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diy solar

Jdb charge - discharge not behaving

Bsjoling

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Feb 20, 2021
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20220630_104857.jpg

A friend and I are both having issues with similar 600Ah 13v builds.
We let charge off for a few days to allow the bank to run down to say 30+40%, then turn charge back on up till around 90% (solar mainly, 1500w)
However the buttons on the app seem to have their own minds completely!
Turn charge on. Nothing happens other than 'setting success' msg. Turn discharge off, then charge on again. Seems to work sometimes. The touch screen device seems to have a better interface as it seems to work, but not always.
I miss my older Daly units, so much simpler!
We also have a sleep/alarm icon on the screen, could this be the issue? Damn weird! Help pls, I've done 5 X 4s2p setups in motorhomes, these jdb/overkill units (in 3 vans, set to ok paramaters) are being so damn random. Sometimes they do as they're told, other times require a complex button dance and wait routine until suddenly they get going 'normally' again!
Thanks for reading.
 
Given the number of people that are successfully using the JBD BMS, I would guess that you're doing something wrong. Most of us are using the app to interface with the BMS, not the LCD display you show. Can you take screenshots of the parameters from within the app?
 
Screenshot_20220630-152449_xiaoxiang.jpg

I got it back on charge with a load of shuffling. The two/3 jdbs I have in service all seem to share the same flakiness..
 
What's the difference between driving and monitoring mode in the app settings?
 
Why are your over/under voltages set so low? Most of us have the BMS set to a pack overvoltage of 14.6 volts. That doesn't mean that we charge to 14.6 volts but that the BMS will cut of charging at that voltage. Most of us charge to only 14.2 volts, but that's a setting that is on the charger, not the BMS. If you set your charge over voltages too low, the BMS may not have enough time to balance the cells.
 
It's all well monitored, conservative settings as I'm getting used to living with it. Balance is generally < .01 only going above that when charging at 80a.
I've noticed the balance buttons go green from time to time, tho will put on an active '5a' heltec unit as well.
Just getting annoyed that I can't just turn charge/discharge on-off when I tell it to
 
It's all well monitored, conservative settings as I'm getting used to living with it. Balance is generally < .01 only going above that when charging at 80a.
I've noticed the balance buttons go green from time to time, tho will put on an active '5a' heltec unit as well.
Just getting annoyed that I can't just turn charge/discharge on-off when I tell it to

Why do you need to turn off charge/discharge at the BMS?
 
I have excess solar and storage through summer, so if I don't turn charge off the bank sits at 100% almost all the time. From my understanding this isn't ideal for lithium, so I like to bounce it between 30-80% and let it run up to 100% once a fortnight.
Satellites go from 40-60% soc and expect around 40,000 cycles, so I'm setting my sights to mollycoddle my bank to see if I can get them to last me forever. Got to be better practice than running against the stops
 
I have excess solar and storage through summer, so if I don't turn charge off the bank sits at 100% almost all the time. From my understanding this isn't ideal for lithium, so I like to bounce it between 30-80% and let it run up to 100% once a fortnight.
Satellites go from 40-60% soc and expect around 40,000 cycles, so I'm setting my sights to mollycoddle my bank to see if I can get them to last me forever. Got to be better practice than running against the stops

Yes, you don't want to be at the top all the time. But your charging devices should be set to achieve that, not your BMS.
 
I understand that in theory, however in practice the BMS is the only really accurate device that determines actual charge stop.
I have coulomb counters and all sorts, with a simple set up I prefer to do things this way. May not suit some.
I would like to control this via the BMS. The Daly does this function just fine. Why does the xianxiang not? Everything else bar that function is fine.
 
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