Troubleshooting suggestions? duct-tape lifepo4s from ebay supplier

[Peter]

Thanks Peter. Now my brain hurts.

Sorry...

It has taken me a while to wrap my head around the functions of a typical BMS, that was the readers digest version.

At first blush I do think you have a BMS issue, there are acceptable 16 cell (48 volt) BMS's available at reasonable cost. Ball park is around $40 each, these would be from a chinese suplier who has given fantastic support over the last 6 months or so. You might be lucky and the balance connector is the same as your current BMS. Otherwise you would need to solder in a new set of balance wires, which you can get from the same guy.

An alternative is an excellent USA designed kit that is about $90 each. But that one is a kit of parts and PCB that you need to solder up. You would then also need a replacement balance wires connector.

Check the voltages, check the BMS's for obvious blown up bits, check the voltage of each parallel cell group, check charger output voltage. We can come up with a plan of attack from there.

Please don't loose sight of the sense of humour, as long as the actual cells themselves are ok, we will be able to resurect your batteries and you will learn a lot in the process

 

[rguy56]

Sorry to not get back sooner, but work, and then a basement flood intervened.

Ok...

I checked my charger output when it's not hooked up to a battery and it fluctuates through a pattern, from a low of 18 volts through a high in the 50s. I'm guessing that it's some kind of smart charger looking for an answer from the battery, or it's stoned.

The batteries are more interesting. When "fully charged", one battery shows 48.3 change, the other 51.3. The interesting thing is that when hooked up to two different controller/motor setups, their voltage, in both cases, drops to 1.6 or 1.7 volts. When I hook up either of my sla packs, the voltage doesn't drop. I had planned to also check the batteries on an ammeter when I had them hooked up, but when I saw the voltage drop, I just thought, "These batteries are ****.", and left it at that...

Pete, I looked at that endless sphere link you passed along, and now that I know what might be inside, I'm amazed at how poorly the batteries were packaged. They were just a paper wrap over the thinnest possible bubble wrap, then tied up with a sort of nylon ribbon to make the pack possible to carry without tearing. As it was, one of two chargers was smashed, and I suspect the charger is more robust than the batteries.

I'm thinking that I might try to pursue a refund through my charge account if that's even possible, unless it's a really simple fix.

Thanks,

Bob

 

[Peter]

Your charger voltage seems off, but I only have experience with my own gear.

You do have a major battery issue, the voltage should not sag like that. I wish you the best of luck dealing with the seller. I assume you used paypal? start there to try and get your refund. It is possible your card company will say something like' you asked us to transfer money to paypal, which we did. ' I have been burnt by that before.

I highly recommend posting your problem on ES. There are a lot of people there who know their way around lithiums a lot better than I do. Absolute worst case you will probably be able to find a buyer for your packs (yes, even with the problems as most of the cells are probably ok) and salvage some of the investment.

Don't give up though. Lithium chemistry rocks and there are good sellers out there who do support their product.

 

[rguy56]

Speaking of e.s., a user of that forum wrote jimmywuu66, and gave him a link to a discussion page where I was sharing my experience regarding his batteries with a lot of perspective customers, and people who will be leading trends in his marketplace.

Well, yesterday, Dan, another guy who writes me from jimmywuu66, besides lau, wrote me and agreed to send replacement batteries, and gave me his address for returning the old ones. It remains to be seen whether that will happen, but it does certainly show me that vendors can have their fingers on the pulse of the maketplace at these forums.

Bob