Electronics » Voltage question

Bikes on tender in garage. Testing shows 12.8 volts power to the sae/usb terminal.

Can someone give me volts I should be seeing when the motor is off not on tender; while idling; while starting?

What numbers should I be seeing at a minimum before starting to think about replacing the battery under the above conditions?

Thanks in advance.

12.8 volts sounds good to me at rest. That sounds like a fully charged battery that is in good condition. I see idling voltage as 14.2 volts on the RS's display. I haven't checked the starting voltage of my RS, but on a couple of my other motorcycles I can see as low as 10.5 volts for just a fraction of a second right before the engine starts. It sounds to me like your battery is fine and doesn't need to be replaced.

Zitat von azqkr im Beitrag #1

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Bikes on tender in garage. Testing shows 12.8 volts power to the sae/usb terminal.

Can someone give me volts I should be seeing when the motor is off not on tender; while idling; while starting?

What numbers should I be seeing at a minimum before starting to think about replacing the battery under the above conditions?

Thanks in advance.

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In 6 years I’ve never read the battery voltage.

In fact, in many, many years I’ve never read battery voltage on 2 or 4 wheels.

The days of playing with wet batteries and topping up cells on the kitchen table are long gone.

The bike lives on a charger through the winter months.

Has never failed to start in 30K miles on original battery.

I’d only start to worry about a new battery if I ever encountered any reluctance to start immediately on demand.

Zitat von fred_jb im Beitrag #4

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Zitat von azqkr im Beitrag #1

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Bikes on tender in garage. Testing shows 12.8 volts power to the sae/usb terminal.

Can someone give me volts I should be seeing when the motor is off not on tender; while idling; while starting?

What numbers should I be seeing at a minimum before starting to think about replacing the battery under the above conditions?

Thanks in advance.

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If you mean that it is reading 12.8V while connected to the charger and on charge, then I would think that is a bit low, unless charging has finished and the charger has shut down. It should preferably read no less than 12.6V, when fully charged, not connected to the charger, and with the bike switched off. According to the following, for a healthy battery the voltage should not drop below 10V while starting the engine.

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Zitat von wessie im Beitrag #7

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Zitat von azqkr im Beitrag #6

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Zitat von fred_jb im Beitrag #4

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Zitat von azqkr im Beitrag #1

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Bikes on tender in garage. Testing shows 12.8 volts power to the sae/usb terminal.

Can someone give me volts I should be seeing when the motor is off not on tender; while idling; while starting?

What numbers should I be seeing at a minimum before starting to think about replacing the battery under the above conditions?

Thanks in advance.

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If you mean that it is reading 12.8V while connected to the charger and on charge, then I would think that is a bit low, unless charging has finished and the charger has shut down. It should preferably read no less than 12.6V, when fully charged, not connected to the charger, and with the bike switched off. According to the following, for a healthy battery the voltage should not drop below 10V while starting the engine.

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So, as another member early on suggested unconnecting the charger [ yes it was on trickly mode, not charging ] for 24 hours. It's been off about 12 hours, no charger attached, not turned on it reads 13.0.

Tomorrow I'll test it when turned on, note the number, start the motor while noting number cranking. Then what it reads while idling.

Appreciate everyone's input. I only asked because I had bought a canbus compatible double usb for the GS. I'd converted it to sae with two usb's. When I plugged the sae into my always available power from the batt plug, I was surprised to see it give me the voltage. Pleasantly surprised as I'll be using it on a trip this summer powered to my tank bag. Just something I can follow and maybe head a problem off before it doesn't have enough juice.

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not sure you will get what you are looking for. An ailing battery will usually show a good voltage unless a cell has completely given up. Your battery tender will think it has fully charged a battery and go into maintenance mode. On the bike whilst you are riding, the integral voltmeter that the bike already has will show full charging voltage of 13.8V to 14.2 V typically.

The symptoms of an ailing battery are lack of amps, not volts. You only find this out when you go to start the bike e.g. with my S1000XR the bike started in the morning and I went for a 70 mile ride. I stopped on the way home for fuel and the bike would not start. I whipped out my jump start pack and was riding away within a couple of minutes.

The best thing you can do to salve any battery anxiety is to carry and know how to use a battery jump start pack. With this, you are carrying a solution not worrying about a problem.

Noco is a well respected brand and their GB40 would be ideal. My pack is a much cheaper item from Ebay and has worked on the 2 occasions it was needed. The XR and my 5 year old car.

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Zitat von wessie im Beitrag #7

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The symptoms of an ailing battery are lack of amps, not volts. You only find this out when you go to start the bike e.g. with my S1000XR the bike started in the morning and I went for a 70 mile ride. I stopped on the way home for fuel and the bike would not start. I whipped out my jump start pack and was riding away within a couple of minutes.

The best thing you can do to salve any battery anxiety is to carry and know how to use a battery jump start pack. With this, you are carrying a solution not worrying about a problem.

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Zitat von wessie im Beitrag #7

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......

not sure you will get what you are looking for. An ailing battery will usually show a good voltage unless a cell has completely given up. Your battery tender will think it has fully charged a battery and go into maintenance mode. On the bike whilst you are riding, the integral voltmeter that the bike already has will show full charging voltage of 13.8V to 14.2 V typically.

The symptoms of an ailing battery are lack of amps, not volts. You only find this out when you go to start the bike e.g. with my S1000XR the bike started in the morning and I went for a 70 mile ride. I stopped on the way home for fuel and the bike would not start. I whipped out my jump start pack and was riding away within a couple of minutes.

The best thing you can do to salve any battery anxiety is to carry and know how to use a battery jump start pack. With this, you are carrying a solution not worrying about a problem.

Noco is a well respected brand and their GB40 would be ideal. My pack is a much cheaper item from Ebay and has worked on the 2 occasions it was needed. The XR and my 5 year old car.

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Forum wisdom needed please

Wemt to my Rs this week, n=t used it for a few weeks. Refused to start battery showing 11.6amp. So no surpirse. Bike is Aoril 17 regsitered on first battery. Connected canbus socket charger and by next day 12.2 amp and startung fine. Discinnected and monitoered ove r a few days. Today 12.1amp and started ok.
In the menatine I bought a new battery as I figured I will need one in next few months. Put that on - sod me - shows 11.6 amp and bike would not start . So battery off and onto charger.
Is the new battery defetive or maybe on thre shelf for a whie and needs a boost to full ampage. its from Halford so easyy ebough to exchange.

Goping away for a few days wednesday and dont want to start the trip with weak battery. Wisdom please !

At the risk of jinxing my own situation ...

I have a September 2016 RS on the original battery which is usually connected via a pigtail to an Optimate 4 when not in use. Never had an issue.

No comments please from those who consider "always connected/conditioning" is a bad thing - it's not.

Trust you mean volts rather than amps, a fully charged AGM battery in good condition should be around 12.8volts. I would put the canbus charger on for at least 12 hours, assuming its an intelligent charger which nearly all or the can use ones are and then turn it off for a couple of hours and check battery voltage, it should be around 12.8volts possibly slightly less as the bike some power even when everything appears to be off.
Batteries as supplied are usually around 70 to 80 percent charged as supplied depending on how long they have been on the shelf.

Chart of typical agm battery voltage showing charge status which may help

state-of-charge-chart-for-agm-battery_2.png - Bild entfernt (keine Rechte)

Zitat von Wayfarer im Beitrag #13

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Trust you mean volts rather than amps, a fully charged AGM battery in good condition should be around 12.8volts. I would put the canbus charger on for at least 12 hours, assuming its an intelligent charger which nearly all or the can use ones are and then turn it off for a couple of hours and check battery voltage, it should be around 12.8volts possibly slightly less as the bike some power even when everything appears to be off.
Batteries as supplied are usually around 70 to 80 percent charged as supplied depending on how long they have been on the shelf.

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