Ctek battery maintainers: Useful when installing new?

[Frodo]

I’m wanting to install a new battery while maintaining all the computer settings/memory items. I’ve got a Ctek battery maintainer. Here’s what I’m thinking I can do (shown with the old battery)—will this work? If so, what setting should I use? (The regular automobile setting, or something short of that, ie the motorcycle setting?) Other than the obvious when working with car batteries (ie don’t short out the positive onto the car chassis or the neg post), anything I have to watch out for/avoid doing using this technique? TIA.

Full disclosure: this is on a 2019 Subi Forester.

[JFP in PA]

The MUS 4.3 does not have the "supply" mode setting that the larger CTEK maintainers do, which is what you normally would use for this purpose. That said, use the normal battery setting, AND BE SURE TO PUT PLASTIC BAGS OVER THE ENDS OF THE BATTERY CABLES after you disconnect them as they will remain "hot" because of the maintainer connection. When you install the new battery, hopefully an AGM model, connect the positive cable first, then the negative, being sure to not let them touch anything while you are in the process of connecting them.

[Frodo]

Originally Posted by JFP in PA

connect the positive cable first, then the negative

...took me a few years but I finally drilled this battery disconnect/connect sequence into my brain.

Originally Posted by JFP in PA

hopefully an AGM model

...indeed it is!


Thank you John.

[piper6909]

Does the battery maintainer have a cigarette lighter plug as well as battery clamps? If so, why can't back-feed from the cigarette lighter or "power socket"? This way you won't have to worry about extra wires in your way while you're swapping batteries and, more importantly, you won't run the risk of the clamps slipping off while you're messing with the battery cables.

[997_986]

The mnemonic is very simple, if i add something, it's (+) (first), i take something away, (-) (first) this is the correct sequence.

[Frodo]

Originally Posted by piper6909

Does the battery maintainer have a cigarette lighter plug as well as battery clamps? If so, why can't back-feed from the cigarette lighter or "power socket"? This way you won't have to worry about extra wires in your way while you're swapping batteries and, more importantly, you won't run the risk of the clamps slipping off while you're messing with the battery cables.

A good thought...I had been a little concerned about clamps popping off (esp the positive one).
I pulled out the bag of accessories that came with the Ctek to check. Does not have a lighter/power socket plug, but it does have this:





I can attach the red one under the nut that the red clamp is attached to in my first pic. The neg one I could probably slip over the threaded portion of the bolt over there at the top of the strut and throw another nut onto the exposed threads to hold it on.

Thanks for the suggestion

[piper6909]

Originally Posted by Frodo

A good thought...I had been a little concerned about clamps popping off (esp the positive one).
I pulled out the bag of accessories that came with the Ctek to check. Does not have a lighter/power socket plug, but it does have this:





I can attach the red one under the nut that the red clamp is attached to in my first pic. The neg one I could probably slip over the threaded portion of the bolt over there at the top of the strut and throw another nut onto the exposed threads to hold it on.

Thanks for the suggestion

You're welcome!
My concern is that if you loosen that nut to put the eyelet under it you'll lose contact and defeat the purpose of your effort. I can't tell for sure because the clamp is in the way, but you probably even have enough thread on the top bolt of the positive terminal for the eyelet and another nut. I think it's 10mm. It just has to grab for a little while, you don't need to thread all the way through the nut. If you don't have enough thread, do you have any old device that plugs into the cig lighter that you could sacrifice its plug? If so, cut it off and splice it onto that pigtail you found in the box.

[Frodo]

More good points. Looked around, found nuts that will fit both locations, so I’ll stack them on top of the existing nuts (with the eyelets in between, of course), thereby avoiding having to loosen either one in the process.

Originally Posted by piper6909

I think it's 10mm.

You were in the ballpark—it was a 12 mm

[10/10ths]

……the cigarette lighter plug to be “HOT” all the time. There are “half-moon” cutouts in the weather stripping on the bottom of both doors to allow a battery maintainer cable to pass through the shut door to plug into the cigarette lighter socket.