2 bank battery charger

[661Bass'n]

Got a question, I am not power/electrical smart, I have a onboard 2 bank charger for my trolling motor batteries. I have not wondered too far from home, until this coming weekend, so I am wondering if anyone uses a portable generator to power thier onboard chargers. My question is, how small/big can I get away with, keep in mind I will only use to power the onboard charger that will charge my batteries while camping....thanks for the help...

[karlow]

Take a look at the charger and see what it's power rating is in watts at 110 Vac.
It's likely no more than about 250 watts. So I would think you can get away with 500watts AC

[DockRat]

Read on the charger the current draw. It should be in amps or watts.
If it is in amps then you will need to convert it to watts since most generators are rated in Watts.

Use Ohm's Law.

http://i1108.photobucket.com/albums/h403/geezer77/21427d1205693970-ohms-law-fuses-american-wire-gauge-ohmslaw.jpg

V, I, and R, the parameters of Ohm's law.Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistance between them.

The mathematical equation that describes this relationship is:
Where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.

Forget the above pic and definition; :Envious:
Let's go plain English.

Example; say you charger says 9 amps.

120 Volts X 9 Amps = 1080 Watts

If you had a 1000 Watt generator then it would not be enough.
The generator should put out 10% min or more than needed.
Don't under power your charger or you could have problems.

500 Watt Generator is good for a 400 Watt Charger
DR

[661Bass'n]

cool...my charger says the input is 5amps...I got a generator from harbor frieght, and they said we can bring it back within 30days. We just have to make sure we empty all fluids out of it...so, I have ran it with my charger already do problems noted, we will see Friday night as I fully recharge my trolling motor batteries after a day on the lake...

thanks for your help!!!

[DockRat]

5 a X 120 v = 600 watts useing Ohm's Law.

To do a more accurate calculation, check the voltage with a voltmeter.
Could be 110 volts or 130 volts ?

http://i597.photobucket.com/albums/tt57/nesc68503/Topical/Electrical/voltmeterCON_142.jpg
DR