Second battery with tow package

I have a 2017 Limited with factory tow package. I was looking into adding a second deep cycle battery for camping and was reading through all the threads on various charge balances, wiring setups, etc. and then stumbled across a thread that mentioned the stock 30 AMP trailer battery charging circuit (https://www.tacomaworld.com/threads/trailer-battery.342516/). Any reason I shouldn't just put a deep cycle battery in the bed and wire it into the existing Aux 12v charging circuit?

 

Do you want a battery in the bed? Doesn’t seem like a great place for it

 

As I only need it when on trips, the bed should be fine. I'm thinking of putting in something like this

$65 Newport Trolling Motor Smart Battery Box Power Center with USB and DC Ports

https://www.amazon.com/Newport-Vess...+Smart+Box+Battery+Case&qid=1596523929&sr=8-2 and then using the terminals to hook it up to a cable with 7-pin trailer plug I can plug into the rear 7 pin jack on the truck. Seems that if that plug really can supply up to 30 amps, it should be enough for keeping the battery topped off while I'm driving or recharging it the next day after using the deep cycle battery overnight.

 

I would use a dc-dc battery charger then feel free to connect it anywhere you want. It will keep your battery properly charged for long life.

 

Isn't that what the aux battery connection on the 7 pin connector is for? I'm trying not to reinvent the wheel and buy more parts + run wiring if the truck is already set up for this scenario.

 

Nope it'll give you power but not necessarily the best power for keeping the second battery in good condition. For the price of a good deep cycle auto battery, I run

$110 Tecmate Optimate DC-DC, TM-500, 6-Step 12V/12.8V 2A Sealed DC to DC Battery Saving Charger & maintainer

https://www.amazon.com/Tecmate-Opti...-LFP-Lithium/dp/B011J76CFE?ref_=fsclp_pl_dp_1 and smaller/cheaper golf cart batteries since I don't use them for starting.

 

If i could do it again, i'd get a secondary battery that is a deepcycle and keep it charged with some dc-dc charger that is configured for the AGM or whatever you have.


I did the offgrid engineering kit with 2x deep cycles. it's badass and great for my winch and gadgets... but it's too much weight in that one spot i'm afraid - although i have not had any issues YET. Also, the VFTuner bit was a shitstorm to get going, but i did end up getting 14.7 volts from the truck

 

I one time tried using the 7-way to charge a deep cycle battery in a trailer and it just trickle charged it. I ended up moving the battery into the tow vehicle with an isolator which it charged much, much faster.