Thread: Electric fans
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Old 07-15-2019, 09:00 AM
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cycleguy55 cycleguy55 is offline
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Quote:
Originally Posted by Gaz64 View Post
Why do some car manufacturers use 70 amp relays, because 30 or 40 amp relays don't have the metal cross sectional area for the high current terminals.

I would always rather over-engineer, than a have a fire.

https://www.ebay.com/itm/12V-4-Pin-7...-/153075476588

Gary
I took a different approach when my cooling fan relay quit. I installed a pair of 40 amp relays in parallel, protected by a circuit breaker. My thinking was the pair of relays will share the load and either of them can handle it, should the other fail.

How will I know if I have a failure of one or the other? As of right now I have no idea, though I could test them periodically by unplugging one at a time. Given their location that seems like a particularly masochistic approach. Regardless, my theory is a relay failure is highly unlikely if each is running at well under 50% load capacity, so hopefully I'll never have to deal with it. I know I won't if I end up installing the PROFORM controller mentioned in my comments a week ago.
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Last edited by cycleguy55; 07-15-2019 at 10:24 AM..
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