Parasitic draw test Blue sea 7622 dual batteries

-Dual odyssey pc1200's
-Blue sea ml ACR
-Main battery has all stock functions
-Second battery accessory

I'm not really sure what's going on, but I think I've got some kind of draw killing my main battery.

When I go to start it and the key is turned to the accessory position the dash lights up normal (idiot lights illuminate)

Once I turn the key everything goes crap and I get very weak dash lights and the interior blue sea selector switch starts to flash very faintly.

I then force combine them, truck starts fine off both batteries. After it's started if I flip the switch to force separate them then flip back to automatic it will then reconnect after a couple minutes like normal.

It may be a radio issue, or have to do with an old alarm I tried to negate, and every once in a while the stereo will glitch out and restart.

My question is, what's the proper way to test for the draw? Do I need to disconnect the entire second battery and mlacr to properly get an accurate reading?

Thanks for any input

 

It gets better. I tested my main battery once all cables were removed and it read 12.6 volts. I don't get it, could the issue be ignition, bad ml acr, bad battery post connection?

 

I had a parasitic draw issue a while back. My mechanic mentioned that most of them are caused by aftermarket items.

Watch some Youtubes on the subject. Basically you are going to use a multi-meter to watch current flow, and disconnect one fuse at a time to see if the flow drops, indicating that the drain is on that circuit. The process is pretty straightforward but there are some intricacies. I like Eric the Car Guy's videos.

Some parasitic draw (around 60 mA) is normal.

Mine turned out to be the Scangauge that I had installed (aftermarket item!).

I hope that helps. Good luck.

 

Mr fish, were you using a current clamp or an in-line current meter to measure... I'm about to embark on a major electrical odyssey and am tooling up... Thanks!

 

I used a multimeter, on the mA scale, in-line.

There may be other ways and tools to do the same thing.

 

Curious about how you tested this battery. Just a multi-meter set to check the voltage? Or did you do it with a load tester?

 

how did you check the current flow on the scangauge? doesn't it plug into the diagnostics port?