Battery size for 84

[sat65]

My 84 came with an almost new Sears group 42 size battery. When that went dead a few months later, Sears was the only place around that had a group 42, so I bought another Sears silver battery. That one died quickly, and was replaced for free. Now I'm into the pro-rated part of the warranty, and this one won't hold a charge. Sears no longer carries group 42 batteries. Any recommendations for a modern size group that fits the 84?

Thanks,

Paul

BTW,

I don't know why this car keeps killing batteries. I've checked a few times for current draw when the car is off, but it is always very low (a few mA). I changed the alternator because the bearing was going out, but both old and new alternators put out around 14.5V. I keep a trickle charger on it when I don't drive it often.

[Gunslinger]

I'm guessing a group size 74 would be appropriate for your car...it was a very common and popular size back then. It's essentially a group size 24 with side terminals. You can measure your battery box for dimensions to be sure.

Your alternator may be charging volts but is it charging amps? The alternator's internal regulator could have been bad...and so could the replacement one. You said it's not drawing much current when turned off but there could still be an open circuit of some kind...but it still sounds like the alternator. Still...never overlook the obvious...check your alternator belt and make sure it's tightened properly.

Does your car have the hydraulic brake light switch? The battery in my '70 was draining for no apparent reason...one evening I went into the garage after dark and saw the tail lights on very dimly. The brake light switch had gone bad and current was passing through it creating the electrical drain. I installed a mechanical switch and disconnected the hydraulic switch and no more problems. I'm not saying this is your problem but it's something to look at.

The brake light switch that was bad was not very old...maybe 2000 miles on the car since it was installed. I guess it goes to show the quality of offshore made parts isn't that great compared to when the car was built.

[Devildog]

Another low cost suggestion, put a 'knife' disconnect on the battery to completely disconnect the battery while setting idle. there are also 'screw knob' type battery disconnects, but the knife blade style are quicker and surer to use.

Also with these older cars, it is easy to have not just a trickle short that drain the battery but a dead short that sets them on fire. Fiberglass body resin burns very nicely.

I use these on all my old cars, trucks, tractors, etc. that sit for days. they are available at auto supply stores, on line and RV centers have them (sitting for months...fires, etc).

Joe

My 84 came with an almost new Sears group 42 size battery. When that went dead a few months later, Sears was the only place around that had a group 42, so I bought another Sears silver battery. That one died quickly, and was replaced for free. Now I'm into the pro-rated part of the warranty, and this one won't hold a charge. Sears no longer carries group 42 batteries. Any recommendations for a modern size group that fits the 84?

Thanks,

Paul

BTW,

I don't know why this car keeps killing batteries. I've checked a few times for current draw when the car is off, but it is always very low (a few mA). I changed the alternator because the bearing was going out, but both old and new alternators put out around 14.5V. I keep a trickle charger on it when I don't drive it often.

[sat65]

I ended up buying a group 34N MAAX battery from Wal-Mart. It is the same depth, so the original top retainer bracket fits over it. It is about an inch longer and an inch taller. The extra height might have been a problem, with the cables reaching over the battery, but the polarity is reversed so I was able to rotate the battery, putting the terminals on the near side. It was not easy to slip it into the tray, but once in, it looks fine. I just need to make sure that the engine doesn't rock enough for the AC pulley to hit the corner of the battery. The original group 42 was only 500 CCA. The 34N is 800 CCA. It has a 3 year free replacement warranty, which will come in handy if I have trouble figuring out why this car kills batteries every 9 months or so.