Sunday, Oct 21, 2018 at 11:15
Same here, three years no balance issues, the video from Enerdrive is rather vague, it implies they are having warranty issues due to the low voltage cutouts failing in their batteries, this appears to be caused by the cut outs operating at currents higher than the batteries rated current which they indicate rather vaguely was 100A for their 100Ah battery.
Now that's rather odd as if the battery is tripping due to low voltage and generally the low voltage cutout limit is very low way under what one would consider 0% SOC, how is the battery able to supply more than its rated current at such a low voltage?
They then allude to cell balance issues caused by the batteries being in parallel the cause of the problem. I and many others are running batteries in parallel and have no such issues?
It would therefore seem they have two issues:
1/ Cell balance issues in their batteries, maybe they need to look at the quality of their cells?
2/ Their low voltage cuts might not be up to the job. This would not surprise me, if you look at a built up 100Ah Lithium battery its physical size is around the same size as a equivalent AGM battery, the protection module on my batteries is rated at 240A and is around a third the size of one of the batteries, cramping suitable circuit into a drop in replacement type unit that can handle the currents involved would not be an easy thing to do.
They also imply other brands would have similar issue, do they? Personally I suspect that all similar looking units are probably made by the same company and branded as per the buyers requirements so maybe they are correct in that regard?
They then go on to say buy a bigger battery rather than two smaller ones, hmmm I wonder how much the bigger unit cost compared to the smaller ones and who's to say you won't get the same cell balance issues with the bigger battery? Also if you have two 100Ah batteries there is a reason for it as one 200Ah would cost less, you most likely have two batteries due to space constraints, at least that is why I have two batteries. Maybe they should have just been up front and advise customers buying two of their batteries that they don't work
well together?
Also they then go on to say if you require higher capacity and load handling ability go for their larger battery or their system that uses built up batteries and separate control units. This again implies the BMS units in the smaller batteries and possibly cells aren't up to the job, but then as I have already written you shouldn't be relying on the batteries low voltage cutout for this function.
When I looked at the drop in solutions three years back I decided not to go that path though it would have been the more elegant and the simplest solution. My concerns were those now being raised by Enerdrive and I'm glad I went with built up battery packs and separate control units.
I'm also rather surprised that company that claims to have such a deep knowledge of Lithium batteries made no mention of not relying on the batteries protection device for normal day to day operation as that is not what it is intended for and most likely will fail if used as the only low voltage cutout. The company I purchased my batteries from made it very clear that the batteries protection system is the last line of defence and separate protection devices must be installed that operate prior to the batteries own device under normal conditions.
I had a quick look at an Enerdrive battery on Ebay and it doesn't appear to have any internal cell balancing system, if this is the case it is another good reason to steer clear of this type of battery as ceell balance issues will result in them being a rubbish bin job, though as I written above, my personal as yours is that good quality cells don't go out of balance.
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