CTEK MXS 5.0 battery recondition mode

My E-Type has a habit of eating batteries.   I seem to get about 2-3 years out of them before they struggle to start the car when cold.   You might be thinking that these batteries are left discharged all the time – but not so!  The E-Type is connected to a trickle charger when not in use and is parked indoors in a moderate climate.

I think there are a few reasons for this.   Firstly, the battery is quite small, and like many things on the E-Type is under specified for the car.   The series 1 radiator fan is the classic example of this.   The small battery was probably primarily for cost, and secondarily for space.   Secondly, the Lucas starter is now over 60 years old and is not as efficient as it once was.     It is trying to turn over a long stroke 4.2 liter inline six, and the battery is too wimpy for the job,

I have three battery chargers.   The primary one is a CTEK MXS 5.0.   This is quite a nice charger, it has a 5A capacity, readouts to show what charge mode it is on, an AGM function and a recondition function.

I’ve tried the recondition function a couple of times with only moderate success.   Out of 3 attempts, only one of them has made a measurable difference on the battery.   In that case, I had left the door ajar on the 300SE.   After a jump start the NRMA cautioned me the battery needed replacement.   I confirmed this with my battery tester, but after running the recondition mode there was a big improvement.     The other two times the result was either same, or in one of them a bit worse.

There was really nothing to loose in trying the recondition mode on the E-Type battery as I planned to replace it.   I have a Solar BA5 battery tester which outputs the CCA rating of the battery when you plug it in.   The battery in the E-Type is rated at 620CCA.   Before the recondition, the output was 325CCA.   No wonder it was struggling to start the car!

Solar Battery Tester

After the test, I plugged in the CTEK MXS 5.0 battery recondition mode and left it for 24 hours.    The battery was indicating 13.7 volts, so it had charged.   The recondition mode had not done much, with the final output a dismal 344CCA.

CTEK MXS 5.0 recondition mode

My conclusion is that if the battery is otherwise good, but has suffered a major discharge, this recondition mode can make a big difference.   If the battery is otherwise on its way out, it really has no impact.     Before I replace this battery I want to research AGM batteries to see if that will work better in this car.   2-3 years does not seem enough in my book.    I also want to add a better disconnect switch and connection for the CTEK charger.   This would be similar to the 250SE.

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