# voltmeter/ammeter prices



## Coley (Jul 26, 2007)

The digital readouts on eBay are very good and don't cost a lot.
The shunt comes with the amp gauge.

I bought the expensive Australian ones first, but the wiring diagram was wrong.

Bought the second set on ebay @ less than 3/4 the price.

They work well and easy to read.

I even bought a spare set just in case and have not had to use them.


----------



## PatricioIN (Jun 13, 2008)

Coley said:


> The digital readouts on eBay are very good and don't cost a lot.
> The shunt comes with the amp gauge.
> 
> I bought the expensive Australian ones first, but the wiring diagram was wrong.
> ...


Are you talking about the handheld mulitmeters?


----------



## e_canuck (May 8, 2008)

Hello PatricioIn.

Nice set of wheels.

I whent to ebay for my gauges. There are a lot to look at. Analog digital, LED, LCD, backlit or not.

There are white, red, blue, green, yellow and what not.

I settled for these.
http://cgi.ebay.com/Universal-Digit...25411QQcmdZViewItemQQ_trksidZp1713.m153.l1262

http://cgi.ebay.com/Universal-Digit...25411QQcmdZViewItemQQ_trksidZp1742.m153.l1262

I chose red LEDs cause my donor car as a cluster illuminated in red and red LEDs on the radio. Got them for 15.00USD and 25.00USD respectively.

Still waiting for the postman...So I ca'nt report on how well they work.

Take care,

DP


----------



## RKM (Jun 9, 2008)

e_canuck said:


> Hello PatricioIn.
> 
> Nice set of wheels.
> 
> ...


e canuck

Nice looking gauges. Will be interested to hear how they work out once installed.

Do you plan to monitor battery amps or motor amps?

Rob


----------



## e_canuck (May 8, 2008)

Hey guys.

I intend to monitor the batteries amps.
Seems better to me. You can see power going up when selecting heat or AC.

Might be a reminder to save power, if you still have a long way to go and you see power usage while on a red light.

I won't convert just now. I will install the gauges and monitor the amperage from the alternator. To test the gauges and help me decide on how big a DC-DC converter I need.

DP


----------



## PatricioIN (Jun 13, 2008)

e_canuck said:


> Hello PatricioIn.
> 
> Nice set of wheels.
> 
> ...


that's funny.. just before I read your reply, I ordered those exact meters from eBay.. I figure they aren't that expensive, so no big deal if I need to go back to the other ones later..


----------



## Coley (Jul 26, 2007)

Those are very similar to the ones I bought.

I run mine off of a 9volt battery, so they are totally isolated.

A pushbutton switch lets me run them or not, instead of all the time.


----------



## fugdabug (Jul 14, 2008)

bought mine for a bit more than that ($US), so if you are talking each guage and a pair... good price per gauge!


----------



## TX_Dj (Jul 25, 2008)

I bought a 0-50vdc volt meter for ~$20, and a 0-30A ammeter w/ external shunt for ~$17.

With the right resistor, and a custom scale, the 0-50vdc will show whatever voltage range you want it to, and with the right shunt and a custom scale, the 0-30A ammeter will show whatever amperage range you want it to.

The Ammeter is a 75mv full scale, so if you wanted it to show 500A all you'd need is a 500A 75mv shunt and design a scale to show between 0-500A in the same distance as the 0-30A scale. Similar is true for the voltmeter. It shows 0-50vdc with no resistor installed, but with careful calculation, you can add a small resistor to it that will expand it's scale. I.E. if I add ~50k ohm resistor, it would be ~0-100vdc instead of 50.

With some creative parts shopping and DIY bodgery, anything is possible, I'm convinced.


----------



## Qmavam (Aug 17, 2008)

e_canuck said:


> Hello PatricioIn.
> 
> 
> I settled for these.
> ...


 Some of the Digital meters cannot measure the battery the are powered with. In other words you need a separate battery for the meter. I checked the site and found no information about that aspect, this leads me to think it needs a separate battery. Send a letter and ask the seller then tell us.
Thanks, Qmavam


----------



## e_canuck (May 8, 2008)

Qmavam said:


> Some of the Digital meters cannot measure the battery the are powered with. In other words you need a separate battery for the meter. I checked the site and found no information about that aspect, this leads me to think it needs a separate battery. Send a letter and ask the seller then tell us.
> Thanks, Qmavam


I asked them that question before purchasing. They can

They have a builtin power regulator. In effect they are isolated from what they read. Or sp is the claim.

Still waiting for the mailman from Hongkong. 7 days now.

DP


----------



## Qmavam (Aug 17, 2008)

e_canuck said:


> I asked them that question before purchasing. They can
> 
> They have a built in power regulator. In effect they are isolated from what they read. Or so is the claim.
> 
> ...


Ok, if you ask and they said it would, great. I will add, the fact that it has 
a built in regulator has nothing to do with isolation.
Qmavam


----------



## e_canuck (May 8, 2008)

Hi Qmavam.

I do not whant to beat that one to death but here are the info they sent me. Look at bullet NO.3

DP


I Product Highlights: 

This Meter is a 3 ½ Digits Panel Meter, is great for measurements that require high precision and stability. It is widely used to measure and display of voltage, current as well as other critical parameters in variety of electrical equipments and instruments. 

※1. Display range adjustable for some of the meters.

※2. Decimal point position can be adjusted.

※3. Capable of measuring its own supply voltage source. 



II Specifications and maim parameters:



Operating Voltage: DC(7V-15V)

Operating Current: ≤ 80(mA)

Display Range: 0 to ± 1999, or (0 to ± 1000)

Display LED Height: 18.6(mm) or 9/16(inch)

Displayed when over-limit: “EEEE” or “-EEE”

Sampling period: 0.3sec

Error: ± 0.5%

Operation Environment:

≤ 85% Relative Humidity

0C ~ 50C, (32F ~122F), Ambient Temperature

Meter External Dimensions: 79x43x20(mm) or 3.11x1.69x0.79(inch)

Opening for Meter installation: 76x39.5(mm) or 2.99x1.56(inch) 



When nothing shorted to 4, no decimal point is displayed.

When 5 is shorted to 4, decimal is between two right most digits

When 6 is shorted to 4, decimal is between two center digits

When 7 is shorted to 4, decimal is between two left most digits.


----------



## Qmavam (Aug 17, 2008)

e_canuck said:


> Hi Qmavam.
> 
> I do not want to beat that one to death but here is the info they sent me. Look at bullet NO.3
> 
> ...


 Hey DP, you didn't beat it to death, but #3 certainly put it to sleep!
Thanks, Mike


----------



## Drizzle (Jun 17, 2008)

I, too, ordered gauges from e-bay, all the way from China. 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370055940783

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370055162161

I paid quite a bit more than you did for the Ammeter e_canuck. Wish I'd found that vendor -- but I'm pretty happy with what I got, and while I don't have the car running (and thus, don't have them connected and working) yet, I think they'll work out fine.

FYI -- they took about two weeks to arrive from China. I thought that was pretty good...

Gosh, I can't wait to experience them IN USE!!! 
Drizzle

Here's how they look on my instrument panel... And the dash prior to adding them...


----------



## e_canuck (May 8, 2008)

Drizzle said:


> I, too, ordered gauges from e-bay, all the way from China.
> 
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370055940783
> 
> ...


Hello Drizzle.

I recognise those gauges. There the ones Gavin (Kiwiev) got. I looked at them initially. Cause they look cool.

The price of the ammeter was a bit too steep. Plus I realised they wouldn't match the rest of the dashboard.

I can tell you carved the fuel gauge out. What else? How was the carving procedure? Translation: "how in tarnation does the gauge cluster still work after that?"

Two weeks? Bummer.

DP


----------



## Drizzle (Jun 17, 2008)

Hey, oh Northern friend...

The gauges should match my dash pretty nicely once it's running... That white instrument cluster is a glow-panel that lights up blue, so the gauges back-lit in blue should look nicely integrated... A bonus for me. Maybe it will help assuage the buyer's remorse on the price hit I took... 

Anyway, yes -- carving out the instrument panel for those gauges was a big challenge. The only remaining working gauges on that panel are the speedometer and tachometer. I hope to find a way of continuing to use the tach -- obviously, I plan to continue using the speedo... But the temp, oil-pressure, fuel level, and chassis volt meter are obviously not useful to my EV conversion -- except perhaps the volt meter... But I think that's a small loss... If I end up feeling I need that later, I can easily add a small gauge elsewhere.

Hey, that two weeks has got to be nearly expired by now, eh? (OTOH, you have the added burden of waiting out Canada Post, right??  )

Cheers,
Drizzle


----------



## Coley (Jul 26, 2007)

Kiwi and I got ours about the same time.

Mine came with a DC/DC converter.

I used a 9 volt battery instead, on it's own switch.

Works well and you can turn off the light (bright) at night.....


----------



## Drizzle (Jun 17, 2008)

Can you dim the light without completely canceling the display?? 

I like the 9V bat idea -- but the need to replace them every month or so, not so much...


----------



## e_canuck (May 8, 2008)

Hi guys.

Canada Post as delivered my gauges after 11 days.

The good:

They look good, the voltmeter works great and measure is own power source.









The bad:

The ammeter only displayed EEEE ( out of limit ) then went blank.

I am going to put it aside, get some food, then look at it again with a fresh mind. Any sugestion? Before I write the manufacturer and try for a waranty replacement?

DP


----------



## PatricioIN (Jun 13, 2008)

update:

The inexpensive ammeter/voltmeter I ordered from eBay (link earlier in thread) were working fine when I finally got my system up and running.. until I fried them by putting too high amp fuse in line.. .my mistake, but they were working fine and looking great! Will be re-ordering them.


----------



## PatricioIN (Jun 13, 2008)

another update:

got second set of meters and having same issues. Can't seem to have both ammeter and voltmeter plugged in at same time or I blow a fuse in voltmeter supply line. Can't for the life of me figure out why, but since another DIYer has had the exact same issue with two of the same meters, my best guess is that these meters just aren't very good. They look nice and seem to work fine individually, but using both... not so good.


----------



## favguy (May 2, 2008)

Hi, I'm using these meters too, they are very good, but you must run each meter's power supply via a 12v dc to 12v dc isolated supply, this resolves the problem you are having. You can buy these from china on ebay for a few bucks each, or any good electronics store will have them.

This is an example:

http://cgi.ebay.com/DC-DC-Converter...996240QQihZ024QQcategoryZ117000QQcmdZViewItem

While I'm on here, I've sourced a fantastic temperature guage for controller or motor temp. monitoring, I've bought two of these myself and they look great in the dash. You need to cut and extend the temperature probe wire but that's easy and wire them via a 12v to 5v converter as they are designed for pc use, but they work great and are really accurate.

Temperature range is 0 to 80 degrees C

Temp guage:

http://cgi.ebay.com/Digital-Thermom...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

12v to 5v converter:

http://cgi.ebay.com/DC-DC-Converter...996227QQihZ024QQcategoryZ117000QQcmdZViewItem

Regards

Paul


----------



## PatricioIN (Jun 13, 2008)

favguy said:


> Hi, I'm using these meters too, they are very good, but you must run each meter's power supply via a 12v dc to 12v dc isolated supply, this resolves the problem you are having. You can buy these from china on ebay for a few bucks each, or any good electronics store will have them.
> 
> This is an example:
> 
> ...


so just for my education, what does the isolated power supply do and why will that resolve my issue? I still don't understand why the fuse is blowing when they are both connected, especially since the fuse is not in the power supply to the meters, but in the load line on the voltmeter.


----------



## favguy (May 2, 2008)

I'll be honest with you, I don't know why your fuse is blowing, but I do know if you use the cars own 12v supply to power both volt and amp meters together they don't work right! they have to have independent and seperate 12v supplies, because they are both effectively measuring pack voltage from the same source, if powered by the same input source, even when bieng seperate from that measured, they bugger each other up, I think it's to do with earth (-ve) feedback or some such, but I don't really know the reason, just the solution!

The isolated power supply uses the 12v power source to create an outgoing power source that is not connected in any way (either -ve or +ve) to the incoming source, how it does it with DC, i have no idea! (I know how it's done with AC via transformer coils ) But they are about 90% efficient for what it's worth.

As that explanation was next to useless, can someone with electronic knowledge please tell us why this actually is?


----------



## PatricioIN (Jun 13, 2008)

lol... no.. that's good enough I guess. At this point, what's another $20 bucks? I'll give them a try once I get my new meters.


----------



## Carroll_1 (Dec 18, 2007)

Here's some experience I gained yesterday, thought I'd pass it along in the name of educational value. (That's my way of handling the embarrasment )

I purchased a set of digital gauges on Ebay. 500A ammeter and 200V voltmeter. Specifically advertised not to need a seperate DC-DC converter for 12V power. They were delivered in about a week. Got around to installing them on a 144V system a few days ago. I installed the gauges in the dash, connected 12V key-on power and 12V ground. I tested the gauges, they backlit fine, and all looked good. But unknown to me at the time I must have suffered a major brain fade several weeks ago and had installed the 500amp shunt on the most positive end of my 12 battery string instead of the most negative end. During the gauge install, I had my battery string uncabled at the 10th battery. After installing the gauge sensor leads, (ammeter to shunt and voltmeter to pack voltage), I began to re-connect the string at the tenth battery located in the trunk. Now I'm telling you it was the tenth battery so you know it was a 120V shot I received in the private parts as I leaned over the trunk and placed my wrench on the battery cable connection. I instantly realized (well my body instantly realized, my brain didn't catch up until later) the ammeter had blown and was providing a path from my battery pack to ground. (More specifically, entering my wrench hand and exiting somewhere between my navel and knees).

Lessons learned: 

1. Double and triple check all wiring layouts. (I must have looked at that shunt a dozen times)
2. Beware of cheap parts. I can't really blame the gauges, but it sure looks like it took out the voltmeter too.
3. Check for battery pack to frame leakage regularly
4. Wear gloves and use insulated wrenches on all battery pack connections
5. When working on conversion, consider wearing a cup.

Seriously, after it happened I began testing and found 150V to chassis ground. Not a lot of amperage, the gauges come with about a 22gauge wiring harness, but it did sting a little. I disconnected the shunt to gauge leads and the pack regained isolation. When I reconnected the voltmeter, I was still getting aboout 2.5V to ground. Don't know whether to try the digital route again, or just drop in a set of Westbergs.

Craig


----------



## DIYguy (Sep 18, 2008)

favguy said:


> Hi, I'm using these meters too, they are very good, but you must run each meter's power supply via a 12v dc to 12v dc isolated supply, this resolves the problem you are having. You can buy these from china on ebay for a few bucks each, or any good electronics store will have them.
> 
> This is an example:
> 
> ...


Hey thanks for the tip on the temp gauge. I personally don't like digital meters so much.... This is nice, gives the benefit of analogue with digital.


----------



## PatricioIN (Jun 13, 2008)

favguy..

I got same size digital meters from another vendor and they came WITH instructions that they must have isolated power supplys!! That would have saved me a ton of time and brain cells if the first (or second) set had come with those same instructions.

Anyway, turns out these fit perfectly in the dash where the old meters were and they were even cheaper. After installing the voltmeter and testing the working power, I find I even like them better as they are backlit blue with black lcd numbers.. easier on the eyes than my first set which were bright blue lcd numbers.

thanks for the isolation info.. the new meters just confirmed all that you already told me with diagrams no less!


----------



## PatricioIN (Jun 13, 2008)

Carroll_1 said:


> Here's some experience I gained yesterday, thought I'd pass it along in the name of educational value. (That's my way of handling the embarrasment )
> 
> Lessons learned:
> 
> ...


My ammeter is also wired in my most positive line, that's the way it's shown in my wiring diagrams from KTA. I'm really thinking the problem is like described by favguy... when using both meters, they must have isolated working power supplys. Will let you know how the new set works once I install them with the isolated supplys.


----------



## reddwarf2956 (Dec 1, 2008)

TX_Dj said:


> It shows 0-50vdc with no resistor installed, but with careful calculation, you can add a small resistor to it that will expand it's scale. I.E. if I add ~50k ohm resistor, it would be ~0-100vdc instead of 50.


You might want to check the volts with a known voltage and use a variable resistor to set the scale correctly. Normally, a fixed resistor will state that its reading is off +/- 1%, 2%, 5%, or even 10%. By having the system checked with a know voltage and then tuning the variable to match the reading the error is removed. 

You do want a variable resistor which can handle the correct ohm range and handle the power.


----------



## Coley (Jul 26, 2007)

My first set came with instructions on the DC/DC converter that was included.
BUT, the wiring diagram was wrong and they both went out.

The second set I wired to a 9 volt battery. Single source for both meters.

No problem with them since....


----------



## PatricioIN (Jun 13, 2008)

ok, I got my new set and some 9-18vdc/12vdc isolated power supplies.. hooked everything up and ammeter was working, voltmeter powered, but no volts showing.. replaced inline fuse for voltmeter load (from when I blew the meters before) and voltmeter started working properly, but ammeter shows gibberish. I don't know what the heck my problem is.. I haven't blown a fuse on voltmeter like before, and nothing appears burned on ammeter.. both still show power, etc... anyway, finally got around to diagraming the wiring on my meters.. maybe there's something obvious on here that I'm missing...


----------



## favguy (May 2, 2008)

Hi,
Your wiring looks fine, that should work ok, the worst case on the ammeter should be -ve showing before the current reading if you needed to swap over the shunt leads, but the meter should never show a garbled reading, I hate to say it, but it sounds like you've got a duff meter this time

Paul


----------



## rmay635703 (Oct 23, 2008)

On the cheap end if you like analog meters, harbor freight has $5 analog ammeters 60amp in my case and $5 analog voltmeters 8-16v.

However If I can figure out how to crack the casing I believe both can be modified for any range, worthwhile if you just can't find a cheap disposable meter.

Cheers
Ryan


----------

