Barry Hanna

I would like to connect my CTEK to the under hood battery connections and have it be a permanent connection to the CTEK extension. The problem is that the positive “blade” connector doesn’t allow for a convenient connection point allowing for the hood to be closed. Has anyone found a connector that might work? I realize that I could do this directly to the battery in the trunk but I’d rather use the hood location if possible.

I’ve toyed with the idea of drilling the blade connector so I could bolt in an eyelet connector, but that would require a small angle drill that I don’t have in my tool chest. Maybe my dentist does. Any thoughts would be appreciated.

kafklatsch

If you remove the ornamental paneling, there is a junction box (Prefuse box) with many live positive connections, including the positive jumper spade. They all have relatively small 3-6mm stud and nuts. You can connect it there as the M1 stud interface connects to the starter - same destination as the positive jumper spade
I can get you the wiring diagram if you don't have access, but stud posts M1, M2, MR3 all come directly from the battery (G1), and the spade ties into that circuit, but you do have choices in there as all are live just as the spade jumper post.

for a visual, search P/N A2225402350 (or without the "A"), it should show a pic of the prefuse module (F32)

***WARNING*** high amperage live circuits, disconnect the ground before any tinkering, and of course do this at your own risk...

what's a CTEK?

Barry Hanna

Thanks for the reply. A CTEK Is a maintenance battery charger. Like a Battery Tender.

kafklatsch

Hi just to close this out, here is a pic of the prefuse box showing the studs, all of these will charge the battery. A ring terminal for the CTEK and nut can be connected here.. The positive jumper spade is visible also.

It is a Great idea you have.


Prefuse box, connections removed, the terminal annotations shown Mx, etc.

JohnLane

Lou your CTEC toy will have a jumper that connects to a positive post and to ground. Be sure it is fused. The fuse is usually built into the leads you connect to the car.

phil34

I have been thinking of doing the same on my S550. I used a CTEK for years on my SL500. On the SL I did it in the trunk and the car did not mind having the trunk slightly open for the power cord. Just got the S550 so I will do the same for it under hood as the trunk would probably not be happy left open slightly due to power closure.

Thanks for power block info.

Barry Hanna

***WARNING*** high amperage live circuits, disconnect the ground before any tinkering, and of course do this at your own risk..

Does this mean that I should disconnect the negative terminal on the main battery before doing this? If so, I’d rather do the “trunk diving” to access the battery than deal with electrical gremlins later, but ‘geeseh!

kafklatsch

There is always a chance of contacting an exposed point on the negative ground of the car body and cause arcing.

Even the hole through the blade could allow a short to ground during the process

Personally i'd do "without" disconnecting the battery by placing a heavy blanket around the area im working to eliminate the possible short. I've done that a dozen or more times in my DIY life.. a thick plastic sheet/tarp will work also

But as a forum, we have to place cautionary notes if the possibility looms

kafklatsch

I like your idea, and if you notice the engine seal strip..., it goes inside the jumper and panel. So the charger cord could route through at the windshield... I am now considering doing this with my "battery tender" brand.... no fancy CTEL for me...

Barry Hanna

Exactly, it looks like connecting to M1 (if it’s threaded) with my ring terminal should be a pretty straightforward install and the connection cord would have an easy exit to wherever the routing is preferred. And, yes, all of the extension leads I’ve seen are fused.

waterzap99

For mine, I wound a think piece of copper wire around the ground to clip onto something. Then rubber block to hold up the hood. No issues

kafklatsch

Yes
That is acceptable for a down and dirty charge...it's what I do now,
but i like the idea by the original poster... i likely will switch over to his suggestion

btw... that compartment is pristine...my own is a 10.... you're somewhere above that... nice
Cheers