charging A 6V Battery

[Anonymous-0]

Is it safe (won't damage battery) to charge a 6 volt tractor battery with a 12 volt charger set at 2 amps? Battery is out of the tractor. I do not have a 6 volt charger and hate to buy one for just one battery.

Thanks,
Glenn

 

[Paul from MN]

You need a 6v battery charger. You can probably find one with low amperage for under $30. If you can wait, you can probably pick one up at a garage sale or auction.

 

[NEsota]

If it were me, I would put a 6 or 12 volt light bulb in series with the battery and hook the charger across the two. If one of the bulb terminals is connected to the battery and the other is connected to the charger, that is a series connection. If it is not putting enough current into the battery you will not hurt anything by increasing the output amps. The only power you will waste is that used by the bulb.

 

[Anonymous-0]

The modern 12 volt battery charger will refuse to charge the 6 volt battery. The vintage 12 volt charger will probably charge, but not as slow as two amps and you will have monitor the charge process by measuring the specific gravity or battery terminal voltage, the 12 volt charger won't taper off automatically.

Its far safer to find a charger with a 6 volt option. Both for you and the battery.

Gerald J.

 

[John T]

As an engineer and an attorney I gotta give you the obvious engineering correct n safe answer, i.e. use a 6 volt charger. That being said, I know this "dude" who has used 12 volt chargers (old style NOT electronic "smart chargers" that may not work at all) to charge 6 volt batteries for yearsssssssssssssss butttttttt the chargers were low amperage types (NOT big amp honkin starter type chargers) and he used them on the LOW charge settings with the battery caps off and in an outside (vented) location and didnt leave the charger connected for long periods n kept an eye out for excess outgassing or boiling over etc. AND USE CAUTION WHEN DISCONENCTING cuz you DO NOT want any sparks right at the battery top where the expolsive gasses are lurking.

Hows that for Disclaimers lol gotta love em

John T

 

[Walt Davies]

I charged my big 6 volt off my Case La a few time with my older 12 volt charge set at 2 amps with no trouble. But as they say its a lot safer to use a 6 volt charger. A lot of the Lawn tractors charge at 16 to 20 volts low amperage. I was really surprised to see that.
Walt

 

[Janicholson]

I know a man who puts a different belt on the generator of his Wc and drives it with a 1/2 horse electric motor. It works! JimN

 

[jubilee johnny]

I would do it right and just get a 6v charger. Why take the chance of something happening? While it is true 6v chargers are harder to find than they used to be, you can still find them, usually in combination with a 12v charger.

 

[Lanse]

Dont take chances with things that go boom. I have a like new charger that will do six volts at 10amps or 2, that I got from Harbor freight a few monts ago but I dont need it anymore,for $30 if you are interested, I could ship it. Call me, 937-570-9263. It also does 12v and crank starting although I never tried to start anything with it.

 

[GeorgeH]

There are some nice looking 6 and 6/12 volt chargers on E-bay.

 

[souNdguy]

Do the right thing and get a 6v battery charger.

Here's one from harbor freight:

2 amp slow charge
6 amp fast charge
Charges 12 volt batteries in 6 - 8 hrs.
6-1/2 ft. long battery leads
6-1/2 ft. long AC power cord
Equipped with ammeter and self-resetting circuit breaker
Auto shutoff in 12V mode
ITEM 45005-0VGA
$24.99

Here's another:

2 amp trickle charge rate for 12V batteries; 4 amp trickle charge rate for 6V batteries
Schumacher Electric# SC-200A
ITEM 95533-1VGA
$29.99

Alternately, if you have any leftover 'wallwart' style plug in transformers, see if you have one in somewhere in the 6v to 8v range.. AND DC.

If so, and you don't need it, clip the wire and add gator clips to it. Preferably 7.2v.. though a 6 or 6.5v one will at least get a battery up to par the longer you leave it. Since most of those are unregulated adapters, they will charge supply votlage above their ratings.. IE..a 6v adapter may kick out near 10v with no load.. IE.. once the battery charges up.. it should top of fin the 6.x range.. but will take time to trickle charge like that.

Soundguy

 

[coflyboy1]

I went to Wally world when I started going south for the winter and bought 4 of their battery 6/12 volt maintainer/chargers and put them on my vehicles. When I come back in the spring those batteries are like new. I think these smart chargers/maintainers extend the life of the batteries thereby paying for themselves. I don't remember what they cost but it wasn't much. Cheaper than a new battery.

 

[Lanse]

Thata less then I paid fer mine new!!!!! Will do $20

 

[bill mar]

if he had two 6 volts coulndt he charge both using the 12?

 

[HENRY E NC]

I just got a dandy little charger at Wal-Mart for 26$ that charges 6 or 12 volt at 2 -4 -6-amps. I hooked it up at 12 volts to a 6 volt and it said check for proper voltage and restart. How about them road appples. Stay with a 6 vlt charger abd be safe.

 

[KEB]

Lead-acid batteries need to charge to a constant voltage, not a constant current. A 12 volt charger will work for a partial charge as long as its current is low enough to avoid overheating the battery, but if you let it go too long even at a low current it'll exceed the rated battery voltage and boil the cells dry. Might be OK for a quick boost just to get something started, but don't depend on it to properly charge a 6 volt battery.

Putting a light bulb or other resistance in series with the battery will help limit the current and avoid overheating the 12 volt charger, but won't do anything to keep the charger from supplying an overvoltage when the battery gets close to full charge.

Buy a 6 volt charger. They're not that expensive. My grandfather had a charger he built by mounting an old 6 volt generator and an electric motor on a board and belting them together. Crude, but it worked.

Keith

 

[David, Surrey UK]

if he had two 6 volts coulndt he charge both using the 12?

Yes, in theory, if they're both identical batteries in the same state of charge. Which in practice they won't be. It wouldn't harm the charger but it might harm the batteries.

If one of the batteries is completely flat and the other is completely full (to take the worst case) then the full one will be overcharged while the flat one gradually charges up.

A lot of books will tell you that the two batteries will eventually equalise in charge if you leave them on float charge in series. But a colleague of mine did some experiments with lead-acid batteries (in the context of electric vehicles) and found that this balancing effect doesn't happen, even though it should. He had to devise some clever charge-transfer circuits to equalise the charges between batteries. He's a full professor of electrical engineering at a highly respected US university, so I trust his findings.

David

 

[Leroy]

I bought that Harbor freight charger a few months back for between 19-20$ when they opened the store and am using it about every 3-4 days and working good.

 

[souNdguy]

Some of their stuff is junk.. but their basic stuff is ok.

Soundguy