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Local Ford dealer is saying I can connect a maintainer directly to the battery and this won't have any affect on the BMS. The research I've done, seems to be mixed reviews if the BMS will be affected or not doing it this way.
Worse case, I'm thinking I'll disconnect the negative, leave the positive hooked up then connect the maintainer.
Anyone have experience using a maintainer and what are you doing? I need to keep it really simple as my wife will be needing to use the truck. So whatever setup I have, it has to be easy for her to return things to normal.
You need to hook the positive side to the battery positive and the negative to the chassis ground.
If you hook straight to the negative battery terminal, you are bypassing the BMS and your truck will not know the correct battery state of charge.
Things like auto SS, deep sleep mode, etc. might not function correctly.
chassis ground is circled in red.
Use ring style terminal clips for the chassis ground and the battery positive. Then you just plug in when you want.
I went a step further and got a 6’ extension for my CTEK maintainer and ran it down and out of the wheel well. I can plug in and charge without opening the hood at any time.
Last edited by 2008__XL; Nov 12, 2025 at 11:43 AM.
You need to hook the positive side to the battery positive and the negative to the chassis ground.
If you hook straight to the negative battery terminal, you are bypassing the BMS and your truck will not know the correct battery state of charge.
Things like auto SS, deep sleep mode, etc. might not function correctly.
chassis ground is circled in red.
Use ring style terminal clips for the chassis ground and the battery positive. Then you just plug in when you want.
I went a step further and got a 6’ extension for my CTEK maintainer and ran it down and out of the wheel well. I can plug in and charge without opening the hood at any time.
But if I'm just putting a maintainer on it; does it matter if the truck knows the correct battery state of charge? If so, I guess I'll just disconnect the negative and put the maintainer on.
You provided a good idea for a long term solution. For now I just need a short term solution.
But if I'm just putting a maintainer on it; does it matter if the truck knows the correct battery state of charge? If so, I guess I'll just disconnect the negative and put the maintainer on.
You provided a good idea for a long term solution. For now I just need a short term solution.
Short term, just use the alligator clips and clip onto the battery positive and the chassis ground. No reason not to as it’s no harder / easier then clipping to the battery negative.
That’s the proper way. And it does matter if the truck knows the batteries current state for certain features to work properly.
Is it the end of the wold if you don’t do it that way? No, but again, there’s no reason not to as it’s no more involved and would actually take more effort to have to unhook the battery negative and reinstall each time.
Do as you wish, but I would follow guidance above! Red to red/battery. Black to ground, not battery. If you go direct to battery, I do believe I once read, eventually the system will figure it out.
Just had a discussion about battery maintainers etc. in the 21 and up forum. Everything discussed is the same for our 13th gen trucks as well. IIRC, there is a link to Ford Tech Makuloco about the same subject, all good info. I suggest you go there instead of rehashing the subject. https://www.f150forum.com/f129/batte...essary-579316/
Last edited by johnday in BFE; Nov 12, 2025 at 03:52 PM.
good reminder, i need to hook my truck up to the maintainer tonight
Gotta move mine out of the barn, need room to work on something else. I plan on the same as you when I stick it back in, no telling when it'll see daylight again.
Short term, just use the alligator clips and clip onto the battery positive and the chassis ground. No reason not to as it’s no harder / easier then clipping to the battery negative.
That’s the proper way. And it does matter if the truck knows the batteries current state for certain features to work properly.
Is it the end of the wold if you don’t do it that way? No, but again, there’s no reason not to as it’s no more involved and would actually take more effort to have to unhook the battery negative and reinstall each time.
This is exactly what I do with my trickle charger: Negative aligator clip to the chasis. :-)
Short term, just use the alligator clips and clip onto the battery positive and the chassis ground. No reason not to as it’s no harder / easier then clipping to the battery negative.
That’s the proper way. And it does matter if the truck knows the batteries current state for certain features to work properly.
Is it the end of the wold if you don’t do it that way? No, but again, there’s no reason not to as it’s no more involved and would actually take more effort to have to unhook the battery negative and reinstall each time.
Is this the chassis ground? Saw your pic but my truck doesn't have something that looks like that.
What to do for battery maintainer?
