Replacing lipos with A123 in 50cc

[andyjayh]

After a few devistating lipo fires lately I have decided it is time to replace my lipos in my EF Yak 88" with A123

Currently I have a FP 3000 2P2S lipo with Smart-fly pin and flag reg to a Futaba 608 2.4ghz rx and futaba 9156 servos. Also 2100 2S lipo through SF ignition reg normal switch and SF Ignition Kill for the DL50.

This system has worked well to date but I am getting worried about lipos and the potential hazards they bring, might be getting paraniod but I have seen some pretty bad results of them going wrong lately

I want to keep it simple and light for the sake of the motor I would prefer the switch to be failsafe like the one as I have already. I have considered the SF Power Expander route as this seems a good solution but probably overkill for a 50cc? However, am I safe using the futaba rx for the power distribution for those 5 digi servos? The A123 packs can deliver high current but will the rx became a bottleneck or does it not work like that?

Like the look of the new Fromeco 30Amp Kodiak Switch but is it just a gimmick? will other failsafe switchs work just as well?

Probably going to use a standard nicad back on the ignition but might go A123 1100 later, either straight or with an in-line diode to step down below 6v.

Any advice on the above set-up?

Andy

[dick hanson]

	Quote: Originally Posted by andyjayh
	After a few devistating lipo fires lately I have decided it is time to replace my lipos in my EF Yak 88" with A123 Currently I have a FP 3000 2P2S lipo with Smart-fly pin and flag reg to a Futaba 608 2.4ghz rx and futaba 9156 servos. Also 2100 2S lipo through SF ignition reg normal switch and SF Ignition Kill for the DL50. This system has worked well to date but I am getting worried about lipos and the potential hazards they bring, might be getting paraniod but I have seen some pretty bad results of them going wrong lately I want to keep it simple and light for the sake of the motor I would prefer the switch to be failsafe like the one as I have already. I have considered the SF Power Expander route as this seems a good solution but probably overkill for a 50cc? However, am I safe using the futaba rx for the power distribution for those 5 digi servos? The A123 packs can deliver high current but will the rx became a bottleneck or does it not work like that? Like the look of the new Fromeco 30Amp Kodiak Switch but is it just a gimmick? will other failsafe switchs work just as well? Probably going to use a standard nicad back on the ignition but might go A123 1100 later, either straight or with an in-line diode to step down below 6v. Any advice on the above set-up? Andy

My two bits (penny) worth having setup a few A123 models ---
One A123 2300 rx pack --rx
one 1100ma ignition pack
This will work on any single cyl ignition -that I use.

no resistors or regs or diodes or any of that ilk----
just good wires -doubled on rx from the battery to make redundant connections,
Dual packs ?
if you wish , tho I see no need for it at all.
Oh yes use a charger which displays each cell voltage and has a balancer
it may not be necessary once cells are up to snuff but for learning the cells and having a constant visual check on anything wrong - well worth the choosing.

[bodywerks]

No need for a power expander at all.
The futaba rx can handle WAY more than 5 digi servos. It is not the receiver that is the limiting factor, it is the connectors on the servos and batteries. On a 50cc plane, a single battery input connector will work, although dual inputs is redundant and also capable of more amps, of course. I like Dick's setup recommendation, or if you want redundancy, go with dual A123 1100's and dual switches. If you are concerned about getting enough power to everything under the most extreme loads, a Fromeco DC-up, at a mere 1 ounce and like $35 is cheap insurance.
Personally, I'd go with a single A123 1100 with dual output leads, dual switches, and maybe a DC-up just to be safe. A 50cc plane only burns about 200-250milliamps per flight, so you could get a few flights easily and then field charge in a jiff.

[andyjayh]

Thanks guys for the input, very much along the lines of how I was thinking.

Suggestions on switches for this set-up anyone? Ideally something with 18awg, or there abouts, input wire from the A123 and dual out leads to the rx. I prefer the idea of a failsafe switch rather than a mechanical one. This way I get the dual input to the rx and the commercial A123 packs are ok as I haven't found anyone that supplies with dual output leads yet.

Something along the lines of the SF reg with ping and flag which I have already would be great but without the reg. I can't find a product like that yet

Cheers

[drewbags]

On my 50cc I have a single A123 through a switch into the RX, could use 2 switches for redundancy. On my 100cc EF YAK running 9 digi servos, dual A123s with independent switches and 3 feeds each. 2 feeds go to the Rx giving me 4 power inputs and then one to the matchbox on the respective wing. Had about 40 flights so far with no issues and using 225mah per 13-15 min flight of mixed IMAC/3D.

I use standard HD switches from JR and the like and if you go for a dual switch setup on the single pack or dual packs can't see the need for failsafe switches? I have made up my own power leads, using EC3 connectors on the batteries and output of the switch, that way it is easy to put multiple feeds commig from the switches. Oh yes and it is much cheaper that way!!!