Recent content by robaroni

What's the difference between this and an MPPT from the PV to the WH? It looks like it's just 4 MPPT's in a box. Also I don't like water heaters, I use a tankless. What I want is a tank that PV heats with an internal tube that feeds my tankless. The tankless is very good at holding temps and...

Hi gang, Here's what happened: I was intertied for ~10 years and net metered. All my generation was subtracted from what I got from the grid. That has changed, now my grid supplier is charging me retail for all the energy I buy and paying me once a year for all my production at wholesale rates...

Hi Everyone, I have a SolarEdge SE6000 system on my roof for ten years now with the SE6000 grid tie inverter. The system works fine but I have a couple of questions. I always assumed the inverter would supply the house needs first then sell excess to the grid, can anyone confirm this - thanks...

LiFePo4's are the best if you're worried about fires. I'm running them in the house, in my basement. I've tested them with a short to dead. Not only do they not explode they can be charged to full again. I didn't believe it until I had a 36V DeWalt pack fail to charge. I had left it in it's...

Legs aren't cells, there are 16 legs in the nominal 48V bank, each leg has 36 cells in parallel. Yes, during, once the charger is off or drops significantly, let's say at night when the modules aren't producing power or it gets overcast and the PV array doesn't put out much the pack comes into...

Yes, right typo 3.42 V! For my bank I set my charge controller to ~54.4V (48V system 3.40 V per leg). This way the clamps aren't fighting the charge controller. This is important, you don't want the charger high total pack voltage to be above the low cut off voltage of each clamp comparator. A...

My bank is 36P @ 5.5A ~200A total. What I do is keep the single leg at 3.4 volts. I use very little if any capacity and I find keeping the battery under the high slope of the charge curve keeps any batteries from charge runaway at lower internal resistances. The balancers work very well, each...

I tried this balancer, actually it's the one I tested that shows exactly what I'm talking about. Yes, if you're going to do small cells with minimum charge current they will work but don't expect more. It still has to follow the wires back to the controller to dump current to other batteries. It...

I tried that balancer and found it didn't keep my pack in balance. I forgot what I tested the current at but it was not as advertised.

duplicates

Thanks for all the comments everyone! Here's the circuit I designed to keep my batteries in balance on my 576 cell 48V pack 16S-36P. it works very well with my two charge controllers on my system which go up to ~60amps if I remember. I keep the max charge voltage to 54.4 or ~3.4V / cell. Because...

It seems to me if I were making a mobile installation I'd use something like these but it might be overkill in a stationary system, although if you have the bucks why not? If you're worried about stresses just leave a small gap between batteries for expansion.

That "thing" is exactly what I'm talking about and they still sell like hotcakes on eBay. I explained why they don't work. You seem to believe you can switch off a high current shunt and instantaneously measure battery voltage, you can't do that with any degree of accuracy and, again, you can't...

Not true, First you can't shut off a comparator to check cell voltage and some of these use comparators. If you want a balancer with 50 or 60mA balance current these are fine but some claim higher current capabilities. Shutting off charging to test cell voltage doesn't work well because...

If you're buying BMS controllers from China and are disappointed as to why claims of higher currents fall short this should help give you some perspective. The problem lies in thin wires supplied, you can't have an AWG 22 wire controlling high currents (over a few hundred mA). It's not that the...