Reliable Voltage Meter ?

[WheezyRider]

If you just want a basic voltage readout only, then a £2 two wire one on ebay will work one just needs to house it in a W/P project box.

This is true, but you need to be a little careful. Lots of these LED displays are designed for typically 12V use and max out at around 30V DC for power input, just for driving the device (3 wire devices, 1 wire ground, 1 wire power input and 1 wire signal to be measured). For a typical 36V pack you need a bit more, so you need to check and look out for this in the operation spec. Alternatively, you can use a Zener diode in the power supply line to one of these 30V max meters to bring the power supply meter voltage back into spec.

 

[saneagle]

I've been using these recently. You can get an external shunt version if required. And of course, if used on the bike you will need to waterproof. It will go up to 100V, whereas most others will only go up to 60V.

View attachment 52590

How and where did you mount it?

 

[StuartsProjects]

Looks good, has the important stuff.

Is the display the type that is visible outdoors in direct sunlight ?

 

[Nealh]

I have mounted both of these or very similar to bikes/batteries , the second being a little dearer oth simple two wire arrangements.

Car Voltmeter DC 4-100V LED Digital Display Round Two Wire panel Voltage Meter | eBay

12V/24V/48V LCD Digital Battery Capacity Status Display Indicator Monitor Meter | eBay

 

[WheezyRider]

I have mounted both of these or very similar to bikes/batteries , the second being a little dearer oth simple two wire arrangements.

Car Voltmeter DC 4-100V LED Digital Display Round Two Wire panel Voltage Meter | eBay

12V/24V/48V LCD Digital Battery Capacity Status Display Indicator Monitor Meter | eBay

They look like nice options.

Here is what I mean about the common 3 wire meters for 100V, the supply can only go up to 30 or 40V:



I have used these quite often as they come with a handle bar mount:

 

[WheezyRider]

Looks good, has the important stuff.

Is the display the type that is visible outdoors in direct sunlight ?

Did you mean this one?



I would say it's a lot clearer than this type:



Plus it goes up to 100V as opposed to 60V max for the one in the photo above. The backlight can be activated or turned off by pressing the button.

 

[WheezyRider]

How and where did you mount it?

As I've only used the internal shunt version so far, and only intermittently when I needed to check something, I have not mounted it too far from the battery, and just lashed it on with cable ties. I used to have the older type on the bike most of the time until it died. I plan to 3D print an enclosure I can waterproof and put on the handlebars. That will most likely be the external shunt version. But, too many projects and never enough time!

 

[guerney]

I'm surprised e-ink displays aren't cheap enough yet to be used in devices such as the ones mentioned, which will mostly be used in daylight, with a front light added for night use.

 

[StuartsProjects]

The one you showed looks like the reflective type, one clue is the switch for the backlight, this suggests the display can be used\seen with no backlight. The other clue is the black characters.

It appears that at some point in time the build of my '150A' Wattmeter was changed to use a non-reflective display, which is OK for indoor use or outdoors at night.

 

[StuartsProjects]

I'm surprised e-ink displays aren't cheap enough yet to be used in devices such as the ones mentioned, which will mostly be used in daylight, with a front light added for night use.

e-ink displays in general are slow to erase and then write too, so not good if your displaying characters that might be changing rapidly.

 

[Del 80]

Well, this has been a fascinating subject, but I might just do what I did with the Powacycle.......it will entail getting a handlebar mount 'phone holder, and a voltage tester, as I recall, on the Powacycle the voltage tester wasn't turned on all the time, just before, and then at various times during a journey, because as stated earlier the true voltage would fluctuate too much when under load......now, which two wires to splice into ?.........

 

[Del 80]

Well, have established that out of the five terminals on the battery, it is the two outside one's that give the voltage reading.......this is a 36 volt battery, so a reading of 40 volts, when fully charged, is I believe correct.......just got to figure out how to attach two wires to the terminals, and we are half way to having a working volt meter......

 

[WheezyRider]

Well, have established that out of the five terminals on the battery, it is the two outside one's that give the voltage reading.......this is a 36 volt battery, so a reading of 40 volts, when fully charged, is I believe correct.......just got to figure out how to attach two wires to the terminals, and we are half way to having a working volt meter......View attachment 52621

40 sounds a bit low. Is it fully charged?

 

[Del 80]

40 sounds a bit low. Is it fully charged?

Not quite fully charged, have been out on it since the last charge.........

 

[Nealh]

40v is not fully charged, it is shy by 2v.

 

[Del Arthur]

Well, just got to get a handlebar mount mobile phone holder, tidy the wires up, and job done......O.k it looks a bit "Heath Robinson" but it does what it's 'sposed to do.......using this I will always know what voltage is left in the battery, and that was the general idea......also, I've thoroughly enjoyed doing it !!.......

 

[WheezyRider]

What does it read if you put it on the 200V setting?

 

[Del Arthur]

Well, just got to get a handlebar mount mobile phone holder, tidy the wires up, and job done......O.k it looks a bit "Heath Robinson" but it does what it's 'sposed to do.......using this I will always know what voltage is left in the battery, and that was the general idea......also, I've thoroughly enjoyed doing it !!.......View attachment 52624

Not sure, as disaster has struck......I let the two ends of the wires touch, and there was a flash......now nothing !!.......presumably there is a fuse somewhere in the battery housing ?........HELP !!

 

[guerney]

Not sure, as disaster has struck......I let the two ends of the wires touch, and there was a flash......now nothing !!.......presumably there is a fuse somewhere in the battery housing ?........HELP !!

That happened to me once - I had badly stripped wires using a box cutter, and left tiny nicks in the insulation of those battery wires and they arced. My battery was and still is fine, BBS01B controller fscked. I've bought a proper wire stripper since. Seller sent me a new controller under warranty under pain of extremely bad Amazon reviews, because I'm that sort of customer. These days I cover all exposed ends with insulting tape, while preparing to solder etc. Hope your battery is ok, of course a far greater cost than the controller...

 

[Del Arthur]

There IS a fuse, but no indication of what amps it should be or anything........any help appreciated.......