Lifepo4 for solar battery?

[yopappamon]

Buss bars read .08v at around 80-100 amps. Not real accurate amps reading on the front of the inverter. Let's say 80 to make the math easier. 0.08v /80 amps= 0.001 ohms. Not to bad. 0.1v across the connections on the disconnect switch.

80amps x 0.08v= 6.4watts. Might warm up the straps over time. I'm more concerned about the 8 watts across the disconnect.

 

[texaspyro]

It's that the plastic case of the Thundersky cells is rather thin. The cells can swell during charging/use and crack. Thundersky says to strap them together snugly with metal end plates and non-stretchy straps (like cold rolled banding steel). See the pic a few posts down at http://www.diyelectriccar.com/forums/showthread.php/thundersky-battery-strapsi-42784.html I would use something like 1/8" aluminum plates. Google "thundersky straps"

For the cell interconnects I would use copper sheet. Two half-width strips on the ends connecting the cells in parallel. Three full width ones doing the series/parallel connections in the middle. If what you are using works for you, great.

 

[CrazyJerry]

I charge my lifepo4's from the solar panels via an Outback charge controller. These controllers are a bit pricey but allow for some very nice user settings to include but not limited to: amps out, bulk charge, float, and there's a free tap where you could connect a sense wire to should a solenoid be needed. The sense wire can be tripped by several settable parameters.

Another added bonus is that the charge controller is nearly silent versus going through an inverter (with an internal fan) then to a fan cooled charger... Trace/Xantrex, etc, may also have a comparable controller.

~CrazyJerry

 

[yopappamon]

I've been using a cheapy eBay charge controller for sla that I modded the upper cut off voltage to be higher. It's been working well. I charge it daily with a 40 watt panel and at night run the living room table lights.


http://endless-sphere.com/forums/viewtopic.php?f=41&t=30198

 

[sapo]

With parallel cells if 1 goes low voltage due to some failure, it drags the others down too potentially damaging or destroying them.
That's the risk you take.