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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...

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...

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...

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 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...

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...

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...

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...

This is a Frabill 19 Quart Bait Station. It works great at keeping fishing bait (mostly minnows) cool and lively. It is very well insulated, like a Yeti cooler, has a sealed lid, and the other other interesting thing about it is the aerator that is attached to the lid. This aerator uses a...

I have a 200w solar panel with 22 volts, open circuit. I have a DROK brand buck converter rated for an input of 8-22v with an adjustable potentiometer that allows an output between 3 and 15 volts @ 3 amps (up to 45 watts). I am wanting to power a 12v heating element that is rated at 25 watts...

I was installing a DIY battery into my boat and had two wires touch that shouldn't have. Lots of sparks for just a second or two. The battery cells still read full voltage, at the cell and pack level. From positive of the battery to B- on the BMS, I get 26 volts (24v nominal battery). From...

I bought a Renogy Rover Elite, 20 amp, MPPT solar charge controller. The manual shows: Max solar input voltage is 100VDC. Max solar input power is 12v @ 260w - 24v @ 520w. (I am charging a 12v LiFePO4 battery) Does this mean I can't use more than 260 watts worth of panels? I recently purchase...

About 6 months ago, I bought a portable power station on an indiegogo campaign and after waiting a long time, it still didn't have a ship date, so I canceled it and decided to try and build one, myself. I had built other batteries in the past, for smaller applications, but this would be a much...

I have built a portable power station and would like to add a USB Type C, bi-directional, power delivery port. To be clear, I'm looking for a component level part that will deliver up to 60 watts of USB-C power and also accept a similar amount of input to charge the battery in the power...

I have watched so many videos talking about low-temp charging protection, and I fully understand that you do not want to charge LiFePO4 battery cells when their temperature is at or even near freezing. I get that if you screw up and allow your batteries to charge when they are in a frozen...

I'm building my own portable power station. I need a small MPPT charge controller (10-20 amp) that will charge 12 or 24 volt batteries. I'm considering the Rover Elite 20A unit. Is this a good choice? Is there something better, or at a better price point, that I should be considering? If I...

When designing a DIY LiFePO4 battery, is there an order or logical arrangement of the components, in terms of which device "cuts off" first? Do you want the BMS to be rated lower than the inverter, so it always shuts down before the inverter reaches its highest possible setting? Do want the...

Maybe I missed it, but I haven't seen a thread covering this specific topic, which seems pretty unlikely. I bought a 70 Mai, Tera 1000, portable power station. It checked most of the boxes for my specific use case and should be delivered in the next month or so, if all goes well. It supports...

If I build a 4P-4S battery from 26650 cells, do I need to run a lead to every single cell (16-pin) or do I just need a 4S BMS with a 4-pin (5, technically?) balance lead configuration?

If you have batteries in your house, at around 70 degrees, then take them out into an unheated garage where the temperature is near freezing, can you immediately plug them into a charger and rely on the heat generated during the charging process to keep them warm? Maybe a better question to...

I have noticed more and more of the larger PPS units are coming out with LiFePO4 batteries, instead of NMC. Due to the increased weight many of these systems are coming with the battery in one box and the balance of the electronics in a separate box. I was wondering if anyone has built a DIY...

I am building a small backup power system that will keep the fridge and a few lights going for outages of no more than a few hours at a time. The initial thought is a 24v, 100AH, LiFePO4 battery, with a 2724 MPP inverter/charger and about 400w worth of solar panels. I already have the...

I have purchased used scooter batteries from Jag35. I bought them for a different project I'm working on but when they arrived and I saw how they were configured, I realized that I could make a small portable power station with these pretty easily. They are arranged in a column of 5 packs...

So, I have my 60280 cells configured in an 8S, 24v arrangement. Long story short...I created a short...for a short period of time. It arced quite spectacularly, but I quickly broke the connection. I tested the individual cell voltages (3.3v) and the full pack voltage (26.4) and both were...

I have placed three 18650 cells into a plastic housing that creates a 3P pack, with roughly 7800mah worth of capacity. I have connected a male 5.5x21 jack to this pack, to power a ~3.5v motor. I bought a 110v power supply for Lithium batteries (4.2v output) with a female 5.5x21 end on it, so...

I have a Frabill insulated minnow bucket (cooler, really). It has a small electric pump that oxygenates the water in the insulated cooler that the minnows swim around in. I have attached a picture, below. This pump can be powered by 2 D-cell batteries, which provide 3V and a total of around...

Forgive me if this has already been asked and my Search skills just weren't able to locate it. I have two 100AH LiFePO4 batteries, connected in series for 24v. To do this, I have a 15" length of fairly heavy wire (6 or 8 AWG) running from the positive terminal on one battery to the negative...