Recent content by Surferdudemi

Resistance between bus bars and battery seems unlikely, when I'm pulling 100A or so into the SkyBox inverter. Likewise when it's pushing 40A into the batteries. The out-of-balance groups switch up over time, too. If it were just resistance, it should be the same cell or group of cells...

Which dividend stocks that are not MLPs and don't subject you to market risk are paying 8-9%? (MLPs have tax implications and extra forms.)

I've got two of the EEL battery boxes. The first was assembled with 271AH cells and I recently built another with the Envision 304 grade B cells. The new one is the latest version of the larger box. It has had strange balancing issues. Groups of 4 or 8 cells are balancing to the same voltage...

Buy 20 and put the 4 worst into a 12V pack for 12V loads or smaller portable inverter. When I ordered from 18650 last year, there was a price break in shipping that made 20 better than 16 anyway.

Just saw a YouTube video where a guy tested bi-facial planted vertically E-W vs conventional and bi-facial facing south. Vertical E-W was competitive, and split the curve to provide power more in line with usage (anti-duck curve). Interesting results with snow, too.

18650battery store prices have come way down and they restocked. EVE 304AH at $109 at the moment. Wondering if they will drop a bit more from oversupply?

I miss going to this show. Used to get a free pass because I worked for a large company. So many great things to see and people to talk to. Once had a chance to chat with Chris Anderson and another well-known guy whose name I can't recall about DIY drones when they were just coming out with...

Should definitely have something between the cells. The case of each cell is tied to the positive terminal (on my Envision cells), so when you've got cells connected together, case metal making contact between cells will short out one of the cells. That blue PVC will insulate them temporarily...

The spec sheet on these cells says they are at 100% SoC at 3.348V. What voltages are you folks using when you test the capacity? I've got a 4-pack on a charger that goes to 3.65V per cell, still pushing its 10A max rate into cells at 3.36V each. OC voltage looks like it's going to settle...

Maybe I'm being dumb here, but it sounds like you just made a little transformer with the secondary shorted on each leg. AC going through the ferrite would generate a current if the ferrite is a closed conductor loop. That would generate heat in the ferrite and do nothing for quenching spikes.

Given this has been in service for 8 months without problems until now, yeah, looks like you've got 1 weak cell and 2 more than are on their way. Given the flat curve of LiFePO4, 11 looks weak as well. I'd consider replacing both of them. How many AH did you draw to get to that point? If...

Do these inverters use frequency-shift load management? I read through the manual and didn't see any mention, so I'm assuming not. I've got Enphase micros on some panels that I'd like to keep.

What settings are you using in the BMS? I've had mixed results with two EEL packs using the (I think) Seplos BMS If you want, you can just dump the XML settings file if you have access to it.

If it leaks out when the cell is punctured, it has not had time to absorb any moisture. So what's leaking out is not HF acid. It might be that over time it reacts with moisture from the air, but not instantaneously.

Someone posted a doc with the composition of the electrolyte in LiFePO4 batteries. Don't recall HF acid being on the list. It was in the post about the battery pack in Germany that was suspected in a house explosion. Edit: went back to find it. The reference is about Li-ion battery...