Batteries and the OptioS50

I have been using Fameart rechargeable batteries - Ni-MH 1800mAh, 1.2
volts - with success.

To improve life of batteries have switched to Hama batteries - 2400 NiMH 1.2 volts.

Sometimes when I insert the fully charged Hama batteries I get a
battery depleted message. I then tested the batteries via the charger
and both come up as full charged. Then when I insert another two of the same batteries everything works OK. Yet all four batteries were recharged together for the recommended time.

Have you any ideas of what is happening please?
Thanks

I know

The Pentax cameras (including the *ist-D) work out what type of battery is installed by the initial voltage. Some of the Hama high capacity batteries overcharge and consequently the camera thinks they are either Lithium Ion or Alkaline batteries which are nearly dead.

I have found no problems with the Uniross 2100mAh batteries, and reserve my Hama ones for flash gun etc.

Hope that helps!
Matt

Thanks for answer. Seems a bit strange though and I've got a few of these Hama batteries! The four batteries in question were all charged at the same time and identically, so it is rather wierd that two worked OK and the others did not?

Do the Pentax technical people look in on this forum? mike

Sorry if I seemed rude in resubmitting my question in the Troubleshooter section. I've only just noticed that you are one of the moderators!

I have tried to do research online via battery manufacturers, sellers etc with no success. Even Pentax's own technical dept had never heard of the problem. It does seem strange.

So it looks as though I am not going to be able to take advantage of the new, more powerful, batteries. Is there anything one can do other than just accept this and keep with the old lower power batteries? Can I delete anything from the camera's memory that would help?

Mike,
No problem
There are two possibilities actually now I come to think of it:

1. The batteries when freshly charged measure too high a voltage and the camera misreads.

2. One of the batteries is duff. This can happen especially if your tester (like a multimeter etc) tests with no load. You can find that it appears to hold charge, but as soon as it's put under load it can't deliver the goods (too high an internal resistance to be specific).

Unfortunately for me the *ist-D takes 4xAA, so finding one dud is more of a problem. However, from what you said that 2 of the batteries work and 2 don't - I reckon it's probably option 2 You could try swapping one of the good with one of the bad to work out exactly which AA is at fault.

Hope that's not too confusing!
Matt

Thanks Matt. I have been thinking it could be dud battery myself. I have recharged all four batteries now and will see, as I suspect, that I have one dud battery.

One other question: I have a 2 year old recharger. Will that cope with the new higher power batteries? It's a Tronic Universal Ni-Cd & Ni-MH. The instructions on it only quotes AA 1200mAh batteries, which presumably were the highest power ones available at that time.

Do I need a new charger as I want to use the new high power AAs? The Optio seems particularly hard of batteries compared, say, to the Kodak camera I had previously.

Have looked everywhere on Google for Tronic, with no luck. Does anyone have contact details for them?

Have just checked all 4 batteries and only one causes the Battery Depleted message, so it's a dud. Checked it on th Test function on my recharger and it shows as being dead, even after a 24 recharge. Thanks Matt.

But I would still appreciate any info re the Tronic charger.

Hi Mike,
I don't have any info on Tronis. I rather suspect it is a badged version of someone else's charger. I don't know where it came from but a guess would be a High street budget shop. (no offence meant )

As to chargers in general:

NiCds and now NiMH batts are charged using a constant current. (As opposed to lead acid, where the voltage is controlled). The normal charge cycle for these is 1/10 the capacity for 14 hours ie for your batts 120Ma. Most rechargeable will accept this sort of charge for much longer periods of time without any undue damage though it may shorten their life. So the circuitry for a simple charger is relatively simple. So called "fast chargers" charge at a much higher rate. The batteries cannot withstand an "overcharge" at this rate for very long without causing some damage. The chargers get round this by either using a time cct in the cheaper ones, or in the better ones monitoring the voltage curve and trimming the current as the battery voltage increases. This "overvoltage" is perhaps one of the reasons some of the very high capacity batteries on fast chargers can cause problems.

So to come back to your question. Generally speaking, it is safe to use higher capacity batteries on a lower rated charger. All that will happen is that they will take much longer to charge. (However, you have to be very careful so as not to overcharge.) Assuming yours is a "simple" constant current charger, I would leave 2400mAH batteries in for 24 hours. If the battery charger is a "timed" one you may need to give it 2 cycles. If it is a sensing one, it should switch itself to a trickle charge when the batts are full. If you can give me some more details on the instructions, "suggested" charge times and light indications, I may be able to be more specific. Personally, I don't like the Ultra fast chargers. They work and are safe but they will reduce the life of the battery with repeated use.

As an aside, it is generally safe to charge NiCds in an NiMh charger but don't use NiMhs in a fast NiCd charger. This is because the internal resistance on NiCds is lower. (Which is why NiCds can give a higher current in flashguns and reduse re cycling times )

Another alternative is to visit 7Dayshop.com. they often have some very good "clearance" deals and a complete set is often the same price as the batts on their own.

Hope this helps

Kim

Just as a general comment, I know lots of people who have problems with batteries, but it's often because they don't use the right batteries or they don't follow the instructions.

We are using 2300 mAh batteries without any problems in the *istDS. We don't buy cheap ones and we don't mix them up - I have seen one friend actually mixing rechargeables with Duracells, with not very satisfactory results....

In older cameras, silver oxide cells give better performance than alkaline cells, predictably.

If all else fails, read the instructions!