Xantrex 600HD Battery Losing Charge?

1. Six years isn't bad life for a gel cell battery, although critical applications (burglar alarm backup, for example) often replace them every two years.
2. All lead acid batteries last longer of kept properly charged. Batteries that remain at zero charge for extended periods typically do not recover when you attempt to charge them.

There's reason the manual says to charge the battery every three months...

John

Thanks. Cute. That explains some other battery failures I've had in the past. I don't ever recall reading that, but then again I probably did not read the section thinking maintenance might not be much of an issue other than not storing it in a hot environment, keeping it on a cold concrete floor, not placing it water, or some similar obvious need. To bad they didn't put that in very large letters on the battery. However, if it hadn't been charged for about 4 months, which is about right, why would it have gone down? Maybe it was longer. Suppose it spent 12 months on the shelf of a store, wouldn't it drop to zero?

Maybe I can get a discount on another one? :-)

Most (all?) rechargeable batteries will self-discharge, some faster than others. For flooded lead-acid batteries it is generally recommended that they be charged once a month to compensate for self-discharge. Gel cells have a somewhat lower self-discharge rate, so can probably tolerate longer periods without charging.

A lead-acid battery (flooded or gel) will become sulfated (an insoluble non-conductive coating of lead sulfide will form on the plates) reducing the usable capacity of the battery - it will then appear to charge, but won't be able to deliver much current.

I've had mixed success reviving batteries with a desulfator (also desulphator) device. It sends a high voltage/current pulse into a sulfated battery with the intent of converting the lead sulfate back to a usable compound. In several attempts with an inexpensive kit (~$20US delivered on ebay) I had success with two 6 volt 12AH batteries (wired in series to use a 12 volt rated desulfator). I had less luck with a 12 volt 3AH and a 12 volt 8AH. The desulfator got the voltage up to somewhere between 8 and 11 volts, but not to the normal 13-14 volt range achieved on the 12AH batteries. Each battery was on a charger adjusted to deliver a C/10 charge to the battery while the desulfator was connected.

I don't know if original quality, battery age, or time in "dead" state were factors in the ability to recover the batteries - the ones I tested were of various vintages and several different brands. Since they were "dead" as far as any use (other than as door stops) I wasn't concerned about any damage that might occur from using the desulfator. Considering the price of two 6V 12AH batteries, I did a little better than break even on the cost of the device. If I use it successfully on another battery, that will be profit.

If you have larger batteries that you want to try a desulfator on, the price goes up with battery capacity - there's a formula for peak current based on battery AH capacity, but I don't have it handy. The simple pricing is $2/AH for the battery you want to recover: 10AH battery, $20 device; 40AH battery, $80 device. Some of the bigger devices have huge components and large wire (#2 or better) to handle the peak currents.

No promses - just a report on my experiences.

John

I found my manual in the garage, and dug around for awhile (there is no index or TOC.) and found a passage I had highlighted that said for best operation charge every three months. Long forgotten by me. In the next sentence it said one can continuously charge the battery.

I'll call Xanetex Monday and see what the scoop is.

I have another battery from CostCo that's mainly for jump starts. I've had it longer, and hardly ever charge it. It seems to be doing well. Probably cost $30-$40. I think it's called a Power Pack, and definitely older than the Xantrex. It has a deterorating sticker near the handle that gives some maintenance tips. Do not charge beyond X hours, etc. It had a full label on the front until about 4 hours ago when I pulled it off and through it out. Not quite sure where. The basket here doesn't have it. 600 something still on the front.

Be careful with continuous charge.

One cannot continuously charge a battery without causing the battery some harm, unless the charger is designed to produce a "float" or "trickle" charge, or in some other way limit the charge when the battery is "full". Even with float or trickle charging, there may be a problem. A "smart charger" that charges the battery only when needed and shuts off between charges seem the better approach.

In some applications there is a trade-off of reduced battery life versus convenience; sometimes crap is sold with little or no attention paid to battery life, as long as the product outlasts the warranty period. And a product manufacturer's description of how to charge the battery in the product might differ from what the battery manufacturer says.

Ed

I'll check with Xantrex tomorrow. Too bad there isn't an alarm that goes off when the charge gets low. Our cell phones have one--a chirp every minute. Of course, since I keep the battery in the garage, there's not a high chance I'd ever hear it.

What you can do is build an on/off circuit for the charger, that is controlled by the battery voltage. If the voltage drops below X, turn the charger on. When the voltage goes above Y, turn the charger off. Or, just put a note on the calendar to charge the battery on the first day of each quarter - or something like that.

Ed