2003 Dynasty Chassis battery parasitic testing…Ranges and Discussion…maybe HOUSE as well..??

[MHRookie]

All,

     Background…

2003 Dynasty.  Lambert broke years ago.  Replaced with amp-l-start.  It’s broke now too.  Going to install Blue Sea ML-ACR….. BUT

In waiting to do this project, I notice the chassis is getting pulled down to below 12.5 in about 3 days.  I’d like to test the parasitic loads to see if something needs fixed.

shore power & inverter appear to be functioning properly as house batt bank is in float at about 13.2-ish…

my chassis battery has quite a few fuses connected here.  See these all ties to the chassis side of RV.  I haven’t tried tracing all this down in wiring books yet….

 

thanks for any insight/direction.

Kurt

[MyronTruex]

That could be very normal. Batteries that are not factory fresh can contribute but my owner's manual is quite specific about turning the chassis batteries off after about three days.

If you really want to chase it, then knowing how much current it is drawing to start is important. Things like step controllers alone can draw a tiny bit of current as well as engine and transmission computers. 

To get a baseline you need an ammeter. Using one properly can be tricky and lead to blow fuses inside the meters if they are protected properly.

The battery's positive or negative lead/s must be disconnected and the meter placed in series, along with being on a proper setting to handle up to about ten amps. Connecting a meter backward can cause issues as well. So take your time and maybe practice with some AA batteries before tackling the real job.

You will likely be looking at 150 MA up to 250 MA. If more than that, you have a serious draw that might be worth chasing. But in my humble opinion, 12.5 in three days is not a serious problem.

I have given this a broad brushstroke but don't want to complicate the issue. It is a matter of marbles in a bucket. How many are draining out over time? 

[MHRookie]

I’ll perform the parasitic draw tomorrow to see what the load is before I chase any fuses.

I need to get my drawings out also.  I think one of the 3 fuse panels in the FRB are linked to the chassis batteries also (not just the ones hooked close to the batteries in the back). 
I’ve seen some owners build a nice plate and attach it to the cross bar mounting each fuse nicely above the battery on/off switch…. That’s a small project I want to get done also.

thanks for your insight.

[MHRookie]

Myrontruex,

UPDATE - set tester on “MA”, unhooked neg posts, red probe on cable, black probe on -batt post…. 00.60 was the largest reading (all were between .50-.60).  Not worth chasing load (in my opinion).

I’ve removed chassis battery +wire from amp-l-start and hooked up another charger.  Time to install the ML-ACR…

Thanks,

mhrookie

[MyronTruex]

That is enough to run them down, but not enough for me to chase it in an RV. In a car that would be terrible. 150 ma is about as much as I would want 

Doing the math at 1/2 amp over X amount of hours will show you how quickly the electron buckets will empty.