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Home > Archive > Home Repair forum > February 2008 > Car current draw
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| ransley 2008-01-31, 5:26 pm |
| What should the current draw be with a car parked, for the night, not
running, Volvo v40 with factory alarm but never activated. How do you
check this. In the morning my battery is low. Can I use a 120v digital
clamp on amp meter.
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| gfretwell@aol.com 2008-01-31, 5:26 pm |
| On Thu, 31 Jan 2008 12:58:23 -0800 (PST), ransley
<Mark_Ransley@yahoo.com> wrote:
>What should the current draw be with a car parked, for the night, not
>running, Volvo v40 with factory alarm but never activated. How do you
>check this. In the morning my battery is low. Can I use a 120v digital
>clamp on amp meter.
No but you could use the Ma scale in series (disconnect the battery,
put the meter in line) but don't turn anything else on. You could
overload the meter.
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| Simpson 2008-01-31, 5:26 pm |
| ransley wrote:
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
I use the amp meter on a digital car multimeter. Normally, when not
running and key off, a car pulls just enough current to keep the
computer and the digital stereo settings alive, which isn't much. I
don't know exactly how much but I would bet it's way below a half an amp.
In any case, to track down a current leak, attach an amp meter and start
pulling fuses until you find the one that is pulling excessive current.
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| Pete C. 2008-01-31, 5:26 pm |
| ransley wrote:
>
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
You should expect a standby current of perhaps .1-.2A at most, composed
of the ECM, radio, alarm and any feature module standby demands.
A clamp on amp meter will only work if it is the AC/DC hall effect type.
Even then, the expected current draw is so low that a clamp meter
wouldn't work well. You will generally need to disconnect a battery lead
and connect the meter in series using the appropriate connections for
it's DC Amp range.
Something as simple as a failed switch on a trunk or hood light keeping
it on will greatly increase the standby current. If the standby current
looks reasonable then the suspects are the battery and the alternator.
Other more unlikely suspects would be stuff like air suspension
compressors running periodically due to a leak, or a power radio antenna
continuing to run after it's down due to a bad limit switch. I don't
know what a Volvo v40 has so no idea if any of those are applicable.
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| "ransley" <Mark_Ransley@yahoo.com> wrote in message
news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
My guess is lower than 100mA. If it is higher than 500mA, it is definitely
suspicious.
Clamp meter is for high AC current. You are trying to measure low DC
current.
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| hallerb@aol.com 2008-01-31, 5:26 pm |
| On Jan 31, 4:33=EF=BF=BDpm, "peter" <nos...@nospam.com> wrote:
> "ransley" <Mark_Rans...@yahoo.com> wrote in message
>
> news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
>
>
> My guess is lower than 100mA. If it is higher than 500mA, it is definitely=
> suspicious.
>
> Clamp meter is for high AC current. You are trying to measure low DC
> current.
fully charge battery and get it load tested, the simplest answer is
usually the solution. how old is your battery? if its over 3 or 4
years its probably bad
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| On Jan 31, 2:21=A0pm, Simpson <2-pa...@epoxy.com> wrote:
>
> In any case, to track down a current leak, attach an amp meter and start
> pulling fuses until you find the one that is pulling excessive current.
Note that if you do this on a recent Honda, you'd better have the
radio security code before you pull all power to the radio. When the
power comes back on, you have to enter the security code to activate
the radio. If you don't have the security code, you need to take the
radio serial number (located, of course, on the back of the radio) to
the dealer for them to look up the security code. It has been reported
in several Honda forums that some less-than-consumer-friendly dealers
have been charging for this information.
Volvo may or may not do this also, I don't know.
Jerry
Jerry
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| On Jan 31, 2:58=A0pm, ransley <Mark_Rans...@yahoo.com> wrote:
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
No.
Use a decent digital multimeter. Turn everything off, make a
connection to the battery negative cable and the battery negative post
(it can be done, be clever) and loosen the negative battery cable
clamp. With the meter set on MA, quickly slide the cable off the post,
take the reading and put the cable back on. For typical vehicles the
reading will be around 30-40 MA (YMMV). This technique won't screw up
fussy alarms, radio anti-theft codes and all that. When you get it
back together, check the charging voltage, which should be around 13.8
at idle, rising to 14.6 or so at 2000 RPM. If the system checks are
all good, read the Consumer Reports on batteries and go shopping for a
new one. Good luck.
Joe
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| Joseph Meehan 2008-01-31, 8:25 pm |
| Maybe if you told us why you are wanting to measure the current, we
might be able to give you some more direct help.
I will add that some cars will draw a lot more than usual dark current
right after they are shut down. Five or ten minutes may be needed before
they are down to static mode. And no you can't use an 120V meter which is
likely an AC only meter.
--
Joseph Meehan
Dia 's Muire duit
"ransley" <Mark_Ransley@yahoo.com> wrote in message
news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
| |
| Stormin Mormon 2008-01-31, 8:25 pm |
| Ransley posted several weeks ago. Original battery in his 2002 Volvo. If
memory serves.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
..
<hallerb@aol.com> wrote in message
news:aa903753-6b99-48fc-af07-810bedeba23b@q77g2000hsh.googlegroups.com...
the simplest answer is
usually the solution. how old is your battery? if its over 3 or 4
years its probably bad
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| Stormin Mormon 2008-01-31, 8:25 pm |
| Maybe my clamp on ammeter is defective. It doesn't specify 120 volts. I've
been using it on both 110 and 220. Maybe if I have to read 220, I need to
cut the amp reading in half?
You'll have to go to the auto parts store, and buy a 12 volt clamp on AC
ammeter.
Buy a new battery, and quit wasting our time.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
..
"ransley" <Mark_Ransley@yahoo.com> wrote in message
news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
What should the current draw be with a car parked, for the night, not
running, Volvo v40 with factory alarm but never activated. How do you
check this. In the morning my battery is low. Can I use a 120v digital
clamp on amp meter.
| |
| Edwin Pawlowski 2008-01-31, 9:25 pm |
|
"ransley" <Mark_Ransley@yahoo.com> wrote in message
news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
How old is the battery? It may not be the parasitic draw, it may just be
the battery slowly heading south. You can try disconnecting the battery and
see if it is weak in the morning. If so, replace it.
| |
| Joseph Meehan 2008-02-01, 9:25 am |
| I believe the problem is AC current vs DC current.
--
Joseph Meehan
Dia 's Muire duit
"Stormin Mormon" <cayoung61**spamblock##@hotmail.com> wrote in message
news:47a28026$0$8640$4c368faf@roadrunner.com...
> Maybe my clamp on ammeter is defective. It doesn't specify 120 volts. I've
> been using it on both 110 and 220. Maybe if I have to read 220, I need to
> cut the amp reading in half?
>
> You'll have to go to the auto parts store, and buy a 12 volt clamp on AC
> ammeter.
>
> Buy a new battery, and quit wasting our time.
>
> --
> Christopher A. Young
> Learn more about Jesus
> www.lds.org
> .
>
>
> "ransley" <Mark_Ransley@yahoo.com> wrote in message
> news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
> What should the current draw be with a car parked, for the night, not
> running, Volvo v40 with factory alarm but never activated. How do you
> check this. In the morning my battery is low. Can I use a 120v digital
> clamp on amp meter.
>
>
| |
| trader4@optonline.net 2008-02-01, 9:25 am |
| On Jan 31, 9:36=A0pm, "Edwin Pawlowski" <e...@snet.net> wrote:
> "ransley" <Mark_Rans...@yahoo.com> wrote in message
>
> news:ee967a13-25cd-468d-9219-4392fa420bb0@q21g2000hsa.googlegroups.com...
>
>
> How old is the battery? =A0It may not be the parasitic draw, it may just b=
e
> the battery slowly heading south. =A0You can try disconnecting the battery=
and
> see if it is weak in the morning. =A0If so, replace it.
Someone said they thought the battery was from 2002. If that's the
case, personally, I'd just replace it. That's near the end of normal
life for a battery. Even if it's not on it;s way out, I'd rather do it
as preventative maintenance, when it's cheap and easy, rather than get
stuck somewhere and have it cost a lot more.
He can also get the battery tested at some auto stores, Autozone is
one that does it for free I think.
| |
| Chris Lewis 2008-02-05, 5:25 pm |
| According to Joseph Meehan <sligoNoSPAMjoe@hotmail.com>:
> I believe the problem is AC current vs DC current.
I don't really know whether the usual retail/consumer grade
clamp-on meters will do DC. But the ones that auto mechanics
use _will_ do DC readings. I've watched one in use testing
a battery/charger - they're not AC only.
These meters don't care what voltage they're measuring. All they
know is magnetic field strength around an individual wire,
and that depends solely on current, not what the voltage is to some
other wire that's arbitrarily far away.
--
Chris Lewis,
Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.
| |
| Joseph Meehan 2008-02-05, 8:25 pm |
| The more I think about it, the more I believe you are correct.
--
Joseph Meehan
Dia 's Muire duit
"Chris Lewis" <clewis@nortelnetworks.com> wrote in message
news:13qhhfmlb51ok71@corp.supernews.com...
> According to Joseph Meehan <sligoNoSPAMjoe@hotmail.com>:
>
> I don't really know whether the usual retail/consumer grade
> clamp-on meters will do DC. But the ones that auto mechanics
> use _will_ do DC readings. I've watched one in use testing
> a battery/charger - they're not AC only.
>
> These meters don't care what voltage they're measuring. All they
> know is magnetic field strength around an individual wire,
> and that depends solely on current, not what the voltage is to some
> other wire that's arbitrarily far away.
> --
> Chris Lewis,
>
> Age and Treachery will Triumph over Youth and Skill
> It's not just anyone who gets a Starship Cruiser class named after them.
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