Just what does electricity weigh?

[Enewton57]

As many of you know, I strived very hard to come in as light as possible with my Patrol. To that end, I had no electrical system and no luxuries.

My empty weight, came in at 1,061 lbs and a CG of 12.8"

Last week I took a week of vacation and installed a minimal electrical system. Again, my goal was to do it as light as possible. So what did having the luxury of a starter, battery and alternator cost me in weight gain? Well, it came in at exactly 30 lbs. all together.

Here is what I added:

Flywheel = 7 lbs.
Skytec Starter = 7 lbs
B&C Alternator = 3 lbs
Regulator = 2 lbs
Lithium Ion Battery = 6 lbs
Battery Box and mount = 1 lbs
Fuse Block and Fuses = 1 lbs
Wires, Switches,
Connectors, etc. = 3 lbs

Total 30 lbs.


So for a minimal system it added 30 lbs to my airplane. I re-weighed my airplane and its actually 42 lbs heavier. the extra 12 lbs came from the tires that I changed to. I previously had 6.00 x 6 AirHawk tires and later put on some 8.00 x 6 Goodyears. The Goodyears are about 6lbs heavier per tire, so that means an additional12 Lbs for the two.

So now my empty weight is 1103 lbs and the CG is 11.3"

Is it worth it? To me it is. It feels really good to be able to not have to tie down the tail, prop start it, untie the tail and then try to get in it before it taxies away without me. As an added bonus, I don't have to haul batteries and chargers for my GPS, radio, etc. back and forth. Now I get to just pre-flight, get in and go flying. I love it.

[marcusofcotton]

Excellent post Isaac, er... Eric. You've also kept the possible advantage of being "not originally certificated with an engine driven electrical system" FAR 91.215(b)(3) & (5).

Mark J

[Enewton57]

Good point. I hadn't thought of that.

[gsnewsome]

Excellent post. I was trying to estimate this for the C-85/LSA.

[Ed.Meyer]

I would be interested in knowing what lithium battery you used and how it is working out. Does it spin the starter plenty fast?

[Phil]

Funny, I just did the same calc. for my Patrol. I figured I could keep the weight of the electrical system to under 40 lbs. Perhaps even more since electronic instruments are lighter than steam gauges. And electronic ignition is lighter than mags.

[Enewton57]

I would be interested in knowing what lithium battery you used and how it is working out. Does it spin the starter plenty fast?

I have the Shorai 21AH battery. It cranks the engine just fine. Hatcher Ferguson has the same battery in his 210 HP IO-360 Patrol and he says it cranks his engine fast as well. If you order one you can get the terminals with the positive on the left or on the right. The LFX21A6-BS12 has the polarity (+ -) with the Positive on the left. The LFX21L6-BS12 has the polarity (- +) with the Positive on the right. Eric Newton - Long Beach, MS http://mybearhawk.com

[Enewton57]

Funny, I just did the same calc. for my Patrol. I figured I could keep the weight of the electrical system to under 40 lbs. Perhaps even more since electronic instruments are lighter than steam gauges. And electronic ignition is lighter than mags.

I took my airspeed indicator out and replaced it with the new AV Map Ultra which weighs only 3 oz. The unit replaces airspeed, altimeter, compass, Turn/slip, VSI, Attitude, and has a built in GPS and "G" meter. My guess is it replaces about 10 lbs of stuff. Eric Newton - Long Beach, MS http://mybearhawk.com

[Phil]

I took my airspeed indicator out and replaced it with the new AV Map Ultra which weighs only 3 oz. The unit replaces airspeed, altimeter, compass, Turn/slip, VSI, Attitude, and has a built in GPS and "G" meter. My guess is it replaces about 10 lbs of stuff. Eric Newton - Long Beach, MS http://mybearhawk.com

So if you include that change as part of the electrical upgrade, it actually only added 20 lbs net.

I've got a ways to go before I buy any instruments, but at this point I'm leaning towards the Dynon Skyview system. Looks like the best bang for the buck right now and they seem to have a good reputation.

[Enewton57]

All I had was the airspeed indicator to start with so it didn't save me that much weight.

[N3UW]

I took my airspeed indicator out and replaced it with the new AV Map Ultra which weighs only 3 oz. The unit replaces airspeed, altimeter, compass, Turn/slip, VSI, Attitude, and has a built in GPS and "G" meter. My guess is it replaces about 10 lbs of stuff. Eric Newton - Long Beach, MS http://mybearhawk.com

Eric, I like that AV Map ultra. I had not seen that unit before. How do you like it. What are you using for engine instruments?

[DRLPatrol]

Eric, I looked up the AV Map ultra and did not see the GPS feature. Am I missing something.

Doug

[Enewton57]

Eric, I like that AV Map ultra. I had not seen that unit before. How do you like it. What are you using for engine instruments?

I am using the EIS system by Grand Rapids Technologies for engine monitoring. Simple but effective. Eric Newton - Long Beach, MS http://mybearhawk.com

[Enewton57]

Eric, I looked up the AV Map ultra and did not see the GPS feature. Am I missing something. Doug

It comes with a GPS receiver that you place on your dash and run the cord to the unit. Here is their spec page: http://www.avmap.us/avionics/instruments/UltraEFIS Hi Doug Eric Newton - Long Beach, MS http://mybearhawk.com

[DRLPatrol]

Thanks, It must have been late when I looked at their site before.

Doug