Cranky Old Guy - Smiths Gauges

[tmsmini]

Email exchange with caerbont, It is in reverse order, so hard to follow

I understand it is old technology. The VDO 20 year old gauge I have is still accurate. My cars charging system outputs 14.2 volts as verified by multiple gauges. The less than a year old gauge reads over 15 which is closer to 5%. I do understand the gauge reading can be relative to the environment.

> "outside these limits you have a problem and need to investigate ASAP"
upon investigation I found the gauge is inaccurate and foolishly bought another.

Very disappointing.

Terry
On 5/31/2024 12:13 PM, Peter Wilkinson wrote:
>
> What you have is a 1960's technology gauge, you are never going to get digital accuracy out of them.> 
>
> Smith philosophy at the time was gauges of this technology was that after a few trips in your vehicle you knew where the normal position was, if it suddenly read higher or lower then consult you garage to investigate the problem. 
>
> We try to give 3 % accuracy at calibration on our gauges and 14 v +3% gives 14.42 volts, so looking at you pictures the gauge is in calibration so we would not change it.
>
> With a voltmeter, if you turn the ignition on and it reads 12v or over and then starting reads somewhere around 14 volts then you have nothing to worry about, outside these limits you have a problem and need to investigate ASAP. 
>
> Regards
>

> Peter
>
> Software Engineer
>
> Direct Phone +44 (0)1639 732243
>
> Caerbont Automotive Instruments Ltd
> Unit1, Caerbont Industrial Estate, Caerbont, Abercrave, Swansea, SA9 1SH
> Company Registration No 2847474
>
> www.caigauge.com
>
> T : +44(0)1639 732200
>    
>
>
> Caerbont Automotive
>
>           Instruments
>
>
> From: terry.smith <tmsmith510@gmail.com>
> Sent: Friday, May 31, 2024 2:58 PM
> To: Peter Wilkinson <Peter.Wilkinson@caigauge.com>
> Subject: Re: volt meter
>
> 
>
> Peter:
>
> So I bench tested as you suggested starting low and going high. The meter still read a volt high at 14 volts. I bought a new gauge and it is high by .5 volt using the same process.
>
> I also realized that the old gauges were not that old as I had purchased them in October of 2023. I found this out when I went to file the receipt for the new purchase. I thought I had replaced the gauges all at the same time, but the voltmeters were only replaced last year.
>
> I checked the gauge against another old one and the newer gauges are definitely reading high.
>
> What can be done?
>
> Terry
>
> On 5/19/2024 10:52 PM, Peter Wilkinson wrote:
>
>     There is no user calibration on the gauges.
>
>     
>
>     With aircored technology volt meters there is an error if you start high and go low as in normal use you turn on the ignition, it goes to battery voltage, then you start the car and it goes to charging voltage. Normally you then complete your journey and switch off .
>
>     
>
>     If you bench test starting at 14 volts and then lower to 11.5 volts you will find they often overread by about ¾ of a volt. Do it the way you would normally use it starting low then go high it would be OK.
>
>     
>
>     Regards
>
>     
>
>     Peter Wilkinson

[MiniDave]

Bottom line, it reads too high, and gives you the frights? Every once in a while mine reads up to 15, then seems to back off again to high 13's, low 14's even after I've been on the road for a while.

What you could do if you want - I put in a USB charging port, and it had a digital readout for battery voltage - the readout is pretty small so it's fairly unobtrusive, especially since it's slightly under the dash. That way the gauge is there for reference only - and if it looks like it's reading crazy you can always check the digi gauge.

https://www.amazon.com/Upgraded-Charge-Qidoe-Aluminum-Voltmeter/dp/B08PTZ17NS/ref=asc_df_B08PTZ17NS/?tag=hyprod-20&linkCode=df0&hvadid=693366125648&hvpos=&hvnetw=g&hvrand=7570642269393117139&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9023906&hvtargid=pla-1186636383770&psc=1&mcid=1cf07338f4f3341297c9cfcc022c08fd&gad_source=1

[tmsmini]

Hard for me to believe that this is acceptable for a brand new gauge. I emailed both Caerbont and Nisonger and they gave the same story.

[94touring]

Fwiw on my bus, reading various volt gauges and outputs, I'll see readings upwards of 1 volt difference between any of the sources.