Gossen light meters with 9V batteries

[BrianShaw]

So if I were Ralph I would want to find out if the meter drain the battery when not being used or the battery self discharge rate is too high. Each should have different solution.

If it were me, I'd make an assumption rather than suspect the meter design: given that it's two different meter models, albeit from same manufacturer and using hte same type of battery and that the alternative battery in use has a known self-discharge characteristic...

Sometimes the better answer is just to resolve the situation without fretting over why.

 

[Chan Tran]

If it were me, I'd make an assumption rather than suspect the meter design: given that it's two different meter models, albeit from same manufacturer and using hte same type of battery and that the alternative battery in use has a known self-discharge characteristic...

Sometimes the better answer is just to resolve the situation without fretting over why.

So if you assume that the meters don't drain the battery and his kind of rechargeable battery has high self discharge rate then I think the Li-Ion rechargeable AA is the answer. Eneloop NiMH does have low self discharge rate but they don't make 9V battery.

 

[Philippe-Georges]

There is an other way to check if the light meter is draining the battery even when automatically shut off, although it is primitive and quirky (=warning!).
Replace the battery by a small transformator 220V AC—> 9V DC and a micro Ampère meter.
Connect the transformator (DC!), with the micro Ampère meter, to the light meter and let it auto shut off and observe if there is still power consumption.
If none then the rechargeable-battery is the problem, if there still is then the light meter is the problem...

 

[Chan Tran]

There is an other way to check if the light meter is draining the battery even when automatically shut off, although it is primitive and quirky (=warning!).
Replace the battery by a small transformator 220V AC—> 9V DC and a micro Ampère meter.
Connect the transformator (DC!), with the micro Ampère meter, to the light meter and let it auto shut off and observe if there is still power consumption.
If none then the rechargeable-battery is the problem, if there still is then the light meter is the problem...

With the 9V battery is quite easy to do. With meter that uses other kind of battery it could be a problem to hook up an amp meter. For the 9V battery devices just get a couple of 9V battery connectors. You can use the 9V battery as power source. You don't need a power supply for that.
Get a couple of connectors like these

https://www.digikey.com/en/products/detail/keystone-electronics/234/303805?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Low%20ROAS%20Categories&utm_term=&utm_content=&utm_id=go_cmp-20243063506_adg-_ad-__dev-c_ext-_prd-303805_sig-Cj0KCQjwwae1BhC_ARIsAK4JfryUS_22WuYNmvD8q5DnMSr6hSdLD0Poi9UPDuvKpQFuaHhMze9yznoaAhYfEALw_wcB&gad_source=1&gclid=Cj0KCQjwwae1BhC_ARIsAK4JfryUS_22WuYNmvD8q5DnMSr6hSdLD0Poi9UPDuvKpQFuaHhMze9yznoaAhYfEALw_wcB

Use one to snap into the connector that is on the meter. Another one to snap onto the battery. Connect the 2 black wires together and insert the amp meter between the 2 red wires.

 

[Philippe-Georges]

When I need 9V battery connectors, I just cannibalise an empty battery, and with some soldering...

 

[RalphLambrecht]

With the 9V battery is quite easy to do. With meter that uses other kind of battery it could be a problem to hook up an amp meter. For the 9V battery devices just get a couple of 9V battery connectors. You can use the 9V battery as power source. You don't need a power supply for that.
Get a couple of connectors like these

https://www.digikey.com/en/products/detail/keystone-electronics/234/303805?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Low%20ROAS%20Categories&utm_term=&utm_content=&utm_id=go_cmp-20243063506_adg-_ad-__dev-c_ext-_prd-303805_sig-Cj0KCQjwwae1BhC_ARIsAK4JfryUS_22WuYNmvD8q5DnMSr6hSdLD0Poi9UPDuvKpQFuaHhMze9yznoaAhYfEALw_wcB&gad_source=1&gclid=Cj0KCQjwwae1BhC_ARIsAK4JfryUS_22WuYNmvD8q5DnMSr6hSdLD0Poi9UPDuvKpQFuaHhMze9yznoaAhYfEALw_wcB

Use one to snap into the connector that is on the meter. Another one to snap onto the battery. Connect the 2 black wires together and insert the amp meter between the 2 red wires.

great idea and thanks for the easy instructions. I'll try that as soon as I go out and buy the connectors at the local electronics store.

 

[Chan Tran]

great idea and thanks for the easy instructions. I'll try that as soon as I go out and buy the connectors at the local electronics store.

the meter you use should be able to measure in microampere range because even with 1mA of current drain the battery would be dead in 2 or 3 weeks.

 

[benjiboy]

I don't use rechargeable batteries because I understand that they can supply the voltage but not the amperage, and I find alkaline 9 volt batteries are so cheap even for me who is a pensioner that hasn't worked for more than twenty years.

 

[Chan Tran]

I don't use rechargeable batteries because I understand that they can supply the voltage but not the amperage, and I find alkaline 9 volt alkaline batteries are so cheap even for me who is a pensioner that hasn't worked for more than twenty years.

It is the reverse. The rechargeable like NiMH can provide more current than alkalines but lower voltage than alkaline. For meter alkaline makes sense because the meter doesnt use much power but I found alkaline leaks and can damage the meter.

 

[dokko]

It is the reverse. The rechargeable like NiMH can provide more current than alkalines but lower voltage than alkaline. For meter alkaline makes sense because the meter doesnt use much power but I found alkaline leaks and can damage the meter.

exactly. modern rechargable batteries like eneloop are better in pretty much every way over alkaline type batteries.

- more energy capacity
- (much) higher discharge current possible
- better in cold climates
- less risk of leaking (never seen one that did and I've seen hundreds)
- better for the environment
- cheaper in the medium and much cheaper in the long run

what I also like a lot is that I never have to worry how much charge the battery still holds - I simply top of the charge before I start a project and always have full batteries.

 

[Chan Tran]

exactly. modern rechargable batteries like eneloop are better in pretty much every way over alkaline type batteries.

- more energy capacity
- (much) higher discharge current possible
- better in cold climates
- less risk of leaking (never seen one that did and I've seen hundreds)
- better for the environment
- cheaper in the medium and much cheaper in the long run

what I also like a lot is that I never have to worry how much charge the battery still holds - I simply top of the charge before I start a project and always have full batteries.

Before the low self discharge like eneloop the problem with NiMH is of self discharge. Many NiMH batteries won't hold enough charge after 2 or 3 weeks and if I use them for something low power like meters it would be a pain that every time you want to use it you have to charge first.

 

[dokko]

Before the low self discharge like eneloop the problem with NiMH is of self discharge. Many NiMH batteries won't hold enough charge after 2 or 3 weeks and if I use them for something low power like meters it would be a pain that every time you want to use it you have to charge first.

true, I had this problem with earlier NiCd and NiMH variants.

now I use eneloops everywhere.
In the light meter and the Nikon F100, I even use the lite, low capacity version with 950mAh, because they are lighter. sometimes I even put them in my flashes - makes the camera and the bag slightly more comfortable to carry (yes, it makes a difference, if only in my mind : )

 

[Chan Tran]

true, I had this problem with earlier NiCd and NiMH variants.

now I use eneloops everywhere.
In the light meter and the Nikon F100, I even use the lite, low capacity version with 950mAh, because they are lighter. sometimes I even put them in my flashes - makes the camera and the bag slightly more comfortable to carry (yes, it makes a difference, if only in my mind : )

Equipment weigh never my concern. I am more concern about size than weigh.

 

[RalphLambrecht]

the meter you use should be able to measure in microampere range because even with 1mA of current drain the battery would be dead in 2 or 3 weeks.

thanks; I will make sure of that!

 

[RalphLambrecht]

thanks; I will make sure of that!

the smallest I can measure is down to o.1mA

 

[RalphLambrecht]

the smallest I can measure is down to o.1mA

@Chan;I did the test. there are no measurable Amps.the only thing concerning me is that during the test, the light meter display was always off even when I tried toactivate it. Does this now mean the auto-shutoff of the light meter works and the battery should last a long time?

 

[Chan Tran]

@Chan;I did the test. there are no measurable Amps.the only thing concerning me is that during the test, the light meter display was always off even when I tried toactivate it. Does this now mean the auto-shutoff of the light meter works and the battery should last a long time?

Which amp meter did you use? The meter should power up when you activate it. Most multimeter to measure current you would have to use a different jack than the one used for voltage and resistance. The exposure should power up and the current meter show current flow then when the exposure meter shuts itself off the current should drop.

 

[RalphLambrecht]

@Chan;I did the test. there are no measurable Amps.the only thing concerning me is that during the test, the light meter display was always off even when I tried toactivate it. Does this now mean the auto-shutoff of the light meter works and the battery should last a long time?

Which amp meter did you use? The meter should power up when you activate it. Most multimeter to measure current you would have to use a different jack than the one used for voltage and resistance. The exposure should power up and the current meter show current flow then when the exposure meter shuts itself off the current should drop.

It didn't happen that way. I used my trusty CRAFTSMAN 82141 at the 200 mA setting, but my issue was that, as soon as all was wired up, the light meter froze, its LCD went blank, and no pushing of any button could wake it up.

 

[Chan Tran]

It didn't happen that way. I used my trusty CRAFTSMAN 82141 at the 200 mA setting, but my issue was that, as soon as all was wired up, the light meter froze, its LCD went blank, and no pushing of any button could wake it up.

Sorry Ralph I showed you the wrong way. You have to connect the red wire from the battery to the black wire from the meter. Then connect the meter between the remaining red and black wire.
When I made the original post I didn't have the connectors in hands. Now I do.

 

[RalphLambrecht]

Sorry Ralph I showed you the wrong way. You have to connect the red wire from the battery to the black wire from the meter. Then connect the meter between the remaining red and black wire.
When I made the original post I didn't have the connectors in hands. Now I do.

I'll try again that waybut yoy refer to a'meter' twice. Once, you must mean the light meter and the other time the amp meter. Please be very clear.

 

[koraks]

@RalphLambrecht here's you could wire it up:

1: Connect battery + terminal (the smaller one; indicated on the battery with a "+") to the positive terminal of the light meter's battery connector. This is the crown-based connector.
2: Connect the light meter's negative terminal to the positive probe (red one) of the multimeter.
3: Connect the multimeter's black measurement probe to the negative terminal of the battery.

In the diagram above I've indicated with arrows how the current flows. It goes from the battery, through the light meter, through the multimeter and then back into the battery.

In reality, it looks like this:

* The multimeter needs to be set to current measurement mode. Otherwise the circuit doesn't work. On some multimeters, this may involve plugging the positive probe (red one) into a different position than when measuring voltages. However, in most multimeters, this is not the case for small currents as we measure here. Refer to the manual of your multimeter.
* Depending on the design of your multimeter, it may have to be switched on for the circuit to work. I.e. with some multimeters, if the multimeter is turned off, no current will flow and the light meter cannot be turned on.
* Try measuring the current first at a relatively high measurement range, for instance a 200mA range. Depending on what you observe, select a lower range for better resolution. Never attempt to measure a current larger than the range the multimeter is set to as it may burn out an internal safety fuse. For the same reason, never try to measure a short-circuit current.

In the photo above, I've set the metering range to the lowest this particular cheap multimeter has to offer (200uA/microamperes). As the meter turns on, there's a brief peak, but the idle current with the display on is around 80uA as can be seen here. This looks like a perfectly normal/healthy current. The power-down current of the light meter will be less and may even be too low to register on the multimeter, unless it's a very sensitive one. As long as you measure a current lower than e.g. 200uA, the light meter itself is not the cause of your battery run-down problem. You can calculate how long a typical battery will last if you know the current that's being drawn.

 

[RalphLambrecht]

@Chan;I did the test. there are no measurable Amps.the only thing concerning me is that during the test, the light meter display was always off even when I tried toactivate it. Does this now mean the auto-shutoff of the light meter works and the battery should last a long time?

Thanks to all;You guys are something else! I'll report in a couple of days.

 

[RalphLambrecht]

@RalphLambrecht here's you could wire it up:
View attachment 375456
1: Connect battery + terminal (the smaller one; indicated on the battery with a "+") to the positive terminal of the light meter's battery connector. This is the crown-based connector.
2: Connect the light meter's negative terminal to the positive probe (red one) of the multimeter.
3: Connect the multimeter's black measurement probe to the negative terminal of the battery.

In the diagram above I've indicated with arrows how the current flows. It goes from the battery, through the light meter, through the multimeter and then back into the battery.

In reality, it looks like this:
View attachment 375457
* The multimeter needs to be set to current measurement mode. Otherwise the circuit doesn't work. On some multimeters, this may involve plugging the positive probe (red one) into a different position than when measuring voltages. However, in most multimeters, this is not the case for small currents as we measure here. Refer to the manual of your multimeter.
* Depending on the design of your multimeter, it may have to be switched on for the circuit to work. I.e. with some multimeters, if the multimeter is turned off, no current will flow and the light meter cannot be turned on.
* Try measuring the current first at a relatively high measurement range, for instance a 200mA range. Depending on what you observe, select a lower range for better resolution. Never attempt to measure a current larger than the range the multimeter is set to as it may burn out an internal safety fuse. For the same reason, never try to measure a short-circuit current.

In the photo above, I've set the metering range to the lowest this particular cheap multimeter has to offer (200uA/microamperes). As the meter turns on, there's a brief peak, but the idle current with the display on is around 80uA as can be seen here. This looks like a perfectly normal/healthy current. The power-down current of the light meter will be less and may even be too low to register on the multimeter, unless it's a very sensitive one. As long as you measure a current lower than e.g. 200uA, the light meter itself is not the cause of your battery run-down problem. You can calculate how long a typical battery will last if you know the current that's being drawn.

Still the same result. There is no measurable current and the light meter display cannot be woken up. The light meter works perfectly with just the battery attached. Somehow, ,this setup doesn't get enough voltage to the light meter?

 

[koraks]

Can you please make a photo of how you have everything connected together and upload it?

 

[RalphLambrecht]

Can you please make a photo of how you have everything connected together and upload it?

exactly as shown above. Trust me, I give up now. Anyhow, thanks for all your help and effort.