Dangerous batteries?

[IHaveThePower]

Good day
So I bought two Chinese lithium 12v 200ah batteries called Moseworth
They were sold as having bms with high and low voltage cutoff but last night while using them they went low enough to sound an alarm through my inverter. We had 3 days of rain.
So I cut the Inverter off but I left the charge controller and the shunt battery meter on and this morning the two batteries which are in a 24v configuration were each separately down to 9.77 volts. I realized a small security camera was also drawing power.

Shouldn't the bms have cut off way before 10v ?

Here's what they claim in their ad:
Upgraded BMS - MOSEWORTH newest lifepo4 battery used high version Series BMS panel, better performance in series/parallel. Also it has overcharge, overdischarge, overcurrent, short circuit low/high temperature cut-off protection.

Should I call them on their overdischarge claim or does this sound within reason.

And have I damaged the cells by letting them drain to 9.77 if there was no over discharge protection?

 

[MrThisIsME]

Sure hope they are still returnable.
Assume that the inverter is not a very smart one? It should of cutoff as well.

 

[Mbosser61]

Good day
So I bought two Chinese lithium 12v 200ah batteries called Moseworth
They were sold as having bms with high and low voltage cutoff but last night while using them they went low enough to sound an alarm through my inverter. We had 3 days of rain.
So I cut the Inverter off but I left the charge controller and the shunt battery meter on and this morning the two batteries which are in a 24v configuration were each separately down to 9.77 volts. I realized a small security camera was also drawing power.

Shouldn't the bms have cut off way before 10v ?

Here's what they claim in their ad:
Upgraded BMS - MOSEWORTH newest lifepo4 battery used high version Series BMS panel, better performance in series/parallel. Also it has overcharge, overdischarge, overcurrent, short circuit low/high temperature cut-off protection.

Should I call them on their overdischarge claim or does this sound within reason.

And have I damaged the cells by letting them drain to 9.77 if there was no over discharge protection?

I just came into the Forum for info about my HIMASSI 24v battery reading 5.4 v after inverter Lvdc at 21.8 v earlier. About a week of cloudy days battery was about 25.6 at sundown , lvdc at 4am, but SCC must have drained further so no charging this AM. The booklet mentions 4 way 14.6v charging as an option. What parameters should I charge at, and I thought my battery also had lvdc and a BMS built in....

 

[BradCagle]

Good day
So I bought two Chinese lithium 12v 200ah batteries called Moseworth
They were sold as having bms with high and low voltage cutoff but last night while using them they went low enough to sound an alarm through my inverter. We had 3 days of rain.
So I cut the Inverter off but I left the charge controller and the shunt battery meter on and this morning the two batteries which are in a 24v configuration were each separately down to 9.77 volts. I realized a small security camera was also drawing power.

Shouldn't the bms have cut off way before 10v ?

Here's what they claim in their ad:
Upgraded BMS - MOSEWORTH newest lifepo4 battery used high version Series BMS panel, better performance in series/parallel. Also it has overcharge, overdischarge, overcurrent, short circuit low/high temperature cut-off protection.

Should I call them on their overdischarge claim or does this sound within reason.

And have I damaged the cells by letting them drain to 9.77 if there was no over discharge protection?

I've drained LFP cells close to 2v for short period, I've also overcharged them to 4.2v for short period. Capacity tests were fine afterwards.

Some BMSs have wider voltage ranges. I suspect this is because a dumb BMS has no logic to account for surge so they just set the cutoff to something lower.

If you still can return, I would drain them down to see where they actually cut off. If it's something totally unacceptable, return if you can.

 

[Goboatingnow]

Li down to 2V per cell is ok

Lots of 12v batteries have discharge cutoffs at 8V

https://www.batteryspace.com/prod-specs/9055.pdf

Remember low voltage cutout is a safety trip. It’s not a way to trigger a low battery point. Your loads battery protection ( or battery saver ) should trigger well before the LVC

At 9.77 they are fine and no need to return anything. Whoever mentioned that doesn’t understand Li BMS protection strategies.

 

[rhino]

For longevity of the battery it should have cut off at least by 10V but as @Goboatingnow mentioned it may be configured for disconnect at 8V to use up every last amp of the battery at the expense of longevity. Note the SOK 12V 100Ah battery is configured to shut off at 10.4V.

 

[IHaveThePower]

Thanks for the feedback, it's been on charge at 10a and it's recovered to 13v so far.
Glad to know I didn't damage the cells.

Moving the whole work trailer setup tomorrow to a better solar window. They've had a good 3 hours a day in full sun but I put in a new pad with the backhoe this week and they will be in 5+ hours of sun, so hopefully they won't go that low again.

 

[Goboatingnow]

Yes I would agree that shutoff at 10,11 or even 12 V is better. LiFePO4 Is fairly dead at 4/12 V ie 3V

8V shutdown is way too low normally

 

[rmcrowe]

I just bought the same battery I think - I got it from amazon - its for a power station in my case, and it's a nice-to-have not really critical for me so I thought I would get the cheapest battery I could. The marketing sounds good on these but the low voltage cutoff, as you have found is pretty low. I took mine down to 9.6v and it the bms still didn't shut it down - I decided not to take it any lower than that. For me it's probably okay because the only thing I will have on this is small inverter that will shutdown at 10v.

I notice also the low charging temperature range is supposed to be :

Charging temperature

14℉~113℉

Which sounds pretty crazy too. Again, not a problem for me I can pick and choose how I want to charge it, but not good in any serious application.

I posted a question on the amazon page to ask what the LVD and low temperature values were, maybe they will answer.
Link to the product on amazon is here: https://www.amazon.com/dp/B08R6TF2TZ?ref=ppx_yo2ov_dt_b_product_details&th=1. (NOTE I am not recommending it)

 

[rmcrowe]

Oh, and my discharge test got me 94ah, not the claimed 100. But I did get a bit more than 1200WH, so I guess if you go 12*100 that works out, still a bit deceptive I think.

 

[sunshine_eggo]

When one checks the specs of "dumb" BMSs, it's pretty common to see 2.2-2.3V and 3.75-3.85 cut-offs.

Quality cells aren't made out of delicate porcelain. While there is little to be gained by venturing into these extremes, they will only be damaged if they are already failing (cheap, low quality cells).

 

[IHaveThePower]

Sorry it has been a busy week so I forgot to check in on this thread. But last night another strange situation occurred which has me considering returning these batteries.
Again the rain was here for two days and the batteries ran low. Last night around 2am I got a low voltage warning from the Inverter and the power cut out. The batteries showed 24.4 volts and the shunt was still active. So I disconnected the Inverter. But left the charge controller and shunt running. The draw was at 0.22 amps so I figured it would get to 7am fine and it was to be a sunny day.
Woke up at 9 and the batteries were dead again. This time out of balance. With one at 4volts and one at 10volts. While connected in a 24v configuration obviously.
Now the one at 4v won't accept a charge.

When I return these what should I claim is happening. Is it somehow my fault or are these under-performing?
Would it it be unsafe to connect them together to 12v while they are so far out of balance? If so what's the best way to wake-up the 4v pack given my charger won't power on when connected to that pack?

 

[rmcrowe]

I don't know if this will help you or not, but I did get some answers to my query on Amazon (and now I just looked and the answer is no longer there! How bizarre! I guess the seller must have retracted it ? ). My question was: "what is the low voltage discharge cutoff and what is the low temperature charge cutoff?" The seller's response was. "10v low voltage cutoff, and 23f low temp cutoff" - however as mentioned that is no longer posted.

I later told them I wanted to return the battery (after all), and this was the first response back:

So sorry for such issue, as for your confused, I have discuss with our engineer. The 10v cut off voltage we said always use as solar system setting, and when use 0.2c/20amps or above load, the cut off voltage is 10v. But when you use 0.2c below(1amps-19amps) load, the BMS auto cut off voltage would be 8.4v.
The BMS has been set to be the most workable protection system, don't worry.
If you have any conern about the data, our engineer could discuss more with you, thanks.
Anna


I then ran a discharge test at 35amps and again brought the battery down to 8.5 volts before my test disconnected (pulling 96AH btw) - I didn't see a point in bringing it lower than that... So I told them I didn't want to argue anymore, I wanted a return label. They did provide that and were professional about the return (so far...) I have not yet received my amazon credit but I buy a good amount of stuff from Amazon and I'm pretty sure they are going to keep me happy regardless of what the seller does. The seller just got the item returned yesterday and per amazon policy they have 5 days to credit me. If that doesn't happen I'll follow up here just so folks know.

OP I'm not sure you purchased from Amazon or not, but this is clearly a defective battery

 

[IHaveThePower]

I don't know if this will help you or not, but I did get some answers to my query on Amazon (and now I just looked and the answer is no longer there! How bizarre! I guess the seller must have retracted it ? ). My question was: "what is the low voltage discharge cutoff and what is the low temperature charge cutoff?" The seller's response was. "10v low voltage cutoff, and 23f low temp cutoff" - however as mentioned that is no longer posted.

I later told them I wanted to return the battery (after all), and this was the first response back:

So sorry for such issue, as for your confused, I have discuss with our engineer. The 10v cut off voltage we said always use as solar system setting, and when use 0.2c/20amps or above load, the cut off voltage is 10v. But when you use 0.2c below(1amps-19amps) load, the BMS auto cut off voltage would be 8.4v.
The BMS has been set to be the most workable protection system, don't worry.
If you have any conern about the data, our engineer could discuss more with you, thanks.
Anna


I then ran a discharge test at 35amps and again brought the battery down to 8.5 volts before my test disconnected (pulling 96AH btw) - I didn't see a point in bringing it lower than that... So I told them I didn't want to argue anymore, I wanted a return label. They did provide that and were professional about the return (so far...) I have not yet received my amazon credit but I buy a good amount of stuff from Amazon and I'm pretty sure they are going to keep me happy regardless of what the seller does. The seller just got the item returned yesterday and per amazon policy they have 5 days to credit me. If that doesn't happen I'll follow up here just so folks know.

OP I'm not sure you purchased from Amazon or not, but this is clearly a defective battery

Thanks for the information.
I asked for a replacement leading to a return if the replacements acted the same.
They seemed like they were OK as long as the voltage was high. But it's a pain to have them act this way under such low loads and at voltages that should hold up.
Any idea what batteries you'll go with this round??

And yes I did buy through Amazon.
I have a 12v battery that lost bms % stats about a month ago and I called the place I sold it to me which is two provinces away and they said it was recalled. Now after numerous call I to them they still won't return my calls to arrange the return so at least when buying g through Amazon there's that pressure to keep the customer happy which is a worth something.

 

[rmcrowe]

Thanks for the information.
I asked for a replacement leading to a return if the replacements acted the same.
They seemed like they were OK as long as the voltage was high. But it's a pain to have them act this way under such low loads and at voltages that should hold up.
Any idea what batteries you'll go with this round??

And yes I did buy through Amazon.
I have a 12v battery that lost bms % stats about a month ago and I called the place I sold it to me which is two provinces away and they said it was recalled. Now after numerous call I to them they still won't return my calls to arrange the return so at least when buying g through Amazon there's that pressure to keep the customer happy which is a worth something.

I will just build my battery - I did that for my RV and the results have been great, I wanted to build a quick little 100h powerstation that I could use for various things (or in case I need more in the RV), and though "hell, the cost of these lifepo4 batteries has come down so much I'll give one of the cheap ones a try". The power station is not all that critical for me, so I figured it's a good experiment. But even at that level I didn't want to keep the battery. Also the fact that it was really large kind of put me off because I was hoping for a more compact solution to lug around.

So I will order up some cells from Alibaba and a BMS and do it myself again. I have time and tools still from the last build.

 

[IHaveThePower]

I will just build my battery - I did that for my RV and the results have been great, I wanted to build a quick little 100h powerstation that I could use for various things (or in case I need more in the RV), and though "hell, the cost of these lifepo4 batteries has come down so much I'll give one of the cheap ones a try". The power station is not all that critical for me, so I figured it's a good experiment. But even at that level I didn't want to keep the battery. Also the fact that it was really large kind of put me off because I was hoping for a more compact solution to lug around.

So I will order up some cells from Alibaba and a BMS and do it myself again. I have time and tools still from the last build.

Cool
Maybe I should go that route too.
I'd love to know what components you choose, I've watched a couple battery build vids and I could handle the process I'm sure.

 

[rmcrowe]

I am far from an expert compared to many others on this forum. I am not in a hurry so probably purchase from Docan on alibaba, or one of the other reputable suppliers (I'm sure there are lists of them somewhere here on the forum now). Be willing to wait a long time though from China. There are several with local stock in the US I think but you pay a bit more. I Might consider going to the 120ah higbee cells, and getting a JDB 100a or 120a bms. I already have a power supply for charging the cells, and a discharge tool as well to check capacity, and also an impedance tester (not sure this is a hard requirement but I have it so I'll use it). You can get these things for not too much money if you don't need the highest quality (i.e. won't be building these things for a living). As stated there are many people here with vastly superior knowledge and skills at battery building than I, I would check out a few of the forums on battery building.

 

[rmcrowe]

just to let you know - I did get a full refund from Amazon this morning, so the seller did come through on that without me having to harass them.

 

[IHaveThePower]

just to let you know - I did get a full refund from Amazon this morning, so the seller did come through on that without me having to harass them.

Yes they seem helpful on this end. I haven't demanded a refund as I need these batteries for what I'm working at but I've made them aware that I'm having issues and keeping a close eye on their performance.

 

[DEEP NNN]

Yes they seem helpful on this end. I haven't demanded a refund as I need these batteries for what I'm working at but I've made them aware that I'm having issues and keeping a close eye on their performance.

How have issues worked out for these batteries? I ask because I am experiencing problems too.