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24v System shutting down ~24.9v

utahbiker

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Joined
Oct 17, 2020
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Hey team, this is only my 2nd post and I'm a little nervous posting up my issue since I'm still very new to the game, but I'm not sure where to turn and if anyone else is using the same setup that I have, hopefully my issue (and possibly answer) might help someone else.

I bought the Growatt SPF 3000TL LVM-24P along with a LiFePO4 24v 100Ah with built in BMS - both from watts247.com. No matter what settings I use, my Growatt shuts down when my battery gets ~24.9v. Doesn't matter if I've got utility power, solar power, or using AC output with minimal pull. My battery will read 8 or 9 volts after the system shuts down and the battery will only jump back up to ~25.5v once I disconnect the battery from the Growatt for maybe 5 minutes. I feel like this is a BMS protection kicking in somehow, but I'm unsure. Also, I don't receive any fault warnings on my Growatt. I've even recorded it all happening and there are zero warnings.

One thing I'm unsure of is the nominal voltage and bulk charge point that watts247.com has stated is needed for the batter... 25.6v for both. That seems low for all of the other LiFePO4 batteries I've seen out there. A Relion battery of similar capacity has very different float and bulk point. I'm not sure if this is what I'm dealing with but wanted to ask, since I can't seem to find any information about this battery manufacturer (e-sunstone.com?).

Any suggestions?
 
Yes, that sounds like it, your BMS is disconnecting for some reason.

It's lifepo4 so you can assume standard charging voltages. Victron chargers default to 28.4V for bulk/boost/absorption (which ever term you prefer), and 27V for float. 25.6V for a 24V lifepo4 is abnormally low charge target voltage. I would contact the battery manufacturer to confirm that voltage.
 
Since it has a BMS in it, I guess I could change my settings to allow for the standard LiFePO4 float and bulk/boost/absorption settings (27V and 28.4V respectively) and see how it does... Since I know the BMS works at what I'd assume is the low voltage cutoff, I can assume it will work at the high voltage cutoff ?‍♂️
 
Hello. I’m following this closely.

Any updates so far? I’m about to pull the trigger on this EXACT setup. Watts247 is running Black Friday deals on this battery which makes it cheaper than any 24V 100ah that I can find. My only concern is the behavior of the BMS and performance under load with the Growatt inverter.

I’m curious of your opinion on it so far and would you recommend I buy it? The same setup would be just under $1700 shipped! Thanks!
 
Any updates so far?
Ya. I returned both the battery and the Growatt system. Despite multiple efforts with them, we couldn't get it to work properly. Battery wouldn't hold a consistent charge and would only output at best around 1kw. I suspect it was either incorrect settings in the BMS or just some bad cells. No way of really knowing unless I tore the thing apart and did individual cell testing, but I opted to just return the whole system to watts247. They were good about it and took it all back, but they did charge me for the initial shipping.

It's hard to recommend this battery. Growatt has some amazing reviews, so I think their LMS systems or their all-in-one systems are probably going to be a safe bet, but my one and only experience with the battery wasn't a good one in the slightest.

I never heard back from watts247 regarding what their diagnosis was (battery issue or Growatt inverter issue, or something else), so I have no way of saying for sure what the problem was.

I'm currently looking at the new Growatt inverter, chargers, and battery systems. All Growatt branded and all UL listed. But I haven't pulled the trigger on anything to replace the watts247 system I returned, yet.
 
Ya. I returned both the battery and the Growatt system. Despite multiple efforts with them, we couldn't get it to work properly. Battery wouldn't hold a consistent charge and would only output at best around 1kw. I suspect it was either incorrect settings in the BMS or just some bad cells. No way of really knowing unless I tore the thing apart and did individual cell testing, but I opted to just return the whole system to watts247. They were good about it and took it all back, but they did charge me for the initial shipping.

It's hard to recommend this battery. Growatt has some amazing reviews, so I think their LMS systems or their all-in-one systems are probably going to be a safe bet, but my one and only experience with the battery wasn't a good one in the slightest.

I never heard back from watts247 regarding what their diagnosis was (battery issue or Growatt inverter issue, or something else), so I have no way of saying for sure what the problem was.

I'm currently looking at the new Growatt inverter, chargers, and battery systems. All Growatt branded and all UL listed. But I haven't pulled the trigger on anything to replace the watts247 system I returned, yet.
You saved me a lot of frustration. I bet you had badly matched cells. The BMS was probably doing its job by cutting off the pack if any of the cells dropped below a threshold, leaving the other cells at a higher state of charge. The 8-9V reading sounds like the BMS cut off the pack. Disconnecting or applying current will usually kick it back into normal operation until a cell drops again.

The Growatt system is recommended by Will. I will probably at least pick that up and wait for other battery deals. Thanks again did the update.
 
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