Battery boosting

[diver57]

Hi I have duel batteries in my truck that are dead after sitting all winter and need to jump them.what battery should I hook up to.
It’s a 2016 gmc 6.6 duramax

[Z-Peller]

I have a 2016 GMC Duramax. GM tech told me everything electrical goes into sleep mode on this truck when it is shut down for a period of time, just like a laptop. I have had no problems at all with 2 month shut down. I pull camper hotwire fuse under hood and do not set alarm, just manually lock doors, then turn off camper batteries main power switch. No current draw anywhere. ......wonder if OP pulled camper charge wire fuse?...

[DWeikert]

Kayteg1 wrote:
OP did not report back, but chances that batteries sitting dead whole winter will recharge are very slim.
That is why I automatically suggest removal from the truck.
Vehicles always draw some current when in park. On old cars/truck you had a clock, on newer one alarm and remote system. Different vehicles can sit longer time without recharging and when my sedans and new F350 will restart after 5 weeks, some luxury cars are reported to drain battery even in 3 days.

He said truck was sitting all winter, not the batteries were dead all winter. My 1+ year old batteries died during a 3+ week spell it rarely got out of the teens. Put the charger to them and they came right back.

Unless the OP knows the batteries are old or just wants the exercise, IMHO it makes sense to attempt a recharge in the truck.

[Kayteg1]

OP did not report back, but chances that batteries sitting dead whole winter will recharge are very slim.
That is why I automatically suggest removal from the truck.
Vehicles always draw some current when in park. On old cars/truck you had a clock, on newer one alarm and remote system. Different vehicles can sit longer time without recharging and when my sedans and new F350 will restart after 5 weeks, some luxury cars are reported to drain battery even in 3 days.

[DWeikert]

Kayteg1 wrote:
Pull the batteries out and charge them. If they will recharge, than put them back, if not get new batteries.

No need to physically pull the battery (they're heavy suckers), simply disconnect the positive terminals then charge. I'd pull the positive that way you can still ground to the frame anywhere. As long as the second battery is still connected don't let the removed battery cable touch a ground.

I had a similar problem with mine over the winter. If the batteries are completely dead don't be surprised if you throw a couple engine codes. IIRC mine had an network error communicating with the TCM (transmission control module) and pre-heater alert. I just cleared the codes and they didn't come back.

Word of caution, the 12v sockets on the dash are hot even with the ignition off. Anything you leave plugged into there will be a 24/7 drain on the battery. Leaving a 12v to USB adapter and bluetooth module as well as a wireless ODBII reader plugged in is what killed mine. The other side of that is you can plug a solar battery tender into one of those sockets, lay the solar panel on the dash and keep the batteries topped off with that.

[3_tons]

Seek appropriate answer in owners manual ??

[cewillis]

Kayteg1 wrote:
Pull the batteries out and charge them. If they will recharge, than put them back, if not get new batteries.

I would do this.

[Grit_dog]

It is likely that newer vehicles will drain batteries over the course of say 6 months. Idk if it's the norm, but I've heard it before and experienced it with a fleet of brand new trucks that were parked for 6 months. A 30 year old truck and most of the 5-10 year old trucks starred as did most of the equipment with master switches. But the brand new trucks were all dead. They also recharged after being jump started so good chance the batteries in yours aren't destroyed.
The safe way and proper way is to recharge them completely though unles you plan on hopping in and driving it for hours straight.

[burningman]

No man... a loose wire will not kill an idle battery. It can make it not charge well when the engine is running and that will make it drain.

The best battery to jump a late model Duramax from is the passenger side one.
That’s it’s “primary” battery. Yes, they are both connected in parallel and it will work either way, but the passenger side has the most direct connection to the starter. The driver side battery goes through longer cables before it reaches the starter.
If you jump from that side there’s more resistance.

Like I said either side will work, the passenger side will work a little bit better. But not much. Not enough to stress over it if it’s inconvenient to reach the passenger side.

Another thing you can do is hook up two sets of jumper cables. That reduces the resistance and flows more current. It’ll start sooner that way.

[SideHillSoup]

diver57 wrote:
Hi I have duel batteries in my truck that are dead after sitting all winter and need to jump them.what battery should I hook up to.
It’s a 2016 gmc 6.6 duramax

It’s not that cold in Surrey that two, 2 year old batteries would die. I live in the Kootenays which is way colder than Surrey in the winter and way hotter in the summer. The batteries in my 2007 Duramax lasted 8 years, actually they were still half decent, but it was time to change them, life was 1 year past usual life of a battery in our climate. I never plugged in the truck here in the winter, unless I go to the kids place between Banff and Calgary.
Now I’m not a Mechanic, and not even close. I know enough to get my self into trouble and that’s about it.
However two, 2 year old batteries die because the truck wasn’t run over the winter.... you have a large power drain someplace. The little scurity system in the radio, I don’t think would kill two basically brand new batteries, becuase the truck sat for 5 months.

I would be talking to a GMC teck, as well ensure all your cable connections are clean and tight, as a loose wire on either battery will help to kill a battery.
Soup.

[Kayteg1]

Jumping dead batteries on digital truck brings some horror stories it can trigger.
Pull the batteries out and charge them. If they will recharge, than put them back, if not get new batteries.
New batteries are still cheaper than fried ECM.

[KD4UPL]

It doesn't matter at all. Hook it to which ever battery you want too.
It's entirely possible, if they've been dead for several months, that they need to be replaced. But, try to jump it off, charge them up, and see what happens.

[deltabravo]

diver57 wrote:
Hi I have duel batteries in my truck that are dead after sitting all winter and need to jump them.what battery should I hook up to.
It’s a 2016 gmc 6.6 duramax

Doesn't matter. They are both connected in parallel. If I were doing it to my Duramax, I'd do it to the one behind the headlight, because that's the most convenient to reach with a set of jumpers cables.