Battery tester

wp1234

wp1234

Joined
Oct 23, 2009
Posts
791
Likes collected
620
Location
Anglesey North Wales
Funster No
9,010
MH
Adria Twin 640SLB
Exp
Since 2010
I am having a torrid time with my batteries at the moment with very annoying sudden voltage drops therefore to prove categorically that the batteries are either good or bad is there a bit of testing equipment out there that can be used without resorting to load testing the battery with a 5 amp bulb and monitoring voltage drop over hours. I’m aware that the Topdon tester I use on car batteries cannot be used on leisure batteries . Tia
 
I think there is a new tester that does a leisure battery test as well as CCA test but it not cheap as it's a bit of professional kit.

Cant really go wrong with a slow discharge test.
 
A ‘drop’ tester can be revealing, quick and cheap to buy
 
I bought an electronic load tester on eBay for about £40. Can set discharge current up to 10A and the cutoff voltage to terminate the test. Has some quirks but I’ve used it to check a couple of leisure and cab batteries. Checked with a load of C/20, so about 4.5A.

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stevec said:
I bought an electronic load tester on eBay for about £40. Can set discharge current up to 10A and the cutoff voltage to terminate the test. Has some quirks but I’ve used it to check a couple of leisure and cab batteries. Checked with a load of C/20, so about 4.5A.
Click to expand...
That sounds good, do you have a link?
I just turn a few things on in the van.
 
EBay item number 394398984026

Not my actual one, in fact a bit better and cheaper!
 
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Lenny HB said:
I think there is a new tester that does a leisure battery test as well as CCA test but it not cheap as it's a bit of professional kit.

Cant really go wrong with a slow discharge test.
Click to expand...
Camper UK say they have a leisure battery tester ( a Sealey product I believe ) so have booked in for a test on both GELs on my way home from Portugal, I hope they know what they are doing 😂. Would you have a link to the slow discharge test voltages on GEL batts please.

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tonka said:
www.ebay.co.uk

150W Intelligent Electronic Load Battery Discharge Tester Meter Detector 150V UK | eBay

Find many great new & used options and get the best deals for 150W Intelligent Electronic Load Battery Discharge Tester Meter Detector 150V UK at the best online prices at eBay! Free delivery for many products.
www.ebay.co.uk
Click to expand...
As an aside, I like how they show the mains adaptor as a 'free gift'! It is actually illegal to place electrical products onto the UK market without a standard compliant 13A plug fitted. A conversion plug can be used but adaptors such as this are not accepted. In other words, this product as supplied is illegal.
 
This site contains affiliate links for which MHF may be compensated.
wp1234 said:
Camper UK say they have a leisure battery tester ( a Sealey product I believe ) so have booked in for a test on both GELs on my way home from Portugal, I hope they know what they are doing 😂. Would you have a link to the slow discharge test voltages on GEL batts please.
Click to expand...
1676577978308(1).png
 
treblid said:
As an aside, I like how they show the mains adaptor as a 'free gift'! It is actually illegal to place electrical products onto the UK market without a standard compliant 13A plug fitted. A conversion plug can be used but adaptors such as this are not accepted. In other words, this product as supplied is illegal.
Click to expand...
What’s the difference between an adaptor and a conversion plug…. and why are they not safe ? just curious .
 
I have yet to find a figure to terminate the discharge test with. All the tables I have seen are state of charge versus rested voltage, not voltage under load. I have used 11.8v as a terminating voltage at C/20 discharge rate and found the after test resting voltage to be about right (only discharge a LA battery to 50%). If anyone has a more accurate figure then I would be interested to hear.

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wp1234 said:
What’s the difference between an adaptor and a conversion plug…. and why are they not safe ? just curious .
Click to expand...
A conversion plug (or over plug) is a one time fitted item which requires tools to fit and is not readily removable. It is fitted by the manufacturer/importer/UK distributor. An example is shown below to convert a flat 2 pin EU plug. Over styles are available.

For this particular power meter, a power supply with a BS1363 13A pin configuration should be supplied as it can obviously not be over plugged.


overplug.png
 
stevec said:
I have yet to find a figure to terminate the discharge test with. All the tables I have seen are state of charge versus rested voltage, not voltage under load. I have used 11.8v as a terminating voltage at C/20 discharge rate and found the after test resting voltage to be about right (only discharge a LA battery to 50%). If anyone has a more accurate figure then I would be interested to hear.
Click to expand...
Termination voltage for capacity test under C/10 discharge is 1.75vpc. Times that by 6= 10.5v. You have to have a charge source at ready if you do a true complete capacity discharge test. The battery can not be left at 10.5v longer than 10 mins. Also the test has to be done at 20 degC to be conclusive, few deg lower, and values will be flawed.
 
bubble63 said:
A ‘drop’ tester can be revealing, quick and cheap to buy
Click to expand...

Such a test will tell you nothing about whether the battery has lost a significant proportion of its capacity.

A battery may pass a drop test but have only half its nominal capacity (i.e. knackerd).

Ian
 
if you want a decent capacity tester, think 4 figures. One place I know has them and will often do a test cheaply is a mobility scooter repair place. The tester is connected to a laptop and the report and graph can be printed out.
 
Raul said:
Termination voltage for capacity test under C/10 discharge is 1.75vpc. Times that by 6= 10.5v. You have to have a charge source at ready if you do a true complete capacity discharge test. The battery can not be left at 10.5v longer than 10 mins. Also the test has to be done at 20 degC to be conclusive, few deg lower, and values will be flawed.
Click to expand...
Is that to discharge to 50%? I wouldn’t like to any further than that.

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stevec said:
Is that to discharge to 50%? I wouldn’t like to any further than that.
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How do you know when is at 50% SOC? The figures I mentioned it says total capacity, as in the lot. It’s the only true test for it’s entire capacity.
 
TheBig1 said:
if you want a decent capacity tester, think 4 figures. One place I know has them and will often do a test cheaply is a mobility scooter repair place. The tester is connected to a laptop and the report and graph can be printed out.
Click to expand...
You can get a chargery, or a zke, with full pc graph to show charge and discharge etc, for about 150 quid.
 
really? God they have come down in price since I last looked
 
Raul said:
Termination voltage for capacity test under C/10 discharge is 1.75vpc. Times that by 6= 10.5v. You have to have a charge source at ready if you do a true complete capacity discharge test. The battery can not be left at 10.5v longer than 10 mins. Also the test has to be done at 20 degC to be conclusive, few deg lower, and values will be flawed.
Click to expand...
I agree Raul, I always use 10.5v as the cut-out.

Geoff
 
Raul said:
How do you know when is at 50% SOC? The figures I mentioned it says total capacity, as in the lot. It’s the only true test for it’s entire capacity.
Click to expand...
50%. After the discharge test I let th battery rest for an hour or so and measure the voltage. Using a table such as Lenny posted above gives me the state of charge. Needs a few goes of trial and error (starting high terminating voltage and decreasing). Also need to do correction for temperature as was mentioned.

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There is a calculation method, which has a few steps to give you the true battery capacity. First charge the battery to 100%. Then take out a known number of amp-hours. Let the battery rest and measure the resting voltage.

Use the chart to find the remaining % charge in the battery. Subtract from 100 to find the % charge taken out by the load, ie the percentage fall from the 100% level..

The Amp-hours drawn (A) represents the percentage fall (P) of the true charge capacity (C).
A amp-hours is P % of C, or as a formula,
A = (P/100) x C which can be rearranged to give
C = 100 x A / P

True Capacity = 100 x Amp-hours drawn / Percentage fall.

For example, if you take 40Ah out of a full battery, and its final charger level is 55%, then the charge level has fallen by 100 - 55 = 45%. The true capacity is 100 x 40 / 45 = 88Ah.

So if it's 90Ah on the battery label, it's fine. If it's 110Ah on the label then it's more of a concern. the capacity has dropped to 100 x 88 / 110 = 80% of its label value.
 
stevec said:
I bought an electronic load tester on eBay for about £40. Can set discharge current up to 10A and the cutoff voltage to terminate the test. Has some quirks but I’ve used it to check a couple of leisure and cab batteries. Checked with a load of C/20, so about 4.5A.
Click to expand...
HI
I have just looked at a few of these on ebay and for some reason ebay have removed the user manual? So how difficult are they to actually use? I have looked at instructions on other sites, all in Chinese/English and it is about as clear as mud to me.

Geoff
 
donkey said:
HI
I have just looked at a few of these on ebay and for some reason ebay have removed the user manual? So how difficult are they to actually use? I have looked at instructions on other sites, all in Chinese/English and it is about as clear as mud to me.

Geoff
Click to expand...
Mine came with instructions. All be it a bit Chenglish! I found a couple of videos on Youtube which I watched before buying.
Try this one which was the model I bought.



The ebay one I tagged has a colour display and a second set of input connectors to monitor the source voltage separate to the current carrying input which is preferred as it takes account of the voltage drop across the current carrying leads.

Another review of mine:


Other reviews of the colour display ones are also on Youtube.
 
Bloody hell ,I never knew battery condition testing was so complex .Is there a degree out there that I can get 😂
 
stevec said:
Mine came with instructions. All be it a bit Chenglish! I found a couple of videos on Youtube which I watched before buying.
Try this one which was the model I bought.



The ebay one I tagged has a colour display and a second set of input connectors to monitor the source voltage separate to the current carrying input which is preferred as it takes account of the voltage drop across the current carrying leads.

Another review of mine:


Other reviews of the colour display ones are also on Youtube.
Click to expand...

Hi
Thanks for the video links. I also found this web page Chinese or English, which actually explains it quite well.https://www.banber.com/banber/637ed0ac186c0a54da90cca0

Geoff

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