14S 100A Active BMS COMS Protocol

chuckp

chuckp

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Jul 29, 2018
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Hi has anyone any info on these.

https://m.aliexpress.com/item/32828948173.html

I was wondering if anyone has any info on the communications protocol.
The battery inverter I'm going to use is the Sofar ME3000SP and was hoping (however much of a long shot) if this would communicate over the coms port? Either via the RS485 or the CAN 2.0.

This will only be a temporary BMS, I'm thinking this will be better than nothing until I can get the Batrium.
 
Above links is NOT active balancing. Its passive balancing at around 50mA max current. The active part is that you can set the thresholds....
 
daromer said:
Above links is NOT active balancing. Its passive balancing at around 50mA max current. The active part is that you can set the thresholds....
Click to expand...

Dang I thought it was to good to be true.
Do you know of a cheap active alternative to a Batrium?
I'm holding out for the watchmon6 release but also want to get my wall up and running.
I have 28 packs sat waiting ready to go.
 
The version that is active has a single large (relative to the board componentes) isolated DC-DC converter on the board and only balances one cell at a time. It takes a DC supply from the whole pack and charges the lowest cell, switched by FET from a common charge bus output from the DC-DC supply..

If the passive balancing can be switched by command (appears yes from the link via jesusangle) then 50mA would work ok for a pack as you can have the balance active for many hours to adjust the energy balance per series set of cells. Would require an external application to effectively take control of the balancing, quantify the energy imbalance and then work out how many hours 50mA drain would be needed to rebalance.... or just switch on until the voltages align to within 0.05V whatever the SoC ?
 
Do you really need active balancing? Most people think they save energy and or money doing active but in real life we talk about 10 years before the cost getting the system is earned...

Have you watched my video regarding it?

Active have its purpose of course but if its to save energy most people are wrong. Is it because you have a pack that do have different sizes or a system you cannot maintain like big ass cells then its a bigger use. Lastly the current many active balance with are very limited compare to the current you need to pull out of the system so on medium to high current systems active wont to much good in long term :)
 
If active balancing is needed to keep your packs balanced, and/or large currents (>100mA/100 cells), then there is something wrong with the cells in the packs. The problem/suspect cells needs to be replaced with better ones that aren't self discharging and/or the capacity from pack to pack is not close enough. Make sure every parallel pack in the series string has as equal to the 'exact' same capacity as the others (this is hard with reused cells, yes, but doable; <100mAh variation is achievable, even <50mAh is as well.)
 
Thanks for the clarification guys, I just assumed active was better due to transferring power rather than just burning it off.

In that case as soon as funds permit I'll go with the watchmon4.
I've tested all my cells, all pack capacities are matched to within a few mAh of each other. Assuming that the accuracy between my Opus chargers are close.
All completed packs have been resting for a couple of months now with only a difference of 0.05V between the highest and lowest. Most are sat at 4.15V. I have 1 pack at 4.10V and two at 4.12V and another at 4.13V.
Very happy that the packs will function as intended and I think they will need very little balancing anyway.

Funds are tight at the moment hence the cheaper BMS for the time being.
 
chuckp said:
Thanks for the clarification guys, I just assumed active was better due to transferring power rather than just burning it off.

In that case as soon as funds permit I'll go with the watchmon4.
I've tested all my cells, all pack capacities are matched to within a few mAh of each other. Assuming that the accuracy between my Opus chargers are close.
All completed packs have been resting for a couple of months now with only a difference of 0.05V between the highest and lowest. Most are sat at 4.15V. I have 1 pack at 4.10V and two at 4.12V and another at 4.13V.
Very happy that the packs will function as intended and I think they will need very little balancing anyway.

Funds are tight at the moment hence the cheaper BMS for the time being.
Click to expand...
Greetings. Did you manage to find a good BMS for Sofar Mass Energy ME3000SP?
 
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