Topic: How to calculate how long a 9v battery will last???

[Cheesecadet]

Hey all...i am just curious how you calculate how long a 9v battery will last?

The device being powered draws between 22ma - 25ma and I am curious how long a standard 9v would last?  I am also curious if liON 9v are a better option instead of regular alkaline as far as increased run times.

If anyone can help me out it would be much appreciated!

PM me or respond here as others may want to know how to calculate this.

Ryan in CA

[NOLAfishwater]

Check the mAh rating on your battery and divide by mA to get hours.

So, if your 9V battery is rated at 600mAh and your device draws at a maximum of 25mA, then your battery would last 24hours in theory. Chances are your battery will not perform up to its specified rating, so I would drop 25% of that time. You can always do a dry run to confirm how long your rechargeables will last.

600mAh/25mA=24h

Someone correct me if I am wrong.

[Church-Audio]

Check the mAh rating on your battery and divide by mA to get hours.

So, if your 9V battery is rated at 600mAh and your device draws at a maximum of 25mA, then your battery would last 24hours in theory. Chances are your battery will not perform up to its specified rating, so I would drop 25% of that time. You can always do a dry run to confirm how long your rechargeables will last.

600mAh/25mA=24h

Someone correct me if I am wrong.

Most 9 volts are 400mA but you wont get that much current at 25mA because of the resistance of the "load" we are talking about so your looking at a run time of about 6 hours... I had Spark'e do the calculations. Rechargeables are not a good idea for the load we are talking about simply because you never know for sure when its going to die and you will have a hard time finding a 400mA 9 volt....

Correct me if I am wrong but I have never seen a rechargeable higher then 260 mAh..

[NOLAfishwater]

I have no idea what 9V rechargeables are rated at. All I know is that when I run my CA9100, I use regular Alkaline. I think it should last for about 20 hours right, Chris?

[Church-Audio]

I have no idea what 9V rechargeables are rated at. All I know is that when I run my CA9100, I use regular Alkaline. I think it should last for about 20 hours right, Chris?

This is not a regular 9100 its a prototype for my version 3.1 preamp that he has. It sucks alot more juice about 24mA vrs the 15.0 mA that the version 3.0 draws. This preamp is still a work in progress. So we will see how things work out. I am looking into using a buffer amp that draws less current as we speak I have just ordered a few to play with. Its hard because I have to get customer orders out first and then work on new designs... I am always looking at making things better.


Chris

[restevezes]

I know this is an old topic but i was wondering how many hours can i run from a single 9v battery in a ugly and/or 9100
Is there any recommended brand for 9v batteries? I can see big difference in prices

http://thomasdistributing.com/shop/kodak-9v-alkaline-batterybrone-9-volt-battery-sold-by-the-piece-p-625.html?SP_id=&osCsid=blm1q2ivak3phb3v2rdd1nlsp0
http://thomasdistributing.com/shop/gesanyo-9-volt-alkaline-batterybr1-battery-card-or-package-p-654.html?SP_id=&osCsid=blm1q2ivak3phb3v2rdd1nlsp0

Too cheap to be fine?

I only need to run the ugly for around 10 shows for the summer. I was thinking on having couple or three for the whole run.
If average is 20 hours per battery (or even 10 hours) I think i will be fine at 1 or 2 shows for each batt (even the "bad" ones)

These 9v always seem to me like "misterious batteries" 

[dorrcoq]

I think Chris has mentioned 35  - 40 hours for a 9V in his preamps

[restevezes]

thanks.... thats a very good reasonable time. I was used to the PS2 and AD20 usage so this is more than welcome