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Old 04-15-2009, 05:23 PM   #1 (permalink)
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,828

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 53.56 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 61.46 mpg (US)
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Solar panel EV charging (ForkenSwift): can anyone help set up a 555/relay circuit?

I want to put a solar panel on the ForkenSwift to trickle charge its 48v battery pack. The car often sits unused for days at a time, and when it is used, it's for short trips only. So using a panel isn't an outrageous idea in this case; it could measurably reduce grid energy consumption.

I don't want to modify the panel itself (12v nominal, 85w, rated for 21v peak, open circuit).

I also don't want to modify the pack (eg. to split it into four 12v pairs, wired in parallel for 12v charging).

Instead, what I was thinking was "rotating" output from the panel to pairs of 6v batteries using an automated relay circuit that switches sequentially through the 4 pairs of batteries every N minutes (where N is a small value, say 2, to minimize the chance of unbalancing the pack as light conditions change).

I've read a small amount about the "555" timer integrated circuit, and it seems (to my non-expert electronics mind) like it might be a suitable foundation for this idea, in combination with some standard 12v relays.

Any of you electronics wizzes willing to guide me in setting up such a circuit?

Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now in progress...
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has launched a forum for the efficient new Mitsubishi Mirage - fuel efficiency info for Geo Metro owners - electric car conversion on a beer budget
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