Any way to measure battery draw while bike is off?
Road Captain
Joined: Sep 2015
Posts: 575
Likes: 3
From: Maryland
It does not seem like it completes any circuit, because it doesn't change the positive terminal. Plus, half the world ties netral wires to ground, and it does not really change anything.
And there's also kirchoffs law, which says that juice just cant flow into or out of the bike, there would need to be another path, which there is not that I can see.
Also, if you want to check the juice while the motors off, be carefull not to turn it on because many digital meters will blow a fuse.
Intermediate
Joined: Apr 2010
Posts: 40
Likes: 2
When I bought my battery at the HD dealer, the parts dude told me this. I somehow graduated from college with a degree in electrical engineering, and have worked in the field for decades, and I think it's bs.
It does not seem like it completes any circuit, because it doesn't change the positive terminal. Plus, half the world ties netral wires to ground, and it does not really change anything.
And there's also kirchoffs law, which says that juice just cant flow into or out of the bike, there would need to be another path, which there is not that I can see.
Also, if you want to check the juice while the motors off, be carefull not to turn it on because many digital meters will blow a fuse.
It does not seem like it completes any circuit, because it doesn't change the positive terminal. Plus, half the world ties netral wires to ground, and it does not really change anything.
And there's also kirchoffs law, which says that juice just cant flow into or out of the bike, there would need to be another path, which there is not that I can see.
Also, if you want to check the juice while the motors off, be carefull not to turn it on because many digital meters will blow a fuse.
Seasoned HDF Member
Joined: Feb 2006
Posts: 6,680
Likes: 602
From: South Florida
Well,it seems like all the responding posts were in agreement on how to check for a draw on the battery.So now you need to check it and return with your findings.
Grand HDF Member
Joined: Jan 2012
Posts: 4,453
Likes: 2,839
From: Oklahoma
Except for which terminal to disconnect. If it were me, I would go with the negative terminal, no accidental sparks that way.
Road Warrior
Joined: Nov 2014
Posts: 1,962
Likes: 140
From: NY
Today my bike barely started when I took it for a spin.. Rode it for about 15 mins and it started fine. Road for another hour or so and it was fine as well. I had last ridden about 2-3 days before today. I am wondering if I have something discharging the battery while the bike is off (I have an audio amp, LED's, and such connected).
Is there anything I can use to measure the draw (In amps or milliamps?) while the bike is turned off to see if I have one of those items that are connected pulling an unusual amount of current? The amp should turn off when the bike is off, and none of the lights are on.
I brought the battery into the local auto parts place and they said it was testing fine and if it was the battery going bad their tester would likely see an issue so they suspected either charging system or something drawing while the bike is off. I know there is some small draw from the radio and security system etc but after 2-3 days it shouldn't be hard to start.
Is there anything I can use to measure the draw (In amps or milliamps?) while the bike is turned off to see if I have one of those items that are connected pulling an unusual amount of current? The amp should turn off when the bike is off, and none of the lights are on.
I brought the battery into the local auto parts place and they said it was testing fine and if it was the battery going bad their tester would likely see an issue so they suspected either charging system or something drawing while the bike is off. I know there is some small draw from the radio and security system etc but after 2-3 days it shouldn't be hard to start.
Quick check is to 1st fully charge battery ,unhook the charger & unhook the neg batt cable.
Then let the bike sit 2-3 days ,re-attach ned bat cable and fire it up to see how fast the motor spins over before it actually starts.
If the motor spins over faster and or starts faster the motorcycle is definatley bringing the battery down in a short 2-3 days.
But keep in mind if the battery is not up to good operating capacity thats how it would act so the question at that point would be is bike pulling too much juice while sitting still in the garage over the few days or is the battery on its way out?
If battery comes into question just fully charge it again and take to your local HD shop/INDY/auto parts store to have it fully loaded tested to see what cond its really in.
Stock AGM factory activated maint free repl battery for HD tourirng bikes is 375-380cca /30AHR.
BTW,i know a few people that bought new Honda Civic's a couple yrs back and when they sat for 3-4 or more days without driving them with the security system on the battery would be low enough that they wouldn't start requiring a jump.
Scott
Last edited by wscott; Oct 11, 2015 at 06:41 PM.
Tourer
Joined: May 2011
Posts: 300
Likes: 6
From: South Carolina
The easiest way to check for drain is to pull the main fuse and test in the sockets. If you see less than 5 ma you're problem most likely is a weak battery. When you first plug the probes in the draw will be high and then settle down to less than 2 ma.
Billy
Billy
Road Warrior
Joined: Oct 2006
Posts: 1,350
Likes: 46
Depending on their tester, it may not show up. Was it one that put a load test on it? The electronic ones that are the small handhelds sometimes don't have the capability to load it properly. I have seen some that had showed 200cca on a 500cca battery & say it is good. Did they say what it tested out as?
Toby
Toby
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Road Master
Joined: Jun 2005
Posts: 1,053
Likes: 39
From: Central Florida
Just a follow up I finally got the equipment to test this properly. Looks like when I first connect the meter in series with the negative I get about 26-28ma until the ECM and stuff boots up and settles down and goes into sleep mode. After about 30 seconds or so I get about 7ma, and then it slowly trails off into the 1-2ma range. So I guess if there was a draw its no longer happening or that is not the issue.
I brought the battery in to another place to be checked and they told me it was putting out like 394 CCA (I think its rated for 400).. If I check the voltage myself it was sitting at like 12.64 after 2 days of not being charged so I think that's good as well.
So I think the last thing I need to check is the voltage output while charging.. What's the proper way to check that? Start the bike up and check the voltage at the battery like I would when its off? I assume I should be seeing 14.5 or so volts when running? (Might have to give it a little throttle?)
I brought the battery in to another place to be checked and they told me it was putting out like 394 CCA (I think its rated for 400).. If I check the voltage myself it was sitting at like 12.64 after 2 days of not being charged so I think that's good as well.
So I think the last thing I need to check is the voltage output while charging.. What's the proper way to check that? Start the bike up and check the voltage at the battery like I would when its off? I assume I should be seeing 14.5 or so volts when running? (Might have to give it a little throttle?)
Grand HDF Member
Joined: Jan 2012
Posts: 4,453
Likes: 2,839
From: Oklahoma
I hadn't noticed your add-ons before. What is the power draw for that amplifier? What else are you trying to power? This may be nothing more than too much equipment for the charging system to supply and the battery never gets fully recharged after a start.