Adding new battery

[danz24 10+ year member]

Im thinking of putting a deep cycle as a second battery. I read here a lot that people always recommended a 2nd battery, which I need as im gettting a 2000 watt system.

I cannot wire the batteries in parallel because one battery is older and different make than the other.

So to wire it I need a battery isolator. Is it true that these things are bad as it causes voltage loss?? Can you recommend what battery isolator I need so I dont have that voltage loss??

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[terra 5,000+ posts]

umm u can still wire them parallel...

 

[Heavy Hitta 10+ year member]

yeah wire them in parallel. im no expert, but i have three diffrent batteries all diffrent makes and such wired in parallel....no problem at all

 

[terra 5,000+ posts]

i have a non deep cycle stock up front, 2 deka deep cycles and a die hard deepcycle in back..all paralleled

 

[danz24 10+ year member]

Because i read that different battery types would have different voltage readings, and because of this voltage difference they somehow drain each other out? someone correct me??

 

[terra 5,000+ posts]

they will all have different recharge rates but not enough to cause any problem at all. as for having different voltages...i would think the alt would charge them to the same voltage..

ill be proof for you. my batteries DO NOT drain each other..

 

[94Mazda626 10+ year member]

No , they won't drain each other, if you put them in parallel they'll charge to the same voltage. The most that'll happen is if say when you turn your car off your original battery sits at 12V and your new sits at 12.5V that lower .5 volt will act like a load on your new battery just until it reaches a balance.

 

[danz24 10+ year member]

so thats it? Just wire the next batt in parallel?? no isolator??

 

[danz24 10+ year member]

and this is fine even if one is a starter battery and the other is a deep cycle??

 

[94Mazda626 10+ year member]

Can't see a problem with it

 

[danz24 10+ year member]

So just to be sure. To connect the 2nd battery its + to + (fused). And for the (-) I can ground in in the vehicle.

1. What size fuse do I use?

2. Is 4ga sufficent? (I have both batteries in my trunk)

3. Does it matter which battery I connect my amps?

Any thing else I should know about before I proceed??

 

[danz24 10+ year member]

ups

 

[terra 5,000+ posts]

So just to be sure. To connect the 2nd battery its + to + (fused). And for the (-) I can ground in in the vehicle.
1. What size fuse do I use?

2. Is 4ga sufficent? (I have both batteries in my trunk)

3. Does it matter which battery I connect my amps?

Any thing else I should know about before I proceed??

i use a 300a fuse..

4ga i guess...if u must.

3. no, id use the new battery for amp connections tho