I have recently purchased the CTEK battery tender for my 2011 XKR coupe. I’ve been using it for 3 days now (not nonstop), have driven the car during the same period. I am currently using it with the alligator clips at the +charge post and the neutral in the spare tire well. It has been in the hatch area with the car locked when in use. I may keep the unit outside of the car so I can watch to make sure it is cycling from charge to maintain. As it is now by the time I unlock and open the hatch it seems to always be on charge mode. When I unplug it I see it switch briefly to the green maintain light before going out.

My main question and concern is how warm/hot do these tend to get when in use? This one gets to be more than warm, fairly hot. When using a cooking thermometer, which might not be a totally accurate way of judging, it gets up to nearly 140 degrees.

Any thought? Does it make any difference being clipped vs hardwired?

Thanks in advance!

 

1st when you unlock the car and open the boot you draw enough current that the Ctek goes back into charge mode. If you leave the unit outside the boot say on the floor it will not change to charge state if it has completed the charge cycle. If it takes a long time say greater then 1/2 hour to go into the maintain state you may be starting to have a battery problem.

 

Read the CTEK manual. I'm pretty sure it says to keep it out of the car while charging. As for the operating temperature, it probably doesn't make any difference if it's hardwired or attached with alligator clips. But vibration can cause alligator clips to loosen; hardwired is more secure.

 

Yes, the battery was new back in March, but I had recently started having some some of the weird glitches indicative of the battery losing full charge. The other day it was completely flat. We put it on a trickle charger and got back up, but the dealer wouldn’t replace it under warranty because when they checked it it took a full charge and showed “normal” still. That’s what prompted me to try the CTEK. Not sure if the battery is sulphated enough to be unable to maintain a full charge. Any thoughts on the temperature of the tender itself?

 

The temperature of the Ctek is normal during the charging state. If you drained the battery then the Ctek is not the right charger to restore the battery. You need to use at least a 5-10Amp charger and give it a full charge. Once done take off the chargers and wait maybe 10-20 minutes and then take a voltage test. You should see at least 12.6 Volts at the battery. Anything less is a battery or a current draw problem. I assume you always lock the car when you get out of it.

 

Assume it’s ok to hardwire it at the remote location, versus at the actual battery?

 

You can do it either way depending on what year car you have. The 4.2 L cars can wire directly to battery but the 5.0 L car you should not mount the neg. wire to the battery but to a independent ground. The pos. can be mounted directly to the battery plus post in either case.

 

2011 5 liter. Is the negative bolt in the tire well the one just t the left of the spare, coming up through the floor. We are thinking the tender might not have been getting a good ground. When we put the meter directly on the battery we got about 12.5, but when we tried the meter on the remote posts we got zero. But after using a wire wheel brush to clean off the surface finish on the ground we were able to get the same reading as the battery. Perhaps it wasn’t make good enough contact to ground, and that was making the tender heat up trying to charge? Without an actual meter on the tender I guess there isn’t a way to tell if it’s actually charging unless the lights switch to green, maintain.

 

OK yes that stud in the spare tire area is good for a ground and yes you need to clean it to make sure you have good contact. As for the battery 12.5 V looks good as an at rest voltage. The Ctek will charge and hold a float voltage once the battery is a full charge. The lights will stay on so take a few minutes to read the Ctek OM. Enjoy

 

Thanks to everyone for their input. The tender did switch to green maintain last night and the unit did cool down considerably so cleaning the paint finish of the remote ground helped. I finished reading the 17 pages of posts on the CTEK thread originally started by Richard in 2013 which had much needed information, and as soon as my CTEK comfort connect extender cable arrives I will hardwire to the battery using the positive post and the recommended ground location before the battery module.

 

This is a good example of why this Forum exists. Knowledgeable members working together to help solve problems. We learn from each other and get things done.

The U.S. Congress should follow our example ...

 

To follow up, I did do the fixed installation of the Cteck tender using the ring leads and the comfort extension. As suggested I attached the positive to the + terminal bolt and the negative to the grounding point ahead of the battery monitoring module. It seems to be working normally, with the light eventually shifting to green.

Any thoughts as to the fairly frequent “parking aid unavailable” at startup. It used to be a more random occurrence that I thought would cure itself after adding the tender. Could it still be a battery issue, or is it more likely a fault with the parking aid module. Should it be triggering codes that the dealer can read? Thanks again for all the advice.

Allan

 

Yes as noted which many members are not aware of unless they read every single thread and post......Any XK from 2010 and after should have the battery ringlets from the CTEK connected to having one at the positive battery terminal and the negative to a good ground but not to the negative terminal of the battery.