alternator size

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123abc
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alternator size

Post by 123abc »

now all of my upgrades are complete my alternator is not quite keeping up, with everything on ac, lights , ac fan , fg thermo fan , amp it only puts out 12.3 -12.6 at idle . im running an 85 amp alt but have been told these older style alternators don't put much out at idle anyway so if anyone has a fix let me know.
it has a good large cca batteryin it , seems to charge ok on a long trip but around town not so good.
hybrid
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Re: alternator size

Post by hybrid »

Have you added up all the current of the devices?
lifeis4living
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Re: alternator size

Post by lifeis4living »

I shouted myself a clamp meter for my 50th from Jaycar and found it a great/safe way for working out total current draw.
nassi
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Re: alternator size

Post by nassi »

lifeis4living wrote:I shouted myself a clamp meter for my 50th from Jaycar and found it a great/safe way for working out total current draw.
Smart move, they are damn good.
123abc
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Re: alternator size

Post by 123abc »

how do I test current draw
Shaunp
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Re: alternator size

Post by Shaunp »

clamp meter
123abc
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Re: alternator size

Post by 123abc »

all good I just googled it I would have to be drawing quite a few amps when everything's on amp, lights, fan, ac, so my m/meter wouldn't measure it it i'm ordering a clamp meter now
so if the amp current draw is close to what my alt puts out do I just add a larger amp alt
Last edited by 123abc on Sat Apr 21, 2018 9:31 pm, edited 1 time in total.
lifeis4living
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Re: alternator size

Post by lifeis4living »

Make sure the clamp meter you order measures high current on the DC settings also. Some will only measure high on the AC settings. Mine will measure up to 400amps dc. Yell out if you need help deciding which is which.
123abc
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Re: alternator size

Post by 123abc »

yeah worked that one from you tube have ordered one that does up to 400 amp,
what is the Margie between draw and available amps
lifeis4living
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Re: alternator size

Post by lifeis4living »

I believe alternators have a voltage vs rpm spec at which they can deliver max current. But if anyone knows better please correct me. At idle with ignition, fans, fuel pump etc and lights I'm drawing roughly 40 amps, with a 65amp alternator. That's not including other run of the mill accessories. So I could be cutting it thin. It also depends on whether the alternator is rated at a certain spec with a plus or minus amp tolerance. So yeh open to other forum members wisdom on this topic.
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