NiMh battery problems!

[Puffer Fish]

I hope you get to the bottom of this. It will be fun anyways. I look forward to seeing what you come up with.

Nonetheless, cleaning contacts etc, if one battery works without cleaning contacts and the other doesn't work as well there is an indication that one is marginal. Besides, I clean the contacts with an eraser. I would as soon use a battery that does not require filing the contact points or other extraordinary measures.

N

There now is a new type of rechargeable AA out in the market...with a higher voltage.

I just tried 4 in an led light to see how they would work...very nice.

Note: For those that don't know, LED brightness is due to the voltage present.. so Nimhs with 1.2 volts are no where as bright as standard batteries.. these new ones are slightly brighter than the standard ones... seem to hold a charge very well...and are roughly the same total capacity as Sanyo

Anyway, they are 1.6 volt batteries...require a special charger, and don't cost a lot more than regular rechargables.

 

[Nemrod]

Thank you for that info, do you have a link? One thing, and I am not sure it will be a problem, but some devices are voltage sensitive also to high voltage. For example, some Inon strobes seem to have this concern, probably others as well. I wonder, do these new batteries have a higher initial voltage than a high quality alkaline?

I noticed exactly what you are talking about with my Dive Rite LED light with alkalines vs NiMH high cap batteries.

Thanks.

N

 

[bvanant]

THe higher voltage batteries are from Powergenix and are Ni/Zn chemistry. You can buy them at Amazon ($13 or so for 4). The historical issues with Ni/Zn batteries is that they didn't have lots of charge/discharge cycles but these supposedly do. I have ordered some to play with. One point is that the discharge cycle is far less flat than the NiMH or the Eneloop types but at 1.6V they should forever solve the problems of the 570. I'll let you know when they arrive
Bill

 

[spoolin01]

... One point is that the discharge cycle is far less flat than the NiMH or the Eneloop types but at 1.6V they should forever solve the problems of the 570. I'll let you know when they arrive
Bill

Well, I hope so, but alkalines start there too, and (at least some of)the Canon cameras don't like them any better than the flat NiMHs. I don't think I ever tried 1.7V Lithium AAs in my 720s, that might have been instructive...

 

[Puffer Fish]

Thank you for that info, do you have a link? One thing, and I am not sure it will be a problem, but some devices are voltage sensitive also to high voltage. For example, some Inon strobes seem to have this concern, probably others as well. I wonder, do these new batteries have a higher initial voltage than a high quality alkaline?

I noticed exactly what you are talking about with my Dive Rite LED light with alkalines vs NiMH high cap batteries.

Thanks.

N

They could... as their no load voltage at full charge is 1.8... however, with any actual current draw, it is around 1.6. I was worried about the 1.8, as 8 of them in my led, could have overheated the LED.. but in use could not see much difference from standard batteries.. except that the fall off over time is slower.. which was not what I expected from the data...have not tried them in my strobe.. but will (testing how fast they self discharge... which seems to be fairly slow.. as we are now three weeks into the test.

 

[lmorin]

Hi,
I am using a PowerShot A570IS and decided to buy a set or rechargeable batteries for it. The user manual say use canons NiMH but it shouldn't matter if you buy another brand right? They all have 1.2V and its only the capacity that differs. I went to the supermarket and bought a energizer charger with 4 energizer rechargables (2450mAh). I charged them with the charger overnight and on the morning it had turned off as it should. I put the batteries in the camera and about 5 min later the low battery came on and 5 min later it turned of and told me I should change batteries! So what happened? I turned on CHDK and checked the voltage and it was between 2.4 and 2.5 as it should with NiMH, so is the camera not designed for 1.2V batteries or why does it turn off. I cleaned the battery connectors on the camera but no difference. Anyway I will try to return the charger today and get my money back and if you guys say it should work with NiMH I will go for Sanyo Eneloop because of the low discharge rate. Anyone tried these?

Thanks for any help!
Niclas

Do you know whether the problem is with the camera electronics, the batteries, the charger or the camera software? I ask, because I have had "issues" with my a570is using CHDK that are similar to yours. First, I used 2500 mAh Energizer batteries that were fantastic! Hundreds of shots per charge before I flooded them and the camera:depressed: I got a new camera, but I have been unable to find the 2500 mAh Energizers. The highest I have been able to find from Energizer is 2450 mAh.

That is one issue. The higher the mAh (milliamp hours), the longer the theoretical discharge time, all other things being equal. Energizer provides no useful information as to why one version of there battery is better/worse than another. That info is needed because not all other things are, in fact, equal. Some batteries are engineered to discharge slowly and cannot handle a high demand well. Others are engineered to do the opposite. Consumers get very little info that allows comparison shopping.

Here is a comment that compares NiMH to alkaline batteries:

This means that a NiMH battery with a rated capacity of 1800 mAh can take many more photos than an alkaline battery with a rated capacity of 2,800 mAh.

A second issue is the accuracy of the information coming from the camera via its software. CHDK has been giving me clearly erroneous battery info. On a couple of dives, I've shot as many as 50-70 shots with the battery low indicator blinking at me the entire dive, the batteries having been freshly charged before the dive. Sometimes, turning the camera off for a few minutes allows the "discharged" batteries to "recharge" and the battery low indicator is no longer blinking at me. I don't know whether the camera electronics are misreading the battery charge or the software is mis-reporting it.

 

[spoolin01]

It seems like it must be a design or QC problem with the cameras. The discharge curves of NiMH batteries are flat enough even under heavy load - not something your camera imposes - that tolerance for the small differences between brands or individual batteries should be easy to engineer around. They run at 1.1 to 1.2V (or whatever the precise voltage is) over most of their discharge curve, the exact shape of the curve in that band, or whether two brands have slightly different slopes, shouldn't be a big deal. Poor execution.

 

[Nemrod]

It seems like it must be a design or QC problem with the cameras. The discharge curves of NiMH batteries are flat enough even under heavy load - not something your camera imposes - that tolerance for the small differences between brands or individual batteries should be easy to engineer around. They run at 1.1 to 1.2V (or whatever the precise voltage is) over most of their discharge curve, the exact shape of the curve in that band, or whether two brands have slightly different slopes, shouldn't be a big deal. Poor execution.

Poor execution or not, all three of my A570 cameras work great, shoot great, great features, great optics for a P&S and work fine shot after shot for a full day of diving with the Eneloop/Duracell Pre-charged batteries.

I am not hard headed, I just go with what works.

N

 

[Maddog59]

The single most important thing to remember with rechargable batteries (be they NiMH, NiCD or NiZn) is that the individual cells must be electronically matched for the pack or the lowest capacity cell will drag the rest of the pack down to a level lower than the minimum required by the camera/flash. This would explain the reason why your energizer 2500Mah pack was so efficent and that you have not been able to repeat those results with another pack of the same brand. I would suggest getting a good charger that measures the load capacity of the cells as they charge (not the perfect way to match cells but as good as the average joe can expect) and buy good quality low discharge batteries. (eneloop, Maha, Imedion or the like)



Maddog59

Canon g10, Patima housing, 2 x Inon Z240-4 strobes hard wired and Maha MH-C9000 charger

 

[spoolin01]

The single most important thing to remember with rechargable batteries (be they NiMH, NiCD or NiZn) is that the individual cells must be electronically matched for the pack or the lowest capacity cell will drag the rest of the pack down to a level lower than the minimum required by the camera/flash. This would explain the reason why your energizer 2500Mah pack was so efficent and that you have not been able to repeat those results with another pack of the same brand. I would suggest getting a good charger that measures the load capacity of the cells as they charge (not the perfect way to match cells but as good as the average joe can expect) and buy good quality low discharge batteries. (eneloop, Maha, Imedion or the like)

Truly defective batteries are not that common. Normal differences between batteries are not some extraordinary engineering hurdle. If designers could make cameras that work with steep slope alkalines (my C-5050 worked just fine with alkalines or any kind of NiMHs), they should have an easier job with the flat NiMhs. You can look at the discharge curve and see that even pairing substantially mismatched cells can't explain complete or near complete loss of function the start of the discharge profiles. The NiMHs that wouldn't power my 2 A720IS's more than 6 no-flash shots - and I tested several sets - were still fully charged, full voltage, same voltage, and worked fine, still do, in other cameras and applications. Poor or venal execution. I say again, for $2 or less you can get 2500mAh in an AA with a nearly flat discharge profile. That should be gold for the designers and marketers. More likely someone designed a chip or sourced a component that simply wasn't up to it and they decided that reworking it for an item that would be obsolete in a year wasn't economical, especially if there was a work around.