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5thgendaily

Electrical Gremlins Appear When Warmed Up

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Just when I thought I killed off the gremlins..... 

 

Once the bike heats up to when the fan kicks on, the idle charge drops from a 13.9-14.1 V down to as low as 12.8 V. Have R/R from roadstercycle (less than year old), hardwired to a Ricks stator (less than 2 years old), and a few month old Shorai Lithium-Iron battery. Just replaced all coolant hoses about a month ago... wondering if this could be a cause? I've done "The Drill" so many times, I now do it in my dreams. Everything checks out fine, stator putting out proper ACV, continuity/grounding tests come out good. R/R is doing its job, I have never seen it hit 15 V,  battery is rock solid. I've checked the infamous orange grounding block, didn't look fried up at all. I'm thinking there must be a shortage or grounding issue on the bike, or maybe something with the electrics involved in the cooling system. I also noticed a burnt out tail light bulb and a headlight bulb that will flicker on and off a few seconds upon starting the bike. Anyone else experience this?

20180328_184016.jpg

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That sounds entirely normal to me. The fan motor is using a fair amount of power, so you will see a drop in battery voltage when it comes on. I can see the same thing when I activate my heated grips. My advice is the same as The Hitchhiker's Guide to the Galaxy - Don't Panic!

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Thanks Terry for the sound advice. However this bike has left me stranded too many times to not panic when electrical issues arise. My concern is that this did not used to happen. It just started about a week ago. If my radiator fan is draining as much voltage as your heated grips, then shouldn't that be alarming? Or is it just chalked up to be poor VFR electrical engineering, and no cause for alarm?

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Out of interest I kept a close eye on my idling bike while fan came on. Prior to this the voltage at idle was steady at 14.1V, once the fan kicked in the voltage steadily dropped and settled at 13.5V. Once the fan stopped, the voltage returned to 14.1V. To me this seems perfectly normal behaviour; you increase the electrical load (and my guess is the fan probably consumes 40 or 50W) and the available voltage left over for charging is less so you get lower voltage at the battery. This would only become an issue if the voltage drop was excessive so that the battery was in a discharging state when idling (below 12.3V according to the manual, but maybe different for a Li battery).

 

One thing you may want to check is whether the fan is drawing excess current. In an extreme case you can draw enough to blow the fuse, that will happen if the fan blade is prevented from spinning freely, e.g. by some debris caught in the shroud, or (as happened on my VTR1000) poor reassembly which trapped a small hose and pushed the shroud into the blade causing it to rub. 

 

If I get a chance I will put my ammeter across the fan fuse terminals and see what the additional draw is when it comes on. 

 

 

 

 

 

 

 

 

IMG_4336.jpg

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9 hours ago, Terry said:

Out of interest I kept a close eye on my idling bike while fan came on. Prior to this the voltage at idle was steady at 14.1V, once the fan kicked in the voltage steadily dropped and settled at 13.5V. Once the fan stopped, the voltage returned to 14.1V. To me this seems perfectly normal behaviour; you increase the electrical load (and my guess is the fan probably consumes 40 or 50W) and the available voltage left over for charging is less so you get lower voltage at the battery. This would only become an issue if the voltage drop was excessive so that the battery was in a discharging state when idling (below 12.3V according to the manual, but maybe different for a Li battery).

 

One thing you may want to check is whether the fan is drawing excess current. In an extreme case you can draw enough to blow the fuse, that will happen if the fan blade is prevented from spinning freely, e.g. by some debris caught in the shroud, or (as happened on my VTR1000) poor reassembly which trapped a small hose and pushed the shroud into the blade causing it to rub. 

 

If I get a chance I will put my ammeter across the fan fuse terminals and see what the additional draw is when it comes on. 

 

 

 

 

 

 

 

 

IMG_4336.jpg

 

That's an excellent fitting Voltmeter into the head stem, very nice installation Terry. Is it a 3wire device so only active once ignition is on? And are the sense wires directly on the battery?

Cheers.

Grum.

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On 4/3/2018 at 9:32 PM, Grum said:

 

That's an excellent fitting Voltmeter into the head stem, very nice installation Terry. Is it a 3wire device so only active once ignition is on? And are the sense wires directly on the battery?

Cheers.

Grum.

Thank Grum; actually I cheaped out and decided to do a non-invasive installation, and this was the easiest thing to do. The voltmeter is a really cheap 2-wire jobbie from eBay. To mount it I found a plastic irrigation hose end plug (13mm??)  that was about the right size for the steering head, cut a couple of snug slots for the spade terminals to slide through, and pressed the voltmeter onto the end plug. The female spade connections just slip up the inside of the plug and secure the VM. The wires pass down through the steering head, and are protected from chafing with a piece of rubber hose. I have a relay fitted near the battery triggered off the taillights, and the relay then directly connects the VM to the battery; I use the same powered feed for my rarely-used heated grips. 

 

This all works really well, but the red LED is not easy to read in sunlight unless you shade it with your hand.

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