Battery life for our 2022 CX-5 was 27 months. Probably due to our usage pattern. (infrequent short runs)
Rather than drive more for no reason a smart charger (as required) is a good option.
After charging the new battery the resting voltage is 12.8 - 12.9V.
This is not sustained and the resting voltage steadily drops back to about 12.5V especially after a longer trip (>1hr).
Does anyone know what the target resting voltage is for Mazda's smart charging system?
When I monitor the battery voltage on the diagnostic display it varies from a high of about 14.7V (regenerative overrun) down to about 12.2V.
It spends most of it's time whilst being driven at about 12.5V suggesting that this is it's target and it allows the battery to drop to 12.5V if it detects that the state of charge is higher.
I am not an auto electrician and would appreciate any clarification on this.

Thanks.

 

Welcome to the forum

If you do a little leg work you will find several Battery topic. Most of your comments and questions have been addressed.
I will tell you that 27 months on a battery that you don't know the age(manufactured) and how it was treated before you got the Mazda is not unusual.
Also the resting voltage @12.5 is where it should be. However I recommend that you get you battery load tested because the charging method you are using does not show or indict the true condition of your battery.

I would also suggest that you do some updated learning about your Mazda which the charging and battery voltage is directly controlled by the ECU. So some of your posted information is very old school, not that it is bad just not accurate for many new platforms.

So first thing is first go get your battery Load tested!

ASE

 

Thanks for the prompt reply.
I have searched previous threads and yes most of what I asked is already there. My apologies.

I will ensure the resting voltage is >12.5V and get the new battery load tested. If it is no good it is under warranty.
I have tested the parasitic drain with the car locked and the fob well away. It started at about 4A and dropped progressively to less than 20mA where it stayed so I don't think it is a problem.
My simple plan if I am going to be away is to charge it to "float" in order to give the parasitic load something to draw on.
For my normal (irregular) use I will keep an eye on the LED lights on the cTek charger connector plug and give it a charge if the red light comes on whilst resting (<12.4V).

I have tried without success to find some useful info. on modern ECU charge control (I found plenty on the old school systems). Can you point me in the right direction please?

Thanks again.

 

Unfortunately unless you have a special ECU, Ecu/EFI Calibration access program the only thing you can do is get a “flash” or pass-through of the most current ECU update available. That will not change the charging maps in the ECU unless the upgrade program itself had it.
But if you have a running program like Versa Tune you can tailor your charging characteristics to better suit your electronics or battery charging curve.

Just an fyi your Mazda has several on board electronics that have a constant power supply , unless you research the test area you may not be correctly getting the proper results and assuming the the area draw is a problematic area. Many platforms have been known if left unattended for long periods can slowly use voltage to a point how a challenging engine start. Especially when the battery unknown health is. Many assume if it charges up and stabilize at 12.5 volts it must be a good battery.

 

Thanks again for the prompt reply.

I think I get the drift. With the right equipment (and know how) it is possible to modify the ECU program to better utilise short runs for battery life however this would not be easy.
Based on this I will stay with my plan to be more attentive and use my cTek charger to keep the battery out of the deep discharge zone.

On parasitic drain I connected my meter in series with the negative post. I assumed that <20mA measured here is an indication that parasitic load is not a problem and I wouldn't need to pull fuses to check individual circuits.
Is this a fair conclusion?

 

1) Load Test Battery
2) use your ctek charger to keep the batter charged during resting periods or if you plan non op for a week or more
3) pulling and measuring the ohms is not the normal action for electrical diagnosis on your year Mazda.


This is would be a company that would access your ECU and make changes to the programing. Lots of learning curve and study of ECU/EFI Calibrating should and needs to be done for advance tunning capabilities. For DIY Basic calibration packages are available as well as to order custom specific target calibration .

Versa Tune
VersaTuner