Car Battery

[RAK]

While in storage, is it ok to disconnect the car battery for short periods (1-2 weeks) between use?
Does this do something to the chip or any of the electrical systems? Thanks in advance for any advice!

 

[CKN]

Your battery should not run down in two weeks-why disconnect it?

 

[d00df00d]

I've done this and haven't had a problem. Not sure what that's worth, but there it is.

 

[SHOZ]

I do if I plan on not driving for a month. Otherwise you need to spend the time on recharging it.

 

[NJ_Car_Owner]

In my own personal experience I've had a car sit for quite a while and not have any issues. I'm talking months of non use, get in the car and it starts up. Not sure what a 2004 Sonata has in it other than it's clock so maybe that's why everything was OK.

 

[Rand]

if you disconnect it.. it will have to relearn idle etc.

I would put a battery maintainer on it.. or if no electric is available
at least a decent solar powered charger.

only disconnect if you are going to be longer than a month IMO.

 

[Johnny2Bad]

If the vehicle was built before 1996, go ahead and disconnect it, zero issues.

If after, the car's computer will be used to manage different driving parameters, transmission shift points, etc. It's not the end of the world, but if the power loss is long enough to discharge the storage capacitors, the vehicle will drive as it did off the lot, as compared to driving after learning your habits, for better fuel economy.

If you are going to take the battery out of the system, disconnect the negative terminal. You can leave the positive where it is.

 

[Donald]

Battery Maintainer is what I would use for storage. But two weeks is not really storage in my mind.

 

[JimPghPA]

It depends on the vehicle. What is the vehicle including year?

 

[The_Jeff]

Even moderately gentle wrenching on top posts can flex them and cause case leaks. Leave them be.

I 2nd the maintainer idea.

Pre 96 injected cars need to relearn idles as well, it's not a particular OBD flavor. But if you have 96+ emissions inspections you wouldn't want it to forget all the monitors.

If you just have to do this, they sell switches for exactly this.

http://www.harborfreight.com/battery-disconnect-switch-97853.html

 

[pkunk]

I make small maintainers for storage of the many batteries I have from 1A-12V power bricks. Just put a couple ov battery clamps on 'em. Need a meter to determine + from -, and they work like a charm. Second hand stores have racks of these for cheap.

 

[andyd]

Whilst I base lined the Rat, I left the battery un-hooked for 4 months. Engine lit right off when I hooked it up.

 

[djb]

It really does depend on the vehicle, not the year of manufacture.

Many BMWs from the 1980s and early 1990s used NiCad batteries in the instrument cluster as back-up power.

They tended to last 20-30 years if never used. But if you disconnected the battery for more than a few minutes, the weakened cells would completely discharge and short out, causing a variety of problems and much higher ignition-off current drain.

 

[i_hate_autofraud]

On late model GMs be careful when disconnecting battery:

You have to let the "Retained Accessory Power" (RAP) time out or the GM Onstar thinks power was interrupted by a car accident and activates it's own batteries that can't be turned off, they run dead and OnStar thereafter likely won't work in a collision.

This means: ignition key out, open the hood, close all doors, wait 3 minutes then take off the Neg battery cable. However, be sure to loosen the Neg clamp then cleanly remove the cable in one action. Accidentally allowing a reconnection restarts RAP timeout. Wrap the Neg cable connector in a rag, etc, so it can't make accidental contact. There's usually not a lot of room to stuff a cable once yanked off.

Nice to know eh?

 

[Eddie]

+3 for a $10 battery maintainer at Walmart. Ed

 

[zzyzzx]

Or a solar battery maintainer if no electric outlet is available.

 

[GMBoy]

Originally Posted By: i_hate_autofraud

On late model GMs be careful when disconnecting battery:

You have to let the "Retained Accessory Power" (RAP) time out or the GM Onstar thinks power was interrupted by a car accident and activates it's own batteries that can't be turned off, they run dead and OnStar thereafter likely won't work in a collision.

This means: ignition key out, open the hood, close all doors, wait 3 minutes then take off the Neg battery cable. However, be sure to loosen the Neg clamp then cleanly remove the cable in one action. Accidentally allowing a reconnection restarts RAP timeout. Wrap the Neg cable connector in a rag, etc, so it can't make accidental contact. There's usually not a lot of room to stuff a cable once yanked off.

Nice to know eh?




Not true on the Onstar part. Yes, Onstar does have, depending on the generation and vehicle make/model, capacitors or a battery that holds a charge long enough to allow it to do it's thing. However, Onstar is NOT activated by power disconnects. It MUST see data from crash sensors (and other sensors) to activate. Disconnecting your battery while in your garage or driveway is fine and nothing will happen. I know this because I work with Onstar engineers every day and have first hand experience on these "mystery" onstar modules.