Wierd Emag pwr issue - Batt OK but voltage low at board

[Aegis]

Can't quite figure this one out - using a new battery which is charged to 20.5 volts. Getting the low batt message, so started checking things out.

Down to this - with the rail off, I am metering from the frame ground to the positive terminal in the rail, the one that contacts the battery terminal. I get 7.9 volts there, and it drops off .1 volt every few seconds - stopped counting at 6.5 volts

Just for grins, I pulled the red wire off the positive terminal. Connecting the battery showed 20.5 volts coming through, so it appears the board is drawing the battery down in a huge way.

Any ideas?

[Tunaman]

sounds like a short or a bad ground. How are the insulators on the positive terminal?

[Aegis]

The insultators are fine. I pulled the red wire and reinstalled the terminal post to make sure. I would go with the bad ground idea, but I am metering at the same spot that produces full battery voltage when the board is not hooked up - from the top of the negative/ground pin in the frame that is pressed into the frame, and the positive post.


If the board had a bad ground I could see how it would not get enough voltage, but that should not draw the battery down - I think.

Thanks for the reply - this is my son's marker and we are playing again soon, want to get it up and running.

Edit:

Checked the ground - I get 0 ohms resistance measuring from the ground lug on the board to the board retaining screw and to the ground lug at the battery mount. This seems wierd, though - not much resistance through the board, does anyone know what kind of reading you should get from teh postive terminal to the negative terminal in ohms? Starting to feel like a short.

[LittlePaintballBoy]

Up, someone must know something that could be causing this!

[Aegis]

Might be on to something here - while checking for shorts, the red power wire pulled right out of the heatshrink at the positive terminal. There is not a trace of solder in the strands - hope that is the problem, either way it is good to find out.

[LittlePaintballBoy]

Help please!!!

[BlackVCG]

Run a tap through the board mount screw hole.

Are you sure you have a nylon insulator on BOTH sides of the positive lead wire? There should be one on the bottom side of the grip frame and on the top side and the lead wire loom goes over the insulator ring that's inside the frame and then the nut holds it down.

[Aegis]

Thanks for the response. I will check the board mount screw hole. previously I had measure the resistance from the screw to the frame and the board to the screw and frame, without finding any measureable resistance.

The positive terminal does have the correct isolators installed. It is not a dead short, that would probably arc considering the strength of the battery. I confirmed this by removing the red wire and reinstalling the positive post, full voltage present.

The positive lead wire was defective from the factory, there was about 1/16th of exposed wire in the lug with absolutely no tinning on the strands at all. I resoldered that, and had an immediate improvement in that the emag would boot and function for about 75 cycles w/o air before flashing the damn low batt message again.

The battery had been on the charger for several hours and peaked at 18.4 volts. It was 16.2 after being on the marker for a few minutes. Now that it has been off the marker for a few minutes, it is back UP to 17.4. Wierd.

[Aegis]

Just in case anyone has a similar issue, it was a bad battery. Voltage was OK but under a minimal load it failed.