Battery PSU with voltage meter.

[TB]

Hello,
I am in process of building external battery based PSU for my Chmoy headphone amp. I want to use it with two 9V batteries or 16 AA batteries. The case will accomodate both. The 16 AA batteries will be used with 2 RadioSchack battery holders ( 8 batteries per holder, which would give me 24 volts to split). The reason for this is practical... I will be able to use AA rechargeable batteries ( RadioSchack part number 2700387). I want also include analogue volt meter. This is for both... aesthetics and practical info. The use of volt meter is what I need advice for... can I use a volt meter constantly connected to batteries or should I use switch to be able to turn it on only when I need it? I am not sure about battery drainage if meter would be constantly connected. The meter is 15 volt one.

Thanks

 

[sofaspud]

An analog meter? How much current it requires depends on the meter. Do you have specs for it? I would modify it for 30 volts full scale if using a ±12V supply, and use a pushbutton. Just above midscale would be recharge time with 16 AA's, just below for 9V's.

 

[TB]

Sofaspud,
Thanks for the fast response. I will need to check the ratings. I have two meters, but I need to find some info about them. And, thanks for the push button advice.

 

[sofaspud]

Most common analog meters are about 50-100 microamps for full scale deflection, but it would be immensely helpful to know yours for sure. If you can't find that info, it isn't difficult to test the meter to determine it.

 

[gmphadte]

Instead of a meter, why don't you use a low battery indicator using an LED. i.e. if the asthetics are not compulsary...

Gajanan Phadte