PicoScope 7 Automotive
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Parasitic Draw and a modified 1965 Chevrolet Impala
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hexibot43
- TwoWaves
- Posts: 123
- Joined: Tue May 10, 2011 5:27 pm
- Location: Redwood City, Californa, USA
Parasitic Draw and a modified 1965 Chevrolet Impala
I am currently working on a car that will kill the battery of this car in little over a week. I really tried to display a picture of the draw with my Picoscope. I just can't do it with any of the low current amp clamps I have in conjunction with my Pico 4423. I even had them rewired with no coiling of the wire and BNC terminated cable. The noise is too much. I would love to be able to look at this with my Picoscope. Just have not had success yet.
1965 Chevrolet Impala. Charging while running at 14.6 volts. Diodes look good. I read with a built in amp meter on my Vantage Pro a reading of 55 mAs drain on the battery. I have a group 24 130rc battery in this car now. Had a 115rc group 24 battery in it before. So new battery and same issue. So I don't believe the issue is with the battery itself. I will take a reading over night tomorrow of the change in open circuit voltage over the course of 24 hours.
As it is right now. By the charts I have of "state of charge" and "Reserve Capacity" in relation to "state of charge" over time. It says I should be able to last 25 days before the battery is to low. I installed the new battery yesterday and it was at 12.60 volts. I am at 12.50 volts this morning. Now looking at the charts again - I am at 90% state of charge. I lost 10% of my charge over night. That is no good. Next day much more promising. Battery now at 12.49 VDC. And the next day after that reading of 14.48 vdc. There must have been a surface charge on the battery when I started this. And today reading 14.48 VDC. Much better. We are going to install a battery tender as well. As it is right now I think it will last at least a couple weeks if not a month. The lost in "state of charge" is better in line with the tables I had for testing.
Now my vantage pro is a graphing multimeter as well as a DSO. I took a look at it graphed and was surprised. I did not expect a pattern like I am seeing here. I am guessing the 55ma is an Average. But does that truly represent the parasitic draw on the battery? Or is there something else I am missing or should be looking at?
Thanks Marcello
1965 Chevrolet Impala. Charging while running at 14.6 volts. Diodes look good. I read with a built in amp meter on my Vantage Pro a reading of 55 mAs drain on the battery. I have a group 24 130rc battery in this car now. Had a 115rc group 24 battery in it before. So new battery and same issue. So I don't believe the issue is with the battery itself. I will take a reading over night tomorrow of the change in open circuit voltage over the course of 24 hours.
As it is right now. By the charts I have of "state of charge" and "Reserve Capacity" in relation to "state of charge" over time. It says I should be able to last 25 days before the battery is to low. I installed the new battery yesterday and it was at 12.60 volts. I am at 12.50 volts this morning. Now looking at the charts again - I am at 90% state of charge. I lost 10% of my charge over night. That is no good. Next day much more promising. Battery now at 12.49 VDC. And the next day after that reading of 14.48 vdc. There must have been a surface charge on the battery when I started this. And today reading 14.48 VDC. Much better. We are going to install a battery tender as well. As it is right now I think it will last at least a couple weeks if not a month. The lost in "state of charge" is better in line with the tables I had for testing.
Now my vantage pro is a graphing multimeter as well as a DSO. I took a look at it graphed and was surprised. I did not expect a pattern like I am seeing here. I am guessing the 55ma is an Average. But does that truly represent the parasitic draw on the battery? Or is there something else I am missing or should be looking at?
Thanks Marcello
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hexibot43
- TwoWaves
- Posts: 123
- Joined: Tue May 10, 2011 5:27 pm
- Location: Redwood City, Californa, USA
Re: Parasitic Draw and a modified 1965 Chevrolet Impala
On day 2 of this testing. I made a roster of the individual drain points and realized 2 of them didn't need to be power at all time. re-wired those devices. I still have an average drain of 55ma but no chatter. Basically a straight horizontal line. The drain is very consistent with one single blip to 80ma Once every couple of seconds. Much more what I am use to seeing of a vehicle with an aftermarket alarm on it. It is now working well enough.