chris-

so your saying to connect the entire shunt in the pos line and have the pos on the shunt face the pos on the battery and neg to the rectifier?

anyone to confirm this?  (not that i don't trust you chris, just seeing if anyone else has any valuable info).

hugh-  i think you may be right on the seperate power supply.  

chris-  i just tried hooking it up the way you suggesting and i almost let the magic smoke out.  two of the wires off the meter got orange and burnt up their insulation almost immediately.  i didn't even have a chance to put a load on it yet.  i'm not blaming you at all.  anytime i hook things to a battery not knowing exactly what i'm doing, i accept that i may ruin things.  the meter doesn't appear to be ruined though, just need new wires soldered into the old plug.  the backlit part still works!  

so back to square one.  maybe next try i'll use a seperate power source like hugh said.  see if it works that way.  

http://www.thebackshed.com/Windmill/articles/PanelMeter.asp

If you have a old unused network card you can use the inverter to provide the isolated power.

thanks so much for taking the time to walk an electronically challenged person like myself through all of this.  

 the original plug was fried, and the wires were 26 awg (so hard to do anything with) so i soldered new and longer 20 awg wires to the existing prongs sticking out the back of the meter.  hooked it up like chris said (twice) in the neg leg.  hooked the power for the unit to a seperate source, and wow, it works!  so then i got greedy, and tried to hook the power for the unit to the same battery i'm using.  wow, still works, but the reading vary by around 55 amps.  so this thing obviously need a seperate supply as many of you mentioned.  

by the way, i'm testing this meter by measuring current being pulled from the battery rather than charging the battery.  it is just easier to get it figured out this way.  then i hook a harbor freight meter up in the negative line along with the shunt meter, and the HF meter reads around .2 of an amp higher than my new meter.  there is a tiny screw on the back.  could this be for calibration?  i don't even know if it is worth calibrating it to a three dollar HF meter...  

i don't know if anyone is still even following such a basic thread, but my next question is if there is a super easy way to trick the meter into thinking it is on a seperate power supply?  like i said, i'm not super good with small electronics.  could a simple transformer work?  if i ran a transformer just for the meter to, say, change 12 VDC to 24VDC, would that do it?  

i know glenn gave me a way to do it, but i don't have an old network card and caps around.  

maybe it's time i read some books on DC theory.  

i think the .2 of an amp id fine for this unit.  if i end up going 12 volt, this is less than 3 watts.  nothing to get my panties in a bunch over.  

ghurd-
no it is not high dollar.  

i like your analogy of the man with two watches  :)

i do have a few small UPS systems.  brand:  APC model: ups-es 500.  i got them for free, so tearing one apart would not be a big deal.  do you think there may be enough electrical bits in one of those to create a isolated power supply to trick my meter into thinking it isn't connected to the batteries it is monitering?  

those ups things are pretty cool.  you can use them as a battery charger or an inverter!  i've been playing around with a little larger unit from APC and found it works really well as an inverter and doesn't need grid power to start up!  yay!  have a small inverter now for free!

thanks again for the help.  

yea the .2 amps difference @ 12 VDC was from a HF meter and my new digi amp meter. the unit will take between 6 and 24 volts to power it.  i'll take rovers gestimates that it will draw 40-60 mA seeings it IS backlit.  

the reason i'm being so intent on not having a seperate power supply is because i plan on using this up at my ranch.  it's a three hour drive and i already need to remember lots of things IE: chainsaw, potable water, deer feed, food, beer, water connections for rain barrels, building materials, gas, propane ect.  

i don't want to have to remember if my shunt battery is full or not, and if i need to bring an extra.  although, now that i think about it, i guess i could use rechargeable 9volts to do the job.  and recharge them up there.  it just seems like it would be soooo much easier if the meter just ran off the bank.  nothing to dink with once it is set up.  

maybe i'm fighting an uphill battle here.  i was hoping to not have to spend the money on a doc watson, and have heard they aren't reliable for their rated capacity, but maybe that is the best solution.  

who knows. i'm sure i will have a clearer view once things are running.  

all of your folks help has been much appreciated!