Devices that say batteries dead EARLY

[InHisName]

Are there many devices that only use up 10 - 20% of NiMH then declare them used and demands replacements ?

I have an Aiptek camcorder that does that. It records to SD cards, no moving parts. I am using 2x AA Kodak that I have truly gotten 2000Mah from in flashlights. It runs less than 5 minutes and says 1/4 full (3/4 empty) another 15 and its kaput. Fresh alkaline Duracells lasted 45 minutes total usage or more.

When I take my discharged batteries out and charge them on my C9000, I can only put in about 285-295Mah into them. Measuring the voltage just before the camcorder quits, I see about 1.38 or 1.39 on each cell. I think the problem is it gives up too early.

Have you noticed other devices that give up on its batteries WAY too early before they're fully discharged ?

Lets keep a running list of what NOT to buy and another list of good battery users.

Aiptek DZ0-V50 camcorder quits at approx 1.38v each cell.

 

[SilverFox]

Hello InHisName,

It sounds like your cells are suffering from voltage depression. Next time when your cells are no longer able to run your camcorder, place them in the C-9000 and select discharge at 1000 mA. As the discharge starts, note the voltage of each cell. Your camcorder may need a voltage of 1.1 - 1.15 volts per cell in order to operate.

Tom

 

[45/70]

A lot of people don't think to do this with their C-9000, but when you do a discharge of fully charged cells, watch the voltage at a discharge rate that most closely approximates the load the cells will see when installed in the device you use them in. What you should see, is a voltage of ~1.20 Volt or greater. If the voltage is under 1.20 Volt, this is usually a tell tale sign that your cells are suffering from voltage depression. The exception would be, if the cells were never capable of delivering that much current in the first place.

Dave

 

[TorchBoy]

When I take my discharged batteries out and charge them on my C9000, ... Measuring the voltage just before the camcorder quits, I see about 1.38 or 1.39 on each cell.
...
Aiptek DZ0-V50 camcorder quits at approx 1.38v each cell.

The charging voltage shown on the MH-C9000 is higher than the resting voltage of a NiMH cell, which is in turn higher than the voltage of the cell under load.

Like the others, I'd also like to know the results of a discharge test.

 

[EngrPaul]

According to your manual, the required power source is "2 x AA Alkaline Battery"

Your camera detects low battery using input voltage. NiMH cells have a lower nominal voltage than Alkalines.

 

[ltiu]

It's because NiMH have lower voltages. Your device thinks your battery is dead (because it's woltage is low) but in fact it's still alive. These devices are designed to use Alkalines and Lithiums.

I have seen this same issue with Energizer Energi To Go cell phone chargers:

http://www.energizer.com/products/energi-to-go/cell-phone-charger/Pages/cell-battery-charger.aspx

I cannot use NiMH in these. I can only use Alkalines and Lithiums.

 

[45/70]

It's because NiMH have lower voltages. Your device thinks your battery is dead (because it's woltage is low) but in fact it's still alive. These devices are designed to use Alkalines and Lithiums.

What you and EngrPaul are suggesting is quite possibly true. Some devices are particularly sensitive to the difference between alkaline and NiMH/NiCd cell voltage.

It all depends on the load under which the cell's voltage is read by the device. To say 'NiMH have lower voltages" is not entirely correct, at least not under all circumstances.

The "nominal" voltage of an AA alkaline cell is determined under something like a 50 or 100mA load, whereas a NiMH cell's "nominal" voltage is determined, I believe, under a 0.4C load, or 800mA for a 2000mAh cell. I'm not certain those figures are correct, but they are in the ballpark. So, if the device in question determines remaining capacity by checking voltage under a very light current load, alkaline cells will "appear" to have more remaining capacity than NiMH's, as their voltage will be higher, and you could run into problems.

If the device determines capacity by measuring the voltage under a working load of say 500mA or more with AA cells, the higher voltage of alkaline cells under low current draw disappears, and the NiMH cells will most likely have an equal or higher voltage than alkaline cells. What can totally throw this off, is if the NiMH cells are suffering from voltage depression, which causes the voltage to sag under load.

I've seen digital cameras that had the same problem as InHisName is having with his camcorder and NiMH's. After reforming ("Break In", on a C-9000) the NiMH cells however, the camera would achieve considerably more shots than with alkaline cells.

While it may very well be that the Aiptek camcorder that InHisName has, measures voltage under a low current, which would mean it "just doesn't like NiMH's", it'd be worth a try, IMO, to try revitalizing the NiMH cells to bring their voltage up under load and see what happens. Ya never know 'til you try.

Dave

 

[Magic Matt]

Check for firmware updates too - my old Fuji Finepix 2800Zoom used to do exactly the same thing with NiCd or NiMH cells, then after updating the firmware it seemed to run for absolutely ages off of batteries it previously said were dead. Sometimes manufacturers get it wrong in the firmware, it's not always about the hardware side.

 

[ltiu]

There are devices where you can go into the "menu" and tell it what battery type you are using - Alkaline, NiMH, Lithium.

My Nikon camera and Garmin "hikers" GPS has that functionality.

 

[InHisName]

I was running it in play mode to run it down and seems to work fine much longer. Its still running at 1.22 & 1.23 v. Tried to record, Can't. "Low Power" message is all I can do.

Put batteries in discharge mode. Both showed 1.18v @1000 discharge. I found 1321 & 1355 remaining in each of the cells. Now that both are discharged they are showing 1.19v

It appears that the record function is very stringent at needing lots of volts. When I said that when I could not record any more, I was measuring the open circuit voltage immediately after removing the battery. So the loaded voltage is lower than 1.38 but probably lots higher than 1.22

I've now fashioned thin wires onto the multimeter to monitor the voltage of each cell while recording. I'll do that and report back that voltage value and the value on discharge mode of c9000 right after it cannot record anymore.

 

[Light Sabre]

One of my digital cameras does the same thing. Doesn't run very long and the low battery light comes on. I have come to the conclusion that the low battery voltage sensing circuit's threshold is too high and needs to be lowered. I just run the camera until it shuts down. It will run a long time after the low battery indicator comes on, so I just ignore it.

I have some weather stations here at home. The manual says alkalines only, no rechargeables. Apparently the barometric pressure circuit is very voltage sensitive. Using another weather station as a reference, I was having to constanly correct the barometric pressure on the first one as the alkaline battery's voltage dropped. So, I put some NMH's in there and the low battery indicatior comes on earlier, but the barometric pressure reading stays constant since the NMH's output voltage stays the same for a long time.

 

[PeAK]

Take a look at this thread of similar problems in a Pentax camera using Kodak batteries. The solution is to use the eneloop batteries which put out a bit more voltage

 

[ltiu]

Take a look at this thread of similar problems in a Pentax camera using Kodak batteries. The solution is to use the eneloop batteries which put out a bit more voltage

My Nikon camera, even though you can tell it that you are using NiMH through a menu setting, still warns of low battery very soon (after only 30 shots or so) after putting in freshly charged "hot off the charger" NiMH, Eneloops or not.

 

[Magic Matt]

My Nikon camera, even though you can tell it that you are using NiMH through a menu setting, still warns of low battery very soon (after only 30 shots or so) after putting in freshly charged "hot off the charger" NiMH, Eneloops or not.

Nikon have something of a reputation for doing that I'm afraid. Fortunately, sometimes pressure from consumers makes them change their mind. Doesn't happen often enough though.
http://news.cnet.com/8301-17938_105-10260790-1.html

 

[adnj]

There may be a rechargeable battery pack available. Little more than two NiMH cells in an adapter that hits the mechanical switch that changes nominal voltage requirements. I have made some of these in the past from odds and ends.

I seriously doubt any limitations of the circuit to use two 1.1 volt batteries under load. I do believe that there would be some design constraints for the battery capacity sensing circuit to work reliably on various battery chemistries in a $100 camcorder.

 

[N162E]

Measuring the voltage just before the camcorder quits, I see about 1.38 or 1.39 on each cell.

Nimh cells are only rated at 1.2 volts nominally. Unless your device has a setting for Nimh cells you should not expect it to operate with them. You need to use standard alkalines or lithium cells. Don't ask these cells to work where they are not intended.

 

[N162E]

Hello InHisName,

It sounds like your cells are suffering from voltage depression. Your camcorder may need a voltage of 1.1 - 1.15 volts per cell in order to operate.

Tom

Tom, Read my post above

 

[Elliot]

I have some old wonderful electronic devices can only function well when using mercury cells. This is because these cells kept an exact 1.35v almost their entire useful life and could be used as a voltage reference in the circuit. Sadly, I did not eBay my stuff before mercury cells were banned in most places.

 

[InHisName]

Wow ! Lots of comments.

I read that web reference, Kodak vs eneloops. That was while I was running down freshly charged Kodaks in record mode of my camcorder. Earlier I could not start recording when playing voltage was 1.25v each cell. Well it recorded for around 2 hours, not the 15 minutes I thought.

I now can't get the camcorder to function right even with fully charged batteries. I think it has something to do with one file 2 hours long on the SD card.

It seems that the Aitek will play long and record pretty long too. It seems to need LOTS of voltage to START recording.

I started recording and battery indicator said "full" for 53 seconds. Then skipped 3/4 and went directly to 1/2 full. It was at 1/2 for over 11 minutes then switched to 1/4 full. It remained at 1/4 full for 1 hour 45 or more minutes where the camera cut off. SD disk full ? It is a 2Gb disk with only 3 minutes of video not deleted before I started.

The loaded voltage during recording just before the 2 hour mark I measured 1.18v on one and 1.21v on the other. It sat at 1.25 for both cells for a very long time.

Looks like once I start recording and pass a time point, that I will not be able to restart recording any more. So I may need to record continously and edit later. [uggh]

I'll experiment some more, at least I now know the Kodaks are in great shape. Now to understand more fully the quirks and design flaws of the Aitek camcorder.

 

[RA40]

Just chime that I also encounter various devices that specify alkies...NiMH in those is a high probability I'll get a low battery waring or shut down. I was hoping to transition to using all NiMH but sadly, not so. The Honeywell climate controller won't work with NiMH. Some other devices will function fine even if they display a reduced battery level.