second battery

[JoseJL 10+ year member]

could i put yellow top battery in trunk to power system as opose to buying new alternator? i know everyone says get HO alternator but just was wondering is there any other way to do so like batterys in the trunk? stock alternator 65A

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[crhye250r 10+ year member]

Yes you could do that. A higher output alternator would be a good thing to get though..considering your stocker is only 65 amps.

 

[ngsm13 5,000+ posts]

well, if u put a battery in the trunk...it will need to be wired to the alternator. Otherwise, there will be no way for it to charge. ALSO, no, i wouldn't do it at all. ESPECIALLY when ur stock alternator is 65amps...all it is doing is adding ANOTHER sufficient load to it....making it work harder to charge both batteries and run ur cars electrical system. First thing i'd do...upgrade stock battery to Red top...that's what i did...they're made to take a beating. BUT now, i got a HO 200 amp alt...things are good...and yellow top is also on the way for me. peace

NG

 

[crhye250r 10+ year member]

I dont like to cause a problem. but when you install a second battery, it charges through the first battery. The two are wired together, and they become like one battery (to an extent).

The second battery doens't become an extra load on the alternator in the sense you are thinking. When the rear battery is discharged from playing the system, it takes charge (or energy if you will) from the front battery. Both batteries (theoretically) will try to have the same charge, as they work together. If you recall the law of conservation of energy, it states that energy cannot be created or destroyed. Therefore, the energy that is taken by the stereo is being pulled from both batteries equally (not instantly equal, but they equal out, or share the load).

So....actually it really isn't an another sufficient load. It really does help.

Also, a second dedicated battery isn't wired directly to the alternator. It is wired to the front battery (in the same fashion as you would an amplifier). THe pos. terminal of the front battery goes to the pos. term of the rear battery (fused in the front and rear of course).

Hope this has cleared things up for ya a little. Keep that in mind. I would still go for the battery in the back..I install them all the time at work..they always work properly..

 

[JoseJL 10+ year member]

how does battery recharge thought?

 

[HowLowd 10+ year member]

If done correctly you would be adding in an isolator to the setup this would keep the two batteries seperate. As crhye250r said the two will attempt to level the charge. This is where the problem comes in. If you drop the charge on the rear battery without it being completely isolated from the front it will in turn drop the charge at the front battery. In addition with only 65 amps from your alternator you ARE NOT going to properly be able to sustain the charge on both batteries for long.

My recommmendation would be in this order

1-Higher Output Alternator

2-Wired MBR 70 (IMO The best Isolator on the market-On ebay for about 50$ all the time)

3-Let me know when you want a yellow top, I get them for about 80$

That would gibe you all of the elementts of a dual battery system with ample charge to support both and not worry about the vehicle not being able to start due to low charge at the front battery.

 

[crhye250r 10+ year member]

I forgot about the isolator, LOL.. I generally use the stinger isolators..i may have to try that one.