I have been getting several questions as to why I do not have two batteries. Am I the only 1st gen CTD to only have one battery? Did it come out of the factory with two?

 

I know its been discussed before on here. I went with a 1200 CCA Deka. I like it a lot, and so does the CB that I alwasy for get to turn off. CHeap, like $70

 

Just get the biggest Group 31 battery available. www.dekabatteries.com for nearest distributor. Not gonna find any other 1260cca group 31 for under $100 as you will in this Deka battery.

 

I just bolted a 3/16 plate to the battery tray and bought a second battery and made a longer holdown, now I have 2 batteries.

 

I have one big yellow Walmart *gasp* battery. It was the biggest oine they had and only cost like 60 bucks. It has a three year warranty, and you can take it to any walmart if theres a problems, and theyll pretty much give you a new one, no ? asked. My trucks spins over no problem, even when cold, and has no problem starting if its cold. If i plug in for 2 hours, its like its 70 degrees out. My battery runs my starter, my older style western plow pump, and a yellow rotator light on my rooof, and has no problem doing it. I find one battery to be more than sufficient.

 

To answer the original question, first gen trucks left the factory with one battery. If you see a first gen with two batteries, the owner has added the extra battery on his/her own. In almost all cases, one group 31 is all you'll ever need.

 

Not to hijack but I acquired another bus battery and would like to install it. any ideas on how to wire the two up. I plan on putting them sideways in the original spot.

Thanks,
Michael

 

How about in paralell?

Bus batteries I'm familiar with have a threaded stud instead of a lead post, if that's the case go to a welding supply distributor and have them make you up a couple of short cables.

 

Unfortunately, you can't connect two batteries in parallel and expect them each to be correctly charged. The alternator doesn't know the difference.
To do so, you'll need a battery isolator. I'm not sure exactly how they work, but they make it so that, if one battery is low on charge, that battery exclusively will be charged without cooking the other.

As an example ~ http://www.e-marine-inc.com/products...isolators.html

 

WRONG!

Almost EVERY peice of heavy equipment I work has 2 or sometimes 4 batteries wired in parallel and not one of them uses an isolator.

My personal truck has two grp 31s wired in parallel. Postive post to postive, negative to negative.

You are correct that the alt doesn't know the difference between the two. It doesn't care as it sees them as one big battery.

 

Understood. But that's based on the assumption all batteries involved are the same.

And I confess, I failed to consider the installations such as you mention. I've done a bunch of car stereo crap and was in auto-pilot mode when I posted. Separate batts for separate, independent loads.




~ easy with the shouting friend.

 

isolators are used in motor homes where one battery is needed to restart the engine when it's time to go home, and the other is used to run 12v accessories. the engine's alternator recharges both batteries, but the various accessories only have access to one. not the same situation as a pickup truck with dual batteries that are both needed to restart the engine.

 

Thanks! what is one group 31? I thought battery power was rated solely in cold cranking amps?

 

The "group number" is how they classify a battery according to physical dimensions and post configuration. There can be several different cold cranking amp values offered under the same group number. Theoretically they will all fit (physically) the same vehicle.

 

If both of the batteries are identical including in age they can be connected in parallel with no problem but even if one is a few years older than the mate then you could run into problems including exploding the weak battery.
My Chevy 6.2 had factory dual batteries; they were connected together at the side post with a lead slug. 2 times I lost a weak battery that were actually the same age. I smelled hydrogen gas and I checked the battery and it looked like a balloon all puffed up and off gassing. The 6.2 had to have 2 batteries or it won't crank because of the 22.5:1 compression ratio. Also one time I melted the lead slug between the terminals and the way the truck is wired, it was now putting out 24 volts and the lights got really bright.
Transit busses had either 4-6 volt batteries wired in series/parallel or 2 to 4 12 volt 8-D batteries wired in series/parallel depending on if it had a Cummins or Detroit power because the Cummins were 24 volt start although the chassis was 12 volt so they use a BIG solenoid called a "series parallel switch"
Also on the subject of how to connect them, I use a Separator/Interconnect for an automated control
http://www.surepower.com/separator.html
But if you use a regular Isolator what most do not know is that because they are just big diodes to block the current, unless you have a strong charging system,
http://www.surepower.com/isolator.html
you will never charge your batteries to their fullest because the diode has an inherent 1.2 volt drop across it. Meaning if your alternator is putting out 13.8 volts into the isolator, you will only get 12.6 volts to the battery. Then of course you are trying to charge 2 batteries, so you get the picture. The only fix is to bump up the regulator to around 14.0 volts.
Or you can get a Schottky Diode Isolator {black looking unit} that has NO voltage drop but is a lot more money.
These are what they use in ambulances and emergency vehicles.

Now you are all confused..
Jim


{reprint}
How I connected mine…
I welded a bracket and installed my second battery on the right fender just in front of the blower motor. In the front I am running 2 group 31 Interstate Workaholics, they are connected to the alternator through a Sure Power Separator/Interconnect http://www.surepower.com/separator.html
with an optional 100 amp solenoid in parallel to handle the possible loads. Both of the new ground cables are made from #2 welding cable directly to the engine block and a tap grounding to the body, the main battery is connected to the starter as it was in stock form but the #2 or auxiliary battery is connected through the separator and relay and terminates at a big insulated stud before it connects to the main battery's positive terminal.
#1 = main battery.
#2 = front auxiliary battery.
#3 = rear 8-D deep cycle battery.
If you check in my gallery you see I dumped the little stock 120 amp ND alternator and replaced it with a Leece Neville 555 alternator, I now can produce 85 amps at an idle to charge all of my batteries.
In addition to the 2 batteries under the hood, I have a group 8-D deep cycle battery in the back behind the left wheel well under the camper shell. There is a single #00 welding cable from the negative to the chassis ground and the positive terminal along the frame rail to the front where it connects to another Sure Power separator and relay and finally terminates at the same insulated stud where all batteries share a common connection on the 12-volt rail. The separators have a smart charge so they will not conduct until the main battery reaches a certain voltage so there is always a few second delay before the auxiliary batteries get power. I had burned out about 6 stock alternators before I cured the problem and went to the 555.
The separators have a parallel switch so you can press 2 buttons and connect the 3 batteries together for full output with a combined output of about 3800 amps so I can spin my starter till it burns out.
After I got the battery system installed I went and rearranged the power feed at the fuse panel and through the use of a number of 30 and 70 amp bosch relays I have isolated the starter and grids to be the only load on the #1 or main battery and the rest of the loads such as the lights to be on #2 that way I could leave my lights on all day till the battery went dead and still have a fresh battery to start the truck. The #3 battery in the back is for the 3000 watt inverter that supplies all of my AC power I use for work in addition to the lighting which includes 2 4' 40 watt fluorescent tubes along the top of the window on each side, these are powered by a high frequency inverter that will give you a nasty bite if you get too close to the output stud. And at the rear window I have 2 100-watt halogen work lights and a strobe.
Jim.