SDS CDI vs Pmag

[Chkaharyer99]

I really appreciate the dialog and the way you interact with those interested in your products. I've learned much this way just by following the conversation. In a word, impressive. Thank you.

[Toobuilder]

Originally Posted by DanH

14 ounces for an extra 40 minutes? I'd take that.

Yep, color me a +1 for that trade.

[rv6ejguy]

Originally Posted by Carl Froehlich

One approach is to look at aircraft power requirements as a system, not as individually components. This way you can find more efficient and effective ways to achieve design objectives instead of the brute force approach of having multiple backup batteries; one or two for the igntions, one for the left EFIS, one for their right EFIS, etc.

Carl

We only care about keeping the engine running if the rest of the aircraft power systems go down for whatever reason, keeping things as light/ simple and reliable as possible. The design goal is to get you over an airport and safely on the ground to sort something like this out. We've seen, after being in this game over 20 years, that many people prefer (or should have) a vendor solution/ option in this regard.

[111RF]

Originally Posted by rv6ejguy

We're into the meat of the backup battery switching and OV protection circuits now. Just a bit of a poll for backup battery capacity/ weight- 30-40 mins and 1.2 pounds or 70-80 minutes and 2.1 pounds?

I'd vote for the 70-80 minutes!

Also, I've been researching EI aux battery options, and one thing I've noticed is that these small batteries don't have nearly their nominal AHR's at 1.5amps (rough EI amp draw). Per the manufacturers data, a Powersonic PS-1220 (2.5AH & 2.1lbs) will only do about 1.5 AHR's at 1.5 amps....approx. 60min of backup. And that's assuming a new battery charged/maintained at 100% capacity.

[rv6ejguy]

Originally Posted by 111RF

I'd vote for the 70-80 minutes!

Also, I've been researching EI aux battery options, and one thing I've noticed is that these small batteries don't have nearly their nominal AHR's at 1.5amps (rough EI amp draw). Per the manufacturers data, a Powersonic PS-1220 (2.5AH & 2.1lbs) will only do about 1.5 AHR's at 1.5 amps....approx. 60min of backup. And that's assuming a new battery charged/maintained at 100% capacity.

We're down around 1.1 amps at 2500 rpm with a 4 cylinder setup. We look at the rating to 9V.

[Chkaharyer99]

With respect to the new CPI2, will there still be independent power inputs for each ECU and each coil?

Said another way. Will your CPI2 dual EI offering have independent ECU or will they be integrated somewhat like the SDS EM-5 offering?

[Larry DeCamp]

I am following this thread closely because I am installing Ross's duel CPI soon. Talking with Kathy (earthx) at Osh, there is a significant difference in voltage available on the amps/time curve. Lead acid goes full charge to zero volts in a straight line. LiIron goes to a minimum voltage able to sustain ignition over the rated period. Maybe Kathy could jump in here and discuss this significant point.

[rv6ejguy]

Originally Posted by Chkaharyer99

With respect to the new CPI2, will there still be independent power inputs for each ECU and each coil?

Said another way. Will your CPI2 dual EI offering have independent ECU or will they be integrated somewhat like the SDS EM-5 offering?

So far the plan is to run the CPI and its coil pack off ship's power. Optional will be a backup battery pack that we offer with the mounting bracket and wiring to sustain power for a period of time if the rest of the aircraft electrical system takes a dump somehow.

You can have a CPI unit with one or two completely independent circuit boards inside to drive either 1 or 2 coil packs. One integral head will be able to access either board something like the current dual EM-5 setup.

[rv6ejguy]

Originally Posted by Larry DeCamp

I am following this thread closely because I am installing Ross's duel CPI soon. Talking with Kathy (earthx) at Osh, there is a significant difference in voltage available on the amps/time curve. Lead acid goes full charge to zero volts in a straight line. LiIron goes to a minimum voltage able to sustain ignition over the rated period. Maybe Kathy could jump in here and discuss this significant point.

I looked for suitable LiFePO4 batteries in this AH range and there's not much to choose from which are economical to purchase. Similar 2.5 AH ones are about 10 times the price but they are about half the weight of course. I wouldn't consider any other alternate lithium battery chemistry as they just introduce more risk in the cockpit potentially. Also, it seems these batteries are not so good at -20C where some of our Alaskan customers operate. Lead acid AGM just seems like the best overall compromise.

We consider the time to 9V as the significant factor to effectively fire the coils.

I will pick up 3 PowerSonic AGMs tomorrow and we'll bench test them running the coil pack and CPI. See how they do.

[6 Gun]

I will second that!Lead acid for me,but others could do their on thing?
Bob