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Discussion: Getting Low Voltage Readings with new SI Batteries

in: Orienteering; Gear & Toys

Oct 8, 2023 3:23 AM # 
I am replacing the batteries in some of our SI units and it seems like more than half of the ones I replaced have low readings when read by SI Config+. The batteries are Shaft 14250 and the date code is 220207 so relatively new. The voltage readings I am getting vary but about half are 3.03V or lower with some below 3V. Others seem to be okay with voltage readings about 3.3V or higher. When I test the batteries with a multimeter, they test about 3.6V

Did I just get some bad batteries or am I doing something wrong or should I not worry about it? The old batteries are 10 years old and they also test about 3.6V with the multimeter.
Oct 9, 2023 1:05 AM # 
Did you do the step where you use SI-Config in Service mode to “tell” the unit it has a new battery?
Oct 9, 2023 1:17 AM # 
Carl: Blaik Mathews here, president of Florida Orienteering (FLO). I have been caring for the club's SI equipment for 8 years, and have replaced many a station battery in my day.
(1) I typically regard any station reading at 3.0V or less as in imminent danger of malfunction. I do a full battery inventory prior to the start of each new season, and typically replace any battery reading below 3.05V and maybe even 3.09V on the theory that it might get in the "red zone" by the end of the season.
(2) I use SIConfig+'s battery voltage as opposed to the voltage the station itself will show in its cycle of info when started with the Service Key. I am presently using SIConfig+ v 2.11.0. Our stations are all currently on firmware release 656.
(3) To get an accurate voltage reading, I will start the stations with a regular finger stick to put them in normal-use standby mode, and leave them there for a few minutes before I test them.
(4) I'm pretty sure I've replaced close to 80-90 batteries over the years (FLO has about 70 stations in all including C/C/S/F/M/R, and I've probably replaced them all at least once by this point, plus I've done some similar maintenance for SOAR (Gord Hunter's club in Bradenton). I do not recall EVER seeing a brand new Saft battery test at 3.0xV right out of the gate like that. Like you, I would regard it as highly suspicious, and not something I would risk in a live event without good explanation.
Oct 9, 2023 1:24 AM # 
So, ideas:
(1) What firmware release are your stations on?
(2) What version of SIConfig+ are you using?
(3) If you turn the offending stations on with the Service Key and let it cycle through to the voltage reading, does it match what SIConfig+ is telling you?
(4) Desperation: Try testing the voltage in SIC replacing first the iron coupler, and then the READOUT station if you can scrounge up an alternate.
(5) Did you use a different kind of solder for these installations than you have previously?
(6) Contact your battery vendor and see if you might have gotten into a bad lot. In my experience brand new batteries should test in the 3.3V - 3.4V range using the method outlined above to get an "under standby load" reading.
Oct 9, 2023 3:00 AM # 
thanks Blaik,
The station firmware is 656. I was using an older version of SIConfig+ so I updated that but it hasn't made a difference. The same units with new batteries that had low voltage before still have low voltage and the units with normal voltage (3.3V ior higher) still have normal voltage. And it is the same solder for both.

I am going to order new batteries from a different vendor and see if that makes a difference.

I did update the battery date but that only seems to affect the % remaining. For example, a new battery with updated date may show 3.02V and 99.5% remaining.

Thank-you for your help
Oct 9, 2023 12:47 PM # 
And now, since I updated config+, I can't seem to update the battery info. I right click the shortcut and append " --service" to the file name, click apply but then when I open it, it doesn't give me an option to change the battery info. I tried going back to my old config+ but it is gone.

I am wondering now if I might have put in the wrong battery capacity in the old service mode and it is using the wrong capactiy to calculate the voltage. Could this be possible?
Oct 9, 2023 2:37 PM # 
I've seen this behavior, and ran across this blog posting from 2015,

It seems that there is a voltage lag in these types of batteries after long term storage, so you should go back and re-measure after the units have been on for a couple of minutes. The comments to that blog posting are also worth a read.
Oct 10, 2023 2:39 AM # 
thanks for the suggestion but the voltage is low even after being on for 1 hour+. And also low after several days of doing repeated readings. With that said, the unit is just on, I have not been "punching" the unit with the finger sticks.
Oct 10, 2023 4:02 AM # 
Uncle JiM:
I suggest a few punches with the finger sticks, then test again
Oct 10, 2023 10:53 AM # 
Have you sealed them up yet? If not, can you read the voltage with a meter at the same time you're reading it on the display?
Oct 13, 2023 3:47 PM # 
Hi, I am responsible for my clubs SI equipment in Sweden, and have replaced some batteries during the years. Have very similar experience as Blaik above: a brand new battery should be read as around 3.30V or above via config+. With a "Service/Off" stick, you can read the same value on the display. Then, it is not possible to read such a value with a (normal) volt meter/multimeter, it will just show something around 3.6V also for an (almost) totally empty battery, exactly as you wrote at start. The reason is that the voltage is very dependent of the current. And the current vary a lot related to what the SI unit is doing, also when active.

Then, as far as I have understood, it is two independant ways to read out the battery condition (from Config+ and also from the display):
1: Battery voltage, just a measured value.
2: Battery "capacity", in percent. This is a calculated value, and depends on things like the battery original capacity when new, when it was inserted in the SI unit (the date you put in via config +), time in sleep mode and time in active mode. My best guess is that this value is independant of the battery voltage value.
Naturally this two values are supposed to have some correlation, but they don´t need to! I trust the "voltage" value much more than the "capacity" value related to when it is time to swap battery.

"Voltage lag" as mentioned above is easy to observe, but to my experience not at all in the range that can explain what you see.

So, except that you might have recieved a very bad batch of SAFT batteris, I can also see an other reason for you problem: It is rather easy to make a very small short circuit during soldering, and that could give the symptoms you see. I normally use a magnifier/microscope after soldering, just to be sure.

Unfortunately no explanation why you have problem with the --service function, but just changing the date (or battery capacity value) will not help you with this problem.
Oct 17, 2023 4:08 AM # 
Thank-you everyone for your help and suggestions. I am pretty sure my problem was bad batteries. I ordered batteries from a different vendor (ATT Battery), and the 7 that I installed all had good voltage readings (generally in the 3.4's). With the previous vendor (Battery Guy), more than half of those I installed had low voltage readings with SI Config+.

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