Trickle Charger Question

[N80]

My mother has a little Ford Ranger that sits in her garage and gets driven maybe once every three or four months. The battery, which is only a year old, is often dead. I can jump it and drive it a bit and get it charged back up but then a few months later and its dead again.

So I bought this little 1.5 amp trickle charger that stays attached under the hood. So all my mom has to do is unplug a regular three prong plug from an extension cord and go.

Schumacher Onboard Battery Maintainer — 12 Volt, 1.5 Amp, Model# SE-1-125 | Battery Maintainers | Northern Tool + Equipment

The problem is that the instructions say that you connect the positive wire to the positive battery terminal and the negative wire to metal on the chassis or engine. Well, I can't find anything to hook it too that isn't painted or plastic. It is hard enough when jumping it to find something to hook the jumper cable to and even that is scary close to the fan belt.

I'm an idiot when it comes to electricity, so I'm just wondering what is the risk of hooking that negative lead to the negative battery terminal and not the chassis? If it is serious I'm just going to have to buy some additional wire to try to run that lead all the way down to the frame or something.

[scesnick]

you could sand a bit of paint off where you hook the ground wire to the body. I usually just use the negative battery terminal. Not sure if that is the wisest thing to do, but so far I have had no issues doing it that way.

[whistlepig]

There is some danger of a spark over the top of the battery where hydrogen gas may have collected. I have blown up a battery this way. You have to blow up your first battery to really appreciate how deadly these things may be.

[ultrarunner]

Find a sheet metal screw or add one...

The guys in the old time car clubs hood the leads to the battery cable clamps.

Some of the later models also use a cigarette lighter adaptor...

[grsthegreat]

The reason they don't want you to hook it up to the battery is the spark that will happen when the ground (or hot lead) is hooked up to complete the circuit. Batteries can disperse Hydrogen gas...think Hindenburg.

By connecting the hot to the battery first and the ground to the chassis, the spark will happen away from the battery. I agree with sand away a little paint under the hood.

[N80]

So it is okay to use a body panel if you get the paint off it? That will be fairly easy.

[deepNdirt]

I know the type charger you talking about, I use to have them in my Boat, and kept them connected directly to both the battery terminals, it might say recommended to connect the ground to the frame or metal part although as you might guess not much in a boat in the way of metal to ground too
if you are not comfortable with connecting both wires to each terminal and if you happen to mount the charger to a metal part, fender well etc, simply bring the ground wire back around to one of the holes that you will put the bolt or sheet metal screw into,
Most all vehicles have a ground strap coming from the frame to the body parts at some location, you may see one from the firewall to the engine and one from the engine to the frame,or even from the frame to the body, its all tied in together with grounds at some point,

[firedog]

Those are instructions for typical hooking & unhooking charging cables or devices. The negative connection at the frame/chassis should be the last connection made so that any spark is made away from the battery.

What I think your talking about is a permanent install of a battery tender. Once the device is connected there is no longer a risk of spark unless it disconnects for some reason (think alligator clips).
All of our emergency response vehicles have battery maintainers that are connected directly the the battery terminals. These are permanent installs by professional folks. I see no reason to connect straight to the battery as long as the connections are solid. You may have to install a different type of battery cable connection with a stud for additional connections.
During your installation process there would be no spark at the battery unless you had the charger/maintainer powered up at the time.

[whistlepig]

Those are instructions for typical hooking & unhooking charging cables or devices. The negative connection at the frame/chassis should be the last connection made so that any spark is made away from the battery.

What I think your talking about is a permanent install of a battery tender. Once the device is connected there is no longer a risk of spark unless it disconnects for some reason (think alligator clips).
All of our emergency response vehicles have battery maintainers that are connected directly the the battery terminals. These are permanent installs by professional folks. I see no reason to connect straight to the battery as long as the connections are solid. You may have to install a different type of battery cable connection with a stud for additional connections.
During your installation process there would be no spark at the battery unless you had the charger/maintainer powered up at the time.

You can blow up a battery this way. I have done it. I have one of these chargers and it has a lead kit install for the battery if you want to check it out. Save A Battery

[N80]

It sounds to me that if I attach the charger to the terminals without the charger being plugged in, then I'm unlikely to get a spark. It also sounds like if I ventilate the area over the battery, with a fan maybe, then there won't even be anything to ignite if there is a spark. And it sounds to me that once the charger is attached to the terminals that there is no more likely to be a spark than just from the battery cables.

The leads from the charger have loops on the end to attach it, not a clip or anything that can slip off or move.