SD600 Battery Drain

lupes5

1

« on: 13 / July / 2009, 04:31:07 »

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Hey guys, im new to this stuff...if this has been answered, please forgive me, i did a bit of searching but couldnt find an answer....

When running chdk on my sd600, i have terrible battery drain (its almost like a countdown)...i see on the wiki that other people have reported the problem.....has there been any new developments on this yet?

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fudgey

1705
a570is

Re: SD600 Battery Drain

« Reply #1 on: 13 / July / 2009, 14:06:17 »

CHDK does not increase battery consumption.

But... it has recently been deduced that Canon firmware of a570 and a590 (and very likely all other models too) have a firmware upgrade safety mode in their battery low detection: before Canon firmware enters a firmware upgrade, it may shut down with batteries half full because it tries to make sure the update itself will not fail due to low batteries.

Problem is, CHDK is always started as a firmware upgrade. CHDK doesn't actually upgrade firmware, but its start mechanism is the same as with Canon firmware upgrades, which is why this safety functionality is triggered.

Logically thinking this feature affects dual AA cell cameras the most because their supply voltage is lowest.

The only solution I know for now is to use a good quality, new (in respect of manufacturing date and recharge cycles) batteries only. In my experience with my dual AA a570 a good pair of NiMH will be discharged almost fully even when running CHDK, but 18 months later the same pair (still in good condition for other uses) may not even let the camera start in REC mode after a full recharge!

And when the camera won't start but you need to shoot, disable CHDK autoboot (by unlocking your SD card) and use your camera without CHDK. It will work for a while longer.

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fe50

3147
IXUS50 & 860, SX10 Star WARs-Star RAWs

Re: SD600 Battery Drain

« Reply #2 on: 13 / July / 2009, 15:48:46 »

The SD600 works with a NB-4L Li-Ion battery (as my SD 400), this one has a low capacity, furthermore this older Ixus/SD series has a bad, low battery lifetime...

You'll see the CHDK battery percentage running down very quickly in record mode, especially when the capacity is > 50%.
But have a look to the Canon OSD battery symbol - you'll see a "full" battery sign even with 20-30%...
When you switch to playback mode or disable the LCD, the shown capacity goes up again...
So - with good cause Canon shows only an extremely imprecise 'battery meter'.

The capacity of Li-Ion batteries also declines (aging); after a year or more the battery normally has less then 75% of the original capacity.

So all you can do is to clean the batterie's contacts to minimize the contact resistance...and to get the best lifetime of all kind of rechargeable batteries: always run full charge/discharge cycles.

When you set up the camera / go through the CHDK menu - switch to playback mode before, in playback mode the camera disables the sensor electronics, this saves up to 50% battery lifetime.

« Last Edit: 13 / July / 2009, 16:26:46 by fe50 »

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fudgey

1705
a570is

Re: SD600 Battery Drain

« Reply #3 on: 26 / July / 2009, 11:45:05 »

Quote from: fe50 on 13 / July / 2009, 15:48:46

and to get the best lifetime of all kind of rechargeable batteries: always run full charge/discharge cycles.

This is highly important only with the now obsolete NiCd batteries, and just plain wrong for most lead acid batteries, gel cells and the like (not found in digital cameras). The extreme example is car starter batteries, which should optimally never be discharged more than a little bit. They were built to source a high current for a little while and then get recharged immediately. Marine/leisure types are typically safe to discharge to 50 % (but even they suffer if it's done slowly, meaning the battery will spend a lot of time partially charged), more expensive AGM deep cell types can go deeper of course.

But NiMH does like to get fully discharged (as long as you don't discharge any of the cells in a pack too deep which could destroy the weakest cells, but this is nearly impossible with 2*AA cameras), and with CHDK running the camera doesn't fully discharge batteries so voltage depression could occur. Still it's quite possible that repeated overcharging (even with low current trickle/standby charger) and plain aging deteriorate batteries more than repeated partial discharge cycles.

For lithium batteries depth of discharge should matter even less.

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