Battery Dead .5~1.0V voltage drop normal?

[StylingSequ]

Purchased a Mazda CX-5 about 14 months ago. For the past 3 months, the car has been used daily. Perhaps, driven every 3-4 days. For the past week, the battery has kept dying. Initially, it lasted a few days but now it doesn't hold a charge for more than a few hours.

I did get into a slight accident in the front about 2 months ago, and some front end work was done (bumber, headlights, grill). Nothing major. I don’t know if this would have an effect.

I initially took the car to the dealer. They tested the battery, which supposedly came up fine. They claimed the fault must lie with the autobody shop as they see this all the time. They claimed they see shops paint wrong areas which lead to shorts or they forget to reconnect a ground somewhere.

So I brought the car to the autobody shop. They insist that they didn’t touch anything that would affect the battery. They tested the battery and when the headlights were turned on, the voltage dropped to 11.5. When the window was opened, it dropped further to 11.1. The shop claims that this means the battery is defective. Even though it’s a new car, they say it happens.

I called the dealer who claimed they were pretty sure that the problem was coming from the front work. They say they can’t replace the battery because Mazda won’t reimburse them since their tester comes out good for the battery.

Does anyone have any ideas who’s right or wrong?

 

[Moonlighter]

Have you tried fully charging the battery using a good multi-stage battery charger? Most of them will also detect a faulty battery.

Then …..I would get the battery load tested at an independent battery shop. If it fails take photos of the test results then go back to the dealer.

14 months from new is very short life for a new battery, and you would definitely expect at least double if not triple that under normal conditions. But sometimes they just fail.

 

[StylingSequ]

Have you tried fully charging the battery using a good multi-stage battery charger? Most of them will also detect a faulty battery.

Then …..I would get the battery load tested at an independent battery shop. If it fails take photos of the test results then go back to the dealer.

14 months from new is very short life for a new battery, and you would definitely expect at least double if not triple that under normal conditions. But sometimes they just fail.

Hey!

Unfortunately, I didn't get to use a multi-stage battery charger. Simply kept the car running for 20 minutes and then drove it around for about 30 minutes.

When I took it the dealer, they used an updated version of the GR8: Battery and Electrical Diagnostic Station. Apparently, the machine determined the battery was fine. I'm wondering how accurate this machine is.

When taken to the autobody shop afterward, the car was hooked up to their equipment (don't know what it is), and the voltage was dropping right away when the headlight and window were used, which they said wasn't normal.

Not sure who to believe…

I guess I can take it to an independent shop but I'm wondering if I should just replace the battery. It seems the cheaper option (≈$150). If it still doesn't work, then I'll know it wasn't the battery. (I already paid $200 for their diagnostic fee that came up with nothing.)

 

[Moonlighter]

A car that is sitting for a couple of weeks while repairs are being done can drain the battery down quite low and it will take a good long drive to charge it up again.

So I would first give the battery a solid overnight charge using a 10-20amp charger. A good charger will show you when the battery is fully charged. Victron are top shelf chargers.

Have you got a charger like that, or can you borrow one from a friend? Might save you the cost of a new battery!

The other thing is the tightness of the battery connections, which may have been undone when the repairs were being done. They need to be TIGHT. A less than real tight may make for a poor connection. So get a spanner on there and get them nipped up nice and tight!

 

[ADS-B]

What is the voltage with the engine running?

 

[Conrad 16.5]

Hey!

Unfortunately, I didn't get to use a multi-stage battery charger. Simply kept the car running for 20 minutes and then drove it around for about 30 minutes.

When I took it the dealer, they used an updated version of the GR8: Battery and Electrical Diagnostic Station. Apparently, the machine determined the battery was fine. I'm wondering how accurate this machine is.

When taken to the autobody shop afterward, the car was hooked up to their equipment (don't know what it is), and the voltage was dropping right away when the headlight and window were used, which they said wasn't normal.

Not sure who to believe…

I guess I can take it to an independent shop but I'm wondering if I should just replace the battery. It seems the cheaper option (≈$150). If it still doesn't work, then I'll know it wasn't the battery. (I already paid $200 for their diagnostic fee that came up with nothing.)

20 to 50 mins of running time is not enough to fully charge a discharged battery. Charge it overnight with a quality charger and then retest. If you don't do this then there's nothing left to discuss here. This is the first step before anything else can be done.

If you have a multimeter, you can do a bit of testing yourself. At rest, engine off, a fully charged battery should read right around 12.5vdc, maybe a little higher but no lower. Once started, the voltage at the battery should be over 14vdc, no less.

 

[Mazdiod2]

A lot of the newer battery chargers have a desulfation charging routine which can effectively help restore a battery that's been abused.

I bought one that looks a bit like this one (which is a bargain for 10A). I don't think mine works as well as something like a NOCO Genius but that kind of power seems to really help rejuvenate a battery.

https://www.amazon.com/dp/ (commissions earned)

 

[StylingSequ]

A lot of the newer battery chargers have a desulfation charging routine which can effectively help restore a battery that's been abused.

Thanks for the recommendation. I never knew what those battery chargers were for.

 

[StylingSequ]

What is the voltage with the engine running?

The car is now at the shop but I'll ask when I get the chance.

 

[StylingSequ]

20 to 50 mins of running time is not enough to fully charge a discharged battery. Charge it overnight with a quality charger and then retest. If you don't do this then there's nothing left to discuss here. This is the first step before anything else can be done.

If you have a multimeter, you can do a bit of testing yourself. At rest, engine off, a fully charged battery should read right around 12.5vdc, maybe a little higher but no lower. Once started, the voltage at the battery should be over 14vdc, no less.

I don't know if this matters but I jumpstarted the car right before I took it to the dealer. When I got out and handed the key to the service guy, he tried to start the car after it had been turned off for about 5 minutes. It failed to start. Wouldn't this indicate that it's not because the battery wasn't charged fully?

The shop tested the car by turning on the headlights and the voltage dropped to 11.5. Then he opened the window and it dropped further to 11.1. He believes this indicates the problem is with the battery.

However, the dealer states that this could also mean that there is a stray wire somewhere that is diverting power when something is turned on.

Who is more likely to be right?

The dealer believes the problem is due to the previous front-end work, and wants to closely inspect everything the shop touched. I'll have to pay for all of this. $500 for the inspection plus the cost to fix it. He's certain that it's not a battery problem because of what his GR8 said.

The body believes this is unnecessary. He says that evidence points to the battery. He believes that it's simply cheaper to replace the battery. If it still doesn't work, then we can go onto the more expensive route of taking things apart such as the fender.

 

[StylingSequ]

A car that is sitting for a couple of weeks while repairs are being done can drain the battery down quite low and it will take a good long drive to charge it up again.

So I would first give the battery a solid overnight charge using a 10-20amp charger. A good charger will show you when the battery is fully charged. Victron are top shelf chargers.

Have you got a charger like that, or can you borrow one from a friend? Might save you the cost of a new battery!

The other thing is the tightness of the battery connections, which may have been undone when the repairs were being done. They need to be TIGHT. A less than real tight may make for a poor connection. So get a spanner on there and get them nipped up nice and tight!

I had to jumpstart the car to take it to the dealer. Then I drove about 20 minutes to get there. After I gave the keys to the service guy, he tried to start the car. The car had been off for less than 5 minutes and it wouldn't start. Does this indicate that there is an issue with the battery?

During the front-end work, the battery wasn't touched. They only replaced the hood, bumper, headlights, and radiator support. The shop owner maintains that all of this is plastic, so he doesn't understand how his work could have affected the battery.

 

[cz5gt]

red flag if they did not disconnect the battery l. They were changing headlights that are electrical.

The Mazda test equipment is pretty good and is expensive as well. Almost always its accurate. but best test is to let car sit for 5-6 hrs at least (prefferably overnight) then test

You have few options-
keep pushing the dealer or the shop
charge the battery with a good charger (gotta buy one, $)
buy new battery ($$)

pick which one you want to go with. Its your choice we cant say what to do.

 

[Mazdiod2]

I had to jumpstart the car to take it to the dealer. Then I drove about 20 minutes to get there. After I gave the keys to the service guy, he tried to start the car. The car had been off for less than 5 minutes and it wouldn't start. Does this indicate that there is an issue with the battery?

Not neccessarily. A thoroughly discharged battery can be quickly boosted back up to a usuable voltage, but it won't last unless it's had a good thorough charging, which can take overnight or more.

It's hard to say what is actually wrong. Did something happen to the electronics? Bad connection or ground? Did they somehow completely discharge the battery while they had it in their shop?

I'd say the only way to find out is check all of the items to eliminate what's not wrong. Maybe check the current draw when the lights are turned on, etc.

I wonder if there is a short, why does the voltage sag when these accessories are operated?

 

[StylingSequ]

red flag if they did not disconnect the battery l. They were changing headlights that are electrical.

The Mazda test equipment is pretty good and is expensive as well. Almost always its accurate. but best test is to let car sit for 5-6 hrs at least (prefferably overnight) then test

You have few options-
keep pushing the dealer or the shop
charge the battery with a good charger (gotta buy one, $)
buy new battery ($$)

pick which one you want to go with. Its your choice we cant say what to do.

The problem is the dealer is reluctant to do anything. Even though the car is still under warranty, since they can't prove it to Mazda corporate, they want me to pay for everything even though they know something is wrong.

I'll probably just buy a new battery and see what happens. Crazy that I have to do all this when the car is under warranty. Mazda is really disappointing me.

 

[StylingSequ]

Not neccessarily. A thoroughly discharged battery can be quickly boosted back up to a usuable voltage, but it won't last unless it's had a good thorough charging, which can take overnight or more.

It's hard to say what is actually wrong. Did something happen to the electronics? Bad connection or ground? Did they somehow completely discharge the battery while they had it in their shop?

I'd say the only way to find out is check all of the items to eliminate what's not wrong. Maybe check the current draw when the lights are turned on, etc.

I wonder if there is a short, why does the voltage sag when these accessories are operated?

I did install a dashcam (Viofo A129) that depleted the battery once. The dashcam's hardwire kit where it's supposed to cut power when the voltage drops doesn't seem to work. After that, I stopped using parking mode. (Btw, I don't think those hardwire kits work. Use Viofo's kit as well as a Chinese one in another car. When the cars weren't driven for about a week, parking mode depleted both batteries. Doesn't look good for Chinese parts. ☹)

I initially turned off parking mode but the car continue to die. I then disconnected the dashcam completely but the car is still having trouble…

The shop owner who's a stand up guy believes the voltage sag indicates the battery is bad. The dealer insists the GR8 means it's fine and thinks it's due to the front end work, so he wants to remove the fender and trace all the relevant wires.

 

[HyFlyer]

If I was in your shoes, since you are paying out of pocket for troubleshooting, I would do it myself with ...
1) a good charger like a Noco Genius (it's good to have a charger anyway so now is a good time to buy one). If that doesn't solve your problem, go to 2 ...

2) buy a new battery, hook it up to your Noco charger to verify that it's topped off and install it.

If a new battery doesn't solve your problem, go to autobody shop who did the front end work to solve it.

If a new battery does solve your problem, go to the Mazda dealership to reimburse you for the battery AND previous $100 diagnostic fee that was faulty

That's what I would do

 

[ADS-B]

How about a battery cap check. I bet 50 cents that your battery will fail the test.

 

[stickerbush]

You may have killed the battery by discharging a few times with the dashcam. This likely would not be covered by the Mazda warranty.

 

[StylingSequ]

If I was in your shoes, since you are paying out of pocket for troubleshooting, I would do it myself with ...
1) a good charger like a Noco Genius (it's good to have a charger anyway so now is a good time to buy one). If that doesn't solve your problem, go to 2 ...

2) buy a new battery, hook it up to your Noco charger to verify that it's topped off and install it.

If a new battery doesn't solve your problem, go to autobody shop who did the front end work to solve it.

If a new battery does solve your problem, go to the Mazda dealership to reimburse you for the battery AND previous $100 diagnostic fee that was faulty

That's what I would do

Thanks for the help. You're right. I'll probably get a new AGM battery from Costco (I've read posts in this forum that due to the electronics on new Mazdas, AGMs are recommended) and install it myself. The dealer is supposed to cover all of this, but they're being shady. I'll be out about $500 of my own money, but it looks as if I have no choice.

I'll get this https://www.amazon.com/dp/ (commissions earned) as you recommended. Btw, do you know if https://www.amazon.com/dp/ (commissions earned) is better? Someone else recommended the Victron.

I doubt that I'll get reimbursed the $200 diagnostic fee. I already asked the dealer this, and they refused. They claimed that if the GR8 says the battery is good, they won't get reimbursed by Mazda corporate so they won't reimburse me even if I can prove the battery was at fault. Getting paid is all they care about.

The 2 Mazda dealerships near me are extremely shady. Once, I saw them rip off an elderly guy who had brought in a leased car that broke down. 6 months before the end of his 3-year lease. I was listening to their conversation. They convinced him that they were doing him a favor by taking the car back as is and having him sign another lease. This was during the height of car prices about 2 years ago, so they probably made $10k+ by taking the car back which they could fix under warranty and then resell. Then another $10k by resigning him to another lease at the height of the market. They probably made $20k+ off of him. Once I had the chance to talk to the man alone, I tried to explain to him that the car was still under warranty and Mazda needed to fix the car for free. I asked if the car wasn't covered, why did the dealer simply take the car back as-is? The elderly guy didn't seem convinced. He said the paperwork was all signed and he didn't think there was anything he could do. I felt so disgusted with humanity for the rest of the week. ☹

 

[StylingSequ]

You may have killed the battery by discharging a few times with the dashcam. This likely would not be covered by the Mazda warranty.

Would it have killed the battery by depleting it once?

The same thing happened with my Honda CRV, and it doesn't have the same issue. Since I work from home, I drive Mazda less (every 2-3 days), so I'm wondering if this is a factor.