Date: 3/02/2018 19:19:17
From: Tau.Neutrino
ID: 1183926
Subject: Electrical Question

I have battery 12 V at 12 AH

I have a 12 volt fan specs 36 watts, low 1.7 amps, med 2.3 amps, high, 3.0 amps

How long will the battery last?

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Date: 3/02/2018 19:23:15
From: dv
ID: 1183929
Subject: re: Electrical Question

Tau.Neutrino said:

I have battery 12 V at 12 AH

I have a 12 volt fan specs 36 watts, low 1.7 amps, med 2.3 amps, high, 3.0 amps

How long will the battery last?

Four hours?

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Date: 3/02/2018 19:24:47
From: dv
ID: 1183930
Subject: re: Electrical Question

dv said:


Tau.Neutrino said:

I have battery 12 V at 12 AH

I have a 12 volt fan specs 36 watts, low 1.7 amps, med 2.3 amps, high, 3.0 amps

How long will the battery last?

Four hours?

working:

12 AH * 12 V / 36 W = 4 hours

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Date: 3/02/2018 19:29:08
From: Michael V
ID: 1183934
Subject: re: Electrical Question

Tau.Neutrino said:

I have battery 12 V at 12 AH

I have a 12 volt fan specs 36 watts, low 1.7 amps, med 2.3 amps, high, 3.0 amps

How long will the battery last?

Theoretically :

low: 12 AH/1.7A = 12/1.7H = 7 hours

med: 12AH/3.2A = 12/2.3H = 5.2 hours

high: 12AH/3.0A = 12/3.0H = 4 hours.

See the pattern?

Unfortunately it might be difficult to get to all the stored electricity quickly enough to power your fan for all the theoretical time, so the actual figures might be somewhat less.

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Date: 3/02/2018 19:29:56
From: btm
ID: 1183936
Subject: re: Electrical Question

How old is the battery? Is it fully charged? How long since it was last used? What sort of battery is it? Has it ever been deep-cycled — indeed, is it designed for deep-cycling? What temperature do you intend to operate it at?

All these factors affect how long it’ss last; without knowing any of them, your question is too vague.

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Date: 3/02/2018 19:34:19
From: Michael V
ID: 1183939
Subject: re: Electrical Question

Michael V said:


Tau.Neutrino said:

I have battery 12 V at 12 AH

I have a 12 volt fan specs 36 watts, low 1.7 amps, med 2.3 amps, high, 3.0 amps

How long will the battery last?

Theoretically :

low: 12 AH/1.7A = 12/1.7H = 7 hours

med: 12AH/2.3A = 12/2.3H = 5.2 hours

high: 12AH/3.0A = 12/3.0H = 4 hours.

See the pattern?

Unfortunately it might be difficult to get to all the stored electricity quickly enough to power your fan for all the theoretical time, so the actual figures might be somewhat less.

med: fixed above (3.2——-> 2.3 now). I blame dyslexic typing.

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Date: 3/02/2018 20:10:29
From: transition
ID: 1183943
Subject: re: Electrical Question

always a bit of a lag in the chemistry (related terminal voltage also), so make 12AH 1A for 12 hours, that sort of thing be more like it, AND that only applies for a new battery. To consider what age does (recombination cycles/losses of recoverable lead or whatever, sulfation etc), imagine the battery shrinks over time.

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Date: 3/02/2018 20:31:53
From: Tau.Neutrino
ID: 1183946
Subject: re: Electrical Question

Thanks for those answers

I will add another battery

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