RCU Forums - Shared ECU Battery for 2 turbines. Possible?

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Shared ECU Battery for 2 turbines. Possible?

I have been using A123’s since 2008 for my receiver and ECU batteries and I am sold on their reliability and safety. In my 1/6.25 scale
A-10, I used two 3 cell A123 batteries for the ECU’s (one per engine). Worked great.

I am now putting together the smaller Skymaster A-10 and was wondering could I get by with sharing a single 3 cell A123 pack between the Kingtech ECU’s (to save weight)? If I didn’t start the kerostart Kingtech engines simultaneously, I am sure the current draw wouldn’t be an issue once each engine was running. What other issue(s) might occur with this setup (electronic ground loop, etc.)?

Any thoughts / advice would be appreciated.

Thanks

Nick

Nick , I can only say that in another brand of engines when we put a Y cable on the throttle channel we got feed back that was causing random an un traceable shut downs. When we put the throttles on two separate channels no more problems. If you want to save weight go with two small packs and make a start pack that you can plug in on the ground with a y harness and then remove before flight. I would keep the engines separate from one another.

I have had several planes with multi turbines. I have always used Y leads, on the Arado I have 6 engines with 6 Xicoy ECU's on one Y lead but these are manual start engines are started one at a time. I have 3 engines sharing one A123 battery.

With my Horten I had 2 Wren 44 engines with kero start. Both were kero start but was using a 2 cell Lipo for each engine. I had 2 Jetcat P60 engines in a Su27 and they were kero start each with its own 2 cell Lipo battery and a y lead.

There is absolutely no problem in running multi engines on a Y lead if using Xicoy ECU's with the Kingtech. I have not tried kero start on a single A123 3 cell pack. I see no reason why it would not work, but you may care to try it on a test bed first. Also fit a Y lead to the battery so you can increase the battery power temporarily while starting. If you fit a switch in the signal line from the ecu to the engine you can start one engine at a time lowering the total drain on the battery when starting.

A better alternative is to use a 3 cell A123 1100 mAh for each engine. I have one that I use for my K45 and it does at least 4 10 minute flights with kero start. It sounds a low power pack and looks tiny, but the power does not drop off till it is nearly exhausted and it works well.

John

If there is power an of use one pack
Why use two.

Thanks to everyone who has provided advice. I had forgotten that A123s come in the 1100mAh size which would allow me to use one per ECU and only add 8 or 9 oz of weight!

Again thanks everyone.

Nick