Battery charger recommendations please

[David Collins]

Aready have a CTEK but need to buy a decent 10am or larger battery charger as found battery flat after 3/4 weeks away - not happened before as when away 3/4 weeks three times a year it’s always started first time and I’ve just used my ctek to boost it up for a few hours before using again

Cannot leave CTEK on whilst away 

Car is a 2012 v8 XKR coupe with 26k miles and good Varta battery 2.5 year’s old 

thanks

[Big John]

Hi David.

If you can't leave the CTEK connected I presume yo would not be able to leave another charger connected either.

Your CTEK probably needs more than a couple of hours to properly charge the battery and if it is going flat in 3/4 weeks a "beefier" charger would probably not help anyway.

I would be looking at a solar charger to keep it topped up whilst you are away. Just make sure you use one with a maintainer module or it could overcharge the battery.

https://www.autoexpress.co.uk/product-group-tests/43793/best-solar-chargers-car-batteries-2023

The other, longer term, fix is to check your car does not have an excessive quiescent drain such as an internal light staying on or one of the many computer modules failing to shut down properly

John

[N6 JMX]

Hi David, a battery drain over 3 - 4 weeks on a late model XKR is NOT unusual due to the quite high quiescent current that occurs on modern cars due to all of the background modules "humming away". I assume that you are aware of the "double lock" facility on your car? When locking the car, press the lock button on the fob twice in quick succession (it will then beep at you) and this put the electronics "to sleep" after a few minutes, meaning that quiescent drain is as low as practical.

In addition, the fobs should be stored in a suitable location - a Faraday Pouch, or Box, is best, but in any event at least 20ft / 6m away from the car if simply left on a shelf / key hook. This stops the car from "seeing" the keys and coming / staying awake in anticipation.

I am familiar with the C-Tek unit, but my preferred smart charger is the Ring Automotive RSC 612 unit, which works specifically for 5.0 litre engines. These do so much more than just charge the battery as there are test functions as well, plus they are suitable for AGM batteries on stop / start enabled vehicles. I have several of these chargers and leave them connected to the vehicles long term - like all over the winter when the Jaguar does not poke its nose out. One very handy function is the LCD screen which indicates the state of charge / condition of the battery as a percentage. These Ring Automotive Smart Chargers are not cheap at circa £100, but in my view they are worth it.

N6 JMX

[Jimbov8]

Hi David,

The quiescent drain for our cars is 30 milliamperes or 0.03A so not very high at all. This is also easily checked.

I would ensure the day before you leave, you allow your CTEK to fully charge the battery. However, it would be worth having the capacity of the battery checked as it may have dropped from lack of use.

Lead sulphate begins to form at 12.4v and its these sulphites that strangle the battery.

[David Collins]

Thanks 

[David Collins]

Thanks to all for replying 

going to have to use CTEK on more regularly as not done this before as always.started first time after 3/4 weeks away. Then have put ctek zone for a few hours before taking car out for first run after getting back from the holiday 

The battery is 2 and a half  years old and make same as originally fitted

Always double lock but going down to Independent later this week to get advice and battery check . Don’t know if he can check battery drain but will ask as he has all the gear!