I finally got around to running some tests with rechargeable 9V.
First, I grabbed two no-name ones from Ebay, both DOA. Seller was cool and refunded all money.
Next I got the following:
http://thomasdistributing.com/shop/-maha-powerex-96-volt-230mah-nimh-rechargeable-batterybr1-battery-pack-p-505.html?SP_id=&osCsid=32ce0a978f4ff378c90e3e457d13c6dfand
http://thomasdistributing.com/shop/-maha-powerex-mhc490f-9-volt-9v-battery-chargerbr4channel-smart-battery-chargerbrus-110v-adapter-included-p-436.html?SP_id=&osCsid=32ce0a978f4ff378c90e3e457d13c6dfHere are the results of my battery testing:
Battery test for Powerex NiMH 9.6 volt, 230 mah battery in the MMA6000
Test equipment: DPA4060 > DPAMMA6000 > R09
Test Notes:
--Recorded ambient sound, MMA6000 set to 20db gain.
--Batteries were new and conditioned by charging them fully then,
completely discharging them 5 times before testing.
--Charger used -Powerex MH-C490F
--Batteries were left to charge for approximately 1 hour after
the Charger's LEDs went from red to green.
--The charger took about three hours to go from red to green when
the batteries where fully discharged. So figure on a three to four hour
charge time if they are completely dead.
I ran two different tests one time with each battery then averaged the results
Test A -- Recorded about 4 hours at a time then paused between a couple of hours
to a day between recording sessions.
Results--Average total run time = 18.5 Hours
(Red LED was on for about the last 1 1/2 Hours)
Test B -- Recorded nonstop till battery died.
Results--Average total run-time = 16 Hours
(Red LED was on for about the last 1 1/2 Hours)
No noticeable loss in sound quality while the red LED was on.
I am quite impressed with the time, almost as good as DPA reports for Alkaline batteries.
One note of importance, after charging the batteries, I measured them at about 11VDC!!!
After about an hour or two that would drop to about 10.5VDC. A new Alkaline is usually about
9.3 to 9.6VDC.
I also ran these in my Sonosax SX-M2 and got about 2 1/2 hours before they dropped to the point where
the pre started to distort. 4 of these would cover most two set shows comfortably.