In article ,
The Natural Philosopher wrote:
Anyone know what the efficiency is likely to be of going
mains--battery charger--battery--inverter--mains?


mm..probably around 90% each way. Say 81%

I'd be amazed if it was anything like that high. Charging Ni-Cads at a
1/10th capacity constant current takes 14 hours. More difficult to work
out with a lead acid as the charge current varies with state but my
reasonably new 8 amp (says 11) charger won't *fully* charge a 75 amp/hour
battery overnight - takes about a day. A good inverter is about 90% though.
I'd guess at more like 60%.


In other words, how many kWhs need to go into the charger to get 1kWh
out of the inverter?

As long as the overall efficiency is better than about 50%, you
*could* be better off by buying all your electricity at the off-peak
rate and storing it in batteries - but you'd have a hell of a capital
investment (and probably maintenance/replacement costs) to contend
with.

Well I reckoned about 5 grand..batteries SHOULD do what? 10 years? Hmm.
Not as attractive as I thought ;-)

Caravan types would know how long a leisure type battery lasts - I doubt
it averages at 10 years.

--
*Dancing is a perpendicular expression of a horizontal desire *

Dave Plowman London SW
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