camera batteries

[JRMDC]

I have a Canon 50D, one original battery, four non-brand batteries. Sterlingtek for at least two of them, don't recall what the other two are. Yesterday in the field a battery goes low, so I reach for a trusty backup. No power, no go. Reach for another, no power, no go. Reach for a third, all set.

Well, no big deal, not the first time I have forgotten to check the charge on my backups, I don't go out that often. But now I am at home and I check batteries and, indeed, two of them have lost their charge. But the other two show full volts on my voltmeter, yet when I stick them into the camera, the camera says no power.

Thinking it may be a contact issue, I tried putting some shims before I closed the cover. No go. And anyway, if there is no battery the LCD shows nothing. So the LCD showing the empty/dead battery symbol means connection is being made.

Two non-brand are fine, the Canon battery is fine, two non-brand are not.

Any ideas as to why a fully charged battery (measured by voltage and also by the "full" indicator on the charger) doesn't register with the camera?

[JimThias]

5 batteries? Who needs 5 batteries?

[Mark Gayman]

Well, many of today's rechargeable batteries have an integrated circuit (IC) in them that is commonly called the "gas-guage". The best gas-gauges measure and report the charge going in and out of the cells while some measure and report only the charge going in. If that IC glitches, then its readings will be off, possibly indicating that no charge has gone in. The camera likely believes the gas gauge over the voltage present on the + and - terminals.

Possibly the thing to do is to let the "empty" batteries self-discharge and then charge them again. You could put a load resister between the + and - terminals of the battery and discharge it faster, but choosing the right value for the resistor is critical and depends on a number of factors. If you have a BatteriesPlus store nearby, they might be able to recommend a value, or they could possibly recondition the battery.

[JRMDC]

Thanks for the suggestion.

[Ryan Lewis]

Originally Posted by JimThias

5 batteries? Who needs 5 batteries?

So you can have a backup for your backup, which also has a back up!