winter battery minding & correct size battery?

[dw1]

This is really two topics, but they are related ones.

I know these have been discussed before, but with new products & technology on the market, it is worth revisiting.

First item:
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"smart" battery chargers, standard trickle chargers, and battery tenders?

In simple terms, what is the real difference between a "smart" low-amperage battery charger, i.e. one that changes delivered current and/or shuts off at a designated battery condition vs. a battery tender?

A related question: I see a lot of battery tenders for motorcycle use. Is there a difference between a motorcycle and auto battery tender, assuming they are both for 12v systems? Is one brand/model superior to others?

Is it just best to work around the whole issue and remove the battery from the car if its not going to be driven for a few months, and charge it immediately before re-installation?

Second item:
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What the heck is the correct size battery for an '87 3.2? I've seen references to groups 48 & 49, and a range of CCA. The Interstate MTP-93 (850 CCA) I have for the car now barely fits. (Yeah, I know Optimum will be suggested, but I don't know if I want to go that route.)

Thanks,

- dw
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'87 black/black Carrera 3.2 G50 sunroof coupe w. f&r spoilers, fabspeed euro premuffler, dansk 1-in-2-out, bumperettes deleted, bump steer kit, euro ride height, CDR-220, etc.

[Dublinoh]

First question.....don't know.

Second question......you must avoid acid spill...it will be expensive and can't be ignored. So buy a gel type battery. A 48 size is good, plenty of power and reserve and lighter than a 49. Braille 7548 is a 48 size so it will fit without a custom battery holder, and it is a sealed gel type. That is what you want unless you are trying to reduce weight for racing. Cost is $235+ but should last longer and acid repairs are potentially way more.

[arbita1]

First Question...

This is the one I got. It was recommended by Optima for their batteries.

XTREME PULSE TECH BATTERY CHARGER MAINTAINER | eBay

[E Sully]

From a previous thread.

Originally Posted by Noah930

I have a Schumacher that I recently bought from Walmart. It was under $20 a few months ago, now bumped up to a grand $25. Plus $2 shipping and handling, IIRC. Admittedly it's for motorcycle use, but will work on car batteries as well. It just takes a bit longer, but if you're storing for the winter what difference does that make?

This model was one recommended by a motorcycle list I'm on. The administrator is a retired engineer who (IMO) seems to spend an inordinate amount of time testing these types of things. He feels most battery float chargers (including the Battery Tender line) don't fully charge batteries. They work, but they only charge up to about 13.6-13.8 volts. For a battery to be fully charged, batteries should actually be charged up to 14.4-14.6 volts. The charger may not float the battery at that level, but it should bring it up to that level before floating. Batteries will still work if not charged 100%, but apparently won't last as long. Because every manufacturer says their product works just fine, the only way to really test this is to sit there with a voltmeter and watch what happens after you plug the charger in. I have a voltmeter hardwired into my motorcycle, so that makes it easy to see what's going on.

The one I am using:
Walmart.com: Schumacher SpeedCharge Battery Maintainer and Charger: Automotive

Another one that supposedly works:
http://www.harborfreight.com/6-12-volt-electronic-battery-charger-and-maintainer-with-lcd-display-65834.html

Disclaimer: I am not an engineer, and my understanding of electrical systems rates at about the time the Constitution was written. I'm just regurgitating stuff I've read on the interweb. I'm sure someone can explain this more eloquently than I.

I figure if a guy smarter than I has put in substantial effort into figuring these things out and the recommended product is only about $25, why not? The other charger I've got, a Yuasa, cost about $60+ and doesn't work any better.

[nineball]

i have been using battery tender brand products for 10+ years and never had a problem with any type of battery, specifically lead acid and agm. it's like that old commercial - set it and forget it. literally. i use them on my car, my motorcycle, my lawn mower, my dad's backhoe, his lawn mower, the spare battery i have on my bench, etc etc. basically anything with a battery that sits through our ohio winters.

Battery Tender - Home of the Battery Tender Jr. - Batterytender.com

[scottb]

This is the one I use: Schumacher Charger

I mounted it next to the battery, and it's out of the way and unobtrusive. The car sits on charge when I don't use it (which is for weeks or months at a time), but the battery stays "topped off."