View Full Version : Tale of two batteries

Dave S
12-14-2008, 11:06 AM
Good morning,

Our kitfox, series 7, W/912ULS, is set up with two separate electrical systems with a cross tie. (Two alternators, two busses, two batteries). The primary system feeds the radios, the aux system feeds the high draw stuff - we have the standard strobes/position lights and halogen landing/taxi lights so it pulls amps.

Since the system permits running anything electrical, including the starter, on either or both systems, I decided to use the traditional Odyssey PC680 for the primary side because of its recognized reliability; and, try a low cost equivalent gel cell for the aux system - since, if it pooped - it would not be an operational problem anyway.

:)The Odyssey PC680 on the primary side has worked out perfectly (currently it is 2 years old).

:mad:The bargain battery I installed on the aux system, a bit over a year old now, sold under the brand "Werker" model WKA12-18NB at "Batteries minus", gradually lost its ability to take and hold a charge at all. FYI - the system was constantly checked and monitored to know that the remainder of the system, other than the battery, was operating correctly.

As it worked out - I installed a new Odyssey PC680 after removing the brand X unit for the aux system. The brand X unit was pretty much a waste of time and money,

:mad:The brand X unit, of course, was handcrafted in the far east by skilled artisans in china. I think it is also a fair statement that the little "ISO 9001" logo on the side of the battery is a step beyond meaningless - it is misleading, but, then, I may be unfairly judging the significance of the "ISO 9001" notation - it may only apply to the box the battery came in - not the guts of the battery itself. (don't get me going on quality systems that companies brag about but don't apply in practice - I deal with that in my day job all the time).

Anyway - if there is a contest between these two batteries, it is no contest - the Odyssey wins - costs a bit more, but then, sometimes the other guys who sell for less might know know what their stuff is worth.....


Dave S
Kitfox & Trigear
St Paul, Minnesnowta

12-15-2008, 06:33 AM
Good info Dave, thanks. That's consistent with my experience with batteries also. I'm installing an Odyssey PC680 in my Super Sport also, though only one. I don't know how much lighter it is than the Kitfox supplied battery but it looks to be a coule of pounds. I'm then using a battery box/bracket sized for the PC680 from Van's rather than the Kitfox supplied plastic box which is considerably larger.

Dave S
12-15-2008, 05:11 PM

I also did not care for the plastic battery box & fabricated an aluminum box that exactly fit the Odyssey battery. The attached photo shows what the aluminum box looks like & where it fits - also the aux alternator location. FYI - the second battery is behind the pilots seat, accessible through a hinged door on the back of the seat pan - that also has a fabricated aluminum box; and, now a new PC680.



12-21-2008, 05:42 PM
I have used the odyssey pc680 in two aircraft and have had great results. Joe

12-23-2008, 09:28 AM
Just out of curiosity, I know it killed the cat. But why do you have two electrical systems? Are you flying IFR? I also love the Odyssey.

Dave S
12-23-2008, 06:45 PM
Hi Steve,

Fortunately, we are not cats.....curiosity is a good thing for our species. My decision to go with a dual electrical system had its genesis when I was pondering the practical continuous output from the integral Rotax alternator in the context of what I wanted to have on the plane to start with (day-night VFR); and, what I might add to the electrical demand later. Then other considerations started seeping into the decision; such as, a) just about every system failure I have had on an airplane has had to do with the electrical system, b) the 912ULS, I am told, isn't very easy to flip-start, c) we plan on a lot of extended cross country and back country airports (where electrons are harder to come by than in a metro 'port if you really need them). d) a little extra battery capacity is a good thing in Minnesnowta and Buuurmidji. On the other hand, considered the extra weight and $; but, I already jeopardized my children's inheritance during the build; and, I am kinda on the back side of the bell shaped curve for body weight anyway so I put the pounds in the airplane rather than changing my eating habits. :D


Dave S
St Paul, MN
Kitfox 7

12-29-2008, 12:51 PM
I have a PC680, which holds a charge forever, but with the long battery
runs makes hard starting with the IO-240 in the winter. I sometimes
resort to a second battery on the passenger side floor hooked in with
jumper cables for really cold weather starting (I remove it before flight)

Next year I'll upgrade to a mobile ground support power unit, just like
we had in the Navy ...


12-29-2008, 09:15 PM
I noticed my engine cranking becoming a bit more sluggish when I moved the PC680 in my RV-3 back behind the seat. I'm using 4 ga welding cable, how about you? I was wondering if going to 2 ga would help it.

02-28-2009, 09:03 PM
If I may join in here. I also use the Odyseey battery and found it to be very good. The cold cranking amps do the job for me. I have it mounted behind the seat. I used a aluminum battery box and attached it to the cross member behind the seat using adel clamps. I used #6 copper then went to the #4 welding lead. Good move and it starts much better.

I have been interested in your discussion as I brought this up on the Matronics list. I got the hell kicked out of me for using such a huge battery. Try starting your plane when its 0 and you find out why. I guess we all don't live in Florida ha.


02-28-2009, 09:04 PM
I forgot to mention I use the Odyseey 925