Alternators max safe amp, with using HD elect fan M Series

Alternators max safe amp, with using HD elect fan M Series

Author
Discussion

SquashedCat

Original Poster:

125 posts

113 months

Saturday 8th June 2019
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Electrical experts, I have a situation which has arisen, my 20 amp electric cooling fax cuts out when I turn my headlights on and turns back on as soon as I turn the headlights off. At the moment I have Halogen lights, that draw 15 amps combined. Also HD electrical fuel pump, gauges, turn signals, surely, a 60 amp alternator should handle the electrical load? I am in the process of checking the ground side of the equation and trying to isolate any ground issues. I also, lost my water temp sender unit, gauge just stopped. What is the max safe size alternator in terms of amps that could be used safely on a M series car with mostly original wiring?

phillpot

17,279 posts

190 months

Sunday 9th June 2019
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SquashedCat said:
Electrical experts
I wouldn't call myself one of those but surely if you are running more electrical things than the alternator can cope with they will draw off the battery which will then discharge and as the voltage drops lights will go dim, fan motors will run slow etc?


250 hp from an old Essex V6 isn't too bad, what mods has it got?


Edited by phillpot on Sunday 9th June 08:05

plasticpig72

1,647 posts

156 months

Sunday 9th June 2019
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Do have relays fitted for the Fans , Fuel Pump and Headlamps. Sounds like they are from the same supply. I think also the earths need cleaning.
Alan

Moto

1,261 posts

260 months

Sunday 9th June 2019
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Definitely not an expert but sounds like fan & lights may be sharing a relay

Penelope Stopit

11,209 posts

116 months

Sunday 9th June 2019
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Is there a fan relay fitted........................................If there is..............................

A 12 volt relay will pull-in with an applied voltage of approximately 8 Volts

That same relay once pulled-in won't drop-out until the voltage falls to approximately 5 Volts or less

This means that if your cars battery is good, fully charged and the fan is switched in, when switching the headlights on the voltage won't drop to below 8 volts..........This means that the fan relay would still hold-in

I very much doubt there is a battery voltage problem, check the wiring

Should you ever wish to fit a high output alternator you would need to upgrade the positive cable to it

SquashedCat

Original Poster:

125 posts

113 months

Sunday 9th June 2019
quotequote all
Thank you gentlemen and lady, busy day, took your advice, and here is what happened, I replaced my H4 Halogen light bulbs, with a LED bulb replacement kit, which came with two relays, one for each light. I also, sprayed electrical lubricating oil on my battery posts and connectors, as well as on the main ground where the electric fan is grounded. The cooling fan now turns on even with the all the lights on, and seems to run fine. Water Temp gauge still not working. Not the sender. Voltage regulator, ground or the gauge itself. further testing to do. I have other electrical issues to sort out. I am replacing the turn signal switch(stalk will not park, either right turn signal on, or left, hard to get it to stop and park with no signal), as well as the windscreen wiper switch. Windscreen wiper switch is very dried out and has quite a bit of crumbled plastic falling off of it??? Also, installed the bonnet release cable and pull handle. Old one broke off. Replaced with a Land Rover Defender 67" bonnet release cable, disassembled the cup latches, well oiled and replaced with new cable.

Edited by SquashedCat on Sunday 9th June 23:38