battery charger question

Coyote · Post by **Coyote** » Fri Apr 10, 2009 9:14 am

I have had the pictured charger for about 30 years. It has charged countless batteries in its time and still works. Now I just use it as a tender in the winter months.
This thing is very small. It measures 3 3/4 wide by 2 by 2. As you can see, the output on this relic is only 6 - 12 watts. Anybody know what this would equate to in amps?

johnakay · Post by **johnakay** » Fri Apr 10, 2009 9:36 am

I would've thought around one amp as I have a similar. its nearly as old as me and that to works.

Coyote · Post by **Coyote** » Fri Apr 10, 2009 10:09 am

After some online research, I find that amps = watts divided by volts.
Sooooooo 12 watts divided by 110 volts equals 0.109 amps -- about 1/10 of an amp. At 6 watts the amps are only 0.054 or about 1/20 of an amp.
Is this right?

johnakay · Post by **johnakay** » Fri Apr 10, 2009 10:12 am

what ever it is. its a trickle charger thats for sure.

advant63 · Post by **advant63** » Fri Apr 10, 2009 10:43 am

delete. i thought it is dual voltage

Post by **oldjapanesebikes** » Fri Apr 10, 2009 10:47 am

Coyote wrote:After some online research, I find that amps = watts divided by volts.
Sooooooo 12 watts divided by 110 volts equals 0.109 amps -- about 1/10 of an amp. At 6 watts the amps are only 0.054 or about 1/20 of an amp.
Is this right?

The output is 12 volts, so it actually would be 6 or 12 watts divided by just the 12 volt output = 0.5 to 1 amps to the battery.

Just for info - I use a small solar cell for trickle charging - its output is up to about 80 mA, or about 1 watt at 12 V. Works fine, and its really cheap to operate !

Coyote · Post by **Coyote** » Fri Apr 10, 2009 1:57 pm

You're right Ian. I divided by the line input voltage instead of the output voltage. That makes sense now.