This is not strictly a MB question. I just bought a 12 volt battery for use with a generator. The battery is of the sealed variety and there is no means to add or remove water. The purpose of the battery is to run the generator’s starter motor. We haven’t needed to use this generator for years.

The question are:

1) will there be a difference in battery life if we just leave the battery unconnected verses connected?

2) how long would the new battery hold a charge, providing its not connected?

TIA

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...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Assuming the generator does not auto-start and the cables are easy to attach, leave it disconnected (one cable) and charge it at least once a month. Since this may be difficult to remember a Battery Tender would be a good idea and you can put it on a timer to be energized about 4 hours per day.

Typical auto batteries will usually last at least five years if they are not severely discharged. The best one I ever had lasted eleven years, and I average about seven. (I also live in a mild climate that does not see very low or very high temperatures, and this is undoubtedly a factor in favor of long battery life.)

My experience with small batteries (such as motorcycles) is that they will not last as long as a larger automobile batteries - about five years at best with good maintenance - i.e. keep them charged, don't crank the engine with the battery signficantly discharged, and never inadvertantly/accidentally discharge them to a "dead" state.

"Maintenance free" batteries are a definate asset on a system that is not regularly used. Maintenance free batteries self-discharge about one percent per day at room temperature (faster at elevated temperatures, slower at colder temperatures). The old maintenance type batteries discharged at about three percent per day at room temperature.

Duke

Thanks!

Before your post, I thought that batteries discharged much quicker in cold climate. Is your comment only applicable for new and unused batteries? I debated leaving a trickle charger on it, but was worried about the charger failing after many years of running, over charging the battery, and causing a melt down...

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Overcharging is definitely a concern, even with a new trickle charger. They are not all created equal. I do not have a specific brand to recommend however. I think it is fair to say that once it is in trickle mode that you wouldn't want to see the voltage above 13.2 for long term trickle charging. Does anyone else have a specific answer on this? Is your battery a gel-cell type? This might effect the charging recommendations somewhat.

Mike

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

I recommend one of these units. I have been using the Jr model for a couple of years now for winter storage maintenance, with excellent results. Their products are much more than the usual trickle charger. Lots of good information on this on their website http://batterytender.com/

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1986 560SL
2002 Toyota Camry
1993 Lexus

Where can I buy one of those in Canada?

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1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz

I believe the Battery Mart listed here http://batterytender.com/dealers.php?osCsid=326b2e931693d969d63a0361d6ef9b13 can ship to Canada. I've got two of the Battery Tenders, one for winter storage of my John Deere mower & one for my wifes RX-7 that sits for several months each year. They work great.

Self-discharge is a chemical reaction, and chemical reaction rates generally increase/decrease exponentially with temperature. Thus, a fully charged battery will discharge slower in cold temperatures than hot temperatures.

The Battery Tender and similar devices turn off and on relative to battery charge state, and, if operating properly, will not overcharge the battery. Conventional chargers should not be left on a battery indefinitely, even at their lowest setting.

You can also insure against overcharging by powering a Battery Tender off a timer that you use to turn lights on and off when your not home. Setting the timer at about four hours per day should be okay, but you want to monitor it for a few days and be sure the green light is on when the timer turns off. This means the battery is fully charged.

Duke

Regarding battery tenders...there is a fine unit available at WalMart. Made by Schumacher and costs only about $18 US. If you have Wallyworld in Canada the price should be comparable. I have three of them and keep my old car batteries fully charged through the winter when the cars are in storage. FYI, I checked available equipment at local parts houses and found a nearly identical unit at the Checker Auto...$45!

230/8