Voltage meters for my PC800

Since I was already installing heated riding gear and because of all of the stories of faulty rectifiers and dead electrical systems, I decided to install an analog voltage meter.  I chose the Honda Marine voltmeter [Note: links to this keep changing so your best bet is to go google “Honda Marine Voltmeter” and you should find one for sale]. The gauge is waterproof and lighted.  Rather than buy it from some random website, I decided to get it from my local marine supply store.  Next time I’ll buy it online.  The local store took forever to get it and then charged me double what it would have cost online.  They even charged me for shipping!

While I was at it I decided to get an idiot light because I suspect that if I didn’t have it, I’d end up being an idiot someday.  I ordered a Signal Dynamics Heads Up Voltage Monitor. After going on several rides with it installed, I can say that I am VERY glad that I chose to install both an analog gauge AND an idiot light.

To make the hole for the analog gauge I found an appropriate sized hole saw at the local home improvement store. The small hole for the LED for the idiot light only took a little drill that I had in my tool chest.

I ran wires for the gauges back along the right top frame tube to the auxiliary fuse block I installed in the trunk. Most people hook a voltage gauge directly to the battery. I chose to connect mine to the fuse block instead. Sure, I might lose 0.05 volts going through some extra connections but I think it’s better to be cautious with my bike’s voltage anyway. I don’t need to squeeze every last tenth of a volt out of the system. At least not yet anyway…

My setup. The idiot light LED is in the upper left corner of the speaker blank. It ends up being in the extreme bottom portion of my peripheral vision when my head is up while riding. So far it hasn’t been distracting at all although I haven’t ridden during any dark nights yet. There are plenty of photos of other people’s setups on IPCRC. This is just the way I did it because I liked it this way. I’d be interested to see what other people come up with for their installations in the future 🙂

23 Replies to “Voltage meters for my PC800”

  1. Hey Doug, I’ve got my meter panel off, and I’ve purchased the Honda Marine voltmeter like you show here. Since I don’t have an extra fuse box & don’t really have the know-how to make one, can I just hook it up straight to the battery? Will it always be on & lighted if I do that? I didn’t know it was lighted till I read your description.
    -Scott

  2. Hi Scott,

    You will want to have it fused and with a relay so it isn’t always on. Otherwise, your battery will be drained after a day or two of sitting. Under the seat there is a white plug with four connectors (only three used). One wire is always hot, one is switched based upon key position, and one is ground. I would recommend that you use the switched wire to drive a relay. Have the relay switch power to the volt meter. Draw power directly from the battery and don’t forget to put a fuse in line. That way you’ll get an accurate reading from the battery while protecting the bike from getting drained while it’s sitting.

    Cheers,

    Douglas

    1. I just got a pc800 a few weeks ago and want to install a voltmeter also.But I dont undersand all the info you gave Scott.I understand useing the switched based wire to drive the relay and have the relay power to the voltmeter.But what is the power from the battery going to if it already has power from the switched based wire.Can you give me some info on this so I can understand it.Sorry not very good at electronics.I dont have a fuse block in the trunk.

      1. Hi Dave! Sorry it took so long to reply. I’ve been busy the last few days.

        Depending upon the type of relay you are using, you might have a separate pin that is switched by the relay or that pin might be common with the pin that you apply power to in order to actuate the relay. If it is the second type, you’re done if you have the power plugged into the switched wire. If it is the first type (probably will be this type), you will want to connect the switched pin on the relay (via a 3 amp fuse) to the battery + terminal. That way you will have the most accurate voltage reading possible. If you were to measure the voltage from the switched wire versus the voltage from the + terminal on the battery, you would see the voltage from the wire is about a half volt lower than at the battery. It is better in my opinion to read the voltage from the battery rather than from the harness. I think that gives you a more accurate picture of what is going on.

        Does that make sense? If you could give me the type of relay you are using, I could see about drawing up a diagram and posting it for you…

        Cheers!

        Douglas

        1. Sorry it took me even longer to get back with you.As of now I have not put in a relay or havent got a meter yet so I will get what you think is best.And yes any diagrans you can get to me will be a big help.Tell me whar type of relay I need and where to go to get it.Please. Here is what is going on with the bike as of now.Old battery stoped working when it got cold.Had it tested they said replace it.New one was fine for about a month,riding 1-2 times a week,leaving it out in cold at night then riding it home.Then this week it set in cold garage 7 days and was dead.Had it tested they say its bad gave me a new one.Have not put it in yet.

          1. Hi Dave,

            The easiest fix is to plug the voltmeter directly into the switched pin on the accessory plug under the seat. It will read ~0.5 volts low as compared to directly from the battery but will solve the problem of the voltmeter draining the battery. Otherwise, head down to your local auto parts store and buy a relay like this: https://www.amazon.com/Absolute-RLS125-12-VCD-Automotive-Relay/dp/B0002KR9GG/ref=sr_1_1?ie=UTF8&qid=1356571699&sr=8-1&keywords=relay a wiring harness like this https://www.amazon.com/Absolute-SRS105-5-Pin-Socket-Interlocking/dp/B005EUWMU2/ref=sr_1_4?ie=UTF8&qid=1356571699&sr=8-4&keywords=relay and an in-line fuse holder like this https://www.amazon.com/In-line-ACT-Water-resistant-Fuse-Holder/dp/B0002KR88A/ref=pd_sim_e_5 .

            Run a wire from the battery’s positive terminal to the fuse holder. Put a fuse in the 1-3 amp range in the holder. Run a wire from the fuse holder to pin 87. Run a wire from pin 30 to the positive side of your voltmeter. Run a wire from the negative (ground) side of your voltmeter to the battery’s negative (ground) terminal. Run a wire from pin 85 of the relay to the battery’s negative (ground) terminal. Run a wire from pin 86 of the relay to the switched wire in the auxiliary plug under the bike’s seat.

            It’s as simple as that!

            Cheers!

            Douglas

            1. Well I didn’t get the volt meter on in time.I fried the battery and it was over charging.Parts are on the way.I got a service manual from on line.But now I don’t know where the pin numbers are that you gave me.Can you help me with this.

              1. Hi Dave,

                The pinout is for a standard automotive relay available at just about any auto parts store. The numbers usually are either printed on the top or the bottom of the relay.

                Cheers!

                Douglas

            2. I have read the site about head light bulbs and using a H4ST bulb that is the same wattage as a H4 stock so I should not have to up grade the wiring. But it is not clear if this bulb will be to hot for the housing? Will this be ok to use and not upgrade wiring and not melt any plastic? Can anybody help me with this please?

              1. Hi Dave,

                I’m not sure if that bulb will be too hot or not. If it’s the same wattage, my guess would be that it would put out the same amount of heat. Short of installing it and testing it, I’m not sure what else you could do to determine if it will melt the headlight.

                Please let me know how it goes.

                Cheers!

                Douglas

            3. cant get on the tire information for Dunlop and Metzeler tires that will work on the 1989* PC used Dunlop and only got 10,000 out of it.Just want to know is there a Metzeler that will fit the 89

              1. Hi Dave,

                All years of PC800 use the same tires. Let me know if you still can’t find the Metzeler info and I’ll go down to the garage to look at the info on the tires on my bike. I got about 15k miles out of my last Metzeler bike. Tires aren’t as good as they used to be 🙁

                Cheers!

                Douglas

                1. I thought I read on the site a while back that the Metzeler tires would rub on the rear on 89sYes if you got a Metzeler size that will work I will try one thanks

                  1. As long as you keep the Metzeler inflated properly, it should be okay. I’ve been running Metelers for 30k miles on my ’89 and the previous owner ran them at least another 10k before I bought the bike without problem. But if you let the air pressure drop, it WILL rub. No big deal though. My bike actually has a fiberglass patch where a tire rubbed many years ago. Even if you do get a rub, the worst thing that happens is you might damage a tire ($120 bucks) and need to repair the trunk ($50 bucks in fiberglass stuff).

                  1. Howdy Dave,

                    I’m using Metzeler tires front and rear. Don’t have any experience personally with the Michelin option although I did try out a “Darkside” tire setup with a car tire on the rear. It rode fine.

                    I’m using 120/80H17 on the front and 140/80H15 on the rear.

                    Cheers!

                    Douglas

  3. Douglas:
    The PO put a fuse block in the trunk. I want to put my volt meter on it, but how do I keep it from being on all the time? Do I need to put a switch on it? If I use the white plug under the seat, do I run the power from the switched wire and return the ground back to the plug? I know it sound elementary, but as far as electronics are concerned, I am still in kindegarten.
    Thanks
    Milton

  4. Hi Milton,

    I’m assuming the fuse block in the trunk isn’t already on a switched relay and is always on. My advice would be to use the white plug under the seat to actuate a relay when they key is in the “on” position. Have the relay switch power directly from the battery to the positive side of the volt meter. Return the ground to the battery as well. Don’t forget to put a fuse in the positive wire coming from the battery to the voltmeter.

    Cheers,

    Douglas

  5. Hi Douglas,

    Did you install the Honda Marine or the Signal Dynamics voltmeter?

    Also, what’s the purpose of the LED “idiot light”? Isn’t the Honda Marine voltmeter lighted on its own?

    Thanks,
    Saul
    Richmond, BC

    1. Hi Saul!

      I installed the Honda Marine analogue voltmeter and the LED “idiot light” on my bike in parallel. The analogue voltmeter can tell me what is going on with some degree of precision (enough for my purposes) and the idiot light tells me if I should be paying attention to the analogue voltmeter. If everything is good at cruising RPM, the idiot light will be green. If something is bad, it will start flashing and changing color. Before I converted to LED turn signals and brake lights, it would also flash at stop signs and stop lights because of the drop in stator output due to low RPM. Now it stays green all the time unless I start putting a heavy load on the bike through electric clothing and whatnot.

      The idiot light isn’t strictly necessary but it helps me to know when to pay attention to the analogue voltmeter.

      Cheers!

      Douglas

      1. Hi Douglas,

        On behalf of all the other people on here who appreciate your time and efforts, a big thank you from us all.
        My question is probably more basic than those above – namely how much plastic did you have to remove to get access to the back of the panel to attach the meter? Is there an easy way or does the whole of the front fairing have to come off? I’m really hoping not!

        Cheers

        Phil

        1. Hi Phil,

          Here is the flowchart for removing plastic from the PC800: https://www.douglasvanbossuyt.com/honda-pacific-coast-pc800-service-manual/pc800-service-manual-chapter-2-frame-body-panels-exhaust-system/page-2-3/

          It’s actually pretty easy to get into the meter panel. There are a couple of screws hidden behind some plastic covers. Here is the diagram: https://www.douglasvanbossuyt.com/honda-pacific-coast-pc800-service-manual/pc800-service-manual-chapter-2-frame-body-panels-exhaust-system/page-2-10/

          Cheers!

          Douglas

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