
Originally Posted by
bsasuper
Charging a motorcycle battery is best done at only 1 amp , so most of the retail ones have more than enough grunt.
Yep.
Ideally, batteries require two separate charge cycles. Firstly, they should be charged up to about 14.9-15.5 volts. Then the charger should reduce charge to float them at about 13.8 volts.
The exact figures depend on the type of battery (Lead acid, GEL, AGM etc), and also on the capacity of the battery, the shape and area of the plates, and even temperature.
But the alternator on your bike does not consider any of these things, it just ramps up to about 14.5 volts, and chucks out as much current as it needs to maintain this voltage.
So motorcycle battery manufacturers make the battery as tolerant as possible to cope with a wide range of charging regimes.
Even a tiny charger, that is rated at only 1 amp will charge a vehicle battery, as long as it has a terminal voltage of (about) 14.5 volts.
So all the ones at Supercheap will be fine, as long as you have the time to wait. For example, the 200 amp/hour battery on my boat, if fully discharged would need more than a week...
The main problem with cheap chargers is that they are often completely unregulated. This means that sometimes they don't have a terminal voltage high enough to do the job.
And sometimes they have a terminal voltage that is much higher. This is a problem, as while the battery is heavily discharged and drawing lots of current, these chargers will be OK (as long as they don't melt.)
But when charging is complete, the poor old battery is no longer drawing much current. So it cops the full 16-18 volt output of the cheap charger. Soon the battery will have too many electrons, and it will start to gas, producing hydrogen. This is very hard on a battery, especially if done for a long time.
"Battery tendas" are designed to have a terminal voltage much lower than the gassing point of the battery, so they are a useful tool if you don't use your vehicle often.
The other thing that a charger can do is damage your bikes electrics if you do not remove the battery before charging.
Many chargers do not output pure DC. You get rectified AC, which is just fine for a battery. But the "peak" voltage is higher than the rated voltage. A charger that has a nominal 16 volt DC output, may in fact have a peak output of 23 volts !
That's the voltage it will be trying to apply to your battery, and all your bikes electrics if they are connected while charging with this kind of charger.
Some smaller bikes have a shunt voltage regulator. It will try and regulate the battery charger.
If it loses, you get to buy a new regulator. If it wins you get to buy a new charger.
Even some larger bikes will be extremely stressed by having a big, unregulated charger connected while the battery is in the bike.
My suggestions ?
1. A small unregulated charger is just fine, as long as you keep an eye on it, and remove it from the battery when its charged.
2. If you don't have a charger specifically designed and rated for use while the battery is in the bike, always remove the earth lead or battery from the bike before you charge.
3. Ride your bike every day so you don't need to charge it.
David must play fair with the other kids, even the idiots.
Bookmarks