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battery charging


wwc's Avatar
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12-12-09, 09:00 AM   #1  
battery charging

Is there a way to charge three batteries and use only one charger/maintainer ?

Would the first battery get more charge than the last one?

 
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12-12-09, 01:54 PM   #2  
The weakest battery will draw the most current. I use a battery tender type charger from Wally World - around $20. I keep two batteries up by switching from one to the other every week or two. You can get extra plug in connectors so it is just a matter of unplugging from one battery and plugging into the next.


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12-12-09, 02:27 PM   #3  
Supposedly putting them in series. It assures equal current and equal amp-hours of charge.

What batteries, how fast you want them charged?

 
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12-12-09, 02:46 PM   #4  
I would like to keep three deep cycle marine batteries charged at once without unhooking and hooking each week ( series )
A slow charge is all i need because i just want to maintain the batteries over winter.

 
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12-12-09, 02:50 PM   #5  
Posted By: wwc I would like to keep three deep cycle marine batteries charged at once without unhooking and hooking each week ( series )
A slow charge is all i need because i just want to maintain the batteries over winter.
Good.

You need about 14.4x3 = 43vdc.

Half wave rectified voltage from a 120v wall outlet gives you about 51 vdc.
For a 1 A trickle current you'd need a 3A, 400 PIV diode [try Hosfelt.com] and a common household toaster that measures about 12 ohms. Once you zero in on the current desired you can use a fixed resistor, 20w or so.

For safety you might want to use an isolation 'frmr. or you can get a 'frmr with a 1A secondary and about 60vac out and use a full wave bridge and dropping resistor. You can also combine 'frmrs to get a composite that works for this application.

You need a schematic?

 
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12-12-09, 07:51 PM   #6  
wow way over my head hesaidshesaid,

I have to use a toaster to charge my batterys?lol

Why can't i just use a charger/maintainer from wally world and connect the three batteries in series and connect the charger plus and minus on the two end batterys ,plus on one end battery and minus on the last battery .

 
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12-12-09, 08:02 PM   #7  
Posted By: wwc wow way over my head hesaidshesaid,

I have to use a toaster to charge my batterys?lol

Why can't i just use a charger/maintainer from wally world and connect the three batteries in series and connect the charger plus and minus on the two end batterys ,plus on one end battery and minus on the last battery .
If it puts out at least 40vdc. And there is a minimum trickle charge current you need, probably 4A or somewhat less.
http://www.batterystuff.com/battery-...FR9N5QodPiDd8Q

 
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12-12-09, 09:23 PM   #8  
Wired in series you would need a 36 volt charger (12v+12v+12v). In parallel you need 12v.


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12-13-09, 07:28 PM   #9  
SEM-1562A - 1.5 amp Battery Companion

this is the charger i have now, not sure how much power it has but it automatically switches to 6v or 12 v.

would this work? maybe in parallel ?

 
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12-15-09, 06:44 AM   #10  
The batteries will hold a charge for quite some time, so applying a trickle once a week by rotating your charger will keep them happy.

The charger has alligator clamps, making it easy to swap. To make it easier, you can connect all the negatives together and just swap the positive clamp.

I would never try to charge all three simultaneously-- in parallel or series. The weakest cell of the weakest battery will dictate the level of charge to the entire bank, which means the good cells will be overcharged. Overcharging can damage the batteries.

Keep them off a concrete floor (on a piece of wood). Believe it or not, concrete floors will damage them over the long term.

 
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12-15-09, 03:37 PM   #11  
ok then i guess to be on the safe side i should just have to charge one at a time and remember to rotate on time.

I thought that concrete floors didn't bother new batterys anymore unlike the older days.

 
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12-15-09, 05:41 PM   #12  
You could make a sequencer to switch each battery onto the charger, in turn. ~$20 in parts.

 
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12-16-09, 04:34 AM   #13  
Posted By: wwc I thought that concrete floors didn't bother new batterys anymore unlike the older days.
You may be right. I'm an old guy who hails from older days.

I'm not taking any chances with my bank of one-season-old boat batts, though.

 
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12-16-09, 05:27 PM   #14  
I don't blame you, this is my second set of batterys i have messed up for one reason or another.

I think I charged them too late or something because they won't hold a charge now.
gonna wait till next spring to buy new ones

 
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