deep cycle battery help

[FrankA]

I was ready to purchase a battery(ies) for my TT when it was brought to my attention that I first had to be aware of how many amps my alternator puts out in my tow vehicle (07. 5 Dodge diesel). I found out it puts out 136 amps and to keep this in mind when replacing batteries to my TT's battery bank since they are being charged while in motion. The deep cycle batteries (AGM & flooded) I've been looking at have a maximum charge rate from 62-68 amps; far below what the alternator is putting forth in my vehicle. I was also told that this kind of configuration could destroy the battery bank because of the high output of the alternator in the truck. Looking for any guidance on this. thanks-

franka

 

[LandShark]

What size wire from the truck is used to charge the TT batteries. That will determine the max charge rate. Regular golf cart batteries will work just fine.

 

[B.G. Smith]

The alternator output is regulated by how much voltage it senses in the batteries. Even if the battery in TT was very low the system will see a combination of the two truck batteries and the TT battery and charge accordingly. The highest output from alternator would be immediately after srtarting the truck and that would be dampened by the truck batteries. You won't have to worry about destroying the TT battery. You might find that on short trips that the TT battery doesn't get fully charged. bg

 

[Newt]

Charging RV batteries from the tow vehicle is in almost every case too little rather than too much.

Newt

 

[Wingate]

Charging RV batteries from the tow vehicle is in almost every case too little rather than too much.



Newt

I would think so as well... In this day and age of computers/modules monitoring all outputs...

Is the auxillary batt+ circuit regulated by the TIPM? If so, I would think it would throttle the charge rate.

 

[Bill Stockard]

Charging RV batteries from the tow vehicle is in almost every case too little rather than too much.



Newt

Yep, the size of the battery charge wire going to the 7-way trailer connector at the rear of the truck is so small it will take a long time to effectively charge battery(ies) in the trailer.



Bill

 

[Shadrach]

Mount a 125w solar panel on the roof of the TT and that will charge them up. I have an 80 w and am going to add a 125 as well. I run dual 6v golf cart batteries and am also planning on changing that to 4 batteries when it's time to replace these ones. I agree with Newt and Bill about the rate of charge from the truck. Usually too little to do any good unless you are driving all day. Shad

 

[Road Dog]

Your alternator rating (136A) has nothing to do with the battery charge rate. The charge rate is based on the supply voltage and the battery voltage. The bigger the difference the higher the charge. Factor in the voltage drop from the wire run through the truck and trailer (and connectors) and the battery will charge at less than 5A. Or not change at all. A modern truck will charge the truck battery via a sensor (Dodge has a temperature sensor under one battery) and will reduce the system voltage to trickle charge the truck batteries. This means the trailer battery (with it's extra 30' of wire) won't charge at all.

 

[RCorbeil]

TT feed on an 05 2500 is only 20 amp from the factory, have had no problems in 6 years. Also use a 55 watt panel.



Ron

 

[Wingate]

I run dual 6v golf cart batteries and am also planning on changing that to 4 batteries when it's time to replace these ones. Shad

Without opening a complete can of worms. . is there something to be gained by running 6V batteries?. I assume you are running in series to generate the 12V. . So you are gaining the amp capacity of the two 6v batteries? What is the amp rating of a modern 6v battery? Is it worth having to add the second battery box to do the dual 6V setup??

 

[Shadrach]

Well that can be a big can of worms and there is lots to learn. I spent a lot of time reading and I am happy with my six volt set up. Do a search on here and you should come up with the answer. There are lots of articles on the web about batteries. Here are a few: The 12volt Side of Life (Part 1)

DEEP CYCLE BATTERY FREQUENTLY ASKED QUESTIONS

Deep Cycle Golf Cart Batteries For Power Storage



One thing to remember is if you run 2 sixes and for some strange reason 1 goes dead, you're toast. With 4 sixes this wouldn't be a problem. With 2 twelves you would still have "some" power. A lot depends on how much you rely on your batteries. If you have a genset or plug in most of the time no problem. But if you dry camp and like the peace and quiet then I believe lots of six volts and several solar panel are the way to go. Shad

 

[Buffalo]

Most everyone I know has switched over to the golf cart batteries. They seem to hold more power & also seem to last longer. I like them & wouldn't go back to the 12 volt deep cycle RV batteries.



Joe F.

 

[Wingate]

gotcha... . really not a concern for us then... we always camp where there is shore power. . If we dry camped, I would load up the generator. .

 

[WalterJ]

So, you're saying the 12V power lead in the trailer plug is actually part of the truck's charging circuit... or whatever its amp draw represents, the trucks charging circuit will only respond to its batteries if voltage is lowered?

 

[HBarlow]

What they were saying is the wire in the truck harness to the seven pin trailer connector is small and long so it creates a resistance to charging current.

It is impossible to overcharge trailer batteries from the truck in OEM configuration. Trailer batteries are more likely to remain undercharged if they depend on the truck alternator only for recharge.

 

[Hoefler]

And another thing, 136 amps is what the alternator is rated for full output, It takes tremendous amount of power to run the on board computers, A/C, engine ignition system, lights, radio, charge the truck batteries, preheater, etc. . After all that, there would not be 136 amps available to charge the trailer batteries. Besides,like said above, if you attempted to put 136 amps through the trailer plug with its 12 gauge wire, you would melt it down before you get very far.

 

[HBarlow]

And another thing, 136 amps is what the alternator is rated for full output, It takes tremendous amount of power to run the on board computers, A/C, engine ignition system, lights, radio, charge the truck batteries, preheater, etc. . After all that, there would not be 136 amps available to charge the trailer batteries. Besides,like said above, if you attempted to put 136 amps through the trailer plug with its 12 gauge wire, you would melt it down before you get very far.

Yup. That's a fact. Someone who didn't know crap told the original poster some nonsense. It happens all the time.

 

[EricBu12]

I have 4, 6-Volt Golf cart Batteries, a charge wizard, and 200 watts solar on the roof. . I am replacing the converter/charger in the trailer with a unit that is 65 amp and has a built in charge wizard on it... So whether I am plugged in at a park or just a small cord to keep the batteries up when home, have 2 charge wizards...

Got 5 years on the last set of 4 batteries. .

 

[RonD]

I was ready to purchase a battery(ies) for my TT when it was brought to my attention that I first had to be aware of how many amps my alternator puts out in my tow vehicle (07. 5 Dodge diesel). I found out it puts out 136 amps and to keep this in mind when replacing batteries to my TT's battery bank since they are being charged while in motion. The deep cycle batteries (AGM & flooded) I've been looking at have a maximum charge rate from 62-68 amps; far below what the alternator is putting forth in my vehicle. I was also told that this kind of configuration could destroy the battery bank because of the high output of the alternator in the truck. Looking for any guidance on this. thanks-

franka

The wire running from the Dodge to the Trailer will only carry about 20 amps at the most, don't even worry about that ever happening