Question regarding Charging System on a Honda CBR250R

[menzies233]

I have a copy of the service manual for the CBR250R and cannot get my head around the test to check the charging system. Anyone here got any knowledge on this bike and how the charging system should be performing?

The Honda Manual states " With the headlight high beam, measure the voltage on the multimeter when the engine runs at 5000 RPM"

It then gives two standards - This is what is confusing - "Standard - Measured Battery Voltage < (Less than) Charging Voltage < (Less than) 15.5V

Does this simply mean that the charging voltage at 5000 RPM must be below 15.5V?

At 5000 RPM or any other RPM, battery voltage must surely be exactly the same as the charging voltage as that is what is feeding the battery.

From what I can gather from the actual bike performance, the battery with nothing switched on should be about 13.2V fully charged, so if I make a static reading with the bike switched off and get 13,2V or similar, then measure again at 5000RPM, as long as the charging voltage is more than 13.2 and less than 15.5 then all is good?

The second point is the output power from the coil charging the system. From what I can work out from the specs. it puts out about 340 Watts of charge back to the battery, so is that roughly the equivalent of around 0.44AMP?

(I am busy trying to fit some additional DRL's and want to make sure I keep within a sensible limit.)

Cheers

Edited February 27, 2016 by menzies233

[canthai55]

12V will not charge a 12V battery. Industry standard is 13.7 to 14.5V. Honda specifies the high beam on as this puts as much of a load on the charging system as can be done while testing. 15.5V at 5000 RPM seems a tad high, but they may well just want to make sure - if any other accessories are wired into the system, that sufficient voltage remains to power all loads and keep battery charged. 340 Watts divided by 12V nominal is aprox 30 amps. V time A = W. Wire your accy lights direct off the battery, with a fuse or fusible link, and use a relay.

Edited February 27, 2016 by canthai55

[menzies233]

12V will not charge a 12V battery. Industry standard is 13.7 to 14.5V. Honda specifies the high beam on as this puts as much of a load on the charging system as can be done while testing. 15.5V at 5000 RPM seems a tad high, but they may well just want to make sure - if any other accessories are wired into the system, that sufficient voltage remains to power all loads and keep battery charged. 340 Watts divided by 12V nominal is aprox 30 amps. V time A = W. Wire your accy lights direct off the battery, with a fuse or fusible link, and use a relay.

Ok I missed a couple of decimals on the Amps! Cheers, but it does not make any sense to me really. The 12V / 30A is logical (28 or so less the EFI and the lights that are always on - lights will be about 200 Watts / EFI and fuel pump etc.) This seems OK at 12V but the figure Honda are giving at 15 V or so seems to be overcharging?

15.5V does seem high, on my Toyota they say the rectifier / Alternator is faulty at anything over 14.7V

If the charger is running at 15V or so, then even if the bike is consuming 120W, there is 240W going to the battery - So at 15V and 240W, that is getting on for 15 Amps!

Yet Honda recommend charging the battery on a static charger at 0.6A for 10 hours or so, and 3 hours at 1A.... the more I read the more confused?

Thanks for the info!

Edited February 27, 2016 by menzies233

[papa al]

farang tink too mut

[canthai55]

Not up to speed on that particular bike, but some use a zener diode as a voltage compensating/adjusting device to limit excess. Turns what is not needed into heat, which is released thru the attached heat sink.

[kiniyow]

Put the RPM at about 1000 then Pull the Positive Lead off the Battery..If Engine still runs then you have no problems with your charging system

[CarolJadzia]

Have you got a test meter?

If the battery is ok then you should read 12 v at the battery when the engine is off. Then something like 13 to 15 volts with the engine running.

You should also notice the lights getting brighter and volts going up as you rev it as well.

Long as we are talking about the same model. You have a regulator that controls the output of the charging coils via a stator. There are various things that can go wrong but place to start would be the brushes or the regulator/rectifier

https://www.motorcyclespareparts.eu/honda-parts/motorcycles/cbr250r-2011/e-13-starting-motor-563522/31201mew921-brush-set-a-carbon.aspx

[papa al]

Have you got a test meter?

If the battery is ok then you should read 12 v at the battery when the engine is off. Then something like 13 to 15 volts with the engine running.

You should also notice the lights getting brighter and volts going up as you rev it as well.

Long as we are talking about the same model. You have a regulator that controls the output of the charging coils via a stator. There are various things that can go wrong but place to start would be the brushes or the regulator/rectifier

https://www.motorcyclespareparts.eu/honda-parts/motorcycles/cbr250r-2011/e-13-starting-motor-563522/31201mew921-brush-set-a-carbon.aspx

huh?

the poster has not stated that anything is wrong with the bike.

[canthai55]

Just checked some specs for the CRF250M - uses same engine as the 250R. It lists 24A charging system, not 44 as you posted above. Misprint ?

[Richard-BKK]

Put the RPM at about 1000 then Pull the Positive Lead off the Battery..If Engine still runs then you have no problems with your charging system

On the Honda CBR250R is it not so that the fuel injection system is powered by the battery?