Hyosung battery voltage drops as revs increase. Help!

[thallwright]

Hi all, long story short my 2006 gt250r doesnt really hold its charge, i have a slightly cheap battery in it but when running i would get around 12.6v across the battery terminals (12v not running) then as you rev the engine higher this would DROP to around 12.1/12.2v from memory, im under the impression you want about 14v across the terminals when running

I have replaced the regulator, stator coil and flywheel thinking they were the problem as i initially thought i just wasnt getting enough voltage full stop. im getting around 60 volts ac out of my stator at 5000rpm (service manual says about between 67 and 99VAC at 5000rpm? and if outside these then to replace faulty coil)

i basically have no idea what to do next, only other things i havent replaced are cdi unit, dont think the wiring loom would have anything to do with it?
so frustratedddddjuedkj317d1;

any help appreciated!!!
cheers guys!!!!!!!!!!!!!!!!

[bogan]

Reg/rect is not putting out enough voltage, start checking ground connections and wiring etc between that and the battery.

[AllanB]

Buy another bike .......

[FJRider]

You say "my 2006 gt250r doesnt really hold its charge" .. ???

The bike or battery doesn't hold its charge ... ???

Nothing do do with the "Slightly Cheap" battery ... and the fact it's an 8 year old Hyo' ... ???????????????????


Have you tried borrowing a battery and testing again .. ???

[awayatc]

Your battery wants 13.6 volts when engine runs.

check battery connections, both pos and neg. ( ohm resistance check....)

Try jumperlead between neg of battery and engine / frame etc, to see if voltage across terminals improves..

[Mike.Gayner]

It's a Hyosung sooooo....remove the oil drain plug, replace everything else (preferably with Yamaha parts). Then replace the oil drain plug too.

[Taxythingy]

start checking ground connections and wiring

Yup. Unless your bike has been stored in a drying oven or a desert, you have corrosion in some electrical connections.

Two options (there are others, some already hinted at):
1. Start pulling connections apart and cleaning the snot out of them using fine sandpaper or a dremel with metal brush. Start with the battery connections, -ve battery to frame connection, and move on from there.

2. Use your multimeter to check for voltage drop between components. You are probably looking for a 0.5V drop or larger somewhere. Start bike. Check between battery negative terminal and the frame somewhere. Should be less than 0.2V showing. Check between regulator output and the battery positive terminal, same specs. Battery terminals to battery connections. Either side of the master fuse. Just make sure you are covering either side of any suspect connection.

[thallwright]

Hi all, thanks for the help
i have basically concluded that it is the battery which was at fault in the first place, that fault finding diagram made it much clearer
https://www.electrosport.com/media/pdf/fault-finding-diagram.pdf

I also started the bike and disconnected the battery while it was running and noticed that voltage rose with revs across the terminals that connect to the battery, but when the battery was connected, when the engine was revved the voltage would drop so the battery was preventing itself from being charged?

have tried taking it back to the shop and they are basically saying since I didnt charge the battery before I installed it in my bike (despite them not telling me to but apparently the instruction booklet said to) i have voided my warranty. I tested the battery before installing it to compare it to the old battery and it was above 14v
i had never heard of charging a brand new battery before i had to use it...?

THIS IS NOT THE FIRST ISSUE I HAVE HAD WITH THE MOTORCYCLE GEAR STORE IN WESTGATE, will no longer be using this store (they also have a website) - very poor product knowledge and shocking customer service
the guy obviously had no idea about batteries but sold me one anyway, I am now much the wiser

he says he will send the battery back to the distributor before considering swapping or refunding the battery

anyone have any suggestions regarding this??
thanks