Alternator question

[Sinac]

I decided since winter is coming to clean the terminals on my batteries and load test them. To my surprise, the 4 1/2 year old Duralast Golds passed the load test with flying colors. While I was at it I thought why not see what my voltage is at while sitting at an idle. The voltage is 11.5-8 with the key on engine off. I start it up and for about 15 seconds it sits at 11.5-8 then jumps to 13.5-8. I've never tested this before and was curious if that was normal or not. The alternator is only, at most, 9 months old.

[Highbeam]

That's normal, it is your glow plugs drawing. They stay on after the WTS light goes off. I have a voltmeter in the cab and watch for the voltage jump to happen before I drive.

[Sinac]

Damn they put a hell of a draw on the batteries. I never noticed that before, thanks for teaching me!

[NCHornet]

GP's can draw 200 amps at full power!!! That's why the stock GPR never last very long and should be replaced with the Stancor relay!! It is built to handle a 200amp continous draw for 2 min. I have cut open several stock GPR's and everyone is toasted inside!!

NCH