Alternator output voltage 13.6V - Is that ok? 2021 CX-5

[FerrariF1]

My 2021 CX-5 Turbo recently had it's battery replaced under warranty because the car failed to start. Previous to that it had some slow cranking starts, mainly in winter.

I used a multimeter to test the new battery after 1 month of use, and it's at 11.7V after an hour of shutting the car off. Once I start the car, it's at 13.6V, and the alternator output of 13.7V. Isn't that too low? I thought alternators were supposed to charge at 14.4V?

I checked the current draw after 15min of the car being off and locked, and it's 11 mA (0.011 A). That does not seem excessive and I don't think I have a parasitic draw.

 

[cadcamjim]

Back in the 1970's when I first started working on my cars, a normal charging voltage from an alternator was considered to be between 13.8 and 15.4 volts. In recent years automakers have found that the batteries were being cooked at that voltage and charging voltages were not only lowered but on many cars that vary slightly based on the perceived age of the battery. I know on my Volvo you are supposed to use the Volvo VIDA tool to tell the ECM if you have replaced the battery with a new one so that it can adjust the charging parameters accordingly.

I don't think the 13.7 volts that you're seeing is too low by today's standards but I admit that I don't know what the actual Mazda specs shows for an acceptable voltage range.

The 11ma parasitic draw should not be a concern; I would have expected it to be a little higher than that.

 

[cz5gt]

New cars have smart systems for whatever fuel savings or green party hapiness
Its normal. You would rarely see above 14V (mostly in the winter and if very cold). Mazda avg Voltage/charge as measured in the systems is between 13.6 and 13.9V. Normal parasitic draw is less than 40mA Anything lower than this is perfect.

11.7v for battery at rest (after few hours) means its not at full charge. May be you need to charge it ot drive the car for few hours (time is what matters not miles).
Last time I purchased new battery it was discharged brand new. So its possible yours was not charged when you got it and if you drive for short periods of time it cannot fully recharge.
It should be above 12.5V at rest.

 

[Conrad 16.5]

13.6vdc is fine. What's not fine is the 11.7vdc after sitting an hour, as cz5gt stated, it should be above 12.5vdc.

I suspect that if the battery was fully charged that it would read above 14vdc while running.

Something is up with that battery. Do you have a battery charger or tender? Charge it up, fully.

 

[edmaz]

.... I checked the current draw after 15min of the car being off and locked, and it's 11 mA (0.011 A). ...

In addition to all of the other information that's already been posted, that 11 mA reading that you measured is actually around 2/3 lower than what I'd expect it to be. The 'completely off' draw on mine is slightly over 30 mA, and a number close to that is what almost always shows up in other reports well.

So assuming you're measuring that draw with your meter in series with the negative battery cable, I'm wondering if your multimeter perhaps is not correctly zeroed. And if so, that might also explain the 11.7V battery reading that you're seeing. However, if you're using a clamp meter (capable of reading DC voltage) to measure the draw, then what I wrote above likely doesn't apply, because those tools have operational considerations as well.

 

[FerrariF1]

Thanks you all for the responses. A few days after I got the new battery I drove 2 2h trips to visit my parents, so the battery would have been fully charged after that. I do make short trips (5-10 min max) since I work from home and everything is nearby, so all these short trips could be killing the battery.

Would and AGM battery be better suited for short trips in a cold climate?

As for the meter, it's a brand new Fluke 107 multimeter, so it should be good considering it's a decent brand. I also measured a few household batteries (9V, 1.5V etc) and the readings seemed to be correct.

 

[Conrad 16.5]

Thanks you all for the responses. A few days after I got the new battery I drove 2 2h trips to visit my parents, so the battery would have been fully charged after that. I do make short trips (5-10 min max) since I work from home and everything is nearby, so all these short trips could be killing the battery.

Would and AGM battery be better suited for short trips in a cold climate?

As for the meter, it's a brand new Fluke 107 multimeter, so it should be good considering it's a decent brand. I also measured a few household batteries (9V, 1.5V etc) and the readings seemed to be correct.

No doubt that Fluke is a good brand (I have a 4 of their meters) and that the 107 is a good meter.

Edmaz asked how you measured the current draw; the meter has to be in series, or a clamp-on probe has to be used. Which method was used here?

If you check the voltage of the battery immediately after a longish drive, what does it come up as?

 

[edmaz]

... I do make short trips (5-10 min max) since I work from home and everything is nearby, so all these short trips could be killing the battery ...

Yes, nothing but short trips could be the underlying cause of the low voltage you're seeing. Perhaps you can take a 2 hour or so joy ride somewhere, and then check the battery again a few times after shutting down from that trip, to find out if the voltage comes back up to around 12.5V and doesn't drop down much from there.

.... Would and AGM battery be better suited for short trips in a cold climate? ...

Perhaps a battery tender instead?

....
As for the meter, it's a brand new Fluke 107 multimeter, so it should be good considering it's a decent brand. I also measured a few household batteries (9V, 1.5V etc) and the readings seemed to be correct.

Ok, your meter sounds fine, but that 11 mA residual draw is still puzzling to me. Did you get that reading with your meter connected in series to the negative battery cable and post?

 

[Conrad 16.5]

Ed,

Did you see my questions/comments? Same as yours.

 

[edmaz]

Ed,

Did you see my questions/comments? Same as yours.

Didn't see yours until after I posted, and also missed that 'newer posts' notification. Maybe they should also send an audible to those of us who aren't paying close enough attention to what's going on

 

[FerrariF1]

I measured the current draw by disconnecting the negative terminal from the battery and connecting in test leads in series. The draw was 2.0A right after I locked the car, dropped to 1.8A after about 30sec, stayed at that draw for about 5min then dropped to 0.077A, and after 15min it was drawing 0.011A.

I will take a long-ish drive one of these days and measure the voltage on the battery right after I shut the car off.

 

[RL911]

you can get something like this to monitor your voltage in real time while driving and when it’s parked if you plug it into the live 12v port in the armrest. An alternator should be putting out 13.9-14.4 generally. with car sitting off, voltage shouldn’t drop below 12.4, or it means about half the capacity is gone and it’s time for a new battery. Also, if you do monitor it while driving, keeping rpms higher will boost the voltage.

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[edmaz]

... and after 15min it was drawing 0.011A. ...

So it turns out I learned something today, as a result of what you posted in this thread.

Quite a while ago, I measured the residual draw on my CX-5 of 31 mA, however that was done using a clamp meter. I didn't question that result because it was basically the same as with other vehicles I've owned. One issue with a clamp meter on these Mazdas is that one of the split wire negative battery cable is tucked away under the wiper tray, which makes it difficult to get the clamp centered around it.

So after thinking some more about the 11 mA that you saw, along with the difficulty I had with the clamp meter, I decided a short while ago to try the meter-in-series test. I guess it didn't come as a big surprise to me when the result from that test was the same 11 mA reading as yours.

So thank you for posting your findings, which helped me correct the misinformation that I'd created for myself. And it's also nice to find out that our vehicles have such a small continuous draw.

Hopefully that longer trip will result in a normal voltage on your vehicle, and you'll find a permanent solution that works well for you.

 

[skid00skid0]

Everyone should know that newer cars do NOT charge up batteries to as high a voltage (14.4), to maximize MPG's. You might see it hit that high after first starting, but I don't think even high 13's are used after a while during a drive. I read that, somewhere, I haven't checked mine except with a SOLAR Digital 12V Battery and System Tester. (That can do a 'load' test, to determine cell health, shows charging voltage, and can show how far down voltage goes when starting the engine).

My 2016's battery kept dropping low. I maintain 10 batteries, and I charge most of them regularly. I thought my CX-5 battery was bad, so replaced it. The new one also dropped in voltage. I also checked every single circuit in the car, to see which one was parasitic. I couldn't find any. Even a clamp meter couldn't.

I put a CTEK (56-382) Comfort Connect Indicator Eyelet on the battery, and charge with a CTEK (56-864) MUS4.3 12 Volt Fully Automatic 8 Step Battery Charger. I have enough slack on the eyelet, that I can just pull it out of the grill, check battery voltage, and clip it into the charger when I need to. That charger can also recondition cells, which can help to avoid internal shorts from debris falling to the bottom of the cell.

 

[HyFlyer]

As a data point, I typically see right around 14.5 volts on our 2019 diesel.

A "battery tender" type trickle charger to maintain charge would probably be the way to go for a vehicle that mostly sees short drives.

 

[cz5gt]

Sadly such short trips are not enough to recharge the battery so most of the time it sits partially discharged. Normal flooded battery would die quicker that way - if not charged regularly.
You could move to an expensive deep cycle AGM ($300+) which would help but its not worth the cost.
May be get a battery tender if you are parking in a garage.

 

[FerrariF1]

I ordered a Noco Genius 1 (1A) charger. I'll connect it to the battery on days I won't be using the car, and I'll report back. Hopefully it'll charge to 12.6V.

 

[cz5gt]

it should but may take longer time if battery is discharged below 80% soc due to the fact its 1A only. But if you use it frequently should be ok. Just dont leave it running for days even though some people say its ok

 

[edmaz]

... I do make short trips (5-10 min max) since I work from home and everything is nearby,...

It just occurred to me that I've asleep at the wheel about what you wrote above, by being totally focused on the battery issue. Yes, keeping the battery charged is a problem, however the long-term effect of short trips on the health of the engine is potentially an even bigger one. So with that said, I'll ask what oil change interval do you use?

 

[FerrariF1]

It just occurred to me that I've asleep at the wheel about what you wrote above, by being totally focused on the battery issue. Yes, keeping the battery charged is a problem, however the long-term effect of short trips on the health of the engine is potentially an even bigger one. So with that said, I'll ask what oil change interval do you use?

7500Km / 4600Mi oil changes. Using Motul 8100 ECO-lite 5W-30.

I would drive longer trips, but I have an infant at home and work from home, so...