Electrical Question

kopper_bass · Post by **kopper_bass** » Thu May 28, 2009 6:44 pm

OK,
I am a ME, and i stay away from the EE stuff, so i need some input here from you guys. i am trying to understand just how the on-board battery chargers work and see if i am getting the proper power to it from my Generator on my RV. When i first started charging from it, it seemed to work fine and i got all green lights. But of late when i charge from the generator, i get weird readings on the charger and it "appears" like i didnt get any charge at all - but i know i did because the batteries work fine and last all the next day. The charger works fine too once i am home and plugged into house AC.

So, here are my questions:

#1 -with a 4 bank dualpro that has 10Amps output for each bank, does that mean that it can draw a max of 40Amps total from the power source? If so, that would mean they are in parallel circuit, correct? aren't most all 120VAC circuits at 20 or 25Amps breakers? How does that work? If the output is maxed at 25Amps, then the 4 circuits just divide up that 25Amps evenly to each bank, right?

#2 - when 2 or more guys share an outlet to charge their boat for the night, i know that both are getting less current to their charger than if it was just 1 person; so i assume again they are in Parallel with each other and each has different resistance (mine is 4 bank, yours is 3 bank) so they both don't get the same, right?

#3 - i have a 4800W generator, so it has the capability to output 40Amps max. So, what should i be checking for at the outlet plug to determine what is going on? Should i be looking to read the Amps output, Watts? What could be the problem? I have checked fuses and plugs, all are working and the plug is showing 128VAC on the meter.

Thanks guys for help in advance. Hoping to avoid getting electricuted and not fry any electronics in the process.

Kopper

swim-bait com · Post by **swim-bait com** » Thu May 28, 2009 7:36 pm

Amps is not the issue,unless your tripping the breakers? The amp rating on the breaker(s) protects the circuit. In other words, if your drawing to many amps,the breaker(s) will trip. (in your case, 10amps per outlet). Since it's not tripping, it's not the amps.

Volts is what you need to determine...
A wiggy will help you test the volts($15.00-20.00 @home depot).
Varify that each outlet is putting out 120volts
If yes, no problem with the power source.

yes, the charger bank works fine from the house power.

the problem is the extension cord

#1) to long of cord

#2) the wire gauge of the cord. beef up the cord to atleast #12 wire
#10 would be ideal(for longer cords)

good luck

scottkh · Post by **scottkh** » Thu May 28, 2009 8:40 pm

You re trying to compare between apples and oranges.

Four bank battery charger puts out 10 amps at 12 volts, that is 120 watts (12 volts x 10 amps) for each battery. That means the charger is putting 480 watts total.

Assuming 80% efficiency of the charger, the total wattage would be 600 watts (480/80%). So the input amperage of the charge is at 5 amps (i = p/v, 600/120=5).

The 80% efficiency is just an estimate.

With the 4800 watt generator, you can plug up to 8 boats. (4800/600 =8 )

So, with proper wire gauge and length of cord as swim-bait said, you should be fine. BTW, i am an EE.

kopper_bass · Post by **kopper_bass** » Thu May 28, 2009 9:32 pm

Scott,
When the generator is running, its output is 120VAC, not 12V. So, the charger is wanting 4800W max. (per my calculations). I slightly mis-spoke, my generator is a 4000W generator.

I know i can (or could before) hook up at least 2 boats and charge them both quickly within hours, but now its not doing that. dont know why.

Swim-Bait,
I checked the outlet while the generator was running with a multi-meter, no load, and it registered 128V, so i am assuming its output is right. My thoughts were that the voltage is right, but the actual Amps were real low. not sure.

Kopper

mark poulson · Post by **mark poulson** » Fri May 29, 2009 5:47 am

Write down what kind of a light show you get, and call Dual Pro and ask them. They're the ones who know.

JLS (Jay Liu's Service) · Fri May 29, 2009 4:28 pm

Kopper Bass, Call me and I will talk you thru what is taking place. I can also tell you how to check your generater.

I don't like all this typing.

phone # 530 246-8051

JLS (Jay Liu's Service, trolling motor repair)

civicrr · Post by **civicrr** » Fri May 29, 2009 5:23 pm

If you write down the model of Dual Pro you have, you should be able to find instructions for it on the internet. I was able to find & download/save the manual for the charger in my boat.