Battery tester suggestions please

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Oct 8, 2006
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Thank you Prof JohnL.

My reason for asking if car battery could be tested whilst still connected was that (apparently) my Santa fe could possibly lose the radio code and (I'm not 100% sure) require reprogramming back into the ecu if disconnected.
ECU memory is non-volatile so if the battery is disconnected for safety during service the ECU will resume where it left off (albeit in osme cases it make take a few days running to rebuild its variables data tables.
Ergo the radio code will not be lost either.
 
Oct 8, 2006
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If your battery (or batteries) have removeable cell caps then checking battery charge state is simple. Toddle along to Halfords and buy a battery hydrometer. You then pop the tube into each cell, make the thing suck up some fluid, and see where the float sits - the surface of the fluid will coincide with the markings on float that indicate charge state. Cost about a fiver or so.
 
Jan 3, 2012
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You just require a digital multimeter that does DC and AC which will tell you the battery voltage. Knowing that will give you an indication of charge but not it’s ability to reliably deliver that charge. But it does help somewhat. There are charts that tell you no load volts versus battery percentage charge.
Hi otherclive How much is the digital Multimeter that does DC & AC might be a good investment for me to have next time we have problems with van
 
Jun 16, 2020
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I got a multimeter with both scales. But then found that the DC scale was 0 to 100. So I have little confidence in its accuracy at low voltage.


Something to watch out for.

John
 
Nov 11, 2009
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Hi otherclive How much is the digital Multimeter that does DC & AC might be a good investment for me to have next time we have problems with van
They range from cheap (nasty) to professional ones. Clarke or Sealey are well known and again there are different models at different prices.
£20-25 should get a reasonable one for general caravan, car and domestic usage. Here are the owners instructions for a Sealey meter. It has a number of DC ranges.

https://assets.sealeyb2b.co.uk/pdfs/instructions/MM19_V3.PDF

I will go into my garage tomorrow to check what my meter is. It was less than £20 a couple of years ago. It came recommended by someone on the Forum.
 
Jan 3, 2012
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They range from cheap (nasty) to professional ones. Clarke or Sealey are well known and again there are different models at different prices.
£20-25 should get a reasonable one for general caravan, car and domestic usage. Here are the owners instructions for a Sealey meter. It has a number of DC ranges.

https://assets.sealeyb2b.co.uk/pdfs/instructions/MM19_V3.PDF

I will go into my garage tomorrow to check what my meter is. It was less than £20 a couple of years ago. It came recommended by someone on the Forum.
Hi otherclive that would be great thankyou for your help in this matter
 
Nov 11, 2009
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Hi Clive I have written the details down thanks for looking for me
Be aware that the casing shows XL 830L but in Neoteck product brochure it’s NTK. 019 but the front casing reads XL 830L. Confusing or what. I guess XL830 L has more ” Buyer Appeal” and easier to brag about in the pub 😱
 
Mar 14, 2005
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Lol if you really want to brag then you need to buy a fluke, but most people wouldn’t spend the money on a fluke
But then they wont be getting the safety and performance that high end meters like Flukes, Agilents, Brymen and Gossen-Merowatt meters provide.

But for practical checking of 12V battery voltages 4 digit display will be fine and give a resolution of 10mV.

The next bit is understanding what the voltage reading actually means in terms of battery charge level.
 

JTQ

May 7, 2005
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The next bit is understanding what the voltage reading actually means in terms of battery charge level.

For that you need the battery maker's characteristic chart, good luck getting that for many products, or be in the realms of approximations on generic tables pulled off the internet.
Where such aspects as the lead alloying trace metals and construction is not accounted for, features that can alter the voltage vs the SoC by meaningful amounts.
It will give a guide, but a very approximate one making the small meter errors tendered here, pretty irrelevant. The real life voltages with modern alloying are likely to be higher than generic tables, typically based on pure lead, leading to over estimating the true state of charge.
 
Jan 3, 2012
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Be aware that the casing shows XL 830L but in Neoteck product brochure it’s NTK. 019 but the front casing reads XL 830L. Confusing or what. I guess XL830 L has more ” Buyer Appeal” and easier to brag about in the pub 😱
Hi clive Thanks for the information already made a note of it
 
Jan 3, 2012
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I brought the one otherclive suggested and it says on the product brochure NTK 019 to each your own
 

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Mar 14, 2005
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I feel I should cast a small note of caution when looking at these very cheap multi-meters. There is a common belief that digital meters are accurate. In fact the number of digits does not ensure accuracy, it only allows a reading to be given more precisely.

If you check the manufacturers specifications, most of these cheap meters will have a stated accuracy in the order of 0.5 to 2% of a full scale reading plus a number of least significant digits. And the stated accuracy can be different for other ranges.

For example the Sealey meter mentioned
Vdc accuracy is 1.5% +2 digits
Vac accuracy is 2.0% +2 digits.

To put this into context if you connected this meter to a true 12.8Vdc reference voltage the meter could read as
little as 12.59V (12.8 -1.5% -2 lsb digits)
or as high as 13.01V (12.8 +1.5% +2 lsb digits)
and still be within its stated accuracy limits.

What was also slightly worrying is to read some of the customer reviews about the amazon meter where approx 1% of the reviews reported the meters being "wildly" inaccurate when compared to other models of meters. This leads me to wonder how many customers are using them without realising the reading could be seriously out of kilter.

There were other safety related concerns about the current range which did not apparently have any fuse protection, and heaven only knows if teh cases have the proper creep and blast protection.

Sadly this is an increasing trend with many more cheap multimeter's flooding the markets.

I would suggest spending a little more and getting a recognised brand with more peace of mind
 
Nov 11, 2009
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I feel I should cast a small note of caution when looking at these very cheap multi-meters. There is a common belief that digital meters are accurate. In fact the number of digits does not ensure accuracy, it only allows a reading to be given more precisely.

If you check the manufacturers specifications, most of these cheap meters will have a stated accuracy in the order of 0.5 to 2% of a full scale reading plus a number of least significant digits. And the stated accuracy can be different for other ranges.

For example the Sealey meter mentioned
Vdc accuracy is 1.5% +2 digits
Vac accuracy is 2.0% +2 digits.

To put this into context if you connected this meter to a true 12.8Vdc reference voltage the meter could read as
little as 12.59V (12.8 -1.5% -2 lsb digits)
or as high as 13.01V (12.8 +1.5% +2 lsb digits)
and still be within its stated accuracy limits.

What was also slightly worrying is to read some of the customer reviews about the amazon meter where approx 1% of the reviews reported the meters being "wildly" inaccurate when compared to other models of meters. This leads me to wonder how many customers are using them without realising the reading could be seriously out of kilter.

There were other safety related concerns about the current range which did not apparently have any fuse protection, and heaven only knows if teh cases have the proper creep and blast protection.

Sadly this is an increasing trend with many more cheap multimeter's flooding the markets.

I would suggest spending a little more and getting a recognised brand with more peace of mind

What is "Creep and Blast Protection" Are you saying the cases may not be tight and over time could lead to an explosive event if used in an explosive environment? My main usage is checking battery volts after the charger is disconnected and then monitoring it over a period to assess the decline in voltage. So its trends that I am looking at, and the charger tells me the starting volts which thus far have been exactly the same as those measured by the DVM. It would also be used for any fault finding on the caravan 12v circuits including towbar connections. So its not likely that I will be at risk of a blast event.
 
Mar 14, 2005
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What is "Creep and Blast Protection" Are you saying the cases may not be tight and over time could lead to an explosive event ....?
Essentially yes. But the event is not time related, it relates to incorrect usage. and in that context putting a multimeters in the hands of someone who has said they are not familiar with them raises the possibility of incorrect usage.

I agree the voltages around 12V batteries are not going to produce a hazardous shock risk, but the currents can be if a battery is shorted.

Don't forget that these types of meter can be hand held! If the unsubstantiated report of the Amazon meter not having a fuse on the current ranges is correct then that meter is in danger of actually melting if its current range is put across a 12V battery supply.

But even if a fuse is incorporated, many of these cheap meters don't use HRC fuses they use glass cartridge fuses, and sometimes when glass fuses are exposed to the unlimited current they will explode with quite a force, and some of cheap meters may not contain that explosive energy within the case. There are a lot of good videos on Youtube where meter designs are discussed and examples of where inadequate meters have failed.

The National Fire Protection Association (USA) has established a set of CAT ratings for electrical test equipment which has been widely adopted as the international standard for multimeters safety ratings. This is where a lot of the design effort goes into better quality multimeters not only enhancing safety but also measurement accuracy. All the major meter manufactures seem to apply these standards

However if the cheap meters are only used correctly on extra low voltage systems low, and mishaps are avoided then yes they will usually work satisfactorily but I wouldn't use them on mains supplies.
 
Nov 11, 2009
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Essentially yes. But the event is not time related, it relates to incorrect usage. and in that context putting a multimeters in the hands of someone who has said they are not familiar with them raises the possibility of incorrect usage.

I agree the voltages around 12V batteries are not going to produce a hazardous shock risk, but the currents can be if a battery is shorted.

Don't forget that these types of meter can be hand held! If the unsubstantiated report of the Amazon meter not having a fuse on the current ranges is correct then that meter is in danger of actually melting if its current range is put across a 12V battery supply.

But even if a fuse is incorporated, many of these cheap meters don't use HRC fuses they use glass cartridge fuses, and sometimes when glass fuses are exposed to the unlimited current they will explode with quite a force, and some of cheap meters may not contain that explosive energy within the case. There are a lot of good videos on Youtube where meter designs are discussed and examples of where inadequate meters have failed.

The National Fire Protection Association (USA) has established a set of CAT ratings for electrical test equipment which has been widely adopted as the international standard for multimeters safety ratings. This is where a lot of the design effort goes into better quality multimeters not only enhancing safety but also measurement accuracy. All the major meter manufactures seem to apply these standards

However if the cheap meters are only used correctly on extra low voltage systems low, and mishaps are avoided then yes they will usually work satisfactorily but I wouldn't use them on mains supplies.
Thank you for a very helpful reply.
 

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