Low voltage at idle

Woe unto you that bought the first model year of a major remake, perhaps this section can help address any 2014 and later model Ural "imperfections". Here's a special section for folks with the latest rigs to discuss 2014 and later model-related topics such fuel injection, 3-wheel disc brakes, hydraulic steering dampers, spin-on oil filters and other anomalies that don't belong on true Russsian motorcycle ;-P We've gone from using big hammers and greasy wrenches to needing computers and Ouija boards in order to fix our rigs.
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willt
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Low voltage at idle

Post by willt » Mon Sep 13, 2021 5:49 pm

Just bought a 2019 Gear-Up today with only 1900 miles. Driving home, at a stop light I notice the little buttons on the speedo. I cycle through the displays and stop at voltage. It is showing 12.6 and slowly dropping. When the light changes it was as low as 12.1 but when I applied throttle to the engine the voltage went up to 14.3. I am sure the battery is shot because the guy I bought it from said he kept it on a trickle charger but do I have other problems? Can the alternator not produce 14v at idle?
Thanks,
Wm

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Re: Low voltage at idle

Post by Mr Wazzock » Mon Sep 13, 2021 6:10 pm

Can the alternator not produce 14v at idle?
Short answer is, no it can't. This is normal I'm afraid. :o

Also the wire gauge in the harness could be thicker TBH, so a Voltmeter in the dash can show under Volts. It can only show what Volts it's getting at the end of its supply line, that's also powering other things. Can be quite a common problem with cars too with inbuilt Voltmeters in a dash display.

I'm not a fan of "keeping it on a trickle charger" I think this can shorten the life of the battery - I'm not an expert tho - nevertheless I prefer a charging regime of every couple of weeks if bike is stored / not been used. I usually use an Optimate, but only plug it in for a short time until I get all green lights.
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Re: Low voltage at idle

Post by willt » Mon Sep 13, 2021 6:31 pm

Well I am actually relieved to hear "they all do that". I feel like I am talking to the service manager at the BMW dealership!

Absolutely on the trickle charger. I have had a bunch of Deltrans that ruined batteries after being left on too long. I bought an Optimate 4 about 10 years ago and have not lost a battery since. It will charge until it gets the battery to the proper voltage then it stops charging and monitors the voltage until it drops so low then will start trickle charging again. I TRY to remember to leave it on no more than a day or three once a month.

Does replacing all the lights with LEDs help keep the voltage up?

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Re: Low voltage at idle

Post by Tomcatfixer » Mon Sep 13, 2021 6:46 pm

I've had really good luck keeping my six bikes, lawnmower, and Polaris Ranger on Deltran BatteryTenders, which, of course, are smart enough to stop charging when the batteries are full. With my 2015's ElectroJet EFI, keeping the Mobile Chernobyl on a battery tender has made ALL the difference in wintertime starting.
Does replacing all the lights with LEDs help keep the voltage up?
Converting to LED lights can't hurt. Though I haven't measured the current draw of the incandescent bulbs, I would think that your fuel pump, fuel injectors, and ignition system would be much more of a current draw than the lights.
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Re: Low voltage at idle

Post by Eric N » Mon Sep 13, 2021 7:24 pm

LED's help. Headlight and taillight make the largest difference, you'll need a diode if you do the turn signals (easy enough but some people freak).

If you replace your 2019 ECU with a M2Boxer unit, you'll have control to set the idle at 1,100 and that really helps. Sure it's higher than whatever your current ECU settings are, but spins the alternator a little faster to keep the low voltage light at bay.

https://m2boxer.by/en/home/40-perfomanc ... -2019.html
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Re: Low voltage at idle

Post by willt » Mon Sep 13, 2021 7:40 pm

Eric N wrote:
Mon Sep 13, 2021 7:24 pm
LED's help. Headlight and taillight make the largest difference, you'll need a diode if you do the turn signals (easy enough but some people freak).

If you replace your 2019 ECU with a M2Boxer unit, you'll have control to set the idle at 1,100 and that really helps. Sure it's higher than whatever your current ECU settings are, but spins the alternator a little faster to keep the low voltage light at bay.

https://m2boxer.by/en/home/40-perfomanc ... -2019.html
Interesting bit of kit!

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Re: Low voltage at idle

Post by Trumpetwasher » Mon Sep 13, 2021 8:17 pm

The battery maintainer won't shorten battery life. They automatically switch to a safe float voltage level that keeps the battery charged and yet does not do any harm to the battery. In fact, in most cases, this type of charge maintenance will extend the battery's useful life by at least 50%.
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Re: Low voltage at idle

Post by BinDerSmokDat » Mon Sep 13, 2021 8:45 pm

On the Ural to gear the alternator to produce 14 volts at idle would have it positively screaming at highway speeds.
It's not uncommon for many alternators to not produce full/charging voltage at idle.
It's not an issue because they are still contributing 12 volts to run things and the battery is there as a reservoir.
Ambulances and emergency vehicles are a good example of this, they will have dual alternators for this reason as they sit at idle and run a lot of auxiliary equipment.
Don't worry about it unless you plan to ride your rig only in parades. :lol:

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Re: Low voltage at idle

Post by chaos2 » Mon Sep 13, 2021 9:44 pm

Old BMW airheads couldn't even do 12v at idle. I saw a couple folks kill their batteries by just puttering around all day at rallies.
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Re: Low voltage at idle

Post by ArgonV » Mon Sep 13, 2021 10:32 pm

My 2016 Retro is the same. I have one of the older gauge clusters, and when the battery hasn't been charged properly I will get a "check engine" light after starting it.
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Re: Low voltage at idle

Post by RC20 » Tue Sep 14, 2021 3:50 pm

Also the wire gauge in the harness could be thicker TBH, so a Voltmeter in the dash can show under Volts.
That is only true if you have high current draw. I don't think the Instruments are tapped off the Pump which might lower voltage.

The reality is the alternator can't keep up at low RPM and you get a voltage drop off.

Bulbs don't take that much power, LED might help a bit but your fuel pump, FI and the computer will be your high power draws.

You can hand idle it at higher rpm, about 1200 keeps the voltage up, 1400 you get the full 14.5 or so.
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Re: Low voltage at idle

Post by Mr Wazzock » Tue Sep 14, 2021 4:24 pm

willt wrote:
Mon Sep 13, 2021 6:31 pm
Does replacing all the lights with LEDs help keep the voltage up?
This is one reason why I changed to LED 'bulbs' – another being if a bad contact occurs it won't blow a filament (guess how I know), because there is no filament to blow – the LED lamp would merely not work or only sometimes, but no damage to itself. But yes if I'm waiting in a queue with lights on and turn signal going I can be somewhat comforted knowing the total current draw is less.

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Re: Low voltage at idle

Post by Mr Wazzock » Tue Sep 14, 2021 4:27 pm

ArgonV wrote:
Mon Sep 13, 2021 10:32 pm
My 2016 Retro is the same. I have one of the older gauge clusters, and when the battery hasn't been charged properly I will get a "check engine" light after starting it.
Yes I've also had that in cold weather just after a cold start.
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Re: Low voltage at idle

Post by willt » Tue Sep 14, 2021 4:40 pm

It looks like I will be shopping for LEDs. And a new battery. It did not start this morning without an hour of charge.

OK, here is another question or two. The owners manual says to disconnect the negative terminal before charging "TO PREVENT DAMAGE TO ELECTRICAL COMPONENTS". Is that right? The bike came with a standard trickle charge wire hanging off the back.
The owners manual also says (in bold letters!) "NEVER JUMP START THE MOTORCYCLE!" Is that right, too? I thought I have read on this forum of people jump starting the bike.
Thanks again,
Wm

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Re: Low voltage at idle

Post by aduthie » Tue Sep 14, 2021 4:51 pm

DIsconnecting the negative battery cable first is to prevent you from accidentally creating a dead short between the positive terminal and the frame. It's also step one in almost every instruction set for repairing anything on many motorcycles. But if you're careful, it's not necessary. But again if you're removing the battery, it's a lot safer to disconnect the negative/ground side first.

Jump starting: the primary risk is that you'll short the positive terminal to the frame with the jumper cable clamps. I've always heard if you're jumping from a car, you should leave the car turned off. But I've never experimented to see if doing it otherwise can actually harm the motorcycle. (Logic tells me "no," but the weight of all the anecdotal evidence keeps me wary.)
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