Batteries - Diesel Trucks

Not CTD, but my Duramax batteries are original and over 7 years old. A couple of weeks ago it sat in -5F temperatures for a week and started.

The Duramax forum has a lot of supporters of CAT batteries.

For diesel applications are the AGM batteries better than the lead-acid types?

Cummins12V98 wrote:
"Any reason why your son did not opt for AGM replacements ?"

Sorry missed this.

I would assume it is because of Costco and Interstate usage before. 30 mo free replacement.

Thanks , Been several years since I bought an Interstate battery, always had good service out of them.

After going back, and forth on our OE batteries in the Ram trucks in a Cummins forum, it seems like a lot of members are going with the AGM replacements. I am still up in the air at this point, the Interstate batteries from Costco will be hard to pass up, and at a reasonable price .

"Any reason why your son did not opt for AGM replacements ?"

Sorry missed this.

I would assume it is because of Costco and Interstate usage before. 30 mo free replacement.

Learjet wrote:

ktmrfs wrote:

philh wrote:

Camreal wrote:
My 2005 discharges the batteries 24 hours a day. I have read that this is normal draw from the electrical systems. If I let the truck sit idle for a couple months I know to put a charger to keep them up. Batteries dont like being discharged.

Thanks to all the computers :)

well, I disagree. at least 15 years ago mfg solved the long term accy discharge problem with a several stage shutdown of onboard elecronics.

if they are discharging in less than a few months something is likely amis.

Every vehicle I've had with computers and electronics in it has 3 stages of current draw after shutdown

1) immedidately after turning off ignition with everything off may be in the 1A range
2) exiting and closing doors etc. next stage of shutdown draw goes to the 100-300 ma range
3) after a set time often around 20 minutes full shutdown where current draw is close to battery self discharge rate. takes months to discharge even to 50% SOC

in the full shutdown, things like alarm etc. still are operational but don't wake up until something triggers them.

Now if something is preventing (3) from occuring or there is a fault, and you stay is (2) battery will be discharged way to soon if left unattended.

My truck has Uconnect, which uses a cellular connection to remote start, lock doors and other feature from a phone/computer...your above statement is not correct the cellular radio transmits and receives on a regular basis. Also, passive entry systems use power in standby mode. I think you quoted some old info.

well, my truck a 2015 has similar "features" and a regularly leave it sitting for over a month at a time in the winter and it never has a run down battery. I put it on a battery tender charger (3A) every 4-6 weeks and it on average takes about 3 hours ((9AH) to bring it up to full charge.
Given the batteries are 150AH total, not much drain at all in a month. So at least with mine the "standby" drain is quite low.



In the case of my duramax between shutdown and 48 hours onstar/wifi draw can be as high as 20ma, after 48 hours it wakes up every 10 minutes for a check then shuts down. draw from the remote entry is less than 1ma. after full shutdown.

spec'd max "standby" draw on my truck should be below 30ma after 2 hours.

.030X24=.75AH/day given the truck has 150AH of batteries after 2 months it would be down by 40AH or 75%SOC, easily enough charge to start the truck.

given my experience in trickle charge I'd estimate the standby current is closer to 10 ma.

"After the ignition is turned OFF the control modules will begin to go to sleep (shut OFF). All control modules do not go to sleep at the same time, some may take up to 30 minutes or longer after turning the ignition off before going to sleep. Others such as the ON Star and keyless entry control modules may periodically wake up then go back to sleep."

ktmrfs wrote:

philh wrote:

Camreal wrote:
My 2005 discharges the batteries 24 hours a day. I have read that this is normal draw from the electrical systems. If I let the truck sit idle for a couple months I know to put a charger to keep them up. Batteries dont like being discharged.

Thanks to all the computers :)

well, I disagree. at least 15 years ago mfg solved the long term accy discharge problem with a several stage shutdown of onboard elecronics.

if they are discharging in less than a few months something is likely amis.

Every vehicle I've had with computers and electronics in it has 3 stages of current draw after shutdown

1) immedidately after turning off ignition with everything off may be in the 1A range
2) exiting and closing doors etc. next stage of shutdown draw goes to the 100-300 ma range
3) after a set time often around 20 minutes full shutdown where current draw is close to battery self discharge rate. takes months to discharge even to 50% SOC

in the full shutdown, things like alarm etc. still are operational but don't wake up until something triggers them.

Now if something is preventing (3) from occuring or there is a fault, and you stay is (2) battery will be discharged way to soon if left unattended.

My truck has Uconnect, which uses a cellular connection to remote start, lock doors and other feature from a phone/computer...your above statement is not correct the cellular radio transmits and receives on a regular basis. Also, passive entry systems use power in standby mode. I think you quoted some old info.

There are now anti-theft, telemetry and wireless access devices that run constantly even if at low state of draw in addition to radios and clocks. My F250 and 5500 have a minimal amount of these devices, but my Jetta and Sonic have more vampire loads on the battery than for which I care.

philh wrote:

Camreal wrote:
My 2005 discharges the batteries 24 hours a day. I have read that this is normal draw from the electrical systems. If I let the truck sit idle for a couple months I know to put a charger to keep them up. Batteries dont like being discharged.

Thanks to all the computers :)

well, I disagree. at least 15 years ago mfg solved the long term accy discharge problem with a several stage shutdown of onboard elecronics.

if they are discharging in less than a few months something is likely amis.

Every vehicle I've had with computers and electronics in it has 3 stages of current draw after shutdown

1) immedidately after turning off ignition with everything off may be in the 1A range
2) exiting and closing doors etc. next stage of shutdown draw goes to the 100-300 ma range
3) after a set time often around 20 minutes full shutdown where current draw is close to battery self discharge rate. takes months to discharge even to 50% SOC

in the full shutdown, things like alarm etc. still are operational but don't wake up until something triggers them.

Now if something is preventing (3) from occuring or there is a fault, and you stay is (2) battery will be discharged way to soon if left unattended.

I want to give my thoughts on batteries. My wife has many health issues and a heart that is very weak so if I have any clue of a battery issue new batteries are installed at that time. I figure it is a life or death issue.


chevman

"Be careful when disconnecting. There is a fuse built into the positive battery cable post connector and mine popped somehow during the change. Those post connectors are a dealer only item."

Same happened to my Son. He did not know it had popped. His touch screen was blank and nothing else was effected. The dealer found it while he was getting recalls done. Fuse was $27 and NO labor charge.