Thanks for sharing your experience. It seems the battery packs in these are pretty good. I wonder if the parallel configuration might be more of a heat creator than the series configuration. If the bms might tend to regulate differently than each other and cause a significantly greater amp draw between some of the paralleled batteries than you were actually drawing with the inverter. I’m glad you tested it before sending it out.
New Battery on Amazon and Ebay - Global Power 12V100AH LIFEPO4 - $399! Has anybody actually bought one yet? Torn it down yet?
- Thread starter Indepthdude
- Start date
I think the main issue is the additional heat created by operating the bms at a higher voltage. These bms's already get quite warm at heavy loads on a 12v system. Basically a 1a leak/loss @12v is only 12w which the bms's heat sink can dissipate. However that same loss on a 48v system would be 4x as much Since series wiring causes each bms to have to have to pass the full system voltage. The failed bms's all showed signs of extreme overheat. Even the double sided tape on the back was melted. These batteries have higher than normal internal resistance, so I don't think it was the parallel connections that caused the failure( basically the system draw would have prevented the batteries from draining/charging each other, I also closely monitored each batteries voltage during the test and there was not enough voltage variation for them to be out of balance enough for this. Additionally I used a clamp meter to monitor how much amperage was being drawn from each battery) my end conclusion was that they just need a serious derating @48v nominal. They can probably sustain a 30 min draw @high amperage, but they cannot be used continuously.
My only contact was through Ebay. Listing: https://www.ebay.com/itm/373784150462. They dropped the price to $297. I paid $317 (grrr...)
The Ebay data sheet picture had a phone number on it if you need to contact Jim. Look at it on a computer, Ebay compresses images on mobile devices
Last edited:
Off topic again but getting back to my RV application... It turns out I didn't have as much room as the poster in the link above, so I ended up moving the propane tanks and took the hinges off the box so the cover just lifts off. I'll secure the cover later with some tamper resistant screws (on order). I added two SAE solar panel connectors on either side (routed to a Victron 75/15 controller inside).
Note in the pictures there isn't anything to hold down the batteries which could slide around. I am looking for a battery tray but as far as I can tell these are group 76 specs and there doesn't seem to be any trays this size. Any suggestions on how to secure the batteries? I could screw some brackets around the base, but there might be more elegant solutions.
I'm planning on using these straps https://smile.amazon.com/gp/product/B09CLBGG8Z thru the handle area and some aluminum brackets to make a base for the batteries
Last edited:
At my wife's suggestion (she's smarter than I am) I'm going screw in these positioning squares (https://www.amazon.com/gp/product/B07ZKGHZXL/?th=1) to keep the corners from sliding. (Didn't mean to hijack the thread, I'll shut up).
Nobodybusiness
Solar Sponge.
I have bought batteries from Jim before. He doesn't sell those kind anymore.
I have not purchased any he has on Ebay right now but Jim is a stand up guy.
Jim will not leave you hanging if you get a bad cell or something.
I know him personally but I don't think he would like me giving out his info.
if you contact him on Ebay he will get back with you..
I noticed your latest video about these batteries and the trouble you have had with them. I have 4 of these in series and since I assumed that they were internally out of balance I purchased a active balancer to keep the batteries from walking away from each other while I was using them.
I get close to 14.4 I have 4 ins series at 48v and if I charge at 30amps they will just reach 57.2 volts. That figures out at about 14.3 if I charge slowly 10 amps or less the voltage will be less but the settling voltage seems to be the same.
I was wondering if you had tested the bms to see if it does any bottom balancing. Observing the 5 times full charge and discharge cycles recommended by the data sheet my high cutoff has moved up almost a volt and low cutoff down possibly the sam although I did not think to observe that at first. It seems that some sort of balance improvement has occurred and my banks has improved slightly. I don’t have the time to experiment with these batteries right now and it is such a chore to pull them out that I am considering pulling them out and making a 48volt battery out of them with a different bms. Do you think that might work and do you have a recommendation for that purpose? I need low temp cutoff 70amp continuous or better discharge rate and 30amp or better charge rate.
Beene Brothers
Owner
This is what I used for 48v applications. Haven't had one fail on me yet, other than during installation in which case it could have been me to kill it. https://www.aliexpress.com/item/100...1;74.61;-1;-1@salePrice;USD;search-mainSearch
I have not observed them trying to bottom balance. That's curious.
As suggested by multiple of my viewers I'm planning to swap in 12v JBD BMS's and see how it performs. So far the cells seem perfectly fine. Just the BMS that's giving me fits. What's so odd is that first battery I bought could do 100a loads for 10 minutes and barely get hot. Could touch the mosfets. But a second battery would hit 60a and cut off after just a couple minutes due to high temps at the mosfets. Both were in 12v applications. Go figure.
Beene Brothers
Owner
I haven't seen any that would charge that high. Sounds like yours are relatively in-balance or for some reason do have a working passive balancer. That's great.
Thanks for your input. I will probably get a 16s bms to have on hand in case I have a bms go out. Then I wouldn’t have to wait for another to come in to get the bank up and running again. I don’t get the large voltage spikes at high voltage cutoff that you were getting in your first video. I wonder if the powmr active balancer is tempering that by transfering the excess voltage to the other batteries. One thing I noticed that I did not know if it was normal or not was that if I charge at once I cleared 90 amp hours input batteries the amperage began to decrease slowly until it reached 25 amps then dropped suddenly to 8 amps till I estimate I reached about 96 amps input then It went to 0 amps for 5 minutes and then stopped charging. Maybe the balancer is affecting that to. 30amp charge rate seems to get me the best high voltage cutoff and floating voltage.
Jim Gee recently reached out to me and said he has had plug and play stand alone balance boards made for these, and will provide them free of charge to anyone that had purchased batteries from him and wants one. He sent me an install video, looks like you remove the battery top, unplug the balance leads from the bms, plug them into the balancer, and then plug the balancer back into the bms.
Thanks for the info I have sent a message to him on eBay. That would be great if I can get those.
Appreciate the info. I contacted the seller via Ebay and requested the balance boards for the 3 batteries I purchased.
Received a response within 10 minutes from Jim Gee and he is shipping the boards tomorrow, as well as sending tracking info and install video directly to the email address I provided.
Same here.
Balance boards on the UPS truck out for delivery. BTW, the lowest listing on Ebay for these batteries is now $389. I wonder if they are being sold with the balancer installed.