battery tender hook up
Thread Starter
Instructor
Joined: Aug 2023
Posts: 116
Likes: 12
From: Canton, GA
battery tender hook up
I know im going to get lots of im beginning to be the king of dumb questions.
I just bought a battery tender for my car. Ive seen some threads and videos of people hooking up the positive of the tender to the positive of the battery and negative to negative. Ive also see as many discussions on just positive to positive and the negative goes to a ground on the vehicle somewhere.
Is there a reason? is one more correct or is the amperage low enough for no worries on the negative to negative.
Just curious.
Greg
I just bought a battery tender for my car. Ive seen some threads and videos of people hooking up the positive of the tender to the positive of the battery and negative to negative. Ive also see as many discussions on just positive to positive and the negative goes to a ground on the vehicle somewhere.
Is there a reason? is one more correct or is the amperage low enough for no worries on the negative to negative.
Just curious.
Greg
Drifting
Joined: Feb 2012
Posts: 1,429
Likes: 113
From: Brick NJ
I'm a fan of putting the positive to the positive terminal just under the positive post under the fuse block located under the hood, and then going to the ground terminal near the driver side shock that holds up the hood and running the cable out to the front of the grill, also by using the posts just mentioned when you have to change out a battery or disconnect for any reason you wouldn't have to deal with removing and re installing the ring terminals to the battery, as far as where you choose to connect it doesn't matter either location will get 12 volts to the battery. Just be sure to use the supplied fuse supplied with the battery tender.
Le Mans Master
Joined: Oct 2017
Posts: 5,427
Likes: 2,309
From: Billings Montana. Out in the wild west
I'm a fan of putting the positive to the positive terminal just under the positive post under the fuse block located under the hood, and then going to the ground terminal near the driver side shock that holds up the hood and running the cable out to the front of the grill, also by using the posts just mentioned when you have to change out a battery or disconnect for any reason you wouldn't have to deal with removing and re installing the ring terminals to the battery, as far as where you choose to connect it doesn't matter either location will get 12 volts to the battery. Just be sure to use the supplied fuse supplied with the battery tender.
That’s how I did mine.
CF Community Team
Joined: Apr 2016
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From: Pittsburgh
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Positive wire on the charger to the positive post on the battery, negative wire on the charger to the negative post on the battery...done
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Thread Starter
Instructor
Joined: Aug 2023
Posts: 116
Likes: 12
From: Canton, GA
Ive already ordered the alternator.
at least this way Ill be sure to have a charge after car sitting for several days at a time.
the answers on this thread also verify my point in the question as ive gotten both answers here with no one proving one is better or worse than the other.
Greg
Drifting
Joined: Jul 2022
Posts: 1,364
Likes: 433
From: Central, Mass
The separation of the Wire's is to prevent sparking with the Battery letting out fumes, but long before all the lawsuits and now safety features, I cant count the times I have jump started a car and or truck and Flicked the posts on the battery with clamps to make sure there is spark. LOL Never blew up or maybe say lucky I didn't. But one can get hit by lighting just walking outside! 
I always go straight to battery.
I always go straight to battery.
Safety Car
Joined: Aug 2013
Posts: 4,430
Likes: 608
From: Minneapolis Mn
I wired the plug like turnerg1's picture shows. The connector ends are under the nuts on the cables by the battery. I figured even if the battery was disconnected I could get power via the trickle charger to open the doors etc. I did order a longer set of leads as the ones that came with the charger were only about 18"-24" long.
Thread Starter
Instructor
Joined: Aug 2023
Posts: 116
Likes: 12
From: Canton, GA
So I guess I need to do more digging. After having the tender on my car for several days and showing solid green (float mode) I tried to start the car today. It clicked, all dash lights came on and nothing.
tried again just in case nothing.
Took the tender off and measured battery voltage 12.39.
I'm going to lift the car to be sure the starter connection is sound.
Have had no issue with starter though since I did the harmonic balancer but who knows. Maybe the exhaust connection is leaking on the starter? Maybe wires were already shot?
Maybe my battery is so bad now it can't pull a start even with a reasonable charge?
Greg
tried again just in case nothing.
Took the tender off and measured battery voltage 12.39.
I'm going to lift the car to be sure the starter connection is sound.
Have had no issue with starter though since I did the harmonic balancer but who knows. Maybe the exhaust connection is leaking on the starter? Maybe wires were already shot?
Maybe my battery is so bad now it can't pull a start even with a reasonable charge?
Greg
Burning Brakes
Joined: Sep 2010
Posts: 935
Likes: 385
Hey OP, very basic maintenance suggestion for you, but check out your positive and negative battery cable connections to the battery first. Make sure they are clean and TIGHT. If they are, then your idea of checking connections at the starter is a great idea.
By the way, there are no dumb questions here, so feel free to keep asking.
By the way, there are no dumb questions here, so feel free to keep asking.
Thread Starter
Instructor
Joined: Aug 2023
Posts: 116
Likes: 12
From: Canton, GA
Hey OP, very basic maintenance suggestion for you, but check out your positive and negative battery cable connections to the battery first. Make sure they are clean and TIGHT. If they are, then your idea of checking connections at the starter is a great idea.
By the way, there are no dumb questions here, so feel free to keep asking.
By the way, there are no dumb questions here, so feel free to keep asking.
Just not sure why after 3 or 4 days sitting on a tender it went from starting to nothing.
It probably has to do with either my hookup or the battery is so shot that the tender killed it. I'm at a loss.
I measured the positive nut where I put the positive lead and the ground where I put the negative lead and it reads battery voltage.
Greg
Melting Slicks
Joined: Mar 2013
Posts: 2,157
Likes: 244
From: carlisle pa
I've seen so many gadgets and set ups over the years, plug it in to cigarette lighter, run wire across drivers seat so you can't forget to disconnect, run wire out the drivers side door at the bottom, there is even an indentation to lay the wire in...
Drifting
Joined: Jul 2022
Posts: 1,364
Likes: 433
From: Central, Mass
Yup did that for a couple years, now with mag plug even easier, 🙂 I also forgot to unplug it once when I got back seen connector laying on floor just plugged back in to charge again. 🙂
Thread Starter
Instructor
Joined: Aug 2023
Posts: 116
Likes: 12
From: Canton, GA
I used my neighbors hand held jumper and it started right up. so I did end up getting a new battery and have no issues at the moment.
I do still need to install the alternator I purchased as a secondary measure since the battery was only 1 year old and dead. Of course as ive found out its mostly been my driving habits because I only drive short distances when I do take it out. Shame on me.
I do have the tender permanently mounted so this should do it for me.
Greg
I do still need to install the alternator I purchased as a secondary measure since the battery was only 1 year old and dead. Of course as ive found out its mostly been my driving habits because I only drive short distances when I do take it out. Shame on me.
I do have the tender permanently mounted so this should do it for me.
Greg