What's needed to add a second battery to the engine bay ??

[scoot0073]

I'm wanting to add a second battery to the engine bay/charging system.
Now I'm assuming that I would have to use 31 group batteries both Main and secondary .
Then connect them together in parallel - to - and + to + to maintain a 12 volt system.
Now would the stock alternator be able to maintain a full charge on both batteries or would I need to upgrade the alternator to a higher output ??

Thanks for any advice

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[stamp11127]

Why are you wanting to add another battery?

 

[1955moose]

My question too, are you putting in a competition stereo? Or is it for running a lot of additional equipment? Your stock alternator is usually a 110 amp unit. You can purchase ones up to 300 amp. If memory serves, you'll need a battery isolator, like ones run on camper pickups. You want to run a full size regular battery for your charging/ starting needs. I think its group 65, if yours is the same as my 2000. For your battery that your going to run with motor off, that needs to be a deep cycle battery. Depending on what your running off it, your amperage will vary. But you can go from 550 amp up to monster ones that mount in the back of SUV. Isolator kits come with instructions, how to wire up. Our guys here can probably help with more details, but need to know your intentions.


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[scoot0073]

Main use is longer lasting for stock radio system and lights for when we are camping and night fishing and or any additional accessories that I might use so that I don't have to keep the truck running as often.
But I have pondered on going with deep cycle batteries for main and secondary.
I was thinking of adding the second battery to the engine bay but if I do end up putting it in the back then I'm covered as I still have my 0 gauge amp wiring + & - cable's which should be enough.
I been doing some googling and found some ideas . I would think that my stock alternator would be able to maintain 2 batteries but that's where I'm not that knowable..haha


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[1955moose]

You don't want to use a deep cycle battery for your main battery. It's not designed to be run in a starting/ charging situation. I've seen customers that try to run one in the main system, and it swells up the casing, and fails premature, usually within a year. I don't know if you just redirect stock stereo and accessories over to the backup battery. Second batteries are used for camper use as a rule, where wiring for those items like fridge, stove and lighting are wired separately. Deep cycle batteries are designed to run down low on charge, then recharge back to the 12.6 volts. Automotive lead/ acid batteries are not. That's why they don't last long with any high power add on's like amplifiers, or any high current items.


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[stamp11127]

Here is a thought, calculate the amount of amp draw you need + some overhead then size the new battery to that.

This is overkill but check the capacity @25amps (3rd col).
http://www.trojanbattery.com/pdf/datasheets/8DAGM_Trojan_Data_Sheets.pdf

If you go that route it would help to switch all lights over to LED'S to reduce the current draw.

 

[1955moose]

161 pounds, that thing is a brute! I've used the absorbed glass mat batteries on Harley's and other bikes with very good results. I had a friend that had his original battery 7 years later, unheard of on a Harley. That Trojan battery should give you reserve and then some. I don't believe your stock alternator would be enough amperage to keep up charging both batteries though. You'd probably have to step up to one of the 200 amp or bigger ones available. As Stamp said, see if you or someone can calculate the draw your putting on system. Do you have any large stereo amps in your system? Add all the amperage draws that you'll be using while partying with friends/ family, add a little bumper to that, and you can figure out size of Alternator/ battery combo you'll need for your SUV. One last thing, be sure you run as many power and grounds direct to battery or frame. We have had so many forum members with items that didn't work, they traced most down from shops tapping into existing circuits for power/ ground. You don't need that headache after your install.


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[ExplorerTom]

change all your lights to LED.

Install a volt meter on a momentary switch, like this:
https://powerwerx.com/panel-mount-digital-volt-meter-blue?gclid=COH6xKLS1tECFYQAaQodNW8IUQ
I know volts aren't everything for a starting battery, but for short periods like this it should be ok.

Change your current battery to an AGM.

To do a second battery you need some fairly specialized wiring and controllers. At least the way I've seen them done. And if your engine bay is anything like my first gen engine bay, there's no room for a second battery.

 

[scoot0073]

OK I watched several YouTube videos on adding a second battery and I'm pretty sure that I could use 31 group batteries with 1000 CCA for my needs.
The pricing on Deep cycle batteries and the fact it's not recommend to use as main battery like mentioned above..
Plus I'm very familiar with theses 31 group batteries as I run 96 volts in my Lowrider and plus I already got them...Hahaha
And I know that they work fine as a Main battery and they do good .
I just want to double my run time
I jus gotta order a wiring kit that allows me in able and dis able the second battery via a toggle switch in the cab.
But again I'm still watching YouTube videos to see all the different reasons that people are doing this..
And the stereo system is staying stock.
Just adding LED lights to exterior


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[1955moose]

If your intentions are just to listen to the stock stereo with friends/ family, a strong main battery, will do fine. I do the same thing with my SUV on a regular basis. I've pulled the fuse from my running board lights, useless to me. You could also run a toggle switch for your inside lights, door, overhead. I believe their on one fuse. Then you could leave doors open, without light bulb drain. Are your group 31 batteries deep cycle or start/ charging type. The plates on a deep cycle battery are spread apart farther than a starting type. Because of that fact, they don't give you the quick burst you need to operate starter efficiently. They were designed for running items at a slower discharge rate. A glass mat battery like Tom recommended holds up the best in a single battery setup, but are pricey. I always keep a charged heavy duty jumper box with me, and start my SUV about once an hour. You will have to decide how involved you want to go with this. Did you wire up your low rider yourself? This job might be very labor intensive, but if your doing it, it's your labor, not paying some shop.


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