Friday, June 29, 2012

Still No Trouble at t'Mill

131 daily cycles completed on my lithium battery bank.  No drama, no problem.  Not very interesting subject matter for a blog.

After tinkering with various settings of charging that only seemed to provoke one cell to want to wander off towards "higher ground", I reverted back to the original scheme of charging to 3.50V per cell (28.0V for the pack) but only for 30 minutes instead of up to 60 minutes.  All charging for longer seemed to achieve was to make one cell go high and cause the rest of the pack to drop (as the charger wound back the power).

Charging to the original Voltage and keeping the time short seems to be the best way.  It also has the side benefit that the water heater comes on sooner.

I'm now going into business making these things!

I'm working with a friend who runs Sustainables4U and we're packaging these storage systems for stationary (not moving from the coal shed) and mobile (on a trailer or in the back of a van) applications.

We've taken delivery of a batch of 200Ah Winston cells and will make a prototype portable generator.  Something you can use at a building site or at a festival or even an eco show in a field that will make mains electricity to use without the noise, smoke and smell of a petrol generator - the sort that are always burbling behind burger vans at car boot sales...

We'll have a sort of flight case on wheels that will hold either 4x 200Ah cells or 4x 400Ah cells to give 2kWh or 4kWh of usable energy storage and a 1kW or 3kW pure sine inverter respectively.

I've even invested in some PCB CAD software to turn out a proper version of the inverter interface board so it won't even be bodged together with stripboard and bits of old string.