---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 06/25/05: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:58 AM - Z-22 relay question (Mdharfst@cs.com) 2. 07:32 AM - Re: Batteries in series and parallel (Mark & Lisa) 3. 07:34 AM - Re: Batteries in series and parallel (Mark & Lisa) 4. 09:26 AM - Re: Batteries in series and parallel (Jerry Grimmonpre) 5. 11:32 AM - Re: Batteries in series and parallel (Robert L. Nuckolls, III) 6. 11:35 AM - Re: Batteries in series and parallel (Eric M. Jones) 7. 09:37 PM - Re: Batteries in series and parallel (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:58:16 AM PST US From: Mdharfst@cs.com Subject: AeroElectric-List: Z-22 relay question --> AeroElectric-List message posted by: Mdharfst@cs.com Listers I have a problem I need advice on. My electrical system is from an older version of Bob's drawings but fits the current Z-11 drawing pretty closely with a Z-22 substitution for the way I wire the starter run on relay. I need to replace the S704-1 relay which has gone bad. Can I use a standard starter contactor in place of the smaller lighter relay? It seems that the wiring logic should be the same regardless of whether the smaller or larger relay is used. Thanks in advance. Michael Harfst N9TZ 165 Hrs ________________________________ Message 2 _____________________________________ Time: 07:32:10 AM PST US From: "Mark & Lisa" Subject: Re: AeroElectric-List: Batteries in series and parallel --> AeroElectric-List message posted by: "Mark & Lisa" Bob, Thanks for the info, I was pretty sure I'd heard of such a setup before, just don't know exactly how to arrange it. Mark & Lisa Sletten Legacy FG N828LM http://www.legacyfgbuilder.com --> AeroElectric-List message posted by: BobsV35B@aol.com Good Morning Mark, For What It Is Worth, back when I was flying LaBelle Caravelle, there was a big handle immediately to my left and just below the side cockpit window which switched the batteries from the parallel mode into a series arrangement to provide sufficient power to start the engines. ________________________________ Message 3 _____________________________________ Time: 07:34:12 AM PST US From: "Mark & Lisa" Subject: Re: AeroElectric-List: Batteries in series and parallel --> AeroElectric-List message posted by: "Mark & Lisa" Dj, I'd considered this approach, but if I'm forced to have two batteries I'd like to use both of them for inflight duties in lieu of the second engine-driven power source (see my original post). If I don't have both batteries available I'd need two alternators AND two batteries; up goes the weight and complexity. Thanks for the idea tho... Regards, Mark & Lisa Sletten Legacy FG N828LM http://www.legacyfgbuilder.com --> AeroElectric-List message posted by: Dj Merrill Just a random thought - if you do not mind dedicating one battery for just the starter, you could have just a single battery in-line with your starter contactor (or whatever device you choose to do this function), so when you engage the contactor, you get the 12v from the "regular" battery and feed it in series with the "starter" battery for 28v. Everything else only gets the 12v from the "regular" battery. ________________________________ Message 4 _____________________________________ Time: 09:26:46 AM PST US From: "Jerry Grimmonpre" Subject: Re: AeroElectric-List: Batteries in series and parallel --> AeroElectric-List message posted by: "Jerry Grimmonpre" Hi Mark ... Just wanted to relate to you what my Ford tractor mechanic did to modify my tractor and this mod was acceptable practice. The mod involved changing out the 6Volt generator, battery, and light bulbs for 12V alternator, battery, and light bulbs. The 6V starter was left as is ... 6V. The gas engine started "right now" with a very fast spin from the starter, as one could imagine. There was no down side to this mod. The tractor was used for 20 years in this configuration and never had a starter problem. I'm not advocating anyone put a high value airplane starter into this environment ... just a data point. Jerry Grimmonpre ________________________________ Message 5 _____________________________________ Time: 11:32:32 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Batteries in series and parallel --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:24 AM 6/25/2005 -0500, you wrote: >--> AeroElectric-List message posted by: "Jerry Grimmonpre" > >Hi Mark ... >Just wanted to relate to you what my Ford tractor mechanic did to modify my >tractor and this mod was acceptable practice. > >The mod involved changing out the 6Volt generator, battery, and light bulbs >for 12V alternator, battery, and light bulbs. The 6V starter was left as is >... 6V. The gas engine started "right now" with a very fast spin from the >starter, as one could imagine. There was no down side to this mod. The >tractor was used for 20 years in this configuration and never had a starter >problem. I'm not advocating anyone put a high value airplane starter into >this environment ... just a data point. This was a common approach taken by some hot-rodders in my school days during the transition from 6->12 and gen->alt hardware. High compression 6v engines were often "bumped up" to 8v systems by purchasing the right 4-cell battery and tightening the spring on the voltage regulator control relay. This "fixed" a weak starter problem on high-compression engines. Later, many builders left their 6v starters in place after converting the rest of the vehicle to 12v. I did such an upgrade for a friend of mine on a '38 Merc Convertable. We installed a 60A alternator on a flat-head v8 and even put an aftermarket, under-dash a/c in the car. He took a number of prizes at local shows for his finished project. The car did just fine with the original 6v starter installed. Starter motors of the era were series wound and VERY tolerant of increased operating voltage. Bob . . . ________________________________ Message 6 _____________________________________ Time: 11:35:02 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: Batteries in series and parallel --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: "Mark & Lisa" >a) Power a 24V starter from a pair of 12V batteries, or....... Mark, Here a schematic to do the job in the standard series-parallel way: http://www.periheliondesign.com/downloads/12-24V_System.pdf However, if it were my bird I would question the idea that Deltahawk can't do the job at 12V. Here's why-- The voltage of a starting system in not as important as the system's ability to delivery current to the starter. This is also a function of the resistance of the battery and connections, etc. An Ultracapacitor in parallel with the battery and close to the starter motor is now often used to start diesel engines. These go for $20/Farad (12V) and the cost is in freefall. I'd try one of these on the Deltahawk. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "Every act of conscious learning requires the willingness to suffer an injury to one's self-esteem...." -Thomas Szasz ________________________________ Message 7 _____________________________________ Time: 09:37:43 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Batteries in series and parallel --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:33 AM 6/25/2005 -0500, you wrote: >--> AeroElectric-List message posted by: "Mark & Lisa" > >Dj, > >I'd considered this approach, but if I'm forced to have two batteries I'd >like to use both of them for inflight duties in lieu of the second >engine-driven power source (see my original post). If I don't have both >batteries available I'd need two alternators AND two batteries; up goes the >weight and complexity. Thanks for the idea tho... > >Regards, What you're asking for has been done on several aircraft in the past . . . but it needs to be accomplished with careful attention to the potential for shorting batteries with VERY hard faults when the system is dependent on relay transition times for avoiding faults. Further, the batteries should be fitted with ANL limiters such that (1) opening a limiter doesn't take BOTH batteries off line and (2) things come to an orderly conclusion in case of a stuck contactor. Relay timing issues can be washed out my design. I'll offer the following suggestion: http://www.aeroelectric.com/PPS/Engine/Starter/24V_Starter_14V_System.pdf Bob . . .