1. Dismiss Notice
  2. Hey Facebook people... We've created a group for XS650.com members to connect. Check it out!
    Dismiss Notice

Inexpensive voltmeter, monitor voltage while riding

Discussion in 'The Garage' started by TwoManyXS1Bs, May 2, 2013.

  1. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Found some inexpensive ($3 plus change) digital voltmeters on eBay for lab projects. Wanted to monitor charging system on XS1B while riding. The unit is small, could fit on handlebars, inside instrument, under seat, or even behind side cover near regulator. Only (2) wires, one to ground, other to switched power.

    Pic 1 - Spec sheet
    Pic 2 - Mounted between instruments
    Pic 3 - Ignition 'on', shows 11.2 volts

    Huh? 11.2 volts? Need to charge battery...

    Attached Files:

  2. Considering the stock charging system on these bikes, a voltmeter should be one of the first mods anyone should do....seriously. I've got analog voltmeters on both of mine picked up at the farm supply store for around 15 bucks. The price of that digital meter you have and the way it fits in there should should be an incentive for all to do the upgrade.
  3. Visegrippe

    Visegrippe lurker extraordinaire...

    i wonder why the ammeter fell out of style... is there a reason y'all are choosing volt meters vs. ammeters? is it just the ease of installation?
  4. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor


    You did a nice job of mounting! For sure, a voltmeter is a must have on these old bikes. At such a low cost, why would anyone not have one of these.

    An ammeter and a voltmeter tell us the same information, but just in a different way. Because the ammeter has to be capable of passing a somewhat large current, which could be up to 10 or 12 amps, you would want to run #14 gauge wire (might get away with #16 gauge) to the ammeter. With a voltmeter you can use very small wire such as #24 gauge wire, making mounting very simple. A voltmeter tells you everything you need to know.

    I have used an analog voltmeter for the past 4 or 5 years. Cost me $7.00.

    When you go to a doctor for a physical check up, does he/she measure your blood flow or your blood pressure? They measure blood pressure of course, because its just a simple way, and gives all the information they need.

    Attached Files:

  5. racerdave

    racerdave ^ Gone not forgotten ^

    Nice looking install, Toomany. Is that designed to be out in the elements?

    Retiredgent, that one is oldschool:thumbsup:
  6. resto

    resto XS650 Addict Top Contributor

    If you order the voltmeter carefully, they will fit nicely into the later indicator lamp console. I removed the brake light bezel and replaced it with smoked plastic.

    Went with the voltmeter instead of the ammeter because it gives you a better heads up on an overcharging condition that can cook your battery.

  7. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Actually there is a way to simplify the mounting wiring for an ammeter. An ammeter consists of a shunt (low resistance piece of copper) and a voltmeter to measure the voltage drop across the shunt. Normally the shunt is inside the voltmeter, but it does not have to be so. The shunt could be mounted directly in the normal location where the bike's wiring is situated, and then run some light gauge wire (#24 gauge) up to the handlebar area for easy mounting and viewing.

    Not worth the trouble.................just use a voltmeter.:)
  8. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Well done resto.......................looks factory done!
  9. resto

    resto XS650 Addict Top Contributor

    Best $4 I ever spent on eBay.
  10. xjwmx

    xjwmx It's just the unknown. Top Contributor

    There's a great free mod that turns your headlight failure light into a charging system failure light, and it also comes on when the key is on and turns off when the engine starts (begins charging) like an auto ignition light. You can look it up or if there's any interest I'll look it up.
  11. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Yes, I think that is one of Pamcopete's mods using the Reserve Lighting Device. While somewhat useful, it really only operates as a total failure alarm. A voltmeter is a real time continuous monitor that will give you some warning as wiring, connections, brushes start to deteriorate.
  12. xjwmx

    xjwmx It's just the unknown. Top Contributor

    ^It was. My logic for choosing it for myself was that most failures I think are going to be total if you keep an eye on things like brushes and connections. Or they will fail gradually with lots of warning.

    It doesn't actually use the reserve lighting thing but you can keep it in the circuit if you choose. In that case when the light goes on you figure out if it's your headlight or your charging that's broken :) I removed the reserve lighting because I didn't know how it fails if it fails. It might turn my good headlight bulb off.
  13. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Resto's install looks factory, good job. His setup will handle the elements. RetiredGentleman has probaby written over 100 postings on charging system failures/diagnostics/foibles/risks, so I took the hint and figured I should start checking mine. Couple years ago I rebuilt the regulator, rigged-up battery using $6 deer feeder batteries (couldn't find any 12N5.5s), and need to fine-tune the regulator. For the price, I got several of these, in different colors, and plan to stick them in my trucks, RV, lab equipment, the dog and my crainal implant.

    There's a very tiny of potentiometer on the back, not sure if it's to calibrate. Would like to reverse-engineer and see if there's a way to dim the display, triggered by the lighting circuit...
  14. bergoff

    bergoff XS650 Addict

    Thanks for posting this. I'm ordering one for mine. Thinking about mounting it in the tail light idiot light spot maybe.
  15. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Yew betcha, bergoff. The eBay seller was 'Sashawigs' (where do they get these names?), out of China. Free ship, but takes a month on that slow boat...
  16. EvenmoreXS

    EvenmoreXS 1981 XS650

    I saw these on ebay, but the price discouraged me. Too cheap, .... must be CHEAP !. Im gonna watch for a bit and see how it works over some time. LOVE the idea if the cheapo guy holds up. Looks great though.
  17. Grinder

    Grinder XS650 Guru

    My version.

    Attached Files:

  18. My version, John Deere lawn tractor item trimmed to fit. Ten bucks.

    Attached Files:

    • 001.JPG
      File size:
      194.5 KB
  19. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Wow, nice installs, look factory. Last eBay check showed them down to $2. EvenmoreXS, tempted yet?
  20. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    A little thread update.

    Well, sure 'nuff, my original 2-wire digital voltmeter bit the dust two years ago, after a few months in service.

    Found the cause was intermittant negative voltage spikes, which are caused by inductive kickback of the alternator's rotor when the ignition is switched off. PMA charging systems don't have this foible.

    The 2-wire voltmeter doesn't have reverse-polarity protection. But, the near-identical 3-wire version does indeed have reverse-polarity protection, and at a similar budget price.

    So, I replaced the 2-wire version with the 3-wire version. For this 3-wire version, simply tie the voltage supply and voltage sense wires together, and run them to switched power. The two colors may vary, depending on model, might be red and white, just tie together the colors that aren't black. The black wire is ground.

    Otherwise, it's no different from the 2-wire version. The 3-wire version has been working fine, and paid for itself by alerting me to an intermittant weak connection at the battery.

    Attached Files:

Share This Page