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recharging bottle battery with a different AC charger?(5 posts)

recharging bottle battery with a different AC charger?redman
Jan 12, 2002 2:44 PM
What would it do to my Vista-lite bottle battery (couple years old) to recharge it with an AC adapter that wasn't designed for it?

My Vista-lite AC charger output is 7.5 VDC, 300milliamps if I remember right, and the charger I want to use (Palm m500 AC charger) has an output of 5.0 VDC, 1.0 A "regulated."

Need to ride home with my light tonight (the charger is at home) but I don't want to cook the battery.
re: recharging bottle battery with a different AC charger?B2
Jan 12, 2002 4:11 PM
I did something similar to that (charged with a lesser voltage) with a radio battery a number of years ago. The battery didn't work real well after that. It never lasted very long after that. Although after about 50 more cycles it slowly came back to near full strength, but never as good as it should have been.

Bryan
More amps ok, less voltage not ok....Bruno S
Jan 12, 2002 8:36 PM
When recharging batteries the recharger has to have aprox. the same voltage as the batteries. The higher the amp the faster it will recharge them. Fast recharges can decrease lifetime by 1 amp is still pretty low. You will not cook your batteries but they will not be completly recharged with the 5V charger.
VOlts need to macth, careful with amperagesalmonwheel
Jan 14, 2002 10:00 AM
Voltage needs to approximately match.

Generally charging system that don't include a "smart charger" or rapid charging system have no protection from overcharging. Charging a battery generats heat too much heat can destroy a battery over time. To protect against this batterties are charged with trickle charging. Meaning a low amperage (say 1/10, can't remember the safe rules of thumb, of the total amperage of the battery) slowly charges the battery. If the battery is fully charged the heat can be dissipated since it is being charged slowly and will not tend too overheat. If you up the amperage on the charger significantly (i.e. try to charge the battery faster) heat from over charging is not dissipated fast enough and the overheating can reduce the life of your battery if your not careful.

Smart charge systems monitor the charge (some by monitoring the temperature, others the change in voltage) to charge at a fast rate initially then trickle charge when the battery is close to being fully charged. So you can charge a battery with a fairly high amperage just be careful not to let it over charge.

At a past job we used a variable rate charger to recharge batteries for our radio telemetry stations. If we had a time crunch, we would charge at a high amperage (having done the math with conservative assumptions) then top off with the trickle charger.

High versus low amperagedepends on the amp hours of you battery. 1 amp is high if you have a 2 amp hour battery, but is low if you have a 10 amp hour battery. The system I built uses a 7.2 Ah battery that I charge with an 800 milliamp charger. Fast charging doesn't decrease the life of a battery ( i.e. the number of charge/discharge cycles) heat does.

I hope this helps.
re: recharging bottle battery with a different AC charger?Peter
Jan 13, 2002 7:41 PM
Think of it this way: Voltage is pressure. If the charger can deliver only 5V of pressure, the battery will only charge up to 5V. The system is designed to run at a higher voltage so the battery will never reach higher than 5V, insufficient to provide full illumination from the bulb. Typically, a charger's output is higher than required by the battery (i.e., the battery is probably a 6V), but the charger's voltage output will drop when under load from charging the battery, if that's of interest to you.

The best solution is to purchase a spare charger to keep at your "other" location.