I know there's some wizard out there with this answer, but for me....I just need some knowledge. I'm thinking of putting in a 12in fan (portable) down below on my 23.5 (get's awful hot in texas). The fan draws 3amps....how long can I expect it to run off a 12 volt battery by itself?? I know there must be some formula for determining consumption on that battery, just need to know so I can figure if other things are set up also. Can someone help???
Battery Consumption Question
- Thread starter strobeone
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O2 Fan
Depends on the Amp Hour capacity of your battery, is it fully charged? 3 Amp for 8 hrs consumes (3 x 8)24 amps
Instead consider the O2 Fans (West Marine, Walmart). It has built in rechargable battery, and you put in 8 D cell batteries. It can operate and charge off of DC (cigarette adapter) or plug into an AC outlet to opearate or charge.
Depends on the Amp Hour capacity of your battery, is it fully charged? 3 Amp for 8 hrs consumes (3 x 8)24 amps
Instead consider the O2 Fans (West Marine, Walmart). It has built in rechargable battery, and you put in 8 D cell batteries. It can operate and charge off of DC (cigarette adapter) or plug into an AC outlet to opearate or charge.
a 3 amp fan draws 3 amps/hr
excluding inefficiencies and losses. How big is your battery?
amps/hr x hours = total amps
excluding inefficiencies and losses. How big is your battery?
amps/hr x hours = total amps
Assuming you have a "deep cycle" battery
look up the number of capacity amps it is rated for and divide by 2. Example, if is rated at 90 Amps you should only use 45 Amps or 50% discharge before recharging to maintain its average life. If your fan uses 3 amps theorically you may use it for 15 hours but in practice with temperature fluctuations and inneficiencies I would say 11 hours. A fully charged battery at rest will show 12.65 volts; at 12.2 Volts it is down to 50%. Get a digital voltmeter to monitor your estate of charge. If your battery only shows cranking amps and does not provide capacity figures it is a starting battery and should not be used as a house battery as it will not last long.
look up the number of capacity amps it is rated for and divide by 2. Example, if is rated at 90 Amps you should only use 45 Amps or 50% discharge before recharging to maintain its average life. If your fan uses 3 amps theorically you may use it for 15 hours but in practice with temperature fluctuations and inneficiencies I would say 11 hours. A fully charged battery at rest will show 12.65 volts; at 12.2 Volts it is down to 50%. Get a digital voltmeter to monitor your estate of charge. If your battery only shows cranking amps and does not provide capacity figures it is a starting battery and should not be used as a house battery as it will not last long.
Is that a 12VDC fan? From where? That size is of interest to us . . .
it gets pretty hot here in AL too.
it gets pretty hot here in AL too.
Fan Availability!!
Just go to www.westmarine.com and they have several fans available that are 12v. The o2 cools come in three sizes. The same fan is available at Lowe's, but only has battery/120 ac options for $15.50. The ones from westmarine have four options for power. Hope this helps. Chris
Just go to www.westmarine.com and they have several fans available that are 12v. The o2 cools come in three sizes. The same fan is available at Lowe's, but only has battery/120 ac options for $15.50. The ones from westmarine have four options for power. Hope this helps. Chris
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