Hi all.

Here's a weird one.  So I reinstalled Windows 10 onto my laptop earlier in the week so had to go through the process of reinstalling everything I use on it, one of the programs being Forscan.  Anyway, I install the drivers and Forscan then I take it out to the car to check it's communicating with the car properly.  All goes well, just did a connect to ECU, checked for any DTC's as it was heading for MOT in the morning then disconnected.

I disconnected by ignition key to off, close Forscan on laptop then remove odbii plug from socket under dash.

 

Fast Forward to next morning, come out to take car for MOT and turn key, click / flat battery.  Throw battery on charger for a bit and car starts, go for MOT, car runs fine for the morning.  When I get home, as a precaution, I disconnect battery negative lead for 30 minutes.  After 30 minutes I:

01/ setup multimeter between disconnected earth lead and negative battery pole and watch amp draw.  500mA on the meter.

02/ check battery voltage: 12.6v on meter

So I reconnect battery backup to car, start car, run for 5 minutes then get my clamp meter out (I have a normal multimeter and a clamp meter).  So I wrap the clamp around the negative wire coming from the pole on battery and switch off ignition then close door and check clamp reading.  500mA. then I:

03/ open door to trigger interior light, meter rises momentarily to 1A then backs off to 500mA.

04/ similar with car stereo, on then off, clamp reads similar, meter rises momentarily to 1A then backs off to 500mA.

Finally, with car running, check battery voltage, around 14.1v so alternator appears to be fine.  Alternator was reconditioned 1 year ago, new battery 1 year ago.

 

So, come out this morning after leaving car overnight to a hard frost this morning.  Pop bonnet and check battery voltage, reads 12.6v.  Car starts first time, plenty of cranking power in battery.

Suppose my questions are:

Q1/ have I connected and disconnected Forscan properly? as it's like one of the modules on the CAN bus stayed awake and flattened my battery overnight?

Q2/ Is 500mA OK for a trickle drain for the fist 20 minutes after switching car off?  I'm assuming 20 min as the red Info panel on the dash stays lit for 15-20 min then goes out after key off.

Any ideas, as I've got a bad back at the minute and can do without lying upside down probing fusebox, chasing false parasitic drain, if I don't have to.

thanks in advance.

 

 

31 minutes ago, Bar72 said:

Q1/ have I connected and disconnected Forscan properly? as it's like one of the modules on the CAN bus stayed awake and flattened my battery overnight?

Possibly. Always click the disconnect button before closing the program

 

31 minutes ago, Bar72 said:

Q2/ Is 500mA OK for a trickle drain for the fist 20 minutes after switching car off?  I'm assuming 20 min as the red Info panel on the dash stays lit for 15-20 min then goes out after key off.

Yes, PATS probably draws this much

Are you sure that the Battery was flat as opposed to having a coincidental temporary starting glitch.

I have been using FORScan for years and never had a Battery drain problem, so I doubt it is a FORScan problem.

5oo mA is higher than I would expect for a car of that era after 20 minutes, although I would expect that with a more modern car. Personally I would leave it at least double that time and check it without waking anything up. For that car I would expect less than 50 mA once fully asleep. 

2 hours ago, DaveT70 said:

Possibly. Always click the disconnect button before closing the program

 

Yes, PATS probably draws this much

 

thanks for the info Dave.  Come to think off it, think I just clicked the top right X in the forscan windows and not disconnect.  I'll bear that in mind for the future though.

 

32 minutes ago, Tizer said:

Are you sure that the Battery was flat as opposed to having a coincidental temporary starting glitch.

I have been using FORScan for years and never had a Battery drain problem, so I doubt it is a FORScan problem.

5oo mA is higher than I would expect for a car of that era after 20 minutes, although I would expect that with a more modern car. Personally I would leave it at least double that time and check it without waking anything up. For that car I would expect less than 50 mA once fully asleep. 

 

Yeah Tizer, pretty sure.  It's a 60Ah / 500 CCA battery so cranking a 1.8 petrol is usually effortless to it.  The usual flat battery symptoms of a click from starter solenoid / Led Panel on Dash dimming when trying to turn it over.  The alarm goes off everytime I lift the bonnet without unlocking it so I'll try rig the switch on the bonnet catch so it doesn't wake up the CAN bus on lifting.  I'll report back when I've measured it for 45m - 1hr and see what the reading is.

OK, so I pulled the wiring plug for the bonnet catch, hooked up meter and left for 1 hour.  It's only drawing 10mA which isn't a parasitic drain then.  I'll keep an eye but possible a glitch with not disconnecting from Forscan properly?

Thanks for the info on what it should be drawing Tizer, that's a good reference for future use.

2 hours ago, Bar72 said:

possible a glitch with not disconnecting from Forscan properly?

I mostly use my Wireless Adaptor with the Phone version of FORScan and I normally just pull the Adaptor without closing FORScan so the contents of what I have recorded remain in the phones cache and I have never had a Battery drain problem.

Wired Adaptors with the Windows version may be different though.