v85tt excess electrical capacity

[chimchim]

Hello All,

New here.  Just got a 2021 v85tt Centenario and outfitting it for cooler weather. Can't find anything on it in terms of people hooking up heated gear. Anybody know how much wattage it has to spare? Alternator makes 430 watts but I don't know how much bike uses, so don't know how much excess it has. My Ducati st3s alternator makes 520 watts and heated grips and jacket are ok in that system. The grips and jacket take about 115 watts total. The Guzzi uses led lights rather than incandescent of Duc so Guzzi probably needs less wattage to function, so maybe 430 is enough to spare if I outfit it for heated grips and jacket  but don't want to overtax battery. I tried to look at a wiring diagram online but I couldn't discern anything about the bike's electrical power needs to figure out how much it has left to spare. Any help is appreciated. 

Regards,

CC   

[Huzo]

Just get a zero centre ammeter and put it in line from the battery. Put an electrical load on the system and see what it takes to centre the needle.
That way you know what it’ll stand.

[Wayne Orwig]

I have not installed an ammeter, but I have a battery monitor that records the battery voltage 24/7.
After my V85 has sat in the garage for days and days on end, when I start it, the voltage instantly jumps to 14.6 or 14.7 volts. At idle even. I'm convinced that it has way more than enough current behind it to handle such loads.

[Huzo]

Most aircraft that I’ve flown have a zero centre ammeter on the panel.
Part of the after start check list is to check that the ammeter registers a discharge just before contact and jumps into charge immediately upon start.
As you bring more systems on line, you’ll see the needle flick towards zero momentarily then resume a static position on the positive (+) side.
I’d put one between the positive battery lead and the loom, (not the high amp starter lead), and monitor the current flow as the load increases.

[chimchim]

Huzo and Wayne,

Thank you for your replies. I looked it up. Yes, looks to be an important gauge in aircraft. Could give warning of electrical system malfunctions.  So, I could purchase a zero center ammeter and place it in line with the positive battery lead and run everything the bike comes with for maximum load, and if it's still positive in scale I have some reserve. If the ammeter scale is calibrated in amps and say it reads +10 amps, then I've got about 140-150 watts of reserve power if the voltage is indeed 14-15 volts running per Wayne. Sounds straightforward in theory. I may research doing that if I can't find the info. Appreciate your replies gentlemen.

Regards,

CC     

[Huzo]

Huzo and Wayne,

Thank you for your replies. I looked it up. Yes, looks to be an important gauge in aircraft. Could give warning of electrical system malfunctions.  So, I could purchase a zero center ammeter and place it in line with the positive battery lead and run everything the bike comes with for maximum load, and if it's still positive in scale I have some reserve. If the ammeter scale is calibrated in amps and say it reads +10 amps, then I've got about 140-150 watts of reserve power if the voltage is indeed 14-15 volts running per Wayne. Sounds straightforward in theory. I may research doing that if I can't find the info. Appreciate your replies gentlemen.

Regards,

CC     

No worries.
Or just get a number of globes that add up to what you’re intending to use and whack them on line on your bike.
Then start her up and see if the battery registers a discharge..

[Kiwi_Roy]

I ride all year around so I run heated vest and gloves.
It depends a lot on what type of riding you are doing, in city traffic you will be running out of juice. I don't think an Ammeter will give you enough information.
I recommend a simple Voltmeter then when you see the voltage dip below about 12.5 you can shed some load to boost it up again.
I have something like this, really cheap, buy half a dozen and give them to your friends.
These meters dont work below about 6 Volts, I have mine connected across the City light (Park light), I prefer the ones with green display but they all work.
These ones say they are waterproof which is a bonus, I just poured some 2 part epoxy over mine.
https://www.amazon.com/Voltmeter-Digital-Display-Waterproof-Compatible/dp/B094CWMVHV/ref=sr_1_6?_encoding=UTF8&c=ts&dchild=1&keywords=Automotive+Replacement+Voltmeter+Gauges&qid=1632631009&s=automotive&sr=1-6&ts_id=15729811
My V7III only has a 268 Watt alternator so its really struggling but your V85TT shouldn't use any more power to run the motor so it would seem at 430 Watts you have lots of spare capacity.
I still recommend a Voltmeter.

[John A]

One caution on ammeter installation in general: over tightening the terminal nuts on the ammeter can cause needle oscillation.

[Huzo]

I ride all year around so I run heated vest and gloves.
It depends a lot on what type of riding you are doing, in city traffic you will be running out of juice.
I don't think an Ammeter will give you enough information.
I recommend a simple Voltmeter then when you see the voltage dip below about 12.5 you can shed some load to boost it up again.
I have something like this, really cheap, buy half a dozen and give them to your friends.
These meters dont work below about 6 Volts, I have mine connected across the City light (Park light)
I prefer the ones with green display but they all work.
These ones say they are waterproof which is a bonus, I just poured some 2 part epoxy over mine.
https://www.amazon.com/Voltmeter-Digital-Display-Waterproof-Compatible/dp/B094CWMVHV/ref=sr_1_6?_encoding=UTF8&c=ts&dchild=1&keywords=Automotive+Replacement+Voltmeter+Gauges&qid=1632631009&s=automotive&sr=1-6&ts_id=15729811
My V7III only has a 268 Watt alternator so its really struggling but your V85TT shouldn't use any more power to run the motor so it would seem at 430 Watts you have lots of spare capacity.
I still recommend a Voltmeter.

Well Roy.
If you say it, I believe it.

[Sye]

I think it's doeable if you use the genuine grips as they turn themselves off if there is insufficient charge. Maybe there are some aftermarket grips that do the same? I know that the genuine Honda grips do the same.
There are connectors for an additional USB port rated at 3.5A and spotlights rated at 2A, so you should be OK with the heated gear too.

I could be wrong but I think you should be fine.

[Kiwi_Roy]

Huzo, all the old Brit bikes I grew up with had the centre zero ammeter as you mention connected between the A terminal of the Voltage regulator and battery positive, they didn't have to worry about electric start of course and even electronic ignition was a long way off let alone fuel injection. I always thought it ironic that the Lucas regulators had 4 terminals F A D & E

Take a look at the V85TT wiring diagram, https://www.thisoldtractor.com/guzzi007/schematics/2019_V85_TT.gif you would need to connect your ammeter in the unfused red wire between battery + and the two main fuses using a fairly large wire up to the bars and back to avoid Voltage drop.
Another possibility would be to use a shunt in place of the red wire with a millivolt meter at the bars, I think this would be more complicated however as you need a separate supply to run the meter, a battery Voltmeter uses the Voltage below measured range to power up its electronics.

A suitable shunt can be made using a few inches/mm of ordinary electrical cable or you could pick it off the bikes own wiring if you have a suitable length of un-terminated wire between the two points.
This shunt will give you 1 millivolt for every Amp flowing, the multimeter of course also indicates which direction its flowing.
A multimeter is fine for testing purposes but it will power off at the critical moment to save its battery power.

You can run this millivolt signal as far as you like, the current is so tiny you can ignore Voltage drop.
Here's a drawing I did years ago showing the shunt length for common Nth American wire size.
You probably buy wire in metric sizes, its very easy to figure out the spacing between the meter points you just pass a known current through a meter or so and see what it gives you millivolt wise then back calculate the tapping points, you cannot measure the millivolts across a joint.

Your metric wire shunt will be in mm of course LOL

[80CX100]

I ride all year around so I run heated vest and gloves.

I recommend a simple Voltmeter then when you see the voltage dip below about 12.5 you can shed some load to boost it up again.

I have mine connected across the City light (Park light),

Hey Roy,      Being somewhat challenged in the art of electrickery, can you please expand for me a bit, on your installation of the volt meter across the City light (Park light)

ie.

     Do you connect both the VM power lead to the yellow? wire/terminal at the connector and the ground lead to the black? wire/terminal at the connector; or should you connect the ground wire to a nearby dedicated ground line? (on my bike I have a dedicated ground wire close by running from the R/R back to the main ground).

     When you connect the wires from the volt meter to the wires/terminals at the City light, are you skinning a little bit of the insulation off the wire just before the terminal and twisting and soldering a connection below the connector or are you actually soldering the VM wire to the base of the metal terminal itself?

     Those are small wires and connectors, I've been practicing my soldering skills, but it's still not pretty and the plastic Molex? connector at the base of the City light doesn't have a lot of spare room for a messy job, I'm trying to work out a plan of attack with the highest likelihood of success.

      Tia

[Kiwi_Roy]

Hey Roy,      Being somewhat challenged in the art of electrickery, can you please expand for me a bit, on your installation of the volt meter across the City light (Park light)

ie.

     Do you connect the both the VM power lead to the yellow? wire/terminal at the connector and the ground lead to the black? wire/terminal at the connector; or should you connect the ground wire to a nearby dedicated ground line? (on my bike I have a dedicated ground wire close by running from the R/R back to the main ground).
You can do it either way, I just used a pair of small wired cut off an old phone charger aka Wall Wort.

     When you connect the wires from the volt meter to the wires/terminals at the City light, are you skinning a little bit of the insulation off the wire just before the terminal and twisting and soldering a connection below the connector or are you actually soldering the VM wire to the base of the metal terminal itself?
Yes, it doesn't really matter how you connect it, I don't worry about chopping into the wires inside the headlight bucket whereas I don't like to modify the main wiring loom

     Those are small wires and connectors, I've been practicing my soldering skills, but it's still not pretty and the plastic Molex? connector at the base of the City light doesn't have a lot of spare room for a messy job, I'm trying to work out a plan of attack with the highest likelihood of success.
Once you put the headlight back in it hides a multitude of sins, just do your best, you can always replace the wiring later.

      Tia

[80CX100]

     Excellent idea re the thin wire from the wall warts, 18 ga has been the smallest I've been able to source locally:thumb:     

     Roy, once again, tks very much

     
   

[Wayne Orwig]

If you have a smart phone, just get a just get a voltage data logger and be done with it. Just a bit of $20. Hooks to the battery. Simple.