JBD BMS FAILED IN SERIES. WHY? & I FIT AN ACTIVE BALANCER. WHY NOT?

[@letsdiymyhome]

I run 3 of the same 200AMP JBD BMS w/Active Balancers on my 280ah cells and love them, works mint! 2 yrs now.... NOTE:1. I disconnect the Active balancers when in storage 30% state of charge 6mo. out of the yr. 2. I do have the default BMS balancer on, just dont engage the balance when charging only. I run it as a 12V system in my RV and also have ran it as 36V... but for simplicity I went back to 12V and works for my needs.

[@ericklein5097]

Add a switch to that balancer. All of them that I've seen of that style have a solder pad labeled switch. You can short the pads with solder to have it permanently on or you can run a short wire off each pad and then to a small switch. NEVER balance your battery when below 3.45V per cell. You are just unbalancing your battery because when the voltage curve is flat there is no relationship between SOC and Voltage. So you are just playing the voltage game when the whole point of "balancing" is to balance the number of amp hours in each cell.

[@DCGUY]

Cheers 🍻

[@cmyanmar13]

Worth noting that the copper(?) terminals from eBay and Amazon are notorious for being extremely thin, which is fine for balancing, but not for inverters.

[@RobinRastle]

indeed Very important double check your wiring before connecting to bms and battery - else disaster smoke

[@gajendrasinghbandi875]

Hi this is gajendra .i have sp series 24 s jbd smart bms.After wiring with all pre cautions it is not reading cell voltage in bluetooth app. Also when i am connecting 48 volt charger bms is not detecting it. On the bms there is a charger detection port but i do not know where to connect two wires of charger detection port.

[@ericklein5097]

If you still have that BMS it's likely some mosfets that have shorted. There are tutorials on here on how to test mosfets. Look up the part number and see what the max voltage is for the fets and I'm guessing they can't handle 48V (I've seen an SFK video about this exact model saying the stock JBD can't but the special SFK version made by the same manufacturer uses different fets that can handle 48V)

[@DCGUY]

Thank you for this cheers 🍻

[@johnshaw359]

I would switch off the BMS balancer, no experience mind you, just instinct as the balancing algorithms might clash.

[@DCGUY]

Thanks for taking time to comment and I tend to lean towards disabling the function but I wonder what would happen if the active balancer failed, its a dillema for now 🤔

[@johnshaw359]

@@DCGUY Disabling the balancer shouldn't disable the voltage protection circuits, it should still be monitoring the cells unless the BMS stops reporting their status when you disable the balancing feature.

[@DCGUY]

@@johnshaw359 cheers 🍻

[@aureltanasan1413]

Fogstar batteries are fitted with jbd’s, how is your other fogstar battery?

[@DCGUY]

It's perfectly OK 👍 just this particular battery. Probably just been unlucky I guess as I don't know what went wrong or why.

[@letsdiymyhome]

@@DCGUY I think it was a bad BMS from the start for I no of folks running that BMS with 48V. Im not saying run it again now ether I would have cold feet too.... Maybe the inverter isnt playing nice wth them DBS.... That doesn't make any sense to me

[@DCGUY]

@letsdiymyhome yes, just unlucky the other units are fine

[@vandettec]

I crimp then solder my connections , little less work than your method , I use a 1 amp active balancer on all my batteries and leave the passive balancer turned on in the BMS settings , BMS is only 30mah or something , next to nothing so I don’t worry about. Note don’t buy the 170 amphr renogy batteries unless you want to deal with issues ,too long of a story for a KZbin comment

[@DCGUY]

Thanks for taking the time to comment, and I can just imagine the renogy issues. I'm considering swapping the pro bms over to jbd as I dislike the Renogy App

[@Granty400]

The JBD bms does not support series connection as the switching mosfets aren’t of a high enough voltage rating,

[@DCGUY]

This particular model does support series connections and that was double checked with JBD however your right in saying some models aren't

[@Granty400]

@@DCGUYI stand corrected, I didn’t realise JBD were making series compatible units. Really enjoy your videos, keep up the good work.

[@DCGUY]

@@Granty400 appreciate your input and taking time to watch and comment 👍

[@kennethbarli4469]

If you are going to connect in series, the BMS must be compatible. The mosfet cannot withstand 48V, that is the problem. You might think that each battery is 12V, and that is certainly correct, but when you connect it in a circuit, the mosfet gets 48V and gets burned. If the BMS had a 60 volt mosfet, they would have worked fine.

[@DCGUY]

@@kennethbarli4469 It's puzzled me as the other batteries using the same bms units are OK and I never saw any blown Mosfets, all pins intact and no visible sign of failure and the manufacturer states they are good for 4S which is very confusing. What you say makes sense though. I live and learn. Thanks for taking time to watch and comment.