Battery drain....after a rewire/battery!

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Apr 18, 2008
pismo beach ,ca
Hello gents,
I have a 74..40 w/ a sbc. I recently just did a major overhaul, including powersteering, shackel reversal...etc. In the process I moved my battery under the drivers seat and had to move my alternator to the passenger side of the motor for the power steering. I purchased a small optima battery (think its for an import car) that according to the catalog had the proper amout of CC Amps to fire a sbc. The problem is since all of this is done the rig will not start after driving for awhile and espically if I turn the elec. fan on. Any thoughts/ suggestions?

FYI...I have to get this problem worked out this week due to the fact that I leave for moab next wed. Any help would be greatly appreciated.
It sounds like it is not charging. What is the voltage across the battery when the engine is running at 1000 RPM?
If it's not the alt., check the size cable (assuming you ran new cable) to the battery, and how/where you attached the battery ground. A small gauge battery cable will not pass much current when it gets warm/hot.
Also check connection at starter motor.

Jerry D.
(a) The further away you put the battery, the thicker/heavier gauge the wire has to be.
(b) Noticed you mentioned SBC, hope you did not wire the alternator wrong. GM has three different alternator wiring configurations, two of them will instantly burn out the alternator if wired wrong. PM me with your alternator specifics and I'll tell you how to check the wiring.
4 ga is a little puny for starting power, but it will be fine for charging. 12.5 V suggests that the alternator isn't putting out. Check the voltage at the alternator B+ 2 wire. If it is more like 15V, then you probably have a bad connection somewhere in the charging wire. If it is 12.5, the alternator isn't putting out the power.
Thanks for all the replies guys. I figured it out. After much debate....I rechecked my connections found some questionable connections. Retested my battery at idle it tested 15 volts. Still was having the starting problem. Figured out later that it was a starter solenoid on its way out. Thanks for all the help.
Monitor that voltage, if it does not come down to around 13.8 volts after the battery is charged, you need to address it. 15V is too high for long periods. You can boil the electrolyte at that voltage. The regulator may be fried...

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