Will DC to DC charger charge 2 diffrnt amp Aux batteries?

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brettavey
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Will DC to DC charger charge 2 diffrnt amp Aux batteries?

Unread post by brettavey » October 5th, 2015, 8:20 am

Hi, I have a dc to dc charger and 2 deep cycle batteries. One is a 200amp and the other is a 100amp. The larger keeps my fridge cold and the other does the freezer. Because these batteries are not the same ampage but same type can I run them parrelel or can I just run another output to 100 amp from charger? If so will this mean instead of putting out 14 volts will it only put out 7 for each?

Comrad
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Re: Will DC to DC charger charge 2 diffrnt amp Aux batteries

Unread post by Comrad » October 5th, 2015, 9:27 am

You probably need to give a few more details before we can answer with total confidence.

Firstly, if you’ve got two deep cycle batteries, the 100 and 200 figures you’re quoting aren’t amperage, as such, its amp hours. It’s merely a level of the capacity or size of the battery. Not how much current you could put out, which would be the CCA/MCA rating you would see on cranking and all-round batteries. So, you’ve really got nothing to worry about in terms of linking them. If you connect them in parallel, you’d be charging both via your DC-DC charger and essentially you’d just have one large battery (A battery by definition is simply a collection of electrochemical cells configured in series or parallel)

The only thing to consider now is that in effect you’d no longer have one battery powering your fridge, and one powering your freezer, you have a single parallel configuration acting as a node. Therefore, you’d want to put in some manual isolators if you wanted to disconnect a load.

If you wanted some automatic load regulation, and would give preferential power to one battery (I.e, if the voltage starts dropping, make sure the freezer battery still gets charge, but the fridge is less important, etc…) you’d have to have something like VSR in place where the DC-DC charger would charge your more important battery (probably your 200AH one?) and then you would use a VSR to connect that battery to your other deep cycle battery. I feel like maybe I’m making it sound more complicated that it really is, but, it’s quite straight forward. If you want more information about this, I can provide a diagram.

I hope this helps.

brettavey
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Joined: December 26th, 2007, 4:26 pm
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Re: Will DC to DC charger charge 2 diffrnt amp Aux batteries

Unread post by brettavey » October 5th, 2015, 9:38 am

Thank you for the information it will help greatly.

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