The Powerall

[Anonymous]

The mini-powerwall took me a little by surprise. It’s not really a whole house system, but it’s a lot of power. I’ve been looking at a LiFePo battery for powering an RV. I’m looking at the standard Ebay stuff, like the 48v and 20 AH. Basically, your price is pretty close to that, and it’s remarkably light weight. It’s almost ridiculous when I think of my two golf cart batteries. I have a 36v LifePo, and I’ve been testing it with a very low price DC-DC converter, basically designed for golf carts, 48 to 12 volts. It works and doesn’t get hot with 60 watt loads.

I’m a little confused by the assembly instructions. The 6 cell modules are basically a big parallel battery slab, right? There are multiple connections across the nickel strip. Anyway, every other slab is oriented up and down. Once a slab is connected, all the terminals on that side are connected. The multiple connections are to reduce the resistance? On one video there were 3 or 4 connections on top of each other. That seemed like a lot of work. I’m not sure how many connections you would have to make? It looks like a fairly simple, not confusing, soldering job. The one in the video, with the three cell modules, seemed to get tricky. In theory you could mask the ‘next’ row of cells and just expose the two being soldered.

I know that people are selling RV specific LiFePo packs, and they seem to run $1200 per kwh. So this is an intriguing price. It’s easy enough to find 48v inverters. There are some 48v solar regulators.

The flat pack seems very well thought out, if I understand the connections. I see a market for this type of pack. Not sure I want to buy one, since I have a 52 cell Shark pack with NCRB cells. It’s just clunky for a little trailer.

I hope you can get this idea rolling, beyond this campaign. Lots to like.

[Anonymous]

Thanks George. Yes, you’ve hit the nail on the head about those 6 cell modules. Each module is one big parallel ‘slab’ as you put it. You just line them up, each one alternatively facing up or down so that they will be in series when you connect them, then solder between the modules. Here are the instructions for that type of pack: http://www.diybatteries.com/2016/10/23/how-to-build-a-diy-powerwall-with-maker-batteries/

They’re easier to assemble than the triangular modules, especially for someone that has never built a battery before, because they’re just more straightforward. The triangular modules allow some interesting shapes to be made, but the straight modules keep everything nice and simple in terms of the soldering layout.

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