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Box Builder
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Anyone done this? I would like to add a battery under the hood. I have a 2005 F350 V10. I already have an upgraded alternator. I've read that it can be done, but I'm looking for someone who might have done it and knows if anything needs to be moved or not. Also, is it necessary to have an isolation setup for the battery? Also, do the batteries have to be matched, or could I run a deep cycle battery as the 2nd one? Thanks, Nick.
 

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I've done it on two, one had an isolator, I wouldn't do it again without an isolator. Batteries don't have to be the same.
 

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I just saw an inverter today and am interested in setting something up but want to add a second battery also that is independent off the main battery. I want to put a microwave in the van, haha.
 

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My truck has two batteries, if I change one I change both pretty simple. If you wire them in parrallel and they are the same age and capacity it should be fine.
 

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Check the cable size that runs from the alternator to the starter. It should be at least 6 ga. SAE. It gets real ugly if that cable fails under full load. It is not unusual to fully load the alternator if you run down the battery using the investor during the engine off period.

You should use an isolator, keeps the main battery from being drained.

The isolator can be an electronic one or a continuous duty normal open solenoid. There should be a blank relay plug in your power distributin box under the hood. Use that space to install a closing relay for the soliniod. The diesels are factory equipped with 2 batteries, straight forward upgrade on your truck.

I change my batteries in pairs.

Tom
 

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Head Grunt
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If using an isolator then the two batteries can be different but if only wired in parallel then they must be the same CCA. Heavier the wire between them the better. Some people prefer to only ground the two at the body but i prefer to run grounds in between the batteries and body.

Do you need an isolator? Depends on what your using the 2nd battery for. If it is for a plow i would not bother. For a winch yes, long term hard draws will kill the batteries quickly and over come the alternator thus stalling the truck. Same would be for when using say a power inverter when the truck is off, you can drain the battery and still be able to start the truck. An isolator will remedy that. I never used a fuse on the power in between, i always preferred a breaker instead so it would automatically reset itself under load.
 

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If using an isolator then the two batteries can be different but if only wired in parallel then they must be the same CCA. Heavier the wire between them the better. Some people prefer to only ground the two at the body but i prefer to run grounds in between the batteries and body.

Do you need an isolator? Depends on what your using the 2nd battery for. If it is for a plow i would not bother. For a winch yes, long term hard draws will kill the batteries quickly and over come the alternator thus stalling the truck. Same would be for when using say a power inverter when the truck is off, you can drai oe battery and still be able to start the truck. An isolator will remedy that. I never used a fuse on the power in between, i always preferred a breaker instead so it would automatically reset itself under load.
Why would the two batteries need to have the same CCA if in parallel without an isolator? I know mine didn't.
 

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Head Grunt
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Most battery chemistries allow serial and parallel configuration. It is important to use the same battery type with equal capacity throughout and never mix different makes and sizes. A weaker cell causes an imbalance. This is especially critical in a serial configuration and a battery is only as strong as the weakest link. Even in parallel the load will only pull at the lowest amp rating. Say one battery is 1000cca and the second is 700cca, the load drawn off the batteries will only reach the 700cca. The load will still pull off the 1000cca battery but only at a rate of 700cca so you would not be getting the full potential of the battery.
 

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Most battery chemistries allow serial and parallel configuration. It is important to use the same battery type with equal capacity throughout and never mix different makes and sizes. A weaker cell causes an imbalance. This is especially critical in a serial configuration and a battery is only as strong as the weakest link. Even in parallel the load will only pull at the lowest amp rating. Say one battery is 1000cca and the second is 700cca, the load drawn off the batteries will only reach the 700cca. The load will still pull off the 1000cca battery but only at a rate of 700cca so you would not be getting the full potential of the battery.
I really don't see how that is possible.
 

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I own stock in FotoMat!
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I have a lawn-mower sized second battery in my van, for the purpose of running a 2000/4000w inverter. Both batteries are run through an isolator so neither one is affected by the other.
 
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