B. G. Micro (http://www.bgmicro.com) is a surplus electronics dealer that often
has great deals. I noticed that their current "sale" page has a Magnecraft
199DBX-3 power relay (contactor), item# REL1151, for $7.50 each. This contactor
has a SPST 40amp 150v DC contact with blowout magnet. If you check the data
sheet, it can also switch much higher DC voltages at lower current. These are
ideal for switching heaters, chargers, and other high voltage DC loads in EVs.
It has a 24vdc coil; but such coils usually pull in at half voltage, so it would
be OK on 12vdc while your DC/DC converter is running.
Or, I have a "Doubler" that converts 12vdc into 24vdc to drive such contactors.
See <http://www.sunrise-ev.com/LeesEVs.htm#doubler> for details.
The principal defect in a storage battery is its modesty. It does not
spark, creak, groan, nor slow down under overload. It does not rotate.
It works where it is, and will silently work up to the point of
destruction without making any audible or visible signs of distress.
-- Electrical Review, 1902
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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