Is it okay to hook up a deep cycle marine battery as the second battery in a Ford OEM setup?

 

Yes. You may want to check out www.wranglernw.com before you do though. They have a lot of neet, high quality, off road electrical stuff.

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98 F-150 XLT 4X4 ORP Super Cab Short Bed, 4.6, Auto. Magnacharger supercharger. Superchip, Gibson sing. cat-back, 80/100w German head lamps. Warn HS9500i winch with semi hidden mount. Wrangler dual battery kit with red & yellow top Optima batteries. Torsion bars cranked up 2 turns. Needs one more door.

 

98fword,

Thanks very much! fish

 

gofish, it totally depends on what you want that battery to do. Deep Cycle batteries are designed to provide a low amount of amps for an extended period of time and are more resistant to damage from discharging than are normal batteries. In boats, it's used as a "house" battery to power lights, radios, fridges, inverters, etc. A starting battery on the other hand is what's in our trucks and also in boats. They're designed to put out a lot of amps for a very short period of time.

A deep cycle battery can start an engine, but won't do it as well as a regular battery. In fact, you just might find it difficult to start an engine that needs a lot of amps to turn it, like a diesel.

What makes a battery a marine battery, besides the wing nut terminals and carrying handle is the basic construction. The plates are designed for rough service. A car battery in a boat can be destroyed in one outing. Most car batteries cannot standup to the pounding a boat battery needs to withstand.

Finally, the only deep cycle batteries that I know of that don't need water added frequently are gel batteries, but they are expensive and have very specific charging requirements. I think our trucks' charging system would destroy a gel bettery.

Check out the batteries from Optima. They're tough and can operate in any position since they're built under U.S. Military specs.

 

Thanks a bunch for the detailed advise, Dennis! I want to use the battery as a backup; I'm not sure if it's possible, but I had hoped to wire it in parallel (I think it's called) to enable me to run 6 165W Daylighters and a 30 Amp electric fan all at once in addition to a 'normal' nighttime load. From your advice, it looks like that's not possible even with a switch installed to take the battery out of service for startups, because I need a lot of amps continuously.

Thanks again. fish.

 

Actually, you *can* run two batteries in parallel so long as the batteries are the same and both are of equal capacity. They will work as one big battery when in parallel.

If you want to run the batteries separately, you'll need something called a "combiner." It's a set of relays that will disconnect the auxilliary battery from the charging circuit. This will keep you from discharging the main starting battery. As soon as you start up the truck and the charging voltage goes up, the relays kick in and will start recharging the battery. Once installed correctly, you'll be able to run your auxiliary lights until you kill the battery and you will still be able to start your engine because the starting battery will be untouched.

Stay away from the diode type of combiner. Diodes will decrease the voltage to the battery and will not allow you to charge the auxiliary batteries fully unless you can increase the output voltage of the alternator to compensate for the diodes.

You can get a combiner from some of the marine equipment supply stores. You can try West Marine. I know they have what you're looking for.

I'm sure you can find a deep cycle battery that will fit your needs. You just need to figure out how many amps you will be drawing and for how long. There are deep cycle batteries out there that can put out a tremendous amount of power for extended periods of time. The only problem is, they're big and expensive. Check out either marine or RV stores. They have the most experience with this type of battery.

I was just thinking. If you have the tow package, you already have an auxiliary charging circuit in the trailer plug outlet. I'm not 100% sure if it isolates the "trailer" battery from the rest of the truck. If it does, then all you need to do is tap into that circuit and you may not need the combiner. If there isn't any power to that circuit unless the truck is running, then you got your problem solved right there. With the engine running, there should be around 14 volts, I think.

 

Dennis,

Thanks again for your time and advice! I very much appreciate this. fish