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Amp(current) check on charging system

S

schnidly

Member
Hi Forum, I have a clamp-on amp meter. Where is the best spot to check current(amp) on my unregulated charging system? My motor is a 1988 Mercury 90hp 3 cylinder, 0B302485. I only have a rectifier, stator and battery for my charging system. It is a 9 amp system on my outboard. Should I check it on the positive battery cable close to the battery with the motor running or should I check it directly off of the red wire coming off of the rectifier to the battery?
 
if you measure off the big wire coming off the battery you are going to read the current drawn by the complete 12 volt system...once the engine is started and the starter is disengaged the that current is theoretically zero but you will have some leakage...you will also have some low current to gauges etc....so the little red wire coming off the terminal strip is where you want to measure it...that wire is a ''stub'' so to speak and is not in series with the main 12 feed..

this to me is an inconclusive and unnecessary exercise in trouble shooting a simple system like you have...it is inconclusive for two reasons...you are charging off peaks as i think i explained in another string of yours...and a clamp on amp meter will not measure low currents accurately...you need an inline meter placed in series between the regulator and the battery to even get started with accurate readings...the condition of the battery and rpms also play a big part in the process...ir is unnecessary because 99% of the trouble shooting of this system can be done in 15 minutes with a voltmeter..

i dont mean to be critical of you...we all have gotten into theory and spent time out there...its all part of the learning process...plus i dont know what you are trying to accomplish ..so good luck with the project...
 
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