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battering wiring on horse trailer

Posted by chrissymustang (My Page) on
Fri, Sep 30, 11 at 14:01

I have a horse trailier with what I think is a 6 volt battery on the trailier to activiate the emergency electrial brakes. I just installed an electrical tongue jack wired to a 12 vdc riding lawn mower battery.

The 6v gel battery appears to be hot wired from the truck plug to provide a continuous trickle charge when hooked up.

How do I wire up the 12vdc battery to receive a trickle charge also?

thanks keith


Follow-Up Postings:

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RE: battering wiring on horse trailer

Go to an RV store or somewhere else and get a battery isolator.


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RE: battering wiring on horse trailer

oops, my bad, I have a 12volt 5amp battery for the brakes.

thanks, Ill look into that. can I use the same trickle charger for both?


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RE: battering wiring on horse trailer

The battery for the brakes is only for the breakaway switch. It is NOT used for regular braking.

I would keep the tractor battery for both functions and run the charge lead to it.


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RE: battering wiring on horse trailer

That's better. I wondered how a 6V battery was being charged from the truck charging system.


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RE: battering wiring on horse trailer

Should I run the power wire to an isolater, then split off two wires; one to a trickle charger connected to the brake back up and the other wire to the larger battery? do I need 2nd trickle charger for the larger battery down line from the isolater?


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RE: battering wiring on horse trailer

The trouble with charging batteries off of the truck charging system is that the battery chemistry of the batteries changes the float voltage. A gel cell battery should have a float voltage of about 13.4 V, AGM 13.5 and flooded-cell 13.8.

Your truck probably has a flooded-cell starting battery and the voltage regulation is tailored to that. Overcharging or chronically undercharging batteries will seriously shorten their life. In addition, the charge rate of gelled batteries needs to be externally controlled, not voltage-controlled. Do you really have a gel-cell battery? It will likely be damaged by the tow vehicle starter battery charging system.

Your use of the term "trickle charge" is confusing. Do you have a charger of some sort of these batteries or are they just hooked up to the tow vehicle's charging system? If the latter, this is not a trickle charge. (Do you have the right fuses in place? I hope so or you could easily make smoke and damage your property.)

One diode-type isolator for each battery or shared? One should work. Again, what kind of batteries? The diode in the isolator will drop the voltage about 0.3V, IIRC. If you are isolating AGM batteries, lucky you, that drops the voltage about the right amount for battery health. If you have flooded batteries, you will undercharge them. If gel, you will overcharge them. Check with the battery manufacturers.

The easiest thing for you to do would be one of two things, if you only do day trips, charge the batteries when you get home. This may not be legal or the brake battery, but I really have no idea about those regs. The other is to use two flooded batteries and hook them up to your charging system with suitable wires and fuses. You might want to use an isolation relay.

If you want to use sealed batteries, get two AGM batteries and use a diode-type battery isolator or build your own.


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