D/c pump power

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Old 03-30-12, 01:33 PM
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D/c pump power

Hi guys,
I just bought a dc pump that is 12v and 1.8a. I am trying to figure out what battery type I need (I know 12 v) but does amperage matter? Would the pump run the same off a 12 v 7ah battery as it would of a 12 v 10ah battery?
 
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Old 03-30-12, 01:46 PM
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Would the pump run the same off a 12 v 7ah battery as it would of a 12 v 10ah battery?
Yes, it just won't run as long on a 7ah.

What is the pump used for?
 

Last edited by ray2047; 03-30-12 at 03:16 PM.
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Old 03-30-12, 02:58 PM
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The pump will be used for a DIY solar hot tub (It is a high temp pump). But I just wanted to make sure that the pump wouldn't need a specific type of battery (like if it didn't have a 10ah battery it wouldnt run at all)
 
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Old 03-30-12, 03:11 PM
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Ampere-hour ratings of batteries are made with a specific time frame, usually 20 hours but sometimes for some batteries it is 10 hours.

What this means is that a 7AH (10 hr. rate) battery will deliver approximately 700 milliamperes for ten hours. A similar battery but having a 20 hr. rate would produce about 350 milliamperes continuously for twenty hours. Trying to "pull" 1,800 milliamperes from the either battery will discharge it at a rate far in excess of what the battery was designed to deliver and at the very least cause it to go dead in a much shorter time frame than you might first assume. I doubt that you would get even 90 minutes usage at that fast a discharge rate.
 
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Old 03-30-12, 03:41 PM
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So does anybody know approximately a good ah rating for such a pump?
 
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Old 03-30-12, 06:55 PM
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Charge and pump

Hey everyone
I have a 12v 1.8 a pump. I bought a dPower battery charger that supplies 12v 1.8a. Could I use this as the pump's power supply?
 
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Old 03-30-12, 07:17 PM
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Probably not. The pump will require uninteruptable power and controlled amperage which the charger does not have. Check with Radio Shack or others for a regulated power supply
 
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Old 03-30-12, 08:48 PM
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Do you think a 18ah 12v would be best?
 
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Old 03-30-12, 10:32 PM
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Obviously it takes a 12 volt battery for the pump. If you want to run it on battery power then you probably want the largest ampere-hour capacity battery you can afford and have room for. Further, you really should use only a battery designed for deep cycle applications. Using a standard automobile battery which is designed for starting the car and then "floats" on the generator output will soon destroy the battery.
 
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Old 03-30-12, 10:38 PM
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I'm going to slightly disagree with Chandler. The battery charger MIGHT run the pump okay but since battery chargers rarely output "clean" direct current (more of a "choppy" direct current with a high alternating current component) the pump motor will likely have a much reduced life due to arcing between the brushes and the commutator.

Honestly, using a pump that has an AC motor is far preferable to trying to cobble up a battery or battery eliminator system.
 
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Old 03-31-12, 03:41 AM
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I don't think you disagreed. I think we may have had different pages in the hymnbook, but basically I like the idea of AC motors anyway, too. Battery chargers.....well....they charge batteries.
 
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Old 03-31-12, 03:44 AM
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In addition, this is a second post on this same subject. Look at the advice on both threads. Ray may combine the posts if necessary, since the subject matter is the same, not sure.

Mod Note: Posts have been merged
 

Last edited by ray2047; 03-31-12 at 08:17 AM.
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Old 03-31-12, 05:53 AM
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A Marine/RV deep cycle battery is probably your best bet, but you'll need a charger that can keep up with it.
 
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Old 03-31-12, 05:57 AM
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So a regular sealed lead acid battery wouldn't work as well?
 
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Old 03-31-12, 08:19 AM
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If you have electric for a charger why would you want to use a DC pump. A complete explanation of your project may be helpful in helping us help you.
 
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Old 03-31-12, 09:23 AM
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So a regular sealed lead acid battery wouldn't work as well?
Batteries are designed for specific applications. An SLA battery may be made for "float' operation such as for automatic emergency lighting or alarm panel back-up power where the battery is constantly connected to a charger and only has to supply power to the load when the AC power is absent. There are also installations where the batty is the sole source of power for extended periods of time, being connected to the charger ONLY wehen the battery needs to be recharged.

These different applications use different technologies in both the construction of the battery itself and in the method used to either keep the battery charged or to recharge it when necessary. Using the wrong battery in an application will lead to premature battery failure.

I'm going to assume that you want to use an existing DC powered pump simply because you have it already. That is really foolish non-logic. You will have the additional cost of a battery, charger and additional maintenance over just getting the correct pump.
 
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Old 04-26-12, 02:45 PM
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You can use a PC power supply for regulated 12vdc power. There are a few step-by-step instrux on the internet and it is fairly simple.
 
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