top of page

Battery Care - CTEK MXS 3.8

Since owning my Lotus Exige I've tended to only drive the car on dry spring, summer and autumn days. Now we all know the British weather can be less than fantastic although the summer of 2018 would probably create some argument regarding that statement, based on the average however the car hasn't seen regular use.

To abate any battery issues from irregular use I invested in a CTEK battery charger and it's been an effective solution during the 4 years of ownership resulting in perfect battery operation.

I expect the Caterham 7 to be used in a similar fashion and so I've invested in a second CTEK charger to manage the 7's battery. In this blog, I'll briefly cover the product purchased and initial use.

I opted for the CTEK MXS 3.8 battery charger which is recommended for cars of the size of the 7.

The kit is supplied with the usual accessories including.

  • Comfort connect clamp

  • Comfort connect eyelet

  • Storage bag

CTEK Comfort connect clamp
CTEK Comfort connect clamp

CTEK Comfort connect eyelets
CTEK Comfort connect eyelets

CTEK Storage bag
CTEK Storage bag

In CTEK's jargon 'Comfort connect' relates to a handy plug system which is inline on the charging side of the charger's cabling. It permits different methods of connecting to the battery along with rapid connection to the battery. The following photos show the plug disconnected and connected.

The solution has been incredibly useful on the Lotus Exige as I've permanently connected the Comfort connect eyelet option to the battery and then used the Comfort connect plug to connect up and start charging. This of course works on the Lotus Exige as the battery is accessible in the boot when the tailgate is open.

I spotted an issue with the 7 from the outset. Sure I could connect the Comfort connect eyelets or even clamps to the 7's battery for charging, however this would mean removing the bonnet every time I wanted to charge the car. One of the key benefits of the CTEK charge system is the speed and ease, meaning you can quickly connect the battery for maintenance when parking up, this won't work if I need to keep removing the bonnet. In the long run I can see damage to the bonnet occurring along with a reduced inclination to use the charger.

Step in CTEK' clever accessory, the Comfort Indicator Cig Plug. This accessory connects to the Comfort connector plug and then plugs into the 12V socket on a car and subsequently charges the battery through the connection. The plug comes with a clever adapter ensuring it fits both 12mm and 21mm 12v sockets, although to be honest I wasn't aware there are two different sizes. The accessory also has inbuilt LEDs to inform the user as to the status of their battery.

CTEK Comfort Indicator Cig Plug
CTEK Comfort Indicator Cig Plug

In theory, the plug should connect to the Caterham's 12V socket located under the dash within the fusebox cover. If you are a keen reader you will probably spot I've never mentioned the fusebox cover in previous posts, I need to cover a number of trim topics in upcoming posts. I'll discuss the fusebox cover in more detail then, for now please just be aware the 7 has a 12v socket in the fusebox cover.

I say theory because as I write this blog I've not actually tested the accessory yet and so don't know if there is any unforeseen gotchas. Is there anything peculiar in the 7's wiring which will prevent this from working? Will I need the ignition switched on to position 1 or 2 for 12V socket to be closed circuit and connected to the battery?

Time to test..... I'll post a follow up blog detailing how I get on.

And the outcome....



696 views0 comments

Recent Posts

See All


bottom of page