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UPDATE: Yes!! the Xantrex is easily able to handle the load of a single air conditioner. The problem turned out to be the 150A breaker which wouldn’t trip externally. It would trip internally after reaching 60°C but you couldn’t tell otherwise. I replaced the positive with a 4/0 cable I found...

Hey thanks! I never considered testing at the board for a different voltage. Example: So if I measure the battery cell terminals and come up with 3.0v and then measure at the circuit board of the capacity tester, and come up with 2.7v then I should suspect the alligator clips and swap out the...

Thank you to everyone here for helping me out. I really appreciate it. I’ve already used this knowledge to help other in the Marina with similar problems and identifying wires which are too small and things heating up.

Hey Hey thanks! The battery cells have all been testing at around 85Ah to 89Ah. So as long as they are above 80, it sounds like I’m still good to go if I want to reinstall them. I’m making a list of the Ah Capacity test results. People here told me to pair the best with the worst. So #1 with...

Hey thanks! That’s really good to know. I’ve since reinstalled the LiFePo4 cells in thier new 3P-4S configuration. Each 300Ah battery having its own overkill Solar BMS and on:off switch. They’ve passed the stress test with flying colors!! I’m so happy this nightmare on my boat is finally...

Yup! I made my own jumpers for the load with 10 gauge wire and ring terminals.

Oooops, sorry I have so much going on, that I gave you the wrong readings. (I posted the correct ones above though.) The bad readings I gave you were from two bad cells that we took out of the system. After 12 days, the majority of the 48 good cells I tested in the standing resistance test...

Thanks. I guess I'll not take any chances and just charge the batteries at the standard 3.65v max.

Hey thanks. I didn’t know they were the same size. Any links to a good deal on a 304Ah cells?

Good catch! I can’t read where it said it went down to 2.77v? The smallest I saw was 2.85v when he started the test. The clips I used were supplied by the Chinese company, but it was 14AWG wire so not that thin and it was connected well to the alligator clips. I’m not so sure I would have gotten...

How would you test PV panels using one of these capacitor testers and why? I usually just hook up a DC Amp meter around the cord for the panel to see what it’s putting out.

I plan on doing that. Great idea. Today I was busy replacing more small cables, bad connectors, and all sorts of other stuff. It sucks. It’s 90° inside with no fan and 100% humidity.

Nice! If I had time I would probably do the China shipping thing. I found 280A/hr Eve cells for just $110 a cell if you wanna wait 40-60 days. I just don't have that time.

I paid $400k and it came with a “free yacht”. ? They were the 6-year old house bank batteries that the previous owner installed poorly. They were damaged as a result. I had to take them all out and assess how bad they were. Out of 50 cells, 48 of them still worked and were over 80Ah which is...

Hey thanks for the reply. I finished upgrading my entire battery bank from the ground up last year. I replaced most of the cables with incredibly thick 4/0 marine welding wire and performed a stress test with a FLIR unit discovering multiple other problems with the system installed by the...

Ok, so 2-5% of the total Ah of the battery bank. My Lead Acid battery bank is about 800Ah, so my End Amps setting should be 16A to 40A is that correct?? (*Right now it’s set on 4A.) When I reinstall my Lithium batteries, I have to choose a number and Zero isn’t an option. So I’ll choose 1A...

I replaced the load wires with very thick 10AWG wires which was the largest the device could take and made sure they were the same length at 10” inches. I placed ring terminals on the end. The tests so far have shown that all the batteries are around 85-89Ah. I’m pretty disappointed. I was...

Overkill Solar BMS. I have one for each battery. They are stuffed in between the batteries and very thin. The people here on this forum have overwhelmingly recommended them and it turns out they were pretty good.

Thanks for the straight forward answer! Ok, one BMS per battery and they don’t need to connect in any way. Do you think 250A BMS per battery is too much, too little or just right? Since I already have a 500A DALY BMS still new in the box, I plan on using that one and ordering three 250A BMSs...

No, I plan on installing the LiFePo4 soon. I had a 5th Electrican stop by the boat and we went through everything. I had him replace any cable that was going to connect to the LiFePo4 batteries with 4/0 tinned copper positive red wire which he had on his boat. I’m keeping the 3/0 black negative...

I ended up replacing the original one and bought the uograded 180w color screen version on Amazon. The biggest difference was that it had 4 battery leads which made it much more accurate with the actual battery voltages. Having the voltage readings on a separate wire than the load made all the...

Sounds good. I've re-designed the system now to have 4 batteries of 3P 4S. (12 cells in each battery, 300Ah 12v). And the four batteries connected in Parallel for a total of 1,200Ah 12v (48 cells total). I'll need my Victron 500A Smart Shunt to give me an aggregate state of charge for all 4...

I finished the capacity tests weeks ago. I made sure I replaced the leads with 10 Guage wire for the load and added ring connectors and a fuse as well just in case something happened while I tested in my sleep overnight. All 48 cells took me about 2 weeks. The average capacity was 85Ah.

Hey everyone, My system is almost ready to put back together. I’m trying to figure out how to match the cells together and follow the advice I was given here. Any advice on the order? I’m designing a 12v 1,200Ah 3P 4S system with four batteries. Each 12v 300Ah battery has 12 cells and the...

For the last month I've been testing all 48 cells and performed both a standing resistance test and a individual Capacity Test for each cell. (See results on my other posts). Thats the reason why they aren't fully charged. (Also see the Matching SOC post I made.) I do not have a 30v charger...

After I installed the ring terminals and upgraded to 10 gauge wire, the voltage difference went down to just 0.1v at a 20A load from the capacity tester. When I lowered the tester down to a 10A load, the voltage difference was only 0.5v (all of this using the old 150w tester while I wait for...

When the cells were in the original 4S 1P configuration, the voltages of all cells were the same (I never took one individual cell out to test it by itself.) The entire system would drop from 13.6v immediately down to 11v within about 2 minutes. So by “runners” you are referring to cells...

Hello everyone, I’m wondering if you can charge very discharged LiFePo4 cells at higher voltages to temporarily charge them faster. I’m guessing the answer is no, but I’m mainly wondering why. It probably has something to do with gassing? I just got finished capacity testing 48 CALB brand...

Ok, so my plan on the original post matching #1 with #48 and #17 is a good plan? That way the capacities would all average out all four batteries to about 85Ah each. However, some people said to match the best 12 in one single battery?? This would create 4 batteries with different averages in...

If I wasn’t selling the boat, I would replace all the cells and start from scratch using 6 BMS units and make 6 batteries of 2P 4S. And I would spend a little more time trying to figure out how the batteries are charging with 5A when the engines are on?? Where they are connected? And why two...