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How to hook up a battery charger/maintainer?

K

kenora

Member
This is a T-18.

The battery is inconveniently located behind the baggage area (I will be changing that as soon as I can).

I would like to know (please) how to hook up the charger to the a/c.

I am embarrassed to say I have always crawled into the back of the airplane to do this but am getting too old (and fat) for that and would like an easier way.

Positive to ????? (I am thinking its the battery side of the relay on the firewall!)

Negative to ???? (ground).

I know I should know, but I don't so please don't berate me too much. I learn by asking.:confused:

Thanks

Tim
 
Get a voltmeter...

kenora said:
This is a T-18.

Positive to ????? (I am thinking its the battery side of the relay on the firewall!)

Negative to ???? (ground).
Tim
Click to expand...

...if you're trying to determine which side of the solenoid is attached to the positive battery cable, with the Master off. Then you can attach the + charger cable there and the other to a good ground.

This, if I understand you correctly..
 
Yes, you could do it the way you are thinking. When the master switch is off you will have an isolated circuit for charging. What I did for my PC680 was to wire a charger lead from the battery to a bracket near the oil door. That way, I only have to open the oil door and plug the charger into the lead; I'm sure you could run leads to a more convenient location in your aircraft. I'm using one of the Battery Tender chargers, which has a nice quick-connect for the charging leads or alligator clips; depending on your charger you may have to work something out that you can connect to.
 
Be advised, if the leads are hooked up in reverse and the battery is totally discharged the battery may take the charge in reverse and be reversed when it is fully charged.

A friend did this by feel with an Odyssey battery under his instrument panel and the next time the master was turned on, there was blue smoke quickly everywhere. Fortunately, the avionics circuit was not powered but it did cost a few bucks replacing many fried wires. :)
 
I lost my taste for charging the battery in the airplane after once seeing the remains of a Luscombe in wich the owner had done just that.:(
 
Remember that a smart charger

will NOT charge a dead battery, you need a dumb charger to do that. I have a "smart" charger on my firewall, but if I leave the master on I have to put a dumb charger onto the battery to wake the smart charger up to start charging. I love the convenience of opening the oil door and just plugging in an extension cord onto the standard three way plug I have mounted onto the engine mount, but I sure wish my charger had a dead battery switch.

Hans
 
If you install a charger pigtail, make sure it has a fuse in it. This way, if the terminals get somehow shorted, all you loose is a fuse, not an airplane.

Here is an example - we actually use this type on all of our club's gliders (batteries get charged after every day's flying). The fuse is an automotive ATC blade style, housed in a plastic cover. The charger connection has the ground connection exposed and the positive recessed, and has a plastic plug that fits onto the terminal very solidly. Nice design, nothing to short.

ring%20terminals2.JPG


TODR
 
I wired in a small float charger that is permanently mounted in the bay aft of the baggage compartment (as is my battery) and installed a recessed male plug in the bottom of the fuselage. I have a small cap that covers the plug while flying, but I simply take off the cap and plug the airplane into an extension cord to keep my battery topped up. Note this is a float charger and it will only maintain a charge, not charge up a discharged battery.

greg
 
I bit the bullet and removed the rear panel at the rear of the baggage compartment to get to the battery. I tried to remove it but found it too heavy to lift up out of the box given the awkward location, consequently I unhooked the battery cables and then used a "dumb" charger to bring it up and then hooked up my "smart" float mode charger.

Turns out the solenoid on the firewall was for the starter.

After the incredible PIA it was to get to the battery I decided I will be moving it forward about a foot into the baggage compartment for easier access, besides the C of G would be easier to manage as its too easy to load this a/c at its rear limit.

Thanks all and I will be wiring the float charger for easy hookup.

Tim
 
I am currently going through some charging issues and am thinking about wiring in a pigtail so I can just charge it..
 
Wire size/length for charging

Tim,
Glad you got things sorted out. But to the rest of us... I have seen a couple of guys plug their maintainers into the cigarette lighter then walk away. Well, if the battery isn't up, the charger kicks into high gear. This COULD cause the smoke detector to go off if the wires from the lighter are too small to handle the higher charge current.

I did what "flion" and "the other dough reeves" did, put the fused pig tails under the oil cooler door.
 
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