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CHDK voltage meter, 4x AA NiMH batteries?

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Offline jojo99

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #10 on: 09 / June / 2008, 07:23:46 »
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Quote from: DataGhost on 09 / June / 2008, 05:26:21
You could also just relax a bit and just forget about those few millivolts. The battery indicator is meant as a guideline, it can never be accurate because of the graph GrAnd showed. Just calibrate the graph at something which works for you and then don't adjust it again unless you switch to another brand or type of batteries. On my S5IS, I see that the voltage drops quite fast to 5.2V and then gently slides down to 5.1V, where it stays for a while. As soon as it drops below 5V, I know it can't be long anymore. I set the CHDK battery meter to show 0% at 4.7V, as the Canon firmware shows the battery indicator around 4.6V and shuts off shortly after that. I guess the Canon indicator measures the voltage drop and if it's large enough it tells the user the batteries are empty. Because of the amount of different batteries that can be used in the cameras, it's near-impossible to implement a battery indicator which works across the entire range, so I guess that's why Canon chose not to do that.

It's hard to relax when I don't know what numbers to use!  There has to be some logic behind how these numbers are developed and interpreted, doesn't there? 

One of the pieces of info I was hoping to get with CHDK was an accurate battery display, since Canon's icon only shows up when the batteries are about to die.

How are you getting the voltage numbers you mention above?  Does the S5 show them or are you seeing them on some kind of charger?  I brought this high end MAHA C-9000 charger and only after some weeks and a conversation with the support guy, discovered that it doesn't show the current voltage of any batteries.  Sheese.  All you can do is run the batteries through a charge cycle and see the results at the end of the cycle.  While this charger has a pretty display, I wouldn't recommend this MAHA charger to anyone.
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Offline fe50

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #11 on: 09 / June / 2008, 07:29:55 »
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How are you getting the voltage numbers you mention above?  Does the S5 show them
Have you set (in CHDK menu)  "OSD Parameters" -- "Battery" --"Show Battery volts" ?
(Also have a look to the "Step Size" parameter...)
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Offline cybercom

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #12 on: 09 / June / 2008, 11:00:33 »
@jojo99:

You'll just simply have to experiment. There are no absolutes when it comes to batteries.

Wait until the camera tells you to replace the batteries then measure the actual voltages and use that as a reference point.

Do you want to know a little before or a lot before it's time to change? That will determine your lower value.

Fortunately, my TX-1 uses Lithium ion batteries which have no memory, so I just recharge them whenever I feel they might need it. I know it's hard to believe, but there really are times when I'm not shooting... ::)
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Offline jojo99

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #13 on: 09 / June / 2008, 18:50:29 »
Quote from: cybercom on 09 / June / 2008, 11:00:33
@jojo99:

Wait until the camera tells you to replace the batteries then measure the actual voltages and use that as a reference point.

So how do I measure the actual voltages?
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Offline wontolla

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #14 on: 09 / June / 2008, 19:39:26 »
As fe50 already said, go to "OSD Parameters" -> "Battery" -> "Show Battery volts"
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Offline dzsemx

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Re: CHDK voltage meter, 4x AA NiMH batteries?
« Reply #15 on: 10 / June / 2008, 02:17:43 »
chdk shows ACTUAL/realtime battery voltage
NI-MH batteries are only simple battery cells with nonlinear discharge and with other problems...
li-ion batteries have almost linear discharge curve and some of them got battery life management (like notebook batteries)
so it's more easy to predict battery life...
I use within chdk only battery volts display, because i have different sets of batteries with a little bit different discharge carateristics, so i can decide how many time/shots i got
I've got some cheap(12$/4batts) Lenmar 2700 mAh batteries, pretty ok almost real capacity, with an extra cheap charger and i charge them about  24 hours (150 mA)
At first charge NI-MH batteries needs a little bit overcharge to have all of it's capacity, so i charged them about 28-30 hours first time and at first use i've got great battery life
Precharged batteries have to be  discharged first.
My camera shuts down at  4.4-4.3 volts, which tells me that the batteries are in really good condition.
I've got a fast charger too, but i use it only in case of emergency, i don't reccomend to use these... they just kill batteries
« Last Edit: 10 / June / 2008, 03:01:49 by dzsemx »
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