BZ MPPT250 and other controllers

I wonder if some of the solar experts could help me diagnose the problem with my charge controller. I have talked to Manufacture and the retailer and they both claim the problem must be with my system.

I recently purchased BZ's MPPT250 controller. I really wanted to get one made in the USA and the write up from the retailer, a company called Go Electric in Alhambra California, made it seem like a good choice. Well, after I started having problems with it not performing as promised (I was actually get less amperage out of the controller than the solar array was producing), I asked if I could exchange it for a PWM controller. They gave me the run around and told me no one has ever complained so the poor performance in my system must be due to some other problem and would not do an exchange. Now that I have read about BZ's products on the various forums, I know I'm not the only one having a bad experience. Some experienced solar techs have even called BZ's controllers junk.

This is how my system was configured. There are 2 Kyocera 120 watt panels on the roof of my RV. the run from the panels to the controller is 12 feet of stranded 6 AWG. From the controller to the 12V battery bank the run is 13 feet of 6 AWG, for of 25 feet total. the panels were originally wired in series (per BZ's recommendation) and the batteries are brand new. On an average day in November at 11am, the panels produce 39v at 3.9 amps (readings taken at the back of the controller). The output from the MPPT250 to the battery bank varies from 2.8 to 5.7 amps at 12.5 to 13 volts. The manufacture had me check the voltage drop to the battery (they said the had to be the problem) which was 0.0 on the negative side and 0.03 on the positive side.

I thought MPPT controllers were supposed to have a 30% gain, that's why they cost so much. I really don't see how there can be a problem with my system as the retailer tried to infer because I was taking all the readings at the controller. I also told them that if the panels were wired in parallel, I felt I would be getting close to 8 amps from the array (which is why I wanted to switch to a PWM controller).

I have now rewired the array in parallel and it is producing 8.9 amps at 19 volts, but the MPPT250 is still only sending about 5amps to the batteries at 12.6 volts. Does this right? I thought the problem might be that the batteries cannot take more than 5 or 6 amps when their charged to 12.6 or 12.7 volts but no ones ever mentioned that. Also, there is a constant load on the batteries from the radio, water pump, and gas refrigerator that draws a small amount of current everyday.

Anybody have any ideas about the cause of my problem or was I expecting to much from the controller? Since a PWM controller is just a pass through device, I would at least get what the solar panels are producing. Right now, I think I'm losing half my capacity. BZ said there is no way the problem is with the controller,so I think I'll just have to wright it off as a loss (they never got back to me after the last call).