In my DR-107 weight reduction program this winter I have successfully removed 41.2 lbs!! Removed alternator completely, -10 lbs, went to light weight x-drive starter, -5.5lbs, removed -8.5 lead weight from tail, removed firewall starter solenoid, -1lb, added oil filter adapter +2.2lbs, went from gel cell to Aerovoltz 16cell battery -18.4. My C.G. is just aft of the midpoint with 10 gallons of fuel, so I'm pretty happy. If I find I need more aft C.G. I'll put some of the lead back in the tail.
Since I'm not running an alternator I wanted to see just how many starts I'm going to get out of a charge on the 16 cell Aerovoltz. I only have a handheld comm, the fuel pump and a hobbs meter, so not much draw other than starting.
Turned the engine over for 30 to 40 seconds with no plugs to get oil pressure. Then with plugs in, mags off, did 20 start cranks of 3 to 4 seconds each with 15 second break in between. Monitored battery voltage and temperature. Around the 18th crank started to notice voltage drop off (down to about 9.8 volts during cranking). At 2 seconds into the 20th start crank it hung up on the compression stroke, voltage quickly dropped to +/-7 volts. Battery temp was up to 105. Let it rest for 2 minutes voltage recovered to 12.1 volts and was able to do a 3 second 21st start attempt.
Not wanting to damage my new battery I figured that was more than enough for my needs. This season will be the final test, but so far I think this is going to work very well. The battery is still mounted just aft of the spar, don't know if longer run would affect it much.
I'm using Aerovoltz balance charger to keep the battery charged up, figured that was cheap insurance against damage.
Now to loose 10lbs off myself and I'll be really happy!!