Parasitic draw and the HMMWV

[Gamble]

It seems to me that these trucks are more susceptible to parasitic draw. Not sure if the issues stem from the smart start box, TCM, or an accessory but if these trucks aren't driven or started for a number of weeks it appears that the batteries will be weak. I now need to diagnose the problem.

Out comes the multi-meter but I am curious if most of you have the same experience. BTW, I have standard start Switch and minimal accessories running only on the hot start wire and not always on power wire. Again these accessories (rear view mirror camera) are on the 12v side of a 24 to 12v step down and fuse block.

I'll let you know what I find.

BTW any recommendation on a battery charger so I can keep these things topped off?

 

[Coug]

My batteries drain down due to my dash cam. Takes about a week when just sitting there (group 24 AGM batteries, so about 2/3 the capacity of the 6Tagm)

NOCO Gen5X2 (or the Gen 2X2, or 10X2) are designed for marine application charging/maintaining on board multi battery charging.

Designed to safely charge batteries that are installed in series.

Mount it in the battery compartment, or that small slot next to the batteries, and plug in when not in use. I've been using mine for about 3-4 years now. I just have the cord run through the little notch at the back of the passenger seat and sitting by the lower seatbelt mount.

NOCO - 2-Bank 10A On-Board Battery Charger - GEN5X2

The GEN5X2 is a 2-bank 10-amp waterproof on-board battery charger for lead-acid and lithium batteries and rated at IP68.

no.co

 

[DREDnot]

Don't those 24 to 12 step down converters draw power all the time?

I installed a 200 amp keyed battery disconnect switch on my truck and the original DEKA automotive batteries from 2020 that were in it from gov planet are still going strong with no jump starting required.

 

[Gamble]

Don't those 24 to 12 step down converters draw power all the time?

I installed a 200 amp keyed battery disconnect switch on my truck and the original DEKA automotive batteries from 2020 that were in it from gov planet are still going strong with no jump starting required.

I believe there is a minor load when the vehicle is off. It's called quiescent current. A minimal pull to keep the internal voltage regulators and control circuits functioning even though there is no load.

Hmmmm... Now you've got me thinking. If the converter is tapped into the ignition hot, when the vehicle is off how can it pull a load... Even a minimal one at that.

I'll confirm.

 

[Coug]

if it is controlled by a switched power source off of an ignition hot wire, then in theory it should NOT be drawing power with the ignition off.
I'd either start looking for the draw, or maybe install a battery disconnect when it's going to sit for longer periods of time.