O.T. — Battery in ICE car ...

[jonquiljo]

When I am not driving my Model 3, I drive my wife's (old) Mercedes. It doesn’t get driven much, and barely in this pandemic.

I had a question about the battery in an ICE car. I think mine bit the dust.

the car drove fine until the pandemic (reliable SOB for 15 years). I have had a couple of battery replacements Over the last 15 years and I think this last battery is 5 years old or more. Enter the pandemic and shelter in place.

Dead battery about 10 days ago. Car hadn't been driven in a long while. I did a thorough charge and drove it again for 1 1/2 miles. 7-10 days later I try to start it up and it is very dead again.

that was yesterday. I did a thorough recharge again (yesterday) and it stated fine after the recharge. I tried to start it tonight and it was dead again!

Is this how 12V batteries go in ICE cars - really fast??? I never had one die over the course of a month. Then again it gets driven maybe a mile in a month lately It is getting old - a couple of years ago I had to charge (the same battery) twice because of non-use. Is the batter toasted, or is there a drain somewhere that is causing this? User diagnostics on a 2005 Mercedes are crude, but it has no obvious errors on Command system. I’m guessing its old and cant deal with constant recharging because we don’t drive it.

I ask this because I have to get it fixed when things are barely open around here. I am high risk for COVID and have to get someone else to drive to the shop for me to get it fixed (not dealer!). Still perfect way to get ripped off..

Boy could I use a Tesla ranger right now, but its a Mercedes. Ideas? Thanks.

 

[destructure00]

When batteries die they can take the alternator with them sometimes. Could be the alternator isn't charging anymore, and that's why the battery goes so quickly. Both can be tested at most auto parts stores.

 

[MXLRplus]

If you leave a lead-acid battery sitting at <9 vdc with a drain on it, it will cause an internal short in one or more cells. Once you have an internal short, it will not hold a charge long.

If the internal short gets really bad, it will pull juice from the alternator so the car won't even run with the battery in it. Replace the battery.

You need a "battery tender". They have a small harness that permanently attaches to the battery, then a base unit that plugs in the wall. When you park the car for more than 1 week, plug it in.

 

[jonquiljo]

When batteries die they can take the alternator with them sometimes. Could be the alternator isn't charging anymore, and that's why the battery goes so quickly. Both can be tested at most auto parts stores.

Thanks. Last time (two days ago), I fully charged the battery - checked it by starting the car and running it for 30 seconds - and came back the next day to test it again. The battery was dead. I didn’t drive the car at all for the day after I charged it. I Can jump the car with an external jumper battery. It will have to do.

The battery won’t hold a charge overnight - even without driving it. I don’t get it as I’ve had bad batteries before - just not batteries that can’t even hold a charge for a day.

Shall I assume that a 5 year old battery that has occasionally died from lack of use has now just given up?

If you leave a lead-acid battery sitting at <9 vdc with a drain on it, it will cause an internal short in one or more cells. Once you have an internal short, it will not hold a charge long.

I think my battery is definitely dead. I’m just trying to figure out what else could be wrong as I am COVID “high-risk” and have to get someone else to bring the car to a shop. It’s a real PITA and I want to avoid getting taken to the cleaners. Thanks.

 

[Aikidoka]

I had a similar situation with my wife's Lexus ES 300 Hybrid. We didn't drive it for a few weeks and the battery was dead. I jumped it and drive about 30 minutes. An hour afterwards it wouldn't start. This was the original 7 year old battery. The Lexus service manager said that this is the way they died and the alternator was probably OK. I drove it to the Lexus dealer and bought a new custom sized battery for too much money and installed it myself since they weren't regularly having mechanics onsite. The new battery is working fine and staying charged. Frankly, I'm shocked the 12v battery lasted so long.

 

[MXLRplus]

Thanks. Last time (two days ago), I fully charged the battery - checked it by starting the car and running it for 30 seconds - and came back the next day to test it again. The battery was dead. I didn’t drive the car at all for the day after I charged it. I Can jump the car with an external jumper battery. It will have to do.

The battery won’t hold a charge overnight - even without driving it. I don’t get it as I’ve had bad batteries before - just not batteries that can’t even hold a charge for a day.

Shall I assume that a 5 year old battery that has occasionally died from lack of use has now just given up?


I think my battery is definitely dead. I’m just trying to figure out what else could be wrong as I am COVID “high-risk” and have to get someone else to bring the car to a shop. It’s a real PITA and I want to avoid getting taken to the cleaners. Thanks.

An internal short (sulfated cells) will drain the battery just like any other short circuit, but slower. If just one cell is bad, you can't hold enough voltage.

Undo one battery post. Charge the battery to full using an automatic charger. Disconnect. After 30 minutes observe the voltage. It should be above 12.70 volts. If it's below 12.4 volts, it's bricked. If it is above 12.4, then measure it again in 24 hr, and it should still be above 12.4.

 

[David.85D]

I know this is an old thread, but thought I would chime in. Over the course of the pandemic I’ve had to replace the 12V battery in all three ICE cars I maintain (wife’s, kid’s, MIL’s). They don’t like sitting around…

 

[MXLRplus]

I know this is an old thread, but thought I would chime in. Over the course of the pandemic I’ve had to replace the 12V battery in all three ICE cars I maintain (wife’s, kid’s, MIL’s). They don’t like sitting around…

And if the car has electric door locks, and the battery is in the electrically locked trunk, that's when the REAL fun begins.

 

[bhorn]

And if the car has electric door locks, and the battery is in the electrically locked trunk, that's when the REAL fun begins.

Chevy HHR!