Reply by Jeff Liebermann November 11, 20212021-11-11
On Wed, 10 Nov 2021 17:01:12 +0100, "Carlos E. R."
<robin_listas@es.invalid> wrote:

>So I have a look at Amazon, and most battery testers seem to measure >voltage, there is no mention of loading the batteries. > >So I thought if someone has a table of voltages each battery type should >yield when loaded with some resistance. Or if someone has designed a kit >for doing this, or if someone knows of a proper tester sold at Amazon,
My guess(tm) is what you want is a battery capacity discharge tester, which measures the remaining capacity of the battery in ma-hrs. You can't do that with a voltmeter. If the LiIon battery were perfect, it would have the same voltage everywhere between zero charge and 100% charge. That's not very useful. What you probably want is a graph of the battery that looks something like this. This is a single (cheap) 18650 LiIon cell: <http://www.learnbydestroying.com/jeffl/LiPo/Ultrafire%20LiPo%203000%20ma-hr%2018650%20test.jpg> The capacity in ma-hrs (or amp-hrs) is where the voltage begins to drop. The energy stored in the cell is the area under the curve. Both capacity and energy curves will change as the battery ages. Your unspecified model DECT phone batteries will have a similar curve. I created the graph using a West Mtn Radio CBA III which is no longer being produced: <http://www.westmountainradio.com/product_info.php?products_id=cba3> <http://www.westmountainradio.com/cba.php> My test setup looked like this mess: <http://www.learnbydestroying.com/jeffl/LiPo/Ultrafire%2018650%20test.jpg> The clamp is to make sure I have a good connection to the cell terminals. The basic procedure is to charge the cell or battery to 100%, clamp it into the tester, set the test conditions (mostly discharge current), and wait for the computer to produce the graph. There are also devices on the market which will produce a single number for the battery capacity in ma-hrs. I have a few of these and find them nearly useless. There's no way a single number can be used to describe the graph curve. <https://batteryuniversity.com> <https://www.candlepowerforums.com> <https://budgetlightforum.com> Good luck. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558
Reply by Phil Allison November 11, 20212021-11-11
 Carlos E. R. wrote: 
 =============== 
>> > >>> Next closest standard resistor is 15 ohms. > >> > >> I wondered about doing the load circuit with a controlled transistor. An > >> adjustable, controlled, current drain. I have not yet thought about it. > >> > > > > ** Don't bother. > > > > Loads used with non rechargeable cells are like resistors. > > While rechargeable types have steady voltage outputs till exhausted. > > Not thinking of that...
** Then try. Constant current is unrealistic for single use cells and meaningless for the others.
> just of having a variable current drain for > different battery types, at relatively high power, more than what a > potentiometer stands.
** So use a few fixed resistors and a switch. How many hours of you life do you intend wasting on this exercise ? ..... Phil
Reply by Carlos E. R. November 11, 20212021-11-11
On 12/11/2021 01.17, Phil Allison wrote:
> Carlos E. R. wrote: > =============== > >>> Next closest standard resistor is 15 ohms. >> >> I wondered about doing the load circuit with a controlled transistor. An >> adjustable, controlled, current drain. I have not yet thought about it. >> > > ** Don't bother. > > Loads used with non rechargeable cells are like resistors. > While rechargeable types have steady voltage outputs till exhausted.
Not thinking of that... just of having a variable current drain for different battery types, at relatively high power, more than what a potentiometer stands. -- Cheers, Carlos E.R.
Reply by Phil Allison November 11, 20212021-11-11
 Carlos E. R. wrote:
===============

> > Next closest standard resistor is 15 ohms. > > I wondered about doing the load circuit with a controlled transistor. An > adjustable, controlled, current drain. I have not yet thought about it. >
** Don't bother. Loads used with non rechargeable cells are like resistors. While rechargeable types have steady voltage outputs till exhausted. ..... Phil
Reply by Carlos E. R. November 11, 20212021-11-11
On 11/11/2021 19.53, Rich S wrote:
> On Wednesday, November 10, 2021 at 4:06:25 PM UTC, Carlos E. R. wrote: >> Hi, > >> My quick getaway will probably be buying a 1.5 volt incandescent bulb >> somewhere... Even finding that on Amazon draws no hits on a quick test. >> Wait, I found a pack of 50! 14&euro;. I found others for 3 volts, and some >> with a delivery time of one month.
> Hello Carlos, , > Instead of light bulbs, > Do you have an assortments of resistors?
Yes, but not here. Temporary place.
> To know which resistance value to use, calculate R = V / I > V is the battery/cell's nominal voltage > I is the test current. For this go here: > https://en.wikipedia.org/wiki/List_of_battery_sizes > Find your battery in the table, look at its "Typical Capacity (mA hr)" -- > -- divide this number by 10.
YES! This is the data I wanted. Thanks :-)
> > For example, given a "AA" carbon zinc, > V = 1.5 V, > I = 1100 / 10 = 110 mA > R = 1.5V / 110mA = 13.6 ohms. > Next closest standard resistor is 15 ohms.
I wondered about doing the load circuit with a controlled transistor. An adjustable, controlled, current drain. I have not yet thought about it. -- Cheers, Carlos E.R.
Reply by Rich S November 11, 20212021-11-11
On Wednesday, November 10, 2021 at 4:06:25 PM UTC, Carlos E. R. wrote:
> Hi,
> My quick getaway will probably be buying a 1.5 volt incandescent bulb > somewhere... Even finding that on Amazon draws no hits on a quick test. > Wait, I found a pack of 50! 14&euro;. I found others for 3 volts, and some > with a delivery time of one month. > > -- > Cheers, > Carlos E.R.
Hello Carlos, , Instead of light bulbs, Do you have an assortments of resistors? To know which resistance value to use, calculate R = V / I V is the battery/cell's nominal voltage I is the test current. For this go here: https://en.wikipedia.org/wiki/List_of_battery_sizes Find your battery in the table, look at its "Typical Capacity (mA hr)" -- -- divide this number by 10. For example, given a "AA" carbon zinc, V = 1.5 V, I = 1100 / 10 = 110 mA R = 1.5V / 110mA = 13.6 ohms. Next closest standard resistor is 15 ohms. cheers, RS
Reply by Carlos E. R. November 10, 20212021-11-10
On 10/11/2021 22.35, whit3rd wrote:
> On Wednesday, November 10, 2021 at 8:06:25 AM UTC-8, Carlos E. R. wrote: > >> Many moons ago I bought an analog multimeter, and one of its functions >> was to test batteries. >> ...... I have a look at Amazon, and most battery testers seem to measure >> voltage, there is no mention of loading the batteries. > > I've sometimes used an auto headlight for load, but > my trusty Radio Shack Battery Tester works well for common > cell types; its ranges are marked > > Alkaline button cell: 1.5V 1 mA (implied load 1500 ohms) > Lithium coin cell 3V 1 mA (3k ohms) > AAA cell, N cell 1.5V 50 mA (30 ohms)
This seems to be 10% of the A&middot;h rating of 550mA&middot;h, which I recall reading somewhere that was the guide.
> AA cell 1.5V 150 mA (10 0hms) > Photo 6V > Rectangular 9V > 12V > 22.5V > (those last ranges don't identify the load; possibly > they just use a single resistor at circa 3k ohms, which would > be appropriate for the 9V at least). > > <https://www.picclickimg.com/d/l400/pict/232907151786_/Vintage-Radio-Shack-Battery-Tester-Cat-No-22-090.jpg> > > So, there's a wide-ish range of load resistances to consider.
Thanks :-) -- Cheers, Carlos E.R.
Reply by Carlos E. R. November 10, 20212021-11-10
On 10/11/2021 22.15, ABLE1 wrote:
> On 11/10/2021 11:01 AM, Carlos E. R. wrote: >> Hi,
...
> > Check these out!!&nbsp; Yes, maybe expensive on your Dollar Scale. > However it works great!! > https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=ZTS+Multi-Battery+Tester&_sacat=0 >
I can see it in Amazon, but no detailed description that lets me find out why it would be a good one or not. Only a single photo. And two weeks delivery time. <https://www.amazon.es/ZTS-MINIMBT-Multi-Battery-Tester-Battery/dp/B0002EH4YO> -- Cheers, Carlos E.R.
Reply by Carlos E. R. November 10, 20212021-11-10
On 10/11/2021 22.51, Phil Allison wrote:
> Carlos E. R. wrote: > ============== >> >> Many moons ago I bought an analog multimeter, and one of its functions >> was to test batteries. It loaded the battery with a resistor, drawing >> some significant current (for three battery types) and then measuring I >> don't know if voltage or current (typical green-yellow-red zones). > > ** Measures voltage. > >> So now comes a friend that says the battery for a DECT phone doesn't >> last long. I offer to test it, but then I realize that ... > > ** It is a rechargeable type - so not easily tested. > And not with that meter at all !! > > Cell capacity of NiCd or NiMh cells can only be tested by timing a discharge cycle. > Tell you friend to buy new cells.
Yep and yep. -- Cheers, Carlos E.R.
Reply by Carlos E. R. November 10, 20212021-11-10
On 10/11/2021 19.54, amdx wrote:
> On 11/10/2021 12:28 PM, Jan Panteltje wrote: >> On a sunny day (Wed, 10 Nov 2021 17:01:12 +0100) it happened "Carlos >> E. R." >> <robin_listas@es.invalid> wrote in <8v6t5ix288.ln2@minas-tirith.valinor>:
> &nbsp;Yes, so you need to find a discharge graph of the battery and use the > proper load resistor.
Well, yes, that is the question. Who has published tables of what current on a given resistor should each type of battery yield? Give me that and I will build a perfect tester, thankyou.
> > &nbsp;Although, if it doesn't last long, it is probably bad. If you think it > is the charger (unlikely since it does get some charge) > > Switch the phone to a different base. You might compare the loaded > voltage of the (bad) battery to one in another phone, assuming > he has a three phone system.
Not the case, single base. I have charged the batteries (Panasonic Ni-MH, AAA, 550mAh) on a separate charger, and also tried with fully charged batteries of my own. Originals: 1.345 V 1.334 V Mine: 1.384 V 1.386 V But the phone itself indicates both battery sets are empty. I can read the voltage, but not the capacity. A rule of thumb was that the battery should provide 10% of the A&middot;h rating at nominal voltage, but I don't have a set of resistors here. And I don't know if the tiny voltage difference is important. I have a table printed on a commercial tester on Amazon: 1.2 1.5 3V 9V Good > 1.25 > 1.3 > 3.0 > 7.3 Low 1.25-0.9 1.3-1.15 3.0-2.0 7.3-6.3 Replace < 0.9 < 1.15 < 2.0 < 6.3 According to that, both sets are very good. I would have to do a full discharge test to find out if the A&middot;h is good. -- Cheers, Carlos E.R.