Dual batteries

[Burns]

I want to run dual batteries, because, for starters, I run offroad lights, but also because when I use a power window if seems to dim my headlights a little. When other people set up dual batteries, do they run them inline, or just as 2 seperate batteries? And can a stock electrical system handle twice the power safely? And is there a way to squeeze 2 fullsize batteries in the space of a single one, or do I need to look for a dual battery kit? Thanks.

 

[Seabronc]

I want to run dual batteries, because, for starters, I run offroad lights, but also because when I use a power window if seems to dim my headlights a little.

Is the engine running when this happens?

When other people set up dual batteries, do they run them inline, or just as 2 seperate batteries?

The best setup for dual batteries is to have them separated with an isolation relay. In that configuration, you power the things that you want to run when the engine is not running from the isolated second battery and when it is running the two are connected in parallel for charging purposes. This makes sure you will not have a case where you run the battery down when the engine is off and don't have a way to start the engine.
If your not running stuff with the engine off, then you don't really need a second battery. What you need is a larger alternator that can handle the load. In normal operation, once the engine is running the alternator should be supplying the load. If it can't then you will be draining the battery. You shouldn't be compensating by adding a battery that only delays the problem, it doesn't solve it.

And can a stock electrical system handle twice the power safely?

The ability of the existing wire to handle loads is based on the demand on a circuit. Older vehicles were not wired for all the extras. In fact you can probably double the brightness of your head lights just by rewiring with heavier wire, most people do the headlight wiring upgrade to accomplish this. So can you add stuff? YES. Just make sure the wire it is connected to is large enough for the application.

For example your 100 watt lights require a little over 8 amps to run them. They should not be attached to the head light circuit or any other circuit. If you overload a circuit, one of two things will happen the wire will heat up and cause a fire or if you are fortunate, it will just blow a fuse. If you are on the edge of the wires tolerance and hooked up with some other stuff, you may see dimming, that means there is an excessive voltage drop caused by the amount of current being drawn. Solution: reduce the load on that circuit.

Note: Dimming can also be caused by poor grounding.

And is there a way to squeeze 2 fullsize batteries in the space of a single one, or do I need to look for a dual battery kit?

I have seen the second battery mounted on the wheel well just behind the first one. If I were to add a second battery, I'd put it in back with my other one. I am using the original battery location for my Under Hood Fuse Box (it replaces fused links and gives me a place to add circuits for powering my Head lights, Fan control, DRLs, Fog lights, MSD ignition, etc.

Thanks.

Hope that helps

This is how Ford hooks up the auxiliary battery

Good luck,

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[jrmyrgd]

run a larger alt. if you go with 2 batts. watch how you conect them! paralell or serize (sorry on spelling) I know that one way you will get 24 volts not 12 volts and blow out almost everything.

 

[Tennessee Jed]

Most definitely do not hook it in series! That is where you put the negative of one battery to the positive of the other battery and use the positive post of one battery and the negative of the other to hook up to the vehicle...DON'T DO IT!! (unless you are using 6 volt batteries) that will cook everything electronic on your car with 24 vdc.

You must hook them parallel + to + and - to - with an isolator either an automatic or manual switching device (aka isolator/combiner) as to not drain both batteries when the engine is not running and you are running equipment.

Hellroaring seems to have one of the best ones and they cost less than Painless and Wrangler for the all electronic models. If you go with a manual switch you have to remember to switch it or you might use all of the batteries up while running accessories with the engine off.

I myself do not have a dual set up on my Bronco. I drive and operate bucket trucks a lot for work and I use one that is older and it has both batteries just hooked up to one another one is a heavy duty and the other is a deep cycle. When it has went too low to turn over the engine it takes just about five minutes to refresh itself with everything powered off. To be fair though it runs much of its equipment off the PTO and the only time I have drained the batteries down too low to crank the engine was when something else was wrong as well (fuel delivery problems) like it stalling while I am raised and having to use the electric hydraulic pump to park the bucket then cranking the crap out of the engine. But I have noticed they recover fast just hooked up straight together. The newer trucks with isolator/combiner boxes have not failed me at all battery wise. So that says something...I think.

 

[Bulldog99]

have you tried just upgrading to a strong batter like Yellow top or Redtop which is specificly made for 4x4

 

[Blue beast]

First get the highest amperage you can fit and afford (cca1000 amp) should be good. Make sure all your positive connections are clean and protected by

dielectric grease. Double check and clean all the ground points in the truck(probably a 4 hour job) Go through remove the terminal ends sandpaper them till shiny and use a wire brush or dremel with a wire brush and clean the frame,body or motor where it attaches, coat it in dielectric grease and reinstall the terminals. I recommend getting the aerosol CRC dielectric grease it is easier to work with. If that doesn't help your power issue then running two batteries and a manual switch http://www.jamestowndistributors.com/userp...witch+-+Keylock Is the way to go you can split the load up use a regular cranking batt for the truck electronics(battery #1) Then for all the high drain devices use a marine deep cycle battery(battery#2) Hook your fog lights, stereo, amplifier, cb, Etc. to that battery. You can even run the headlights

to the #2 battery thru a relay set up and keep the high drain headlights isolated from the truck electrics. With the manual switch I linked too you can

choose to run the truck off of batt#1 1000cca or batt#2 deep cycle battery or you could use both to give yourself a jump start, Say it takes 700 amps

to start your truck and you ran both batteries down so neither one will provide the 700 itself you can switch to both and have the required amperage!!

And the cool thing with the switch is you have a off position that has a key to prevent theft and battery drain while not driving.( put a small 16agw wire

so your computer doesn't lose it's memory!!) I have that switch on my boat, my fathers boat and when he sells his boat I am taking the switch and putting it on my truck.

 

[Seabronc]

have you tried just upgrading to a strong batter like Yellow top or Redtop which is specificly made for 4x4

Red Tops are indeed a superior battery, but should not be substituted as a fix for an alternator that is under sized for the load requirements http://www.1st-optima-batteries.com/ . The alternator is supposed to be sized to handle all the loads when the engine is running. If it isn't you draw from the battery and if that happens long enough you can even run a Red Top down enough so the engine can't be started even when the engine is running. That is not to say a stronger battery is a bad idea, but not to supply a load the alternator can't handle.

Good luck,

>-

 

[Burns]

Red Tops are indeed a superior battery, but should not be substituted as a fix for an alternator that is under sized for the load requirements http://www.1st-optima-batteries.com/ . The alternator is supposed to be sized to handle all the loads when the engine is running. If it isn't you draw from the battery and if that happens long enough you can even run a Red Top down enough so the engine can't be started even when the engine is running. That is not to say a stronger battery is a bad idea, but not to supply a load the alternator can't handle.
Good luck,

>-

I've been trying to find a new alternator, one from JBG at 170 amps, but I'm not sure which of the 2 styles I need (stock plug or stock plug with offset mounting). The weak alternator might just be why my rear window is sloooooow and I need to do an up/down dance to get it up or down past the halfway mark.

 

[Blue beast]

You need to clean all the contacts in the rear window wiring. Radio shack has a pen that cleans contacts, leaves a protective coting and increases the

conductivity so it can flow more amperage!! They also make a pen that lays down a layer of gold to keep contacts corrosion free for a long time, I ran

out of the cleaner pen and when I get back I am going to get that gold pen too. It definately cleans contacts good and keeps them clean. Check all

your ground points from the battery all the way to the rear bumper. Adding a couple of ground straps would not hurt either, Try putting one from the frame to the tailgate it self. I would use 10 gauge wire and use existing holes or screws to connect the terminal ends to putting an extra ground to the

tailgate may stop some corrosion if you are having galvanic corrosion problems!! Clean the drain holes while you are working in the tailgate, I would

paint the inside of the gate with cold galvanizing paint or put a ZINC anode inside it to prevent further rust!!

 

[Seabronc]

I've been trying to find a new alternator, one from JBG at 170 amps, but I'm not sure which of the 2 styles I need (stock plug or stock plug with offset mounting). The weak alternator might just be why my rear window is sloooooow and I need to do an up/down dance to get it up or down past the halfway mark.

Is it always slow? I wouldn't expect the alternator to be the problem, but I would expect bad connections top cause that.

Bad grounds are definitely a problem in older vehicles. Note that the ground for the motor is back through the driver switch and attached to the firewall supports under the dash.

Also, if it is sticking 1/2 way, you may have some sort of bind in the mechanical part. Try a little WD40 on the side tracks and **** the motor gears and window regulator tracks. Try raising it and lowering it with the gate open, be careful with it up while the gate is open as the glass has no support. You don't have to go past the 1/2 way point to see if it operates differently in this condition. Ii is necessary to either cheat the safety switch or completely bypass it.

Here is the motor circuit in case you need a diagram.

Good luck,

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