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I had cycled this battery dozens of times over the last 6 months, in the 30% - 100% range, with deviation between (pairs of) cells no more than 10-20mv. It just suddenly had one pair of cells drop to 2.5 volts, while the others were at 3.25 to 3.3 volts. It was like only that one pair of cells...

I recently had a 2nd-life battery do something weird. The BMS shut down the discharge because one of the cells (it's a 2P-4S, 240AH, FLP battery, so technically it was 2 of the 8 cells) went to 2.3 volts. The other cells were all closer to 3.3 volts. I thought for sure something had gotten...

Have you used one of the battery equalizers? I have four 12v, 100AH batteries. I have them connected in series pairs to make two 24v, 100AH batteries. These are then connected to a bus bar. I have learned the lesson about batteries not staying in balance, when connected this way. When I...

I recently built a 4S-9P battery, using 2nd life 26650 LFP cells. I tested and grouped them prior to building the pack, choosing only the best cells so that the capacity and resistance were very similar, for each of the parallel strings. I was very confident in the pack when I sealed it all...

They are two sets of 12v, 100AH, LiFePO4 batteries. One is a set of Power Queen batteries and the other two are 4S packs I built a year or two ago, but with no more than maybe 25 cycles on them.

Below is a picture of a 24v (2P-2S) system I just set up. Note that the battery switch is in the "OFF" position. I have not yet wired the solar or AC, incoming or outgoing. I am not sure it's safe to turn the battery switch to the "ON" position before precharging the capacitors. I have a...

Yeah, I wouldn't even think of doing this with lead acid...I should have specified LFP and individual BMS's for each battery in my original post. Per the video posted of Will doing exactly what I asked about, it seems that you can do this, but you really want to be precise with your cable runs...

"(Safe to do, but not the best)" I guess that about explains it.

This has always been my understanding, as well, but if the battery with lower capacity is topped off, and the BMS cuts off charging, wouldn't the current supplied to the bus bar continue charging the higher capacity battery until its BMS stops allowing it in? If your solar array is still live...

I know when you connect two batteries in parallel, they should be the same voltage, and you should verify they are at roughly the same state of charge so there isn't a huge inrush of current from one battery to another. In my research on this, it seems that the voltage is crucial, but state of...

Regarding your last two comments: I have used a lot of 12 and 24 volt devices during my lifetime, mostly in the camping and boating world. I know that many of the things we plug into AC ultimately run off a DC motor or circuit. Edison was (obviously) a genius and recognized the advantages of...

Well, that sucks, but thanks for verifying it's not just me doing something stupid. :)

I'm using a couple of 100ah LFP batteries I built 2 years ago to power a small DC fridge. Once the fridge is at temperature, the draw on the batteries is very low, meaning under 5 amps worth of draw. I know from prior experience that the Daly BMS on these batteries doesn't "wake up" for less...

I'm afraid you're right. I'll have to look and see if it's still under warranty.

I have a 200w BougeRV 9bb solar panel on the roof of my carport with a VOC of 21.62 volts. It worked fine for a few weeks, but then I noticed it would no longer charge anything. I checked all of the cables and the disconnect switch, but everything seemed to be secured properly. I then used my...

Since you are probably very tuned into prices, both historically and more recently, can you elaborate on what prices were in the last 3-5 years and what you're expecting to see, going forward? Some reports are claiming panel costs will drop 30-50% and I just find that hard to believe.

I have been hearing rumors of a price war between some of the major solar panel manufacturers. Does anyone know if there's any truth to that? Looking at it from a different perspective, can someone list what the typical or average price per watt for residential panels has been over the last few...

There is now a 40amp breaker in-between the SCC and inverter. Will has built systems using this exact design, so I'm hoping it's still acceptable.

The positive lead from the SCC goes to the inverter. That line is now fused. The connection between the battery and inverter is also fused, as shown in my original post.

I mentioned in the original post that I needed a breaker between the SCC and inverter/batteries. That has since been installed.

When I read the specs of your system, in your original post, my immediate thought was, "why so little battery storage capacity for a system with those capabilities?" Glad to hear you've added the 3rd battery and that they are apparently charging properly. Also, hope you figure out how to get...

DOH! I feel really stupid, now! :D Thank you for reminding me that 120v DC is NOT 120v AC! I knew I should have had my 2nd cup of coffee before posting this. :)

Pretty much all household appliances in the US use 120 or 240 volt power to run. During my lifetime, batteries were 12 volts, 24 volts, or even smaller, depending on the use case. However, I'm seeing the voltage of batteries increase to where 48v now seems to be the preferred option. I'm also...

Not sure why you feel the need to be dismissive when having a simple discussion. The AGM battery in my boat is capable of 1200 CCA (30 seconds worth). It's a VMAX XAC31. My puny 135HP 4-stroke never needs more than 5 to 10 seconds of cranking to start up, but it's nice knowing I can do that...

John, I just now saw this comment. The cable from the positive post of the batter to the fuse is <18". You're saying that is too long? I get that shorter is better, so that if "something" happens, the fuse fails quickly. The wiring charts (plural) I checked online said that, at this total...

If that's true, ask yourself why no automobiles or diesel trucks or tractors (which require even more CCA) use LTO? LTO is "superior" , in some ways, but not when it comes to cold cranking amps. I don't know why you're having a hard time wrapping your head around that, but it's just the facts.

I think Hedges pretty much covered it. What will work on an easy-starting engine at 75 degrees may not work on a cantankerous old 2-stroke, at 27 degrees. AGM's are superior when it comes to CCA, plus they're the correct chemistry for the current your alternator puts out. Please don't...

Li-Ti is short for lithium-titanate, just as LiFePO4 is short for lithium iron-phosphate. LFP and LTO are also acceptable abbreviations. The battery you linked to is not suitable for cranking large outboards in cold conditions. It's probably fine in warmer temps, with engines that start...

While that is a link to Li-Ti battery cells, none of the cells shown is really suitable for building an AGM replacement, at least not in terms of adequate CCA for challenging applications.

Link?

There are companies out there building LFP batteries with a large capacitor that will generate the amount of cold cranking amps we expect out of a good AGM. They also have circuitry that allow them to be safely charged from the high-output alternators on large boat engines. Those are the only...

The fuse on the positive wire is 150 amps, so I'm protecting the wires running to the load, I just wasn't sure about the wires in-between the batteries. At the very least, I will replace the 8AWG with 6 gauge, to be consistent. The BMS on each battery "should" disconnect if it exceeds 100...

I have built a small off-grid shed system that uses two 100ah, 12v, LFP batteries, wired in parallel. (Picture below...still need fuse for incoming solar) My question revolves around the wires that go between the two batteries, creating the parallel connection. I wasn't sure what size wire to...

I feel sorry for the OP in threads like this. His SLA battery got too hot, bubbling acid onto his LFP battery, but it really wasn't the fault of the SLA, or the fact that they were placed in such close proximity to one another. The issue, as I see it, is that he put raw cells (with very good...