? Edit: YES! 😁

[@frankowalker4662]

I was wondering if you could remove the mosfets ? But then I realised that was a stupid idea that wouldn't work. So I won't ask that.

[@davestech6357]

Why not make your own bms? Your a smart guy.

[@jensschroder8214]

short the transistors and it will work

[@deslomeslager]

Dead easy solution, I agree.

[@RobinRastle]

What has this got to do with Sodium Ion batteries? clickbait?

[@-Graham]

I assume it's because Na-ion voltage ranges are higher and Julian is playing with different chemistry off the shelf modules in tandem to use the full range effectively

[@KrotowX]

In future I see no problem to introduce LiXXX/NaXXX compatible BMS-es. Put adequate MOSFETs in circuit and switchable resistor and zenner diodes or whatever set to switch between chemistries. Either as discrete element set or put together in IC package.

[@guywhoknows]

But that will heat up, why not use a programmable smart BMS?

[@JulianIlett]

On another battery I will use a smart BMS. I have a load more sodium ion batteries coming :)

[@guywhoknows]

@@JulianIlett what are they capacity testing like? I've seen a few around, which have been small, but unknown names. So I've not dabbled. Yet.

[@bitealarmtones3104]

Do they need a bms any way

[@davey2k12]

Probably why you only use 1 bms Maybe its the common ground between 2 boards Dont think u should be paralleling the 2 boards balance connections either like 1 bms is trying to short the other 😂

[@pscheuerling]

I would use a buzzer for discarge and a lipo charger for charging atm.

[@saeidmousavi7380]

Thanks for the time 🙏🙏🙏so much like 🙏🙏🙏🙏

[@chrisw1462]

@10:55 Yes, power is both I^2R and VI, whichever you have the information to use.

[@michaeltempsch5282]

Or U²/R P=VI, but V or I can be calculated by Ohm's law, as RI or U/R, and substituted into VI, giving the RI² and U²/R versions for power.

[@Sylvan_dB]

​@@michaeltempsch5282 U? I was raised with "E" for electromotive force (or "elektromotorische kraft") rather than V(olts). This gives P=IE (or PIE) and I=E/R (or Indian sees an Eagle over a Rabbit) for memorable mnemonics. I also do not use A(mps) but I for "Intensität" and not W(atts) but P for power. As a child I had a handy pie chart on my wall with the center having the desired value in each of 4 quadrants (PIER) and then the slices from that quadrant having all the possible combinations of the other 3 values to compute the desired value for that quadrant. It was a useful reference as I learned these equations shortly after learning multiplication and division in school.

[@PietroZambon]

​@@Sylvan_dBU can be used in place of V in some situations. I don't know if it's always interchangeable or there are situations where it isn't.