ive got a xps 2 bank on board charger on my aluminum g3 and when its plugged in and charging i can fill some current on the boat not enough to fill with my hand but if i put my arm against it i can fill a lil tingle disconnect it and it stops all connections are good is this normal on an aluminum boat ?

Need more information.  

Are you sitting in the boat when you feel this, or standing beside it in a trailer, or sitting on a dock?  Are you feeling it on the hull?  If sitting in the boat, what else are you touching at the time?  Do you feel it once as you touch or release, or is it continuous while you are in contact?

You should not be feeling anything however it is possible to "feel" the 12 volt charging voltages under certain conditions.  

For safety sake, I would make sure you are using a grounded outlet to supply the charger and the charger uses a 3 pin connector too.  If the charger has a metal case that is grounded it may help to have this case electrically in contact with the hull.

I have 5 batteries in my Tracker with the negatives of 4 of them gounded to the hull (for sonar interference elimination) and when charging I have not noticed any voltage-to-ground leakage. I use a 3 bank Dual Pro for the bow trolling motor, and two Schumacher single bank portable chargers for the other two batteries.

If your boat is sitting in the water and you feel this remove the boat from the water or stop charging. I believe what you are feeling can cause electrolisis. I'm not sure of the spelling but what happens is a current field can start between your boat and the water and two different medals. I wish I knew enough about this to explain it, but I have seen the results and they amount to pin holes around the entire boat at the water line. My neighbor left his charger on all night while tied to his dock and his tin boat nearly sank from the holes. His insurance refused to cover the damage also.

This problem is the reason for anodes on motors and trolling motors. Maybe someone can explain it better..............Al

the boat is on the trailer in the driveway its plugged into a grounded plug  i cant really fill it on the gunnel rail but have 2 al brackets screwed to the rail and when i lean against those or put my arm skin on there i can fill a lil tingle i dont have anything grounded to the boat i thought the battery negative was the ground ? i dont fill it when its not plugged in the charger is screwed directly to the inside of an aluminum box could this maybe cause this should i put some rubber washers between the charger and boat to isolate it ?

Does it have a three prong plug on it?  If so, that means they probably have the case of the charger connected to the bonded ground.  It's possible you may be getting several ohms loss between where your switch box is bonded ground is and where you're boat is.  This has the possibility of developing a small voltage on the chassis of the charger and it's transfering it to the boat.  You can measure just how much voltage is there if you have a metal water line outside thats buried in the ground.  Park the boat next to it plug your charger up and measure the voltage between the hull of the boat and the water line.  Check it in AC and DC.    If it's very much, I would insulate the charger from the hull.   12VDC can  sting your arm when touching soft skin.  When hot and sweaty working on equipment, I have the batteries voltage sting me a lot, sometimes enough to feel like it's burning.  I've had 48 volt batteries down right shock me when getting soft skin grounded.

if the charger is setting on the boat, you may feel the small transformer of the charger, they'll hum and feel like vibration at times, just like the one next to your house, they hum and vibrate at times.

  You can't leak or lose ohms. Resistance can break down over time, but not in the manner that was mentioned.    

 Ohms is nothing more than resistance.    Is it possible to build an EMF with charging of 5 batteries?, I'd say so.     Ever walked under a power line and had hair stand up?   Or get that tingle feeling?

     

   

FWIW: I have two Guest chargers and they both have 3 - prong grounded plugs, but the chargers are fully encapsulated, ie no exposed metal.   Before you try to measure any voltage off the hull, make sure you are plugged into a GFI outlet.  

Matt Fly, I think not in my case. It's only 5 separate small 12V output transformers all powered from a single 120V outlet and are not combined into a single larger one powered by power grid voltage. It is not much different than having an entertainment center in your house with all it's components (all of which have a common 120V power source with multiple transformers). It has no comparison to the high voltage power grid.

Most transformers hum, whether they are a step up or step down transformers , no matter whether its 1000 volts or 5 volts, no matter if its on a telephone pole secondary grid or a $5.00 peanut transformer in a Sega Train track set.

It don't matter if you have 20 chargers plugged into the same outlet either.   Its not the supplied voltage causing any issues.

You can eleminate each one individually.    You can remove the leads individually on each battery to see if it disappears.   Every battery has individual leads from the bank charger or individual chargers.     Just remove the postive wing nut and remove those wires  on that battery, if systoms gone, you have isolated the problem .