Charging deep cycle question...


Founding Member
Jul 13, 2002

1... i have the 140amp alt in my stang
2... i am thinking about adding one to my f150 for the same reason ( stock is 70amp )
3... i do ALOT of mobile stuff for work and recreation, so i have 2 750watt & 1 400watt inverter in the truck
4... this is what i am curious about...

i can hook up a second battery seperate from the first, this one being a deep cycle like a marine battery... and when it is completely dead just charge it back from the alt when the truck is running, normally wiht a shallow cycle battery completely draining it would kill it, and tring to "charge" a battery that is completely dead would normally kill an alt.

the whole point is to let me do what i want w/o always having to have the truck running.
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Ideally, you will need to permanently install a battery charger into the truck that runs off of the charging system. Anytime the vehicle is running, your deep cycle will charge. It'll be up to you how elaborate this system will be. JCWhitney used to have some neat stuff for this kind of thing. Battery and electrical system isolators and power switch boxes that would automatically prevent deep cycle charging until the truck's main battery was fully charged. That also reduced the load on the alternator.

But to answer your question simply. Yes.. you SHOULD have a deep cycle charger installed that regulates power for charging.


Here's a link for a 3 battery isolator/charger: