Does anyone run an under hood dual battery setup? I think I have more than enough room under the hood to run another battery... I wouldn't have to use ridiculously heavy cables as it would be pretty close to the other, I wont be using speaker wire, haha --- but wont need like 0 gauge....

also, what is the best way to wire it in? Ideally, I want the system to just be there, maintenance free.... but with the ability that if I leave accessories on, with the engine not running, that it might kill 1 battery, but not touch the other one, so I can still start it... is this possible? or would I need to put a switch to toggle between the 2?

 

Several threads exist discussing this. Use the search function.

 

I actually did do a search, in the van forum here, and did not find anything. All I found was people that have done it, or were thinking about doing it on a van, that mounted the second battery inside the cabin. this is not what I want to do, I want it in the engine compartment

 

I have bought the parts but not installed them yet.

Automatic relay:
http://www.ebay.com/itm/Voltage-Sens...xT9-sX&vxp=mtr

Breaker:
http://www.ebay.com/itm/371169691845

You have to pick the breaker based on the size of your alternator. There is a chart on the bottom of the 1st page of the following document, it is for another brand isolator but should be the same for any brand.
http://www.allbatterysalesandservice..._Isolators.pdf

Regards, Steve

 

I don't know what the output of my alt is, how do I find out?

from looking @ parts websites, looks like it is a 90 or 120 amp


Also, interested in how to mount both under the hood..

I have never seen a dual setup that way.... that way looks really good, and no maintenance

 

I think you need to send your VIN to Dodge Customer Service to get the build list for your van. Mine is 120 Amp and has two V-belts, maybe that is a clue.

You may want to decide on what you want for a 2nd battery and then see if it will fit. If you get a non-conventional battery you could mount it sideways under the van. Mine has two large 6-volt batteries installed under the van...about 2 feet behind the drivers seat. There is a hole cut in the floor to permit access to them.

Steve

 

Is there a website where I can look it up myself?

Whenever I give my VIN to someone, they say it doesn't exist.... I tell them keep looking, and they say it is a cab/chassis

I don't have dual V -belts, just 1 serp belt

 

after years of using three different Dodge vans ('85, '94 and now '01) for boondocking camping and running lots of juice from my battery blasting music for hours at a time, I found that buying the biggest group 27 deep cycle battery that you can find and installing it in the stock bat tray will keep you going for quite a long time... I have used a $30 solar panel on occasion to help re-charge, and I always had a spare smaller charged starting battery in the back with jumper cables just in case I needed it... much easier then what you are proposing to do... cheap LED lighting is also now a great option, as I used to always disconnect the current sucking incandescent bulbs and use flashlights... I even carry around a $100 Harbor Freight generator and charger if I really get myself discharged... so I can charge my battery back up with a gallon of gas and about 8 hours of run time... never been stuck yet

 

I actually have carried a full size battery around, and it wasn't enough to start it up.... got close, but no dice....

I have owned one of those jump boxes, and it wasn't enough either....

 

If you run a battery dead enough to not accept a jump, then disconnect one of the battery cables from the dead battery... and jump to the released cable, taking the dead battery out of the circuit, and the additional charging load that it takes away from the starter motor.

Of course at that point your run-down battery may never again regain a full charge... especially if the dead battery measured less than 10.5 volts with no load on it. This battery may charge back up, if you use a specialty charger on it like this
http://www.northerntool.com/shop/too...3764_200483764
but it will never perform as a new one and will discharge much quicker next time you use it.

Those jump boxes work best on 4 cylinder cars... usually not enough capacity to get an 8 cylinder or even a large 6 cylinder turned over.

Do you own a voltmeter? You should always be using a deep cycle battery for long discharges and monitor the voltage on the battery to not get lower than about 50% of charge without harming the battery.

battery voltage and % of charge chart below
12.6+ 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
10.5 0%

Using battery power is all about voltage and load management.