Hey guys this is my first post on dtr but am a regular on cumminsforum and compd. Anyway i have been going through the tech articles and reading on the headlamp relays to achieve full "power" i guess you could say. And also the write-up on the blower for the air conditioner by bc437. (A expert of the 1st gen might i add from reading his posts on various sites). Anyways, could wiring in a second battery be a fix for all the electrical shortcomings for power in our trucks. It would be as simple as hooking hot to hot and negative to negative correct ? Would this benefit anything? I know it would help on starting atleast...

 

Welcome to DTR! I like the pair of optimas I have on my truck for winter. I haven't had any luck with the last few group 31 conventional batteries. Been through about one a year.

 

Alritey may I ask how you sit the batteries in te compartment and how u wired them up ?

 

theres also a group 31 blue optima, there much larger, d31m model number, 240 bones, yellers are close to that, but not sure in the cold of winter, crank capacity specs cca 900 at o degrees f, yellers are 750 at 0 degrees, for group 27

 

I would think duals would help you with starting issues (if you have any), but once the truck is running all the power comes from the alternator, not the batteries (unless your exceeding the alternator output).

 

Unless you live in the frozen North there is no need for more than the standard single group 31. Mine fires up just fine unplugged all winter long here in PA.

 

Two batteries will help you when it's cold, not when it's warm, like Schamran said. Our trucks are recommended to have a 750 CCA battery, but going bigger is fine. You're only going to draw what you need, not what's available. Your headlights won't shine any brighter, if that's what you're after. Jim Lane's relay write up in the sticky will do that.
Remember what CCA means. COLD cranking amps. A 750 CCA-rated battery will give you 750 amps, (assuming a full charge of 12.6V) at 0°F. Anything under that and your amperage drops off. All doubling up on batteries does is gives you a deeper well to draw from, which can be necessary on cold winter mornings!
Just for the record, I've been running an el cheapo AAP battery of 650 CCA for the last 4 years, and it's still going strong. I just don't need high amperage here in South Florida.

 

Stock battery is 1100CCA (group 31 battery).

I run twin group 65's that are 875CCA each for a total o 1750CCA on my W350, but I've had scares with other diesels while deep in the woods in Maine winters, so I'm being cautious. The 2WD truck I use just the stock battery and have had no issues.

This will not help the headlights or blower, only cold starting. The issue lies with undersized wiring, and cheap connectors from the factory that cause a lot of resistance and hence: a voltage drop in the line. 2 batteries in parallel is still only 12v.

 

Like already said, more batteries is not going to be of much benefit with lights and such once the engine is started/running.


However, I am a firm believer in PLENTY of battery power and my battery of choice is the Group-31S stud-terminal battery.

For several years, I have had THREE Group-31s on my truck and would not hesitate to add another if a free one landed in my yard.

Sure, one battery will start the truck; but, numerous big batteries will whirl that starter with genuine authority on the coldest morning.

The death of any electric motor, be it a 12-volt starter or a 120-volt circular saw, is often due to marginal electrical power.

Plug your big Milwaukee 8-1/4" circle-saw into the Christmas-tree cord while ripping a white-oak 2x12 and see how quick the brushes start burning.

The same holds true for 12-volt starters; the more power standing there at the ready, the longer the brushes and contacts will last.


Plus the fact that multiple batteries provide real insurance that the truck is most likely going to start, regardless of how cold or how long the lights got left on.

 

'nough said

 

I have hated dual batteries since the time I had a GMC with a 6.2 diesel.
Identical batteries from the same manufacturer made on the same day do not charge and discharge at the same rate. This starts the beginning of the tug of war where one slightly overcharges. As the batteries age the faster deteriorating battery puts a load on the other battery trying to pull it down. I also had a continuous problem with the solenoid contacts welding together due to the high amperage surge which permitted the engine to crank while running and also with the ignition turned off. I had to put a cut off switch on the battery to compensate for this. The solenoids were top grade as I was a starter and alternator rebuilder back then. Remember this, if you parallel 12 volt batteries together you can hook up welding leads and weld with them. The more batteries you parallel the bigger rod you can burn. Try it if you don't believe me. Just stay a good distance away from the batteries when you do it. This has the same effect for DC current arcing across contacts. Hooking batteries in parallel will give you the same voltage as a single battery, but with a Ah and current carrying capacity equal to the sum of the capacities of all the batteries. See: http://www.gizmology.net/batteries.htm

If I were to install dual batteries again I would consider using 2 high amperage 6 volt batteries in series instead of two 12 volt batteries in parallel or remote mount a single 12 volt 8D size battery.

 

Ok well that def answered my question bout the lights and such. That makes complete sense about old and cheap connectors. Well I'm in Tennessee and winters here are cold but not frigid by Any means maybe 10deg at the coldest and the ole truck still starts fine. Thanks guys !

 

I run only one battery, found one that puts out close to 1000 CCAs, fits the battery tray. Up here in Winnipeg we hit the -30 and -40s in winter. I plug in the truck for about an hour or two prior to starting it in the morning, and it starts right up after the normal 1/2 turn of the motor. At work I leave it plugged in, and the same thing happens. I will be running a second battery soon, but it is a deep cycle and will be used to power my winch and a couple of other accessories.

 

Our experiences with big dual six-volt batteries in series have been anything but desirable.

All of our big John Deeres came factory original with two BIG 6-volt batteries wired in series.

We could never get a year out of a set of batteries; and, after about three months on a set of batteries, we would always have to haul out the jumper-cables to even get started.

I finally convinced the money-man to let me install two Group-31s in parallel, instead of the sixes.

All starting and battery problems were cured.

Now, any one of those same tractors will easily start on the coldest morning and batteries now last five or six years instead of six months.



For what it's worth, I never have any of the oft discussed "problems" of running multiple batteries in parallel.

I don't follow any of the "rules".

I have always replaced batteries one at a time, instead of all at once.

I use mixed brands and mixed cranking-amp ratings.


I even have some trucks that may have an odd-ball sized battery mixed in with a couple Group-31s.


I am obsessive about identifying and record-keeping such stuff

I have a number written on every battery and that battery is listed in a book that I keep marked "BATTERIES".

All dates and any information of note is put in that book.


I always buy factory-second "BLEM" batteries at a HUGE discount; my experiences with blems are no better or worse than my experiences with high-priced first lines; I have gotten bad ones of both, probably fewer bad blems than firsts, as the blems are more rigorously tested before being sold.

I have one battery among the three in my personal truck that is over EIGHT years old; none are less than four years.


When a battery finally shorts internally, if I haven't caught it otherwise, the truck just won't start one morning --- no different at all from using only one battery.


EXCEPT, I dis-connect all the batteries and test voltage of every one, easily finding the dud of the bunch.

I then leave them alone for a half-hour or so, while the remaining good batteries rejuvenate themselves, connect the cables, hit the starter, and away we go = not something I have ever been able to do when I had only one battery to begin with.

The remaining batteries never seem to be any worse for the experience.

 

If you are going to retro fit dual batteries in you truck I do suggest that you isolate them. Its actually quite easy to do, put a HD CD solenoid between them and have it energized by one of two things.. The most important is the starter relay wire, when you energize the start relay you energize the HD CD solenoid, the other is an oil psi switch so that when the engine is running they are one unit.

We have done this on all of our gas rigs that dual batteries, and I plan to do it to my Dodge one of these days. It provides the ability to "jump" yourself if you leave a light or stereo on, etc... We have actually used the feature more than once.