Using a battery maintainer

[ryoung]

I'm going to store my Ram diesel truck for about 5 months and want to keep the batteries charged with a battery maintainer. Will I need to disconnect the batteries to do this?

ryoung

[Ski_Pro_3]

I got an LED display that plugs into the cigarette lighter that shows voltage. My phantom load on my Dodge diesel 2006 truck is 35ma and that I confirmed from the factory to be correct. I keep a battery maintainer velcroed to the side of the battery with it's power cord dangling out the front grill. When I leave the truck long enough that the LED display drops to 12.6 volts, I plug in the maintainer and let it run. Usually within a day or 3, the voltage is back to 13.6 or what ever the float voltage is.

A good tip is to check battery water levels and the specific gravity of each cell. Loosing water and low SP are strong indicators the battery is on it's way out and no amount of conditioning or maintaining is really gonna help. Cold weather is harder on these batteries than warmer as well.

[Harvey51]

I just disconnect the batteries. No problem even at 55 degrees north. I check the batteries every month or two just to reassure myself. If the voltage got down to 12.4 I would charge.

[pauldub]

pnichols wrote:
I keep a battery maintainer hooked up to our RV's engine starting battery 24/7 while the RV is in the backyard being stored.

We're on the RV's 2nd chassis battery in 13 years, and the first OEM chassis battery was still working great when I replaced it just in case.

Similar story for me. I replaced the original battery after 15 years because I was going on a long trip.

[pnichols]

I keep a battery maintainer hooked up to our RV's engine starting battery 24/7 while the RV is in the backyard being stored.

We're on the RV's 2nd set of chassis batteries in 13 years, and the first OEM chassis battery set was still working great when I replaced it just in case.

[fj12ryder]

"Do not understand ??? Why is this even an issue ???"

No issue, just a difference of opinion.

[MEXICOWANDERER]

Disconnect negative

Connect Battery Maintenance Device

Problem resolved. 100% guaranteed.

Do not understand ??? Why is this even an issue ???

[scbwr]

Used a Battery Tender with my Tundra without disconnecting the battery and never had a problem.

[wa8yxm]

No need to disconnect. the voltages put out by the battery tender are not far removed from teh alternator. May actually be lower

[Naio]

I've used different maintainers on different vehicles. My advice is to check the battery once a day or so for the first few weeks.

Some vehicles have resting loads that are larger than the output of some trickle chargers. So you have to make sure the charger you have is working on the vehicle you have.

And yes, if the resting load is too high you can deal with that by disconnecting the ground. But you won't necessarily have to.

[kellertx5er]

RCMAN46 wrote:
Do not use a GFI outlet. I did this on a car for 6 months and some time during the 5 months the GFI tripped possibly due to a power surg.

The maintainer dropped the battery voltage to about 3 volts which destroyed the battery..

I don't think the maintainer drained the battery. More likely, it was the onboard loads in the truck (radio memory, etc.) that drained it. Chargers have blocking diodes that prevent reverse current flow.

[C_Schomer]

I have a collection of Battery Tenders. The 3 amp units do a great job on my CTD and single battery cars. I don't disconnect anything on the vehicles because the 3 amp units provide way more than the parasitic loads. Craig

[RCMAN46]

MEXICOWANDERER wrote:
Peek A Boo spurious loads are about the only thing that can upset the apple cart. That, and as mentioned above -- extended power outages in conjunction with tiny loads that should not be there, anyway.

Not sure what you mean about tiny loads that should not be there. The maintainer that I had was the load that run the battery down.

Some maintainers put a small load on the battery even when they do not have a power input.

[MEXICOWANDERER]

Peek A Boo spurious loads are about the only thing that can upset the apple cart. That, and as mentioned above -- extended power outages in conjunction with tiny loads that should not be there, anyway.

[RCMAN46]

Do not use a GFI outlet. I did this on a car for 6 months and some time during the 5 months the GFI tripped possibly due to a power surg.

The maintainer dropped the battery voltage to about 3 volts which destroyed the battery..