Inexpensive voltage monitoring

[amberwolf]

update: I gave hobbyking cellmeter 7 a try and it didn't work because the voltage display is static. In other words the information displayed only refreshes if you unplug the balance lead and plug it back in again. Unless you feel like plugging and unplugging the thing the whole time, it's useless as a voltage display.

What happens if you just disconnect and reconnect the power regulator inside? Or if it has a reset pin, trigger that. If that will reset it, then you can probably build a 555 timer or something simlar that will reset it automatically however often you wish it to update, or use a momentary switch to do that if you want something less complex and dont' mind manually resetting it.

 

[parajared]

I bet it could be modified to automatically turn on and off every once and a while for less than just buying one that functions properly. I may be losing my sense of the value of a buck. My ultimate goal is to save up enough to secure a decent retirement (I'm 30). I earn $18 per hour so if i hadn't wasted $10 on the cellmeter7 I would have been about 35 minutes of labor closer to retiring. Multiply this times the number of times that I couldn't get something working and just bought a new one, and I could be a retiring a lot sooner.

 

[deardancer3]

hmmmm some intersting stuff

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[amberwolf]

Multiply this times the number of times that I couldn't get something working and just bought a new one, and I could be a retiring a lot sooner.

That's kind of why I do what I do with stuff...except for me it's for day-to-day living, as I have yet to find a way to be *able* to save for retirement. Like my mom used to say--"i'll work till I drop dead, and then I'll get up and do it some more." :lol:

 

[Njay]

Saw this one and remembered this thread. Note the image of its back - has kind of a connector with 2 points marked TX and RX. Humm...

http://dx.com/p/3-digit-voltmeter-for-electric-motorcycle-0v-99-9v-151556

 

[dogman dan]

Three wires input. Very likely that means it measures pack voltage with one wire, but powers up with a different voltage with the other wire, and both share the ground.

Not the same as the two wire, runs on what you got type pointed out at the top of the thread.

 

[SamTexas]

Just a quick update: One of my two units quits working today. It displays 3 dashes (-) instead of digits. 5 months old. Total usage time around 2 hours.

 

[dogman dan]

I was just pleased that both of mine worked right out of the box, and more or less agreed with a dvm reading. China stuff ya know, get two to have one. I haven't used mine a lot, since I have two CA's, but I have done more than 10 hours use on at least one of them.

 

[The Stig]

Can anyone currently recommend a waterproof voltmeter good for outside? (I found one that was recommended by dogman but as he says in the first post its no good for outside - its unreadable in the sun)

Smaller is better,
More waterproof is better,
Doesn't have to be digital.
Red or blue so it doesn't bother during night riding,
read-able in the sun.

 

[wesnewell]

Well, I've been using mine for over 2 years (and still working) and the sun doesn't bother me. I just hold block the sun for a couple of seconds to see it. It's not like you need to watch it every second, I may glance it once or twice an hour. There were LCD ones on ebay some time back. I haven't looked for them lately....

 

[dogman dan]

I can't imagine Texas sun being much dimmer than New Mexico sun. Mounting the meter in a little shadow box helps. I could never quite look at them on the fly even with the shadow box, if it was noon. So I'd have to stop and check.

Like Wes says though, you don't need to even look at all, till you are nearing the end. As long as you started out full, you can count on x miles before you need to look again.

In the end, I just bought a third Cycleanalyst, after a cheap wattmeter failed in a year.

My two cheap voltmeters still work, they are used on my chargers. I like to know voltage then too, particularly if I am sitting around waiting for a charge. Indoors, I can see them fine.

 

[wesnewell]

I'm using a green one. Maybe it shows up better during the day, I've also got a blue one, No red ones. I've never used the blue one either, it may be better or worse in the sun. I don't think the sun puts out much in the green spectrum, however I know it does in the red spectrum.

 

[amberwolf]

FWIW, there is more green than blue or red in the sunlight reaching sea level. I don't recall by how much, though.

However, the human eye has many more receptors sensitive to green and red light than it does for blue---yet it isn't even as simple as that, for how our eyes respond to the colors.

More or less, the average eye responds like this:

There's some information here:

http://en.wikipedia.org/wiki/Color_vision

that I don't pretend ot understand all of.

This image might help, though, if you understand what its' saying (I'm having a little trouble wiht it right now):

 

[The Stig]

hehe thats very thorough amber! Not sure what to do with that though

Well, I've been using mine for over 2 years (and still working) and the sun doesn't bother me. I just hold block the sun for a couple of seconds to see it. It's not like you need to watch it every second, I may glance it once or twice an hour. There were LCD ones on ebay some time back. I haven't looked for them lately....

Wes could you point towards this device somehow? maybe like the model number so I can search it online?

 

[wesnewell]

Here's the red one. They also come in green and blue.
http://www.ebay.com/itm/Waterproof-Digital-Voltmeter-DC-15V-To-120V-Red-Led-Voltage-Digital-Panel-Meter-/121103165316

 

[The Stig]

thanks bud, I'll order a red one for starters, instrumentation in vehicles usually seems to be red... has yours survived any downpours of rain? any drops or hits? ever used a multimeter to check accuracy?

I just gotta be able to see what my crappy little batteries are doing under the current loads im giving them. So I can figure out what current limits to set.

Theres no way I'll buy cycle analysts for all 4 of our run-about ebikes. The CA costs probably on average 1/3 of the market value of these bikes.

 

[The Stig]

Turns out the trick is to search these terms... duh:
waterproof voltmeter red
And then just flick through results till you see one for the right voltages.


did a quick search and this is the one that seems to arrive here the soonest...

http://www.ebay.com/itm/DC-15-120V-..._Measurement_Equipment_ET&hash=item3cdf158b8d



Otherwise this is the only one available from north America. it reads 0-100v but it is weird, it has separate wires for a 3-30v power supply... could it be powered by the throttle's power wires maybe?

http://www.ebay.com/itm/SMAKN-4-Wires-0-56-Waterproof-Digital-Voltmeter-DC-0-100V-RED-LED-Auto-Mini-Vo-/171342837512?pt=LH_DefaultDomain_0&hash=item27e4d43708

 

[drsolly]

I've tried red led voltmeters, yellow and green. The red is most visible in sunlight, but in bright sunlight, I can't read it.

But then I found these.

http://www.ebay.co.uk/itm/New-LCD-Blue-Backlight-Direct-current-Digital-Volt-Meter-Two-wire-Voltmeter-PK-/310977580673?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&var=&hash=item4867b54e81

LCD voltmeter, two wire, you choose the range (I chose 18-80v). Cost £3.06. You can read it even in the brightest sunlight, and you can read it in the dark beause it has a backlight. You only need to connect the two wires. And the current it draws is less than the LED voltmeters.

 

[The Stig]

Hey thanks for chiming into the thread!

So I guess an LCD display might work better for me. This one sounds great but it says in the description "sun exposure: no direct exposure"

 

[The Stig]

Drs i tried buying the lcd one but it said they wont deliver to my countty or something.