Jeep Dual Battery Setup Questions

I am setting up a dual battery in my Jeep Wrangler. I would like to
use dual Optima batteries. I will use a Painless Wiring 250amp control
system which uses a relay/solenoid to manually isolate the batteries.
I'll stack the batteries using a MG or Kilby dual battery tray. I
would like to essentially just replace the stock battery with the new
red-top (so this will continue to power the stock fuse block and the
starter). The new yellow-top will run a second custom auxiliary fuse
block, which I plan to hook up all my accessories to, including a new
winch. This setup should keep the existing stock wiring completely
intact, I'll just be adding a second wiring system that is isolated.

Here are my questions I'm hoping somebody who has done this before can
answer:

1. Is mixing red-top and yellow-top a problem? Some people say you
must have "the exact same batteries" and some people seem to use a
red-top for starting (intermitent shallow use) and yellow-top for
auxiliary use (deep cycle). Has anyone run this setup and had
problems, or premature battery failure?

2. With the painless system, when the jeep is off the batteries are
isolated. When you are driving, you can flip the switch and charge
both batteries, right? Does the fact that your second battery has
less charge (presumably since you have been using it wearing it down)
than the primary battery cause problems? Because they are no longer
"exacltly the same" or might have different charging
rates/characteristics? I am a little foggy on how exactly the charging
takes place.

3. Does my setup sound right? Any problems with keeping the starter on
the primary? I have seen a similar setup, but he had the red/yellow's
reversed and the starter on the "secondary" battery
(http://www.webejeepin.com/Glenns_Jeep/electrical.htm)

Thanks
Lee

The new isolators that are offered have a load sense wire for the second
battery with the intent of mixing deep cell and regular 'starting'
batteries in a system like you suggest. This allows each battery to be
independently charged up properly.

I am not up on the painless system, it could be outdated....

Here is one link with a mess of different isolators:
http://www.hellroaring.com/rv.htm

I would keep the starter on the primary battery.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Lee wrote:
>
> I am setting up a dual battery in my Jeep Wrangler. I would like to
> use dual Optima batteries. I will use a Painless Wiring 250amp control
> system which uses a relay/solenoid to manually isolate the batteries.
> I'll stack the batteries using a MG or Kilby dual battery tray. I
> would like to essentially just replace the stock battery with the new
> red-top (so this will continue to power the stock fuse block and the
> starter). The new yellow-top will run a second custom auxiliary fuse
> block, which I plan to hook up all my accessories to, including a new
> winch. This setup should keep the existing stock wiring completely
> intact, I'll just be adding a second wiring system that is isolated.
>
> Here are my questions I'm hoping somebody who has done this before can
> answer:
>
> 1. Is mixing red-top and yellow-top a problem? Some people say you
> must have "the exact same batteries" and some people seem to use a
> red-top for starting (intermitent shallow use) and yellow-top for
> auxiliary use (deep cycle). Has anyone run this setup and had
> problems, or premature battery failure?
>
> 2. With the painless system, when the jeep is off the batteries are
> isolated. When you are driving, you can flip the switch and charge
> both batteries, right? Does the fact that your second battery has
> less charge (presumably since you have been using it wearing it down)
> than the primary battery cause problems? Because they are no longer
> "exacltly the same" or might have different charging
> rates/characteristics? I am a little foggy on how exactly the charging
> takes place.
>
> 3. Does my setup sound right? Any problems with keeping the starter on
> the primary? I have seen a similar setup, but he had the red/yellow's
> reversed and the starter on the "secondary" battery
> (http://www.webejeepin.com/Glenns_Jeep/electrical.htm)
>
> Thanks
> Lee

Hi Lee,

Mixing non-identical batteries is OK, if they are not discharged or
charged when connected in series or parallel or when you use a diode
isolator.

Kindest regards,

BiLL......

www.batteryfaq.org



On 11 May 2006 09:26:32 -0700, "Lee" > wrote:

>I am setting up a dual battery in my Jeep Wrangler. I would like to
>use dual Optima batteries. I will use a Painless Wiring 250amp control
>system which uses a relay/solenoid to manually isolate the batteries.
>I'll stack the batteries using a MG or Kilby dual battery tray. I
>would like to essentially just replace the stock battery with the new
>red-top (so this will continue to power the stock fuse block and the
>starter). The new yellow-top will run a second custom auxiliary fuse
>block, which I plan to hook up all my accessories to, including a new
>winch. This setup should keep the existing stock wiring completely
>intact, I'll just be adding a second wiring system that is isolated.
>
>Here are my questions I'm hoping somebody who has done this before can
>answer:
>
>1. Is mixing red-top and yellow-top a problem? Some people say you
>must have "the exact same batteries" and some people seem to use a
>red-top for starting (intermitent shallow use) and yellow-top for
>auxiliary use (deep cycle). Has anyone run this setup and had
>problems, or premature battery failure?
>
>2. With the painless system, when the jeep is off the batteries are
>isolated. When you are driving, you can flip the switch and charge
>both batteries, right? Does the fact that your second battery has
>less charge (presumably since you have been using it wearing it down)
>than the primary battery cause problems? Because they are no longer
>"exacltly the same" or might have different charging
>rates/characteristics? I am a little foggy on how exactly the charging
>takes place.
>
>3. Does my setup sound right? Any problems with keeping the starter on
>the primary? I have seen a similar setup, but he had the red/yellow's
>reversed and the starter on the "secondary" battery
>(http://www.webejeepin.com/Glenns_Jeep/electrical.htm)
>
>Thanks
>Lee

Instead of an isolator or manual relay, check out the combiner at
www.Yandina.com.
Combiners are used extensively in boats and motorhomes. They have
several advantages over isolators and can be used with mixed size and
types of batteries.

Doug