DIY: Permanently mounted battery trickle charger (maintainer)

[bmailpb]

If you're like me and don't DD your Mustang, a battery maintainer is the best way to keep your battery in good condition between drives. Modern cars have a lot of electronics that never fully shut down and can slowly drain your battery if you don't keep a small charge on it.

The de-facto standard is the Battery Tender. However, it is upwards of $50 with the alligator clamps. Add $$ on top of that for the permanent mount kit (because if you don't get the permanent mount kit, you have to remove your battery box cover every time to attach the kit, and if you close your hood while plugged in, you run the risk of knocking the clamps off)

Enter the DIY solution:

The optimal trickle charge for a car at 12v is between 1amp and 1.5amps. What do we have here? A charger that outputs 1.3amps and has overcharge protection? Perfect - http://www.ebay.com/itm/272004329420?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
(note, I tested on my craftsman digital multi-meter and it puts out 1.27amps and does stop charging when the battery is full.)

But wait, we already said above that alligator style clips doesn't help us. Right you are. What we need is a way to permanently attach leads to the battery with a quick disconnect.

$2.18 with free shipping AND its fused for us? FANTASTIC. http://www.ebay.com/itm/401172289501?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Finally, we need a way to get the power from our charger to the quick disconnect plug. That'll run you a whopping $1.18. http://www.ebay.com/itm/391484577090?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT


1. Take charger, cut off alligator clips
2. Strip back approximately 1" of wire
3. Red to Red, Black to Black with the bare end quick disconnect wires. Solder or twist together. Cover with heat shrink or electrical tape
4. Install the ring terminal connections to the battery (the nuts are 10mm for removal). Tuck the extra wire and the fuse into the battery box. Run the quick disconnect out from the battery box and allow to hang out with the grounding cable that runs through the grommet
5. Plug your charger into the quick disconnect and into the wall.

Total cost (assuming you have some heat shrink or electrical tape laying around) - $7.xx

When you are ready to go for a drive, just unplug, close the hood and take off.

Sponsored

 

[THX 138]

I just use a Porsche-brand battery maintainer that plugs into the cigarette lighter. :shrug: Yes, it was more than $7.00, but I'm not popping the hood every time I want to park the car for a few days either. YMMV.

 

[Mspeedster]

I just use a Porsche-brand battery maintainer that plugs into the cigarette lighter. :shrug: Yes, it was more than $7.00, but I'm not popping the hood every time I want to park the car for a few days either. YMMV.

I also have the Porsche battery tender (made by Ctek). Does the Porsche cigarette plug work in the Mustang? I believe for Porsche it says to use it in the actual cigarette lighter plug only, not in any other AUX outlet. So I was afraid to try it in the GT350. I also have the battery clamps, which I've been using when the Shelby sits for an extended period.

 

[bmailpb]

I just use a Porsche-brand battery maintainer that plugs into the cigarette lighter. :shrug: Yes, it was more than $7.00, but I'm not popping the hood every time I want to park the car for a few days either. YMMV.

If it's part of your routine, it's not a big deal. I always cover the car after driving, so connecting it is just an additional 30 seconds.

 

[chuckty101]

I just hookup my CTEK Comfort Connect Eyelid to the fuse box under the hood. No need to removed battery cover for charging.

 

[bmailpb]

I just hookup my CTEK Comfort Connect Eyelid to the fuse box under the hood. No need to removed battery cover for charging.

That's fantastic. And this is a diy for those that want the same thing without paying $40 for a ctek and then $12 for the comfort connect.

 

[chuckty101]

That's fantastic. And this is a diy for those that want the same thing without paying $40 for a ctek and then $12 for the comfort connect.

With the comfort connect 3 style traffic lights. Just at a quick glance under the hood, It will tell you if the battery is fully charge (green light) on, partial charge (amber light) on, or need recharging (red light) on. Best $10 investment made for my GT350.

 

[Mike02z]

I went a little further with my hard wire. Pictures are from my former 16 GT. For the GT350 I mounted the connection under the front bumper. Totally out of sight but easy to get too.

 

[bmailpb]

With the comfort connect 3 style traffic lights. Just at a quick glance under the hood, It will tell you if the battery is fully charge (green light) on, partial charge (amber light) on, or need recharging (red light) on. Best $10 investment made for my GT350.

Which doesn't help you actually keep it charged when sitting for 2+ weeks like mine often does.

 

[chuckty101]

Which doesn't help you actually keep it charged when sitting for 2+ weeks like mine often does.

:headbonk: LOL

 

[tom_sprecher]

I'd be leery of a cheap, no-name battery tender plugged in all the time ready to catch fire in my garage. It's not worth the money saved.

There is a Deltran Battery Tender Plus down in my garage that I have used for 15 years on my Harley, a couple of race cars and the YJ. No, it's not $7, but it is US made with millions of units in service for decades.

 

[Mike02z]

I'd be leery of a battery tender plugged in all the time ready to catch fire in my garage. It's not worth the money saved.

There is a Deltran Battery Tender Plus down in my garage that I have used for 15 years on my Harley, a couple of race cars and the YJ. No, it's not $7, but it is US made with millions of units in service for decades.

I agree. CTEK and Deltran are both very good tenders. I have 3 Deltran tenders that are at least 10 years old. Never had an issue. I only went with the CTEK for my Mustang as I've heard so many good things about it. Also that Porsche, Koenigsegg and other high end cars use them. It seems to work fine but does seem to get a bit warmer than I'd like.

Avoid cheap tenders like the plague. You may get away with it or it may just break in a short period but ask yourself if it's worth the risk. We all paid a large sum of money for our cars. Don't get cheap when it comes to a tender or you may regret it.

 

[THX 138]

I also have the Porsche battery tender (made by Ctek). Does the Porsche cigarette plug work in the Mustang? I believe for Porsche it says to use it in the actual cigarette lighter plug only, not in any other AUX outlet. So I was afraid to try it in the GT350. I also have the battery clamps, which I've been using when the Shelby sits for an extended period.

Yes, it works in my GT350. The reason the instructions say specifically to use it with the cigarette lighter outlet only is that the cigarette lighter outlet is always "hot"; it isn't key-switched. Most Porsche/Audi/VW auxiliary outlets are only active with the key switched on, so plugging the battery maintainer into one of those ports will not charge the car (and could, depending on how the port is wired, create a fire hazard). :cheers:

 

[ARS1]

Getting some good ideas here as this will be a must for mine. It's going to be a garage queen and mostly covered up and cozy. After the new car excitement wears off that is! Nothing worse than wanting to go for a drive only to find a dead battery...

 

[bmailpb]

Just checking in for the naysayers. 3 months running constantly on my GT350 and a 2nd identical one on my 911. Checked with multi-meter this morning, still perfect output and the auto-off feature is working too.

Sponsored