JBD BMS App and Nominal Capacity

[hardtop]

I'm a newb trying to build a DIY pack. It has a JBD BMS, 4 304AH EVE cells and a Progressive Dynamics 60A charger. When I installed the app, it asked for capacity and I gave it 1216. Then when I go to charge it, the app says its charge load is 59.xA and then it starts dropping rapidly to like 5A.

I thought since the Nominal Capacity was wrong in the PARAMS SETTING, maybe the low and inaccurate capacity is telling the charger the battery is almost full so it stops taking so much energy. So I re-set (again) the Nominal Capacity, tapped save in the PARAMS SETTING and the Nominal Capacity defaults to 560AH no matter what I do. The pack measures 14.36V.

1. How can I set the correct Nominal Capacity for the BMS?
2. How could I fully charge the battery with the BMS and Progressive Dynamics charger?

 

[S Davis]

The cells are fully charged, that is why your amps are dropping off.

 

[hardtop]

The cells are fully charged, that is why your amps are dropping off.

That makes sense, thanks. Any ideas on how to tell the BMS what battery it has? The user interface of the BMS says its 1/2 full.

 

[S Davis]

Good luck using the BMS for your state of charge, I have found they do a really poor job. A couple of mine will not register a load below about 3amps, I have some loads that draw just below that and I can run the battery down and hit low voltage shut down with the BMS still showing plenty of charge left.

 

[S Davis]

You will probably have to do a few charge cycles to get it to read fully charged.

 

[S Davis]

Here is a voltage chart that will give you a rough estimate of state of charge.

 

[740GLE]

There should be a setting where you enter in the 100% voltage and other % voltage set points

Also I recommend using the overkill app it’s been knock out for me.

 

[hardtop]

There should be a setting where you enter in the 100% voltage and other % voltage set points

Also I recommend using the overkill app it’s been knock out for me.

Still trying to get the capacity right. It reports 560ah after two cycles one of which was a full charge from where the BMS dropped power to protect the battery. These are the voltage set points, do they look correct for 4 304ah cells?