Resurrecting this thread https://www.skoolie.net/forums/f49/n...ast-36214.html
under a new name.
I've had my Daly 250A 4S BMS in operation for about a year. Figured out how to install and program it, and after some fooling around, got the parameters set.
I have a Victron SmartShunt on the 280Ah LifePo battery (built from four cells), then the Daly on the ground/return path.
On the charging side I have 475 watts of solar pumped through a Renogy 40A MPPT charge controller. I also have a household current Noco 20A charger, used rarely, and a Renogy 20A DCDC charge controller, not yet connected.
The Daly worked beautifully for about six months, until one day I was walking past the bus and hear the alarm beep. Low voltage, like 1.5 volts, on one cell! High voltage on another. I unplugged the control line to the Daly, put the multimeter on each cell, and saw they were each within a millivolt of 3.27.
Panic over, I fooled around with the Daly, it still recorded the low/high alarm. Checked voltage at the pin on each lead from the battery, perfect reading. Clearly something was wrong in the Daly itself.
I left it unplugged overnight, and the next day it fired up fine and worked as if nothing was wrong.
Four months later, the same thing. I didn't panic, just unplugged it, left it for a day, and all was right again. but I was irritated enough to go out and buy a RadioB BMS, and said to myself the next time that frikkin' BMS went wacky I'm ripping it out and putting in the replacement.
The Daly must've heard me swearing, because it ran fine all summer, until early this past week. Same thing: a screaming alarm, voltages (each time different cells) showing all over the map. I said no biggie, unplugged it, waited a day, plugged it back in, no luck-same alarm, different cells (not all, some). Fiddled with the BMS, reset it, etc., but no luck. Now five days later it seems to report all is fine, proper voltage readings, but it appears to be turned off or something, multimeter readings somewhere between 2.9 to 6.9 volts on the bus bar. I'm going to rip it out because I can't have flaky equipment.
First nail in the coffin: Daly literature is comically crappy, translation, instructions, programming tips. Daly online advice is either missing or poor. Where Renogy resources for programming are like a B-, I give Daly an F+, the plus because you think you can sort out how to program it but in reality the documentation is just screwing with you and you're completely on your own. Now, in addition, I'm experiencing this weird, intermittent, unexplainable failure. Yeah, maybe it's just a bogus unit I got, but I do not want to buy another Daly.
I've stated my opinion elsewhere here that the DIY community for LiFePo batteries is enthusiastic but the components are generally very poor and not yet adapted to the serious enthusiast. This is (I think) particularly true in the BMS space--I don't see another one that strikes me as any more solid.
For that reason I want to be able to quickly swap in the RadioB unit I got as a temp spare to use if the BMS fails on the road. You can't do squat if your BMS has failed, unless you simply bypass it, which I won't do.
I'm in search of a solid 250A BMS. Any suggestions?
Like I said, I'm done with Daly, but if you have different experience, or any insight into why the thing is failing, I'd love to hear. Tell me I got a bum unit so I don't have to learn a new BMS system.
Cell Balancing note: after more than a year of use my LiFePo battery has never needed cell balancing. When I installed the Daly originally I turned off the cell balancing function. Online research indicated that it either doesn't work or only kicks in under corner case scenarios, and I wanted to understand my cell drift. Along the way I did some research on cell balancers and bought a twenty dollar active balancer and wired it in. Worked like a champ under test conditions, but as mentioned I leave it unplugged and so far despite the Daly screaming otherwise haven't had to use it.