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2003 1200LT
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Discussion Starter #1
I installed a Datel voltmeter while I had the bike stripped and basically just turned on the ignition to make sure it was powered up (using the parking light for hot). This evening I was testing out something and when I turned on the ignition (headlights and stuff on) I noticed that the Datel was showing 11.6. For grins I put my MM on the battery and it settled down to 12v with an occasional blip to 11.98. I didn't start it. My question is I thought a battery at rest and especially after being on a trickle charger through the left bmw port should show 12.5 at least? Charger shows solid green. The left charge port is active, I see led lights when I plug something in it. It has been on a BMW smart charger for a couple of days. Going to hook up a Genius charger directly and see what the voltage is in the morning.

Incidentally I looked up the voltmeter accuracy in the specs and it gives the specs below. I am gonna call this accurate enough, lol, does that sound right or are you guys getting exact matches in the same situation?

Accuracy @ +25°C HI Range ➁ ±0.2V (typ.), ±0.4V (max.) LO Range ➁ ±0.03V (typ.), ±0.06V (max.)
 

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It does sound right. On my 2000 LT I had a analog volt meter, so it never showed the exact voltage. I ran the power off of a block I made that was connected directly to the battery via a relay that was fed from the rear seat heater.
If you have a fuseblock installed on your bike, try installing the feed there to see if the voltage more closely matches the battery voltage.
 

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Enjoy The Ride
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When I used the parking lamp for my source to hook up my volt meter I did notice a little voltage drop from a direct hook up from the battery.
 

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I installed a Datel voltmeter while I had the bike stripped and basically just turned on the ignition to make sure it was powered up (using the parking light for hot). This evening I was testing out something and when I turned on the ignition (headlights and stuff on) I noticed that the Datel was showing 11.6. For grins I put my MM on the battery and it settled down to 12v with an occasional blip to 11.98. I didn't start it. My question is I thought a battery at rest and especially after being on a trickle charger through the left bmw port should show 12.5 at least? Charger shows solid green. The left charge port is active, I see led lights when I plug something in it. It has been on a BMW smart charger for a couple of days. Going to hook up a Genius charger directly and see what the voltage is in the morning.

Incidentally I looked up the voltmeter accuracy in the specs and it gives the specs below. I am gonna call this accurate enough, lol, does that sound right or are you guys getting exact matches in the same situation?

Accuracy @ +25°C HI Range ➁ ±0.2V (typ.), ±0.4V (max.) LO Range ➁ ±0.03V (typ.), ±0.06V (max.)
With the headlights on, the battery is not at rest and thus the voltage will be lower due to the load being drawn.
 
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2003 1200LT
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Discussion Starter #5
Morning! I agree, I went out this morning and didn't really let it rest before I took off the NOCO Genius and the MM showed 12.5 before I turned on the ignition. After I turned it on the Datel momentarily showed 12 something then dropped to 11.8 then 11.7 while the MM again went to 12 and 11.59 again so calling it good. I toyed with the idea of a momentary switch so I could check without the lights but I had to cut a few items SOMEWHERE so I could get it going, lol. This gel wouldn't have been my first choice for a battery but since it was new just before I got it not going to badmouth it :).

Taco Luncho at the Bike shop in a couple of hours and the wind is howling but will be in 60s eventually...should I choose this morning to ride again after my Texas Cage Match with the bike, lol??? Back feels almost normal again :grin:
 

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I think you are flirting with a bad battery. If your trickle charger is not a "smart" charger you may be charging your GEL battery at the wrong voltage. Good chargers figure this all out. Just about every connection lowers the voltage from battery terminal readings a tiny bit.
Here is a little information from one of euromotoelectrics tech articles:
http://www.euromotoelectrics.com/v/.../Tech Tips/Battery_Health_Tech_Tips_Jan18.pdf
 
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Using multiple voltmeters are kind of like looking at multiple watches, they won't all read the same. If you only use one then you will always know what the voltage is and the time.
 
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Discussion Starter #8
I think you are flirting with a bad battery. If your trickle charger is not a "smart" charger you may be charging your GEL battery at the wrong voltage. Good chargers figure this all out. Just about every connection lowers the voltage from battery terminal readings a tiny bit.
Here is a little information from one of euromotoelectrics tech articles:
http://www.euromotoelectrics.com/v/.../Tech Tips/Battery_Health_Tech_Tips_Jan18.pdf
Good points, have a pretty new BMW smart charger that was showing green earlier in the evening. I may go out and see if I can find a draw.
 

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Discussion Starter #9
I halfway suspect my left lower power port may need some attention, not sure, but the BMW smart charger had an SAE pigtail so I put it on, ran the lights for a a bit and then watched on my MM while it went through its process when I plugged it in. Incidentally when I switched to just the parking light on the voltmeter and the mm were just about .3 off on msmt so calling it close enough. Anyway the charger took the battery from 12.5 up to 14.58 slowly over about 10-15 minutes while the green light was flashing and then once the light went solid green the volts dropped rapidly, although I didn't wait around to see where it settled.

I went back after about 45 minutes and it was about 12.99 and 13.02 I think but then my mm beeped and turned on a red light and went out, lol. I'm done with it, waiting for the wind to die down so I can go for a ride.
 

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I don't know this bike and maybe this is a dumb question for you. Are you connecting your volt meter to the line side or load side of your parking light? There would definitely be a voltage drop across the lamp. Just a thought.
 
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Discussion Starter #11
I don't know this bike and maybe this is a dumb question for you. Are you connecting your volt meter to the line side or load side of your parking light? There would definitely be a voltage drop across the lamp. Just a thought.
That is a good point and I don't know at the moment. I noticed my piaa light relay seemed to be attached to the white wire so I just attached to it. I t should be too hard to attach to the other wire and see if it sync up. On the other hand I think I saw the drop when I was turning the ignition ON so I am not sure but I don't think the parking light comes on then? I will check both ways and compare, thanks!
 

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I don't know this bike and maybe this is a dumb question for you. Are you connecting your volt meter to the line side or load side of your parking light? There would definitely be a voltage drop across the lamp. Just a thought.
What do you mean? Most lights are connected to 12V on one side and ground on the other with either side being switched. Not sure what line and load side are. It is either source/battery or ground.
 

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What do you mean? Most lights are connected to 12V on one side and ground on the other with either side being switched. Not sure what line and load side are. It is either source/battery or ground.
I think I will retract my advise until I do some testing on my bench. My train of thought derailed for the moment. Happy hour should help restore it.
 

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I think I will retract my advise until I do some testing on my bench. My train of thought derailed for the moment. Happy hour should help restore it.
You may be thinking of the Voltage drop over the loom wiring. The Votage at the battery and at a decent load will differ because of the resistance of the cable and connectors inbetween.
 

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That is true since BMW engineers the wire size for minimum weight and there is usually a voltage drop over the wire. My analog voltmeter is also wired to the parking light line and reads a bit below what is actually at the battery so I just use it for a relative measurement.
 

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That is true since BMW engineers the wire size for minimum weight and there is usually a voltage drop over the wire. My analog voltmeter is also wired to the parking light line and reads a bit below what is actually at the battery so I just use it for a relative measurement.
That’s called good engineering, John. :grin:
 
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Discussion Starter #17
I don't like it, it bugs me, lol

Could this mean the power port circuit on lower left which I have used on my other bikes for charging causes a voltage drop or would BMW in its wisdom have compensated for that? I regret to inform I lost my plug-in voltage indicator somewhere in New Mexico.
 

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I don't like it, it bugs me, lol

Could this mean the power port circuit on lower left which I have used on my other bikes for charging causes a voltage drop or would BMW in its wisdom have compensated for that? I regret to inform I lost my plug-in voltage indicator somewhere in New Mexico.
There is voltage drop in EVERY circuit. If you want to measure battery voltage, you have to measure it at the battery, duh. >:)
 
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Discussion Starter #19
There is voltage drop in EVERY circuit. If you want to measure battery voltage, you have to measure it at the battery, duh. >:)
I will cut you with my mind!
 

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