A way to measure batteries or chargers?

**ramseybuckeye** · 01-06-2020, 07:38 PM - **1 Like**

Just a curiosity, I have not had problems, but is there a way to measure the charge in batteries, or the effectiveness of chargers? I do use a third party charger more often because it will charge two batteries at once. But how do I know if it is charging them as good as the Pentax charger? I don't think counting shots is an answer, because no two are the same. If I/m out using a tripod I'll be using live view and may take longer to compose an image. A long exposure is definitely going to use more juice. As would using bracketing or in camera HDR, etc. I think I could possibly measure the battery with a multimeter, I know a lot of the members here are way more electronics savvy than I am, so what do you think?

**beachgardener** · 01-06-2020, 07:57 PM

It is a great idea, someone will know for sure, It never ceases to amaze me the level of technical and curiosity on this forum

stevebrot · 01-06-2020, 09:04 PM

Originally posted by ramseybuckeye

but is there a way to measure the charge in batteries

My K-3 seems to think so does my cell phone. Many batteries provide metering circuitry that indicates state of charge. How they work, I have no clue.

Steve

**Bruce Clark** · 01-06-2020, 09:08 PM

I wish there was a way. One of the properties of Lithium Ion batteries is that they hold their voltage until the very end. Unlike the old zinc carbon batteries of years ago that slowly dropped voltage until they failed. A multi-meter alone will not detect impending failure. The battery indicator on the camera display does a better job but can show full green and a few minutes later start reporting problems. I have been caught several times. However, I did get through 6 weeks in Europe on a single generic battery. Some fool (me) put several spares aside then forgot to pack them. At least I had a charger and got through every day without using the rear screen to view images, and turning off the camera at every opportunity.

I had two generic batteries cark it on me last weekend. Both initially showed full charge in camera, both failed after 10-20 shots and both showed full charge again after about 10 minutes of charging. Both in the bin. Interestingly I still use an original Pentax battery from my K-7 bought in 2010 and still going strong. I now get generic batteries from Amazon or the like. 2 Batteries plus a USB charger for less then A$30. I keep one charger in the car and one in the camera bag.

**RGlasel** · 01-06-2020, 09:28 PM - **1 Like**

Originally posted by ramseybuckeye

but is there a way to measure the charge in batteries

There is more than one way, depending on the application. For devices like cameras where the current draw is relatively steady, ampere hours (or more commonly milli-amp hours) is a good way to measure how long the battery can supply a constant level of electrical current. Batteries can also be rated by the maximum current they can provide for a short, fixed period of time (usually at a specified temperature), automotive batteries have a CCA (cold cranking amps) rating. There are also ways to rate batteries for the number of times they can provide bursts of current until they are discharged, how many times they can be recharged before their charge storage performance drops below a specified standard, and so on.

I think there is even an ISO standard for calculating how many shots a camera can take on a single battery charge and I would expect that specifications published by camera manufacturers are legitimate and accurate ratings. The battery manufacturers aren't likely to spend much money on independent testing on every camera model their batteries fit, so I don't expect the same legitimacy and accuracy for third-party, aftermarket batteries.

---------- Post added 01-06-20 at 10:39 PM ----------

I use rechargeable lithium batteries for my cochlear implant, at $200/battery, I have a vested interested in getting the most out of the four rechargeable batteries I use in rotation that I can. To squeeze as much charge into them as possible, I have to use a special dedicated battery holder and power convertor, which also costs $200. If I want to use disposable air-zinc 675 batteries for my implant, I have only one battery manufacturer to chose from that puts enough charge in pairs of their batteries to get close to the same hours of use that I get from the rechargeable ones (the holder for 2 disposable batteries is the same size as the shell of the rechargeable batteries). Even at $200 a pop, the rechargeable batteries start to hold less charge after a year (even if I only use each one every fourth day) and three years later, they only last 50-65% as long as they did when new.

I guess my point is that the least expensive battery that meets your minimum performance standards is probably your best choice. I ended up buying two extra OEM batteries for my K-30 from The Camera Store because even though they were double the price of aftermarket batteries on Amazon, I could afford to pay an extra $30 in total to avoid worrying if my replacement batteries wouldn't be as good as the one that came with the camera. I was happy with the performance of the OEM battery (which I am still using), so why bother taking a chance?

mkgd1 · 01-06-2020, 09:51 PM

Even the "in camera" battery meters work on measuring voltage, same thing with smart phones. As the batteries discharge, there is a slight drop in voltage (not as steep as old zinc carbon or alkaline batteries) Manufacturers calibrate their devices based on this curve. As far as generic chargers, v Pentax, I have heard that some will charge faster than others. If that is the case, their will be a slightly higher output voltage under load.

**James also** · 01-07-2020, 12:10 AM

The fastest charger I have is a modified lap top charger. The only downside is that I have to keep an eye on the battery so it does not over charge.
I have a couple of really good cheapies and a dud Pentax branded battery.All batteries can be a bit hit and miss. Identical batteries will not always last the same time. At work some will last ages in the worst conditions, others in air conditioned comfort fail quickly.

joergens.mi · 01-07-2020, 12:18 AM

Have a look at the Voltage. It should charge up 8.4 Volts.
And the number of shoots is not as bad as you think. You have your way to take photos, therefore the number you can take is typically for you. If a battery will have diverge more than 20 % from your typical count, it will be bad or not fully charged.
My charger shows me the mAH put to the battery and the Voltage.

The voltage of the battery can be seen in the exif Data of a picture. Therefore you can measure it, by taking a photo after charging. You can get the shutdown voltage if you look at the last picture before the camera shut down.

Not a Number · 01-07-2020, 12:20 AM

BU-602: How does a Battery Fuel Gauge Work? ? Battery University

Measuring voltage with a straight voltometer/multimeter will give no indication of capacity. An old battery may show a voltage of 8.4v but as soon as you put a load on the battery will drain to exhaustion in a very short time.

fsge · 01-07-2020, 01:12 AM

Following this thread

biz-engineer · 01-07-2020, 04:14 AM

Originally posted by ramseybuckeye

is there a way to measure the charge in batteries, or the effectiveness of chargers?

Yes.
- Fully discharge a battery by using it or leaving the camera switched on until the camera indicated "Battery depleted" and switched off

- Fully charge a battery
- Insert the battery in your camera
- Set the camera auto power-down to "Off"
- Note time of the day
- Wait until the camera display "Battery depleted"
- Note time of the day, calculate how many hours the camera stayed in standby mode.

Do this for each battery you own, note the difference of how long it takes for each battery from fully charged to fully depleted.

**Lowell Goudge** · 01-07-2020, 05:19 AM

To measure the state of chart page of a battery you need to measure multiple parameters, it is not easy, which is why there have been so many complaints about the built in battery life meters over time. The K10 for example showed full charge until the battery was almost dead, and had only 10-20 shots left once the meter moved off full charge.

Starting with the K7, the Pentax batteries had a third terminal added, and this was largely to better measure the battery capacity during use.

I have never looked into the function directly but I believe it is used to measure the current, because there is a relationship between state of charge and voltage under load.

Even this is not a reliable enough indicator because as the battery discharges you can have the state of charge go from almost full charge to dead , and back as a function of rear LCD use which draws a lot of current.

In short, there is no simple way to get an accurate indication, of useful life, other than to use batteries until dead, and then fully charge them.

**James also** · 01-07-2020, 05:30 AM

Originally posted by biz-engineer

Yes.
- Fully discharge a battery by using it or leaving the camera switched on until the camera indicated "Battery depleted" and switched off

- Fully charge a battery
- Insert the battery in your camera
- Set the camera auto power-down to "Off"
- Note time of the day
- Wait until the camera display "Battery depleted"
- Note time of the day, calculate how many hours the camera stayed in standby mode.

Do this for each battery you own, note the difference of how long it takes for each battery from fully charged to fully depleted.

You forgot the step where you open and then pour yourself a good red wine while you wait.

There are meters that will give you a capacity reading for the battery usually in a percentage..

biz-engineer · 01-07-2020, 06:41 AM

Originally posted by James also

You forgot the step where you open and then pour yourself a good red wine while you wait.

Since the wait would be around 6 hours (or about 3 hours with LV On), I guess the discharge time could be even shorter when recording a dummy video continuously except the SD card would be full before the battery is empty. If I would drink red wine for that long I'm be under the table before the battery is discharged, so I prefer to let the camera on its own for a bit less than the expected discharge time and set an alarm on my phone for when to check it out.

Originally posted by James also

There are meters that will give you a capacity reading for the battery usually in a percentage..

I do have an AA charger that counts the mAh (current based). But I'm afraid that Pentax cameras (and some chargers) indicate battery charge based on a voltage level of the battery (non linear), which is not accurate unless some voltage/charge relationship was established stored in the LUT and accessed by firmware. It would be great if a D-LI90 charger would be able to measure the capacity of D-LI90 batteries and give a good indication of battery charge.

Penview52 · 01-07-2020, 06:45 AM - **1 Like**

You can not measure the current in the battery unless the current is flowing in the circuitry. New chargeable battery takes maximum voltage and maximum current and holds them longer more than a 4 years old battery because the cells wear and tear usage. Determine how much recordable images can a battery takes ( from manual ) except using flash and previews of images that gives you idea how long the battery last. A new chargeable battery is not the same as 4 year old or more and diminish its functionality after a year of use. Never retain an old battery.

01-06-2020, 07:38 PM - 1 Like	#1
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,295	A way to measure batteries or chargers? Just a curiosity, I have not had problems, but is there a way to measure the charge in batteries, or the effectiveness of chargers? I do use a third party charger more often because it will charge two batteries at once. But how do I know if it is charging them as good as the Pentax charger? I don't think counting shots is an answer, because no two are the same. If I/m out using a tripod I'll be using live view and may take longer to compose an image. A long exposure is definitely going to use more juice. As would using bracketing or in camera HDR, etc. I think I could possibly measure the battery with a multimeter, I know a lot of the members here are way more electronics savvy than I am, so what do you think?

01-06-2020, 09:28 PM - 1 Like	#5
RGlasel Site Supporter Join Date: Sep 2013 Location: Saskatoon Photos: Gallery \| Albums Posts: 3,229	Originally posted by ramseybuckeye but is there a way to measure the charge in batteries There is more than one way, depending on the application. For devices like cameras where the current draw is relatively steady, ampere hours (or more commonly milli-amp hours) is a good way to measure how long the battery can supply a constant level of electrical current. Batteries can also be rated by the maximum current they can provide for a short, fixed period of time (usually at a specified temperature), automotive batteries have a CCA (cold cranking amps) rating. There are also ways to rate batteries for the number of times they can provide bursts of current until they are discharged, how many times they can be recharged before their charge storage performance drops below a specified standard, and so on. I think there is even an ISO standard for calculating how many shots a camera can take on a single battery charge and I would expect that specifications published by camera manufacturers are legitimate and accurate ratings. The battery manufacturers aren't likely to spend much money on independent testing on every camera model their batteries fit, so I don't expect the same legitimacy and accuracy for third-party, aftermarket batteries. ---------- Post added 01-06-20 at 10:39 PM ---------- I use rechargeable lithium batteries for my cochlear implant, at $200/battery, I have a vested interested in getting the most out of the four rechargeable batteries I use in rotation that I can. To squeeze as much charge into them as possible, I have to use a special dedicated battery holder and power convertor, which also costs $200. If I want to use disposable air-zinc 675 batteries for my implant, I have only one battery manufacturer to chose from that puts enough charge in pairs of their batteries to get close to the same hours of use that I get from the rechargeable ones (the holder for 2 disposable batteries is the same size as the shell of the rechargeable batteries). Even at $200 a pop, the rechargeable batteries start to hold less charge after a year (even if I only use each one every fourth day) and three years later, they only last 50-65% as long as they did when new. I guess my point is that the least expensive battery that meets your minimum performance standards is probably your best choice. I ended up buying two extra OEM batteries for my K-30 from The Camera Store because even though they were double the price of aftermarket batteries on Amazon, I could afford to pay an extra $30 in total to avoid worrying if my replacement batteries wouldn't be as good as the one that came with the camera. I was happy with the performance of the OEM battery (which I am still using), so why bother taking a chance? Last edited by RGlasel; 01-06-2020 at 09:51 PM.

01-07-2020, 12:20 AM	#9
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	BU-602: How does a Battery Fuel Gauge Work? ? Battery University Measuring voltage with a straight voltometer/multimeter will give no indication of capacity. An old battery may show a voltage of 8.4v but as soon as you put a load on the battery will drain to exhaustion in a very short time. Last edited by Not a Number; 01-07-2020 at 12:29 AM.

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01-06-2020, 07:57 PM	#2
beachgardener Site Supporter Join Date: Sep 2013 Location: Australia Photos: Gallery Posts: 3,842	It is a great idea, someone will know for sure, It never ceases to amaze me the level of technical and curiosity on this forum

01-06-2020, 09:04 PM	#3
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by ramseybuckeye but is there a way to measure the charge in batteries My K-3 seems to think so does my cell phone. Many batteries provide metering circuitry that indicates state of charge. How they work, I have no clue. Steve

01-06-2020, 09:08 PM	#4
Bruce Clark Loyal Site Supporter Join Date: Mar 2010 Location: Ocean Grove, Victoria Photos: Gallery \| Albums Posts: 4,458	I wish there was a way. One of the properties of Lithium Ion batteries is that they hold their voltage until the very end. Unlike the old zinc carbon batteries of years ago that slowly dropped voltage until they failed. A multi-meter alone will not detect impending failure. The battery indicator on the camera display does a better job but can show full green and a few minutes later start reporting problems. I have been caught several times. However, I did get through 6 weeks in Europe on a single generic battery. Some fool (me) put several spares aside then forgot to pack them. At least I had a charger and got through every day without using the rear screen to view images, and turning off the camera at every opportunity. I had two generic batteries cark it on me last weekend. Both initially showed full charge in camera, both failed after 10-20 shots and both showed full charge again after about 10 minutes of charging. Both in the bin. Interestingly I still use an original Pentax battery from my K-7 bought in 2010 and still going strong. I now get generic batteries from Amazon or the like. 2 Batteries plus a USB charger for less then A$30. I keep one charger in the car and one in the camera bag.

01-06-2020, 09:51 PM	#6
mkgd1 Pentaxian Join Date: Dec 2019 Location: Mohave county Arizona Photos: Albums Posts: 1,076	Even the "in camera" battery meters work on measuring voltage, same thing with smart phones. As the batteries discharge, there is a slight drop in voltage (not as steep as old zinc carbon or alkaline batteries) Manufacturers calibrate their devices based on this curve. As far as generic chargers, v Pentax, I have heard that some will charge faster than others. If that is the case, their will be a slightly higher output voltage under load.

01-07-2020, 12:10 AM	#7
James also Site Supporter Join Date: Mar 2010 Location: Victoria Photos: Gallery Posts: 332	The fastest charger I have is a modified lap top charger. The only downside is that I have to keep an eye on the battery so it does not over charge. I have a couple of really good cheapies and a dud Pentax branded battery.All batteries can be a bit hit and miss. Identical batteries will not always last the same time. At work some will last ages in the worst conditions, others in air conditioned comfort fail quickly.

01-07-2020, 12:18 AM	#8
joergens.mi Veteran Member Join Date: Jan 2012 Posts: 408	Have a look at the Voltage. It should charge up 8.4 Volts. And the number of shoots is not as bad as you think. You have your way to take photos, therefore the number you can take is typically for you. If a battery will have diverge more than 20 % from your typical count, it will be bad or not fully charged. My charger shows me the mAH put to the battery and the Voltage. The voltage of the battery can be seen in the exif Data of a picture. Therefore you can measure it, by taking a photo after charging. You can get the shutdown voltage if you look at the last picture before the camera shut down.

01-07-2020, 01:12 AM	#10
fsge Veteran Member Join Date: Jun 2010 Location: Genf Posts: 1,138	Following this thread

01-07-2020, 04:14 AM	#11
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,248	Originally posted by ramseybuckeye is there a way to measure the charge in batteries, or the effectiveness of chargers? Yes. - Fully discharge a battery by using it or leaving the camera switched on until the camera indicated "Battery depleted" and switched off - Fully charge a battery - Insert the battery in your camera - Set the camera auto power-down to "Off" - Note time of the day - Wait until the camera display "Battery depleted" - Note time of the day, calculate how many hours the camera stayed in standby mode. Do this for each battery you own, note the difference of how long it takes for each battery from fully charged to fully depleted.

01-07-2020, 05:19 AM	#12
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	To measure the state of chart page of a battery you need to measure multiple parameters, it is not easy, which is why there have been so many complaints about the built in battery life meters over time. The K10 for example showed full charge until the battery was almost dead, and had only 10-20 shots left once the meter moved off full charge. Starting with the K7, the Pentax batteries had a third terminal added, and this was largely to better measure the battery capacity during use. I have never looked into the function directly but I believe it is used to measure the current, because there is a relationship between state of charge and voltage under load. Even this is not a reliable enough indicator because as the battery discharges you can have the state of charge go from almost full charge to dead , and back as a function of rear LCD use which draws a lot of current. In short, there is no simple way to get an accurate indication, of useful life, other than to use batteries until dead, and then fully charge them.

01-07-2020, 05:30 AM	#13
James also Site Supporter Join Date: Mar 2010 Location: Victoria Photos: Gallery Posts: 332	Originally posted by biz-engineer Yes. - Fully discharge a battery by using it or leaving the camera switched on until the camera indicated "Battery depleted" and switched off - Fully charge a battery - Insert the battery in your camera - Set the camera auto power-down to "Off" - Note time of the day - Wait until the camera display "Battery depleted" - Note time of the day, calculate how many hours the camera stayed in standby mode. Do this for each battery you own, note the difference of how long it takes for each battery from fully charged to fully depleted. You forgot the step where you open and then pour yourself a good red wine while you wait. There are meters that will give you a capacity reading for the battery usually in a percentage..

01-07-2020, 06:41 AM	#14
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,248	Originally posted by James also You forgot the step where you open and then pour yourself a good red wine while you wait. Since the wait would be around 6 hours (or about 3 hours with LV On), I guess the discharge time could be even shorter when recording a dummy video continuously except the SD card would be full before the battery is empty. If I would drink red wine for that long I'm be under the table before the battery is discharged, so I prefer to let the camera on its own for a bit less than the expected discharge time and set an alarm on my phone for when to check it out. Originally posted by James also There are meters that will give you a capacity reading for the battery usually in a percentage.. I do have an AA charger that counts the mAh (current based). But I'm afraid that Pentax cameras (and some chargers) indicate battery charge based on a voltage level of the battery (non linear), which is not accurate unless some voltage/charge relationship was established stored in the LUT and accessed by firmware. It would be great if a D-LI90 charger would be able to measure the capacity of D-LI90 batteries and give a good indication of battery charge.

01-07-2020, 06:45 AM - 1 Like	#15
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	You can not measure the current in the battery unless the current is flowing in the circuitry. New chargeable battery takes maximum voltage and maximum current and holds them longer more than a 4 years old battery because the cells wear and tear usage. Determine how much recordable images can a battery takes ( from manual ) except using flash and previews of images that gives you idea how long the battery last. A new chargeable battery is not the same as 4 year old or more and diminish its functionality after a year of use. Never retain an old battery.