On 9/27/2013 7:32 AM, Stormin Mormon wrote:
16 x 75 watts is 1200 watts. Since you mention four
batteries,I'm guessing you figure to set up four
lamp poles with four lights each.

If we got 90AH batteries they would actually be about 50AH at the
discharge rate we're doing. So that'd be about 600WH so we could do 300
watts (4 lamps) for two hours.

We'd run one cable for every two lamps, so 12.5 amps per cable.

Two lamps would be on each tower, and each battery would power two
towers. However we might decide to use smaller batteries and have one
per tower.

We need to be able bring them out to the practice field as well, which
is a long way from the band room, so we'd need to put them into one of
our golf carts (one battery powered one gasoline powered).

We'd like to avoid gasoline or diesel powered generators. Batteries we
can charge for "free."

The school district is too cheap to pay for permanent lights.

They can't practice in the daytime.

We also have the option of buying some generators and getting AC powered
lights. This may be a better option just because there is no need to
have someone maintaining all the batteries.