Newbie With A Battery Charger Question

[cdhan]

My bass boat has three batteries. Two 12-volt for the TM's and one 12-volt starting battery. I'm looking at the 3-bank onboard chargers but had a question about the circuit size of my outlets in the boat building. Will I overload my 20 amp wall outlet if I plug all three batteries in there with a 3 bank 10 amp per bank charger?

[Long Mike]

In a word, No. You will not overload your wall outlet. Without going into the math, your charger is converting 120V AC to 12V DC. The charger is demanding less than an Amp from your outlet.

[scrutch]

The input current listed for a Minn Kota MK345 onboard charger (3 banks, 15 amp per bank) is 7 amps. Other MK models use up to 10 amps of input current.

Pro Mariner 3 bank chargers can draw up to 14 amps of input current, depending on the model.

Check your manual for the input current listed for your model charger.

[Nitrofreak]

20 amp supply is more than sufficient for most all chargers, couple of things to keep in mind is try not to use long extention cords, make sure the cord you do use is rated to handle the loads and are in good condition, get a decent battery check tool, or take the batteries out once a year and have them checked for health, a short in a battery can lead to trouble, and make sure you read all of the info supplied in the manual.

As a back up I would suggest a GFI wall socket, electronic chargers have come a long way, but peace of mind for that just incase scenario is always a plus.

[cdhan]

Thanks to everyone who replied. I kind of figured I would be OK with my 20 amp outlet, just wanted to be sure. Yes, the outlet will be a GFCI and the extension cord will be a short run.

[SDoolittle]

try not to use long extention cords.

I've always heard that, but I've never understood why. Can anyone explain?

[win222]

I've always heard that, but I've never understood why. Can anyone explain?

Extension cords cause a voltage drop, chargers are designed to operate on 120 volts, if you use a long cord, and the current (amps) are high, you can actually lower the voltage alot, once the voltage drops under the manufacturers specfications, you can reduce the life of equipment or even burn it up.

[scrutch]

The longer the cord, the larger the wire size needs to be to eliminate voltage drop. You can use a 100 foot cord, but it needs to be at least 12 gauge wire.

[Way2slow]

A three bank charger that's putting out 10 amps per bank will only place an approximate load of 400 - 500 watt's, depending on how much internal heat loss it has. 500 watts on a 115 VAC line is less than five amps. Even at 20 amps per bank, you should still be looking at less than 10 amps.

As for a drop cord, for most chargers, you could easily run a 16 AWG, 100 ft drop cord and have no problems. If the charger was drawing 5 amps, that would only be about a 4 volt drop. More than enough voltage at the charger to still run and cause no problem. If you used a better 14 AWG drop cord, there would only be about a 2 volt drop. So, unless you are running iddy biddy drop cords or pulling a lot more than five amps, I wouldn't worry about a drop cord.

Most chargers will still operate at full potential on 105 VAC. I think my ProMariner says it will work just fine on 90 - 135 VAC.