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how to charge a 12v 7ah battery?

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how to charge a 12v 7ah battery?

Old 02-21-2003, 03:16 AM
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dhauch
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Default how to charge a 12v 7ah battery?

Hi,
I have a 1amp motorcycle battery charger, that I was told to use to charge my starter battery with, which is a sealed lead acid,
12v, 7ah battery.
I long do I leave this charger on, Or how do I know when it's fully charged?
I was told this charger can be left on indefinitly, but wanted to check with the masses to see what you all had to say.
Thanks,
Old 02-21-2003, 05:32 AM
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sedunster
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Default how to charge a 12v 7ah battery?

I use a 1.5A for mine, but it has status LED's that let you know charging, holding or a problem.

A 7000mah battery will take 7 hours to charge from full dead with your 1A charger. (Capacity/charge rate) 1A = 1000ma.

If it's a float charger, no problem leaving it on indefinitely, but a lead acid battery holds a charge for a long time.
Old 02-21-2003, 06:02 AM
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thstone
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Default how to charge a 12v 7ah battery?

Can someone explain the difference between a "float" charger and a "regular" charger for us new guys? I tried a seach but didn't find an actual answer.

Thanks.

Tom
Old 02-21-2003, 08:09 AM
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rajul
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Default how to charge a 12v 7ah battery?

Tator, don't let your voltage go below 12.4V. Otherwise sulfation on the plates will occur. That will reduce the capacity and performance of your battery. I have seen some pulse chargers in the market that claim to be able to reverse the sulfation, but I have no idea if this is true.........
Old 02-22-2003, 03:27 AM
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dhauch
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Default how to charge a 12v 7ah battery?

I don't know if my charger is a "float style", is there a certain voltage that it reaches that I could check to tell me when its fully charged?
Thanks
Old 02-22-2003, 03:59 AM
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rajul
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Default how to charge a 12v 7ah battery?

Hi tator, a 100% charged SLA battery should have a voltage around 12.7 V, after any "surface charge" has been removed. Gel cell will probably be slightly higher in the 12.8-12.9V range. However your charger output voltage may be higher than this.
Old 02-22-2003, 04:39 AM
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flatfour
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Default how to charge a 12v 7ah battery?

A true lead acid float charger will hold the battery at 13.2 volts after the charge has completed.

I have a couple of Battery Tenders for my cycles, and use them on the flight box too.

http://batterytendervps.chainreactio.../technical.php
Old 02-22-2003, 05:56 AM
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Default how to charge a 12v 7ah battery?

A lead acid battery which also includes gel cell batteries is fully charged at 14.5 volts plus or minus .1 volt on most meters. A battery held at this voltage on charge for long periods of time build up heat, which is damaging to the battery, as well as evaporating the electrolyte, gel cells are sealed but with a vent that opens to let out the gases produced, also reducing the electrolyte and damaging the battery over time.
If you apply only 13.5 volts (which is not a full charge) the heat produced is much less and is dissipated without damage to the battery, thus you can leave it on this "float"
charge indefinitely without damage and only a small loss in charge capacity

There are chargers that will fully charge the battery to the full 14.5 volts then automatically switch to the float charge of 13.5 v. Then if you leave it a long time if the battery falls below 13.5 volts it will switch back to full charge until it reaches 14.5 v and the switches back. Thus you will get the benefit of having the battery fully charged most of the time you use it.
Old 02-22-2003, 01:44 PM
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Default how to charge a 12v 7ah battery?

The Battery Tender that flatfour has mentioned is an excellent addition to any battery maintenance equipment. The Battery Tender Jr. specifically is perfect for these smaller 12v batteries. If one looks on the internet they can be found for around $25, instead of the list price of $39 that the advertiser has in the model mags.

Vince
Old 02-22-2003, 01:50 PM
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dhauch
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Default how to charge a 12v 7ah battery?

Vince,
That sounds like just what I need.
Any chance you have any dealers web sites that I could look
for you, or a name.
Thanks alot
Old 02-22-2003, 03:40 PM
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Geistware
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Default how to charge a 12v 7ah battery?

While any charger that has a voltage over 13 volts will put energy into a gell cell, I think most people would agree that a costant voltage supply set at about 14.7 volts will fully charge a lead acid battery.
Old 02-22-2003, 04:16 PM
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flatfour
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Default how to charge a 12v 7ah battery?

Found the Tender Jr. for 19.95 at this place. Be sure to check their shipping charges and policies.

http://shop.store.yahoo.com/azmotors...tenjr12vb.html
Old 02-22-2003, 10:25 PM
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dhauch
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Default how to charge a 12v 7ah battery?

thanks for the web site on the Tender Jr.

The only "float style" charger I found today out shopping was a
1 1/2 amp. at Sears.
Will this work, or do I need a 1 amp.?
Thanks
Old 02-22-2003, 11:24 PM
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Vince
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Default how to charge a 12v 7ah battery?

$19.95, that is a steal, I just ordered two of them. Thanks for the web site address, that is as cheap as I have seen them.

Vince
Old 02-22-2003, 11:37 PM
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Default BT Jr. with banana plugs-->power panel

I just ordered a Battery Tender, too. Does anyone think I can/should cut the alligator clips off, and attach banana plugs so that I can use the Batt. Tender charger through my power panel?
Old 02-23-2003, 12:09 AM
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flatfour
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Default how to charge a 12v 7ah battery?

You don't have to cut off the clips. The tenders have a polarized inline plug. Go back to the link in my post above and look at the picture. You can see the plug in the upper right. You can probably get a plug at Radio Shack and make one with bananas.
Old 02-23-2003, 12:20 AM
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Default how to charge a 12v 7ah battery?

Originally posted by flatfour
You don't have to cut off the clips. The tenders have a polarized inline plug. Go back to the link in my post above and look at the picture. You can see the plug in the upper right. You can probably get a plug at Radio Shack and make one with bananas.
Sorry if I'm missing something here, but don't I have to cut off this plug to attach the bananas?
Old 02-23-2003, 12:41 AM
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Default how to charge a 12v 7ah battery?

Tator,

Thanks for the question.

Flatfour,

Thanks for the info on the Battery Tender.

Matt
Old 02-23-2003, 02:09 PM
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dhauch
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Default how to charge a 12v 7ah battery?

Is a 1 1/2 amp charger to much for this battery?
Thanks

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