35 replies to this topic

[ski3pin]

Here are two photos to clarify the issue that can get muddied in my narrative.

 

 

 

 

 

 

13.55V is right at what the BMS app indicates.

 

 

And at the battery terminals the voltage is 11.82V

 

 

 

 

 

It remains a puzzle. I will apply a load to the battery - as per Rando - and post the results.

[ski3pin]

Here is a new piece of data. I connected Will Prowse's recommended capacity tester from aliexpress and got quite a surprise.

 

First off, for a bench mark confirmation the unit works I connected it to my old AGM battery. The voltage reads 12.7V

 

 

 

 

 

 

 

I connected it to the new DIY battery and the voltage reads 1.94V! I went back and confirmed with the multi meter across the terminals that the multi meter still reads 11.82 as it did earlier. Wow.

 

 

 

 

[rando]

It looks like that there is either something wrong with your BMS or the BMS settings, the actual batteries look to be fine.  What you are seeing is consistent with either the BMS being off or there being a fault with the BMS. 

 

The only thing that stands out to me is the setting 'switch function' appears to be off.   It is unclear to me whether this setting disables the 'switch function' or if it IS the 'switch function' and it is set to 'off'. 

[ski3pin]

 

The only thing that stands out to me is the setting 'switch function' appears to be off.   It is unclear to me whether this setting disables the 'switch function' or if it IS the 'switch function' and it is set to 'off'. 

I believe that switch in the app turns on or off the optional external switch that I do not have. I've tried it both ways and it makes no difference. I am moving closer and closer to the BMS being at fault.

[ski3pin]

I spend time this morning continuing to troubleshoot without success, but I did encounter a change. After unplugging the balance leads push connector and then reconnecting, the BMS app now has both the charging and discharge off and will not allowing turning them on. Under protection it now reads "locking". Here's a photo -

 

 

 

 

 

 

Here is the "before" photo.

 

 

 

[pvstoy]

Would you need to disconnect everything and reattach in proper order???

[ski3pin]

Would you need to disconnect everything and reattach in proper order???

Although I've done that 2 or 3 times, I don't believe it's necessary as the only connection between the balance wires and the BMS is through that push connector.

[pvstoy]

Ski i don't know how it is wired, but is the wire that is a push connection supply 13.6 volts?

Measure voltage before pushing it in and after you push it in can you use a sewing pin pushed into the wire and read voltage on either side of the push in connection.

Don't forget the ground wires.

If you can't determine if there is a bad wire or connector then like Rando says it might just be a problem with the BMS.

[pvstoy]

any feature in the BMS for a reset?

[rando]

If you have already removed power from the BMS a few times (reseting it) and that hasn't fixed the problem, it seems pretty likely that the BMS has an issue.   Before spending more time on this, does the BMS provider offer any tech support or a warranty?