BMS What would you use ?

[Burgerman]

You will just have to be patient and see.

[expresso]

yes with everything - thats my problem - no patience lately - my Cells still at Port here in the States - but not unloaded - Covid -

itching to get them and start doing something at least - -

[terry2]

yes with everything - thats my problem - no patience lately - my Cells still at Port here in the States - but not unloaded - Covid -

itching to get them and start doing something at least - -

I did email Telsa for help about this.
I sent them links to my cells ect.

They couldn't advise me because they monitor each battery and not a group of them.
So using Telsa's BMS is out the window. But there are some guys connecting each battery so they can use the Telsa BMS.

[Burgerman]

Why would you expect a sensible answer and why would you think they would be interested. What did you ask them?

Tesla dont use a simple bms in the sense you are talking about. And they dont use lifepo4 in their packs. They are using a lithium ion variant, and in tiny 21700 cell size in huge parallel groups. They are like the AA cells. But a little bigger. I have some here. And a BMS even a simple one work OK with lithium ion. Like the one in my laptop. Or powertools.

Are you confusing cell with battery? These tesla cells are actually panasonic /tesla and lithium ion. Are not monitored and controlled individually in a tesla car or powerwall as they cannot be because they are connected as one in a parallel groups/serial grid. Like the headway packs. They may in the future sell lifepo4 systems to make a chinese variant for the local market at a lower cost with less range/performance.

They basically have the equivelent of a variable power supply and a pl8 type charger system that is controlled by the main cars computer system, and the car is fed AC fro the wall. Totally different very complex setup. And the AI built into the car learns the way you drive etc, and controls the cell water cooling temperature, charge rate/amount and works as a cell/battery monitor for range all at the same time and more. To give best life/range/performance compromise day to day.

[expresso]

If we ever have to really resort to a BMS - i will just get one and try a modular setup - where i plug it in when i get home and charge that way

unplug it when done - it would be awhile even if they stopped PL8 today - i have a few extra so if each lasts 2 or 3 years i should be good for a decade longer - but i also have someone else now using lithium with a PL8 - it would affect her also -

hey worst case BMS - thats it - find the best you can find and use it - if they dont last - nothing you can do - they last 5 years instead of 10 -

it is what it is -

[Vitolds]

It is difficult to translate from Russian technical language, but I'll try. Each time when I did it, you did not understand me.
1. active balancer board. (exactly the active balancer, tuned to the voltage you need) balancing current for choice 0.5A - 2A
https://48volt.ru/bms-balansiry-platy-z ... -balansiry
2. BMS on a chip
https://www.ti.com/store/ti/en/p/produc ... 7694006DBT
3. bms board similar to this with minor additions (atmega 328 + CAN)
https://raw.githubusercontent.com/nseid ... embled.jpg
4. GRUNER 750H
https://www.google.com/search?q=GRUNER+ ... 66&bih=635
5. charging station that can be configured via CAN
http://www.sdsmtdy.com/ (This charging station has the CAN, but I have not tried it.)
6. ESP32 MASTER (CAN) and you can watch what happens while charging

I make this control system, control and charging.

[Vitolds]

balancers are passive!
active not very good, I made a mistake in the translation.

[ex-Gooserider]

It seems like a good question to me in terms of possible PL/8 replacements... The wiring side seems pretty simple to me if one wants an off-board solution. Since we don't need / want the BMS involved while using the chair, why have it on the chair.... I'd simply wire it up just like the PL/8 w/ main charging leads and balance wires going to the chair and the power supply / charger plugging into the BMS... If you used the appropriate connectors, you could even use the same charging cables as you use with the PL/8....

Now how to build the charger / balancer / BMS is a separate question. I think I remember Irving doing some reverse engineering on the PL/8, or making something that did similarly... Perhaps he could make some suggestions.

ex-Gooserider

[expresso]

if this is what it has to come down to

i vision was thinking all you need is a dumb charger as we always used- now if we had to do this - BMS would be connected external to the chair -- extra balance leads made using a 9 pin sub d and another connector just for two power cables - SB 50

i have an marine charger 15A does both AGM and GEL correctly - once BMS is connected to the chair external balance wires etc,

now all you do is connect the SB50 to the charge and thats it - let it charge thru the BMS and let it balance - when done - remove and your good to go -

even if not 100% perfect like a PL8 - its good enough not to worry -- i am curious - i have to find a BMS i have here somewhere -

and try it on one of my ADD On packs i have - just to see if it can actually work good enough - gives me practice also

[Burgerman]

Or you could just be patient and wait for PL8 to be back in stock.

[Rye]

These guys from Aliexpress have a stateside warehouse. They claim about a week for delivery. A lot of people buy from them on Ali.

https://blslifepo4battery.com/collectio ... o4-battery

EDIT: I guess they are useless until the PL8 is back in stock though. I might see if I can get an executive PL8 order from President Biden.

[expresso]

may be true fast shipping - but your paying for it in the price to begin with - you can find much cheaper prices but slow 2 month shipping - always good to have another place to check on - if your not in a rush - can ask how much with slow shipping - i really hate slow shipping though - i am finally getting mines monday - two months - price was good and it was winter so no big deal - unless your in a rush

[sacharlie]

I searched for BMS AND "charge only" OR "while charging".
Got a bunch of talk about that.