Dadvan suggested starting a thread for this. I know in my 91 E-150 I have the isolator for duel batteries in my van,but only one battery. I also have a large audio system (4 amps,1600 watts) power windows,door locks,aux lights,TV, VCR(will be swaped for a DVD soon). So I really could use a duel,If not a triple battery set-up. I have also heard of people useing 2 altanators, Or am I better off with one of the 220 amper modles? Would like to hear from people who have set-up multiple battery/altanator set-ups.

 

Deep Sleep-
I have a diesel so it has a duel battery setup already. I haven't looked under the hood of a gas powered van in this body style, so I don't know how much space you have to work with.

Originally my van came equipted with two different sized batts, Normal 1000 CCA on drivers side and tall skinny one on pass side. I swapped those out for Optima red tops and the pass side one is a really tight fit. Pass side batt is mounted side ways.
If you don't have enough room there, check out the newer diesel vans. I believe they have a frame mounted battery box, might be able to find on in the wrecking yard.

You don't need an isolator unless you plan on listening to the tunes with the engine off (with the power you got It won't take long before you drain an isolated battery anways).

Bigger Alt or more batts?
I would go with more batteries.

 

Deep Sleep,

Thanks for starting the thread! What I want to do is install a "frame mounted" battery like Kaleo mentioned the new diesels have... Since I want to "do it right", I should probably start with the parts list, but I thought I'd seek feedback from those who've boldly gone where I haven't yet! I'll for sure install an isolator like RVs have as the express purpose for this setup is to power multiple amateur radios, laptop computers, lights, etc and still ensure I can start the van to avoid the tornado I'm chasing...

DadVan

 

Dadvan,
For you I think the "isolator'" idea would be better. I am a little skeptical about using some of those cheap isolators found a loacl auto parts stores. A few RV mechanics I know have told me to stay away from those. They say using a constant duty (normally open) seloniod is a better way to go.

You would have to parallel wire the batteries and put the seloniod on the feed for the second battery, then wire the "on" terminal of the seloniod to a keyed power source.

You could even add a push button switch from your second battery to the "on" terminal of the seloniod. That would allow you to energize the seloniod while cranking the starter. That enables you to jump start yourself if you ever need too, assuming the second battery has any power, of course.
BTW, that will only work if you use appropriate size battery cables between the two batteries.

 

I too want to add an auxillary battery. What about the trailer battery charge relay? I noticed the fuse #15 is in the block. I wonder if the harness is there. Maybe someone can tell me where to look for it

 

The battery isolator is only designed to isolate the two batteries from each other. this is to prevent one battery with a bad cell from draining the other battery. to use only one battery at a time you will need 2 CONTINUOS
DUTY soleniods with seperate remote switches.

 

All,

I guess I should consider the "dual battery kits" from someplace like (horrors!) JCWhitney?

DadVan

 

kaleo,
There's no place under the hood of this van for anything. Between the A/C, oil cooler, oversize radiator & air box I'm lucky to fit the stock battery. I would like to up the size of the stock batt and keep it where it is and mount 2 other batteries in a vented box in the interior of the van. This is where I get a little lost, I have asked for advice from the various shops but they always try to sell me there products. This is what I have come up with so far, Anyone with knowlage in this area feel free to give advice
220 Amp alt, 0 gage wire, manual knife switch between batts, 1 1000 cca batt under the hood, 2 RV(deep cycle) style batts in the van.
The manual knife switch was suggested becuse this van will see some trail duty this summer and I need to make sure it will start. The audio shop that I use has suggested a second amp dedecated just for the audio system as my amp gage does quite the dance with the system playing .

 

Just trying to make this less confusing, so please correct me if I am wrong on this.

1) An isolator will only isolate the two batteries when the key is switched OFF, and charge/drain BOTH when key is on, same idea as using the one soleniod. Which will will work for Dadvans application.

2) Useing 2 soleniods with remote switches will allow you to run each battery independently or together, by flipping the appropriate switch, BUT will only charge the that is switched on. Both switched ON= both charging, one ON= one charging, and none switched= none charging.

If the info above is 100% accurate, then method 1 would be a better option. It would be simple way to operate, pretty much automatic.

Method 2 would require you to flip the right switches for the desired operation. I can't think of a reason you would want to keep one or both batteries from charging.

 

Deep Sleep,
What do you mean by trail duty? For me that would mean mud, rocks and low range.

Depending on how often you had the tunes cranked up, you may not need such a big alternator. The extra capacity of mutliple batts will help compensate for alt ouput.

Go with Optimas or similar batts and you won't have a need for venting, plus they can be mounted in any position.

I have been told deep cyles are a little more tempermental when it comes to charging, they require a slower rate. Something you might check into if you decide to go with a big alt.

The knife switch is a good idea, but properly wiring a seloniod in place will disconnect the aux batts when key is OFF, but you must also rewire any thing you plan to use while key is off, to the aux batts. One problem you will encounter is, where to power the head unit from? If you leave it wired the way it is, you will need to leave key on which will drain the main batt. If you wire to the aux batt, you may forget to turn it off, since it will be hot all the time.

You have a '91 right? I have an '86 that I can peek under the hood to see if you might be able to get more batts in there.

 

had to change message

 

 

Do NOT charge two batteries in parallel without an isolator. One battery will charge and the other one won't. They will also discharge each other if they are not perfectly matched. Two matched batteries will only stay matched for a short time.

Your best bet is to use an isolator then use a constant duty solenoid to disconnect the main battery from the isolator when you are sitting waiting for storms (solenoid is ON in run).

The OEM's and RV manufacturers use a parallel wired dual battery setup because it is cheap and the batteries don't give them enuf trouble to "trigger the warranty" before it expires. -But it ain't right.

 

[QUOTE=Torque1st]Do NOT charge two batteries in parallel without an isolator. One battery will charge and the other one won't. They will also discharge each other if they are not perfectly matched. Two matched batteries will only stay matched for a short time.

I will have to disagree with you on part of that. Both batteries will charge without an isolator. RV's and OEM might do it because its cheap, but the big trucks do it too, and it works. KW, Pete, Freightliner, Etc use multiple batt setups( I have 4 on the KW) without an isolator on any batt. Some are more complicated with series-parallel switches, but still no isolator between each batt.

I DO agree with matching the batteries, If they are to be wired together without some sort of disconnect system. It is true that batts will not stay matched in any "isolator" setup, but there is no way around it, one batt will have a deeper dis/recharged cycle than the other.

 

All,

I'm really enjoying the thread *and* learning quite a bit about the subject...

I guess I need to:
First! Get the parts list (and the drawing if at all possible...) for Ford's dual battery inplementation so I can mount the second battery. I sure agree that there's no place to put another one in the engine compartment and I don't want it in the passenger compartment. Well, having said that, I guess it wouldn't be too bad if the battery was truly a sealed unit...
Second! Get some kind of "isolation device". It would seem that for my application one like the example from Camping World would make the best sense. I want simple, automatic operation.

Now, let's talk cable. That's a L-O-N-G run from the engine area to the location on the frame where I've seen 'em stashed. Should I build my own from "welding cable"?

DadVan