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Both seem like great deals. I have done rough calculations for my 18650 packs(mostly 7s100p and some "AmmoBats" 7s32p) and aim for under $200/kwh including all the consumables. Usually the cells themselves are about 30-40% of that cost and for the larger LiFePo4 cells there would hopefully be...

Most LiIon 24VDC nominal systems are 7 in series and that should work fine for most 24v devices.

This is the one I use and is industry standard since it was the primary one taught in all my solar site assessment trainings.

You will get better value with the 150v35A one. With that one you can do 3 panels in series and shouldn't overvoltage as long as you don't get really below freezing temperatures(I have a similar setup and had to upgrade to the very expensive 250v options because I do get very cold -20 temps and...

I would also do some research on the specific brand you are looking at because 3-4 years old is brand new but also long enough that if there is a phantom load draining the battery that whole time and no-one was paying any attention the cells could all be dead at 0V. I have read at least one...

It sounds like you have a lot of poor solder joints which could be working fine at first and then with a little movement or heat become unreliable. It takes a lot of heat transferred fast to head up busbar wire since copper is such a good conductor and one tends to use big wires for busbars. I...

One potential hazard you will want to check with your utility about because an unexpected 0 energy usage would raise flags and sometimes utilities will assume there is a defect and charge "average or expected" energy usage even without any meter reading. Apparently some folks have had that...

This was my first guess since solar cells are made in a way very similar as computer chips(ICs) which can have variance in how "perfect" they are. My other thought is the panels are designed differently which could lead to small changes in efficiency from having more/less diodes and such. How...

That was my first thought as well and based on your later disassembly seems like many cells weren't participating. Probably worth testing the whole pack after making sure all connections are good and also try to get meter readings on individual cells while under load to see if some are behaving...

Touch the battery when it slows down because it might be getting to hot and that would trigger the overheat protection. Or your unit might be faulty. If charging at the 1A The batteries can get hot especially if it is a faulty cell and that tiny fan is awful noise crap that I unplugged on mine.

I have had two incidents where I was disassembling a pack and caused nickel to establish a sustained short. They got to HOT to hold very quickly(within a minute) and I heard a small pop and phsss with the lovely smell of battery chemical so the internal protection kicked in and did it's job. I...

Generally from what I have read the cells decline in Ah capacity slowly over time but most failures happen abruptly from individual cells or components hitting a limit and taking large chunks down with them either temporarily until fixed or sometimes causing other elements to fail because it...

Great idea and lots of different ways you could design it to work the biggest challenge is car batteries are huge and so having an additional battery to charge the car would have to be even bigger to account for losses and batteries are expensive and a wear component. So all that to say your...

I wonder if the PowMr is actually only pretending to be an MPPT and is actually use PWM? I have heard of cheap ones that manage funy business like that. PWM would be fine with that voltage gap. It is also entirely possible that the Victron needs more voltage overhead. Generally the more...

yes Voltage is what maters most for electric shock and ampacity(how quickly it can push energy) maters mostly for heat buildup. And bigger batteries(aka higher Ah) generally are capable of higher ampacity. Many people get confused because car manuals and such will say to use a battery of at...

I agree with above about how the life experience maters more and there are certain colors that I have noticed tend to be more likely to fail testing. The red Sanyo's are one of them also many test fine and some are even really high end cells. I have also had really bad luck with batches of the...

Lead Acid batteries generally don't use a BMS but need to be matched when put into service. There is however manual checking of the batteries if they are the flooded type and regular supercharge(overcharge) procedures that break down buildup that happens internally with the battery.

basically reversed for how Korishan was talking about things. A pack sometimes refers to the entire 52v group but in this case just the pack he is referring to is the clump of 80p cells you put together and the overall capacity of the 80p packs should all match within a string of 14s of the...

Okay been learning and reading more, whew. Turns out Hot to Hot connections don't balance out but add to each other. There is also some square root of 3 numbers in there that means things don't exactly add up like stacking single phase loads would. Based on online 3 phase calculators I could...

This is how my farmhouse has been functioning for over 20 years and it is perfectly safe with correctly sized breakers. The breaker back on your main panel needs to be sized for that wire and so in any overload situation that breaker would trigger. With this method you are basically merging...