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It sounds like you may not have done a true top-balance or a bottom balance. Just checking the voltages in the middle range does not guarantee a balanced state of charge. I don't think it would hurt your battery to run like that for a little while. When the first cell tops off, it'll just...

Well, last night we finally got an 8-hour power outage courtesy of a driver who hit a power pole and downed some power lines in my city. At least a couple or 4 thousand customers were out of power. So, although my system is not quite in its final state, I fired it up, brought an extension cord...

Sorry, I hadn't logged into the forum for a while. I measured just at 200 AH capacity for my 202AH cells, so I'm happy enough. I know the uncertainty of my measuring equipment is probably greater than the 1% difference. I also stopped my test at 2.7 volts per cell, as I saw that my...

I'm a ham radio guy so I am biased towards the Anderson Powerpoles. The 15A, 30A, and 45A sizes are interchangeable with each other - they're just designed for use with different gauge wires. The thing I like about them - you don't have to worry about whether to use a male or female - they're...

Hello, all. I'm a Chemist from Arkansas, a little past my prime, but retirement still far away. I'm a ham radio op, play with electronics, 3d printing, musical instruments, solar, prepping for doomsday as much as I can in a suburban setting. Wife, kids, one dog. Back in the day I built my...

Hi, I'm in a similar stage of setting up an 8S battery using 202AH prismatic cells. I also have the Overkill Solar BMS. I haven't done top balancing yet - I don't have a similar bench power supply (yet) . So to bring all my cells to a high state of charge I wired up my 8S pack with the BMS...

So far so good. My pack is working well. I have 1kW solar array feeding it, and my load is a deep freezer and grow lights for seedlings for my garden. It is staying well balanced. I'm using the Overkill Solar 8S BMS. This system is in my garage, so the lowest temperature it sees is about 0...

I bought a set of 8 from a US seller on eBay. I know I paid a premium because these were already stateside and took less than a week to arrive, but I'm chomping at the bit to get my solar freezer project off the ground. I'm still currently teleworking which saves me 2 hrs of commute time...

I have a Ryobi lawn mower, weed eater, and leaf blower. I have charged them from my modest solar system consisting of 150watts of panels, two 6v flooded lead acid golf cart batteries in series, an MPPT charge controller, and a 400w modified sinewave inverter. I read somewhere that the Ryobi...

When I test my pack, I'll attempt to measure the internal resistance under real world conditions (by testing voltage sag under measured current load). I don't know if I trust internal resistance measurements that some of these vendors make. Under a 100A load a 1.0 milliohm internal resistance...

It looks like your inverter is attached to the load side of the charge controller. Typically the charge controllers are not designed for that heavy of a load so you should attach the inverter with fuse directly to the output terminals of your battery.

I finally got around to doing a capacity test. I top balanced, not in the recommended way first. I was too lazy to disassemble my pack and parallel all cells - I don't have enough bus bars made for that. I have a small buck converter which I set to 3.65 volts, up to 3A. My pack was already...

No. Since the batteries are at the same chemistry and are in parallel (and therefore at the exact same voltage) they will have the same S.O.C. in theory. Now, I know there are sometimes deviations between theory and reality, but I wouldn't be afraid to give it a shot. The smaller battery...

Is there a consensus that the swelling is caused by a breakdown of electrolyte and that breakdown of electrolyte is correlated with increased voltage? In that case it might be better to set the BMS cutoff voltage to a lower value - 3.4 or 3.45 volts so that the cells never see a higher voltage...

I'm building my 8s 200AH LiFePO4 battery inside a cheap 48 qt cooler. Batteries by themselves weigh almost 70 lbs, but with the handles on either side I can move it by myself, or two people can move it together. I have another cooler with wheels and a handle which would have been more...

The cooler I am using is an Igloo 48 Qt. Island Breeze that I bought a couple or three years ago at Wal-Mart. It was cheap and very similar to this one they have now: https://www.walmart.com/ip/Igloo-48-Qt-Laguna-Cooler/169502621 It is pretty close to a plain box which is good - the walls...

That's a larger 175A connector than the 15, 30, 45A ones that hams generally use. I'm less familiar with them, but I understand that there's a convention for those, too. Since these larger ones are one piece I don't think you have to worry about it - it is marked on the connector. With the...

I'm just starting to build a pack about that size using Overkill Solar's 8S BMS. It has bluetooth and low temp cutoff.

I built my 8S 202AH inside an inexpensive Igloo ice chest with room to spare. An 8S 280AH might also fit, but I haven't measured it out - it would be close. The handles on the sides makes it possible for one moderately strong person to move the battery without assistance. My battery is about...

Another update. I know some folks have noticed that their EVE 280 Ah cells swell with the charging cycle. Today is a nice sunny day, and my Lishen 202Ah cells charged to 100% capacity this afternoon using my 1kW array, so I opened my battery box (a.k.a. battery ice chest) and examined my...

Ha! So it is good that I built my battery inside a plastic ice chest and put plastic spacers between the cells! I always cringe a little when I see someone build their battery box inside a painted metal case. What happens after years of jostling about when some of the paint or insulation wear...

Update: The ebay seller has been signing their messages as "Giandel" and it looks like Giandel inverters is all they sell. They might be Giandel's official USA vendor on Ebay. Anyway the latest they sent me after I sent the photos and a photo of the serial number say that there must have been...

Maybe we should ask @Will Prowse to do a video on measuring internal resistance. Hopefully these cells won't turn out to be duds on internal resistance.

This is a bit off topic, but a neighbor of mine has a nice crepe myrtle tree with some branches hanging over my side of the fence. I recently learned about the technique of "air rooting" or "air layering" and I think I'm going to try that on one of the branches over my yard, then cut the branch...

I bought some Lishen 202AH cells from an Ebay vendor in July. Internal Resistance spec is more than proportionally higher than the 280 AH Eve cells, but still plenty low for my application. The pack I built is working well for me, no complaints. Of course this is my first LiFePO4 pack build...

I agree with MichaelK that I would go with a larger inverter than 800 watts. I am powering a 9cu ft and a 7 cu ft chest freezers in my garage using 1000 watts of panels, 24v, 200AH LiFePO4 home brew battery, and 2000 watt pure sine inverter. When one freezer's compressor kicks on my battery's...

As you charge you will notice the voltages creep up very slowly at first. But then as they approach 3.35 you'll notice they will creep faster and faster. One or two cells may creep faster than the others and you will really have to watch those more closely because they will finish first...

I would expect, all other things being equal, same or very similar battery chemistry that the higher capacity cell would have a proportinately lower internal resistance, so higher capacity cells will tend to source more of the current load. As long as the battery + and - terminals are tied...

Not that I recommend this, but one way I sped up top balancing was to wire up my battery in its final 8S configuration and charged the pack using a large solar panel. I depended on my BMS to cut off when one cell reached 3.65V. I did watch the individual cell voltages like a hawk once it got...

Just a quick update. I have been charging my pack at a low rate using one 260 Watt, 60-cell panel and a cheapo PWM solar charge controller. I wanted to see whether there is enough voltage overhead using the 60-cell panel that has a Vmp of 30.7 volts to charge my pack. So far so good. Even on...