Deep Cycle Battery in Pickup

[Beaver Cove Deere]

Same as a boat with starting and house batteries but the wiring is very much different. A battery isolation charging relay is needed.

 

[RancherGuy]

I'm pretty sure these batteries are separated (since that's what I wanted from the installer). As confirmation, when the starting battery died a year ago, the winch battery was fine and had plenty of juice to start the engine - I just placed one jumper cable from positive to positive. I'll check with the installer for an opinion.

I have to say it is unusual that you want to operate the starter with only one battery. I also have Duramax (2003), but use the two batteries as designed by GM. The reason is that while one battery can start an 8 cylinder diesel, it is living a hard life. I always replace mine in pairs, with the largest CCA I can get - spinning off the one "good" battery that is removed to be used in another vehicle that only uses a single battery.

At the current time, I found out one of the two had a bad cell and was discharging the good battery, so I removed it. Yes, it starts, but some of the starts are not very energetic. Before a week passes, I'll be replacing with two new batteries.

 

[Xfaxman]

I have a 2006 Duramax that has been starting on single AGM battery since one of the original batteries died early on.

 

[rScotty]

SNIP>...

Before a week passes, I'll be replacing with two new batteries.

What kind of battery will you be you looking for?
I just replaced most of my batteries in everyvehicle including tractors and generator this year.

 

[K5lwq]

What kind of battery will you be you looking for?
I just replaced most of my batteries in everyvehicle including tractors and generator this year.

Dang man, did you have to take out a second mortgage? Batteries have gotten outrageous.

 

[rScotty]

Dang man, did you have to take out a second mortgage? Batteries have gotten outrageous.

The price seems not much different here....maybe a little higher than years ago, but now there is a limited supply. What is available comes in a range of warranties as well as choices as to wet cell, maintenance free wet cell, and AGM type.

We've got quite a fleet here, and somehow I ended up needing batteries for everything this year. Did a lot of research and went back through my records on all vehicles. Finally came to the conclusion that all batteries actually cost the same....
- That is, one that costs twice as much also lasts at least twice as long.
Although the warranty doesn't always reflect that fact, it still comes close.

I used to buy Optima round cell batteries for everything: Red, yellow, and blue top batteries depending on use. I did that for what must have been ten or twenty years. But the last three (3) Optimas I bought didn't last one year and the warranty is so difficult as to be worthless. They require a special 24 hr. test on a special Optima test setup that most battery dealers do not have. Plus shipping costs half what the battery does. I'll not recommend them anymore.

Optimas were good once, I still have 4 Optimas (two yellow tops and two blue tops) that are eight and ten years old and still going strong, but all the Optima Red Top round cells I bought in the last few years were duds. Every one.

Howerve they taught me that AGMs don't rot cables and connectors, whereas wet cell batteries do. That convinced me to continue to go with AGMs everywhere.
rScotty

 

[Whisperpandy=]

If they're hooked up in parallel, how do you separate their work load? Is there a battery isolater in there somewhere?

Generally, there is a simple Ford style starter solenoid between the batteries. when you have the engine running, the solenoid is CLOSED, and activated, thus charging both batteries. when the engine is not running, the solenoid is open, and Not activated, which effectively separates the two batteries, and the secondary battery is isolated from the starter battery. This allows you to use the winch off only the secondary battery and keeps your starting battery intact. That way you can run the winch till the battery is completely dead and still be able to start your engine. 10-4 ?

 

[Whisperpandy=]

You should have two like batteries i.e. Same capacity and health. If one is down it will always drain the other one. Also there is a risk of overcharging a lower capacity battery to bring the bigger one up to full charge.

The voltage in the two batteries will equalize, then the voltage regulator will kick in and the two will send a single signal to the regulator and prevent any overcharging.

 

[Whisperpandy=]

One question I’d be asking is if an alternator charges at the correct voltage for the deep cycle (or an AGM type if you went that route).
I think the alternator puts out a voltage slightly lower than the deep cycle wants to ‘fully charge’ and does not have the smarts to properly cut off when it’s charged properly. You can get a DC-DC charger but they tend to be a bit pricy.

The batteries CAN be different size. If one is discharged more than the other, then when the connection is made, the voltages will equalize then the voltage regulator takes over to bring the batteries up to the preset voltage. The alternator/generator simply produces the juice, the REGULATOR decides how much of it reaches the load, which in this case is the battery(s).Think, a motor home that has a 12 volt lighting system.

 

[Whisperpandy=]

Some applications will use fancy solid state battery isolators, but a simple starter solenoid such as the older Fords used, or relay gets the job done just as well for a lot less money.

 

[rScotty]

The voltage in the two batteries will equalize, then the voltage regulator will kick in and the two will send a single signal to the regulator and prevent any overcharging.

Yes, the combination of two batteries will send a single signal back to the regulator. As I see it, the result is more likely to be that the larger battery (or AGM in this case) gets undercharged than that the smaller one gets overcharged.
And I don't think the undercharge will be enough to cause problems.
Equalizing always loses some efficiency of the best component. That's the cost of equalization. In battery charging just like in life.
rScotty

 

[MossRoad]

Generally, there is a simple Ford style starter solenoid between the batteries. when you have the engine running, the solenoid is CLOSED, and activated, thus charging both batteries. when the engine is not running, the solenoid is open, and Not activated, which effectively separates the two batteries, and the secondary battery is isolated from the starter battery. This allows you to use the winch off only the secondary battery and keeps your starting battery intact. That way you can run the winch till the battery is completely dead and still be able to start your engine. 10-4 ?

I know how they work. I was asking the OP if he had a battery isolator installed since he said his batteries were in parallel.

 

[RancherGuy]

What kind of battery will you be you looking for?
I just replaced most of my batteries in everyvehicle including tractors and generator this year.

I think I'm going with Costco regular batteries - group 78 as I recall. Wife has the card, so I've got to coordinate with her. I am the original owner and hope to sell it within the next year, so don't need anything with an excessive warranty.