killed my battery to the point of non-start for the 4th time in 6 months. Twice leaving the radiator fan on and twice listening to the FM radio. And I'm about to be adding a 60 watt HAM radio, which won't be helping the electrical system any.

I'm looking into adding a secondary battery under the bed, in the right front corner outboard the frame rail, opposite the gas tank filler neck. I figure I can drill the frame there if holes don't already exist, and mount a marine box directly to the frame rail. Then ground it to the frame rail, and run a #0 (0/1) wire between the two battery positive posts. Add a high amp cutoff switch ($15 at local race shop), and when I kill the start battery, I can just turn on the secondary battery and start off of it.

I can't see the charging system being effected any, so it should be doable, right?

I forget what alternator I have now, but it still works, no sense in changing it.

I have a duralast gold battery, forget what size. 78?

 

Wouldn't just keeping a portable battery booster be easier?

How do you leave the rad fan on? Do you have a custom set up or something?

 

This is accomplished all the time in boating; high cranking to start the boat, then switch to a deep cycle. With boating, you must use the proper switch when changing between the two or you'll do a lot of bad things to the electronics. I assume the same will be true with an auto since the engines are the same except for explosive environment on boats.

This is typical. There are many threads to research @ boatus.com for more information.

Good luck!

 

but that''s to switch between them, right? I would always have the starting battery connected, then have the 300A cutoff switch for connecting the second battery in parallel for emergency starting.

Portable boosters require being plugged in and charged. This way, I can turn it on every now and then just to charge it.

Also, my truck is set up for racing, so I have alot of extra switches and wires and relays that most trucks won't have.

 

You might consider a battery isolator. It's not much more involved than installing the switch but you won't have to do a thing to it to keep the battery charged or your main battery from discharging.

Check this one out:http://www.powerstream.com/battery-isolator.htm

 

We put a Charge Guard on the police cars at work to keep the batteries from getting run down by the radios, lights, etc. It will shut off the accessories after a pre-set (adjustable) period of time, or when battery voltage drops below a certain level.

 

Well this will work for a little bit. In the diesel world where we have 2 batterys. When you add a brand new one to an existing old one the old one will suck the juice out of the new one. Also when you have a complete dead batt its bad to use the alt to charge it back up. Its hard on it on the system. It would be easier to change the fan to a ign power on wire.

 

I gotcha. I assumed you would be switching between the two. Golden.

 

You can always Walter White that thing. Sorry don't know if you watched Breaking Bad. Great show.

On a serious note I see what you're going for now.

So essentially you want to connect the two batterys separated by a switch so you can periodically use the second and charge it when need be?

 

That price....no. $73 aint bad but ain't cheap either [granted neither is this project]

That price!

The second battery would be disconnected most of the time. On maybe once a month for a short drive to keep it topped off, and on when the starting battery is dead (so the engine can run off the spare battery while charging both and going into an off-balance-but-charging state)

right.

A basic battery disconnect switch is $30.