Dynatron - how many amps to turn OS50?

[frogbmth]

I've just bought a Sullivan Dynatron starter and, taking advice from others, have put a 3s LiPo on the side to power it.

Now I am thinking that this delivers 63A maximum, do I need to get a bigger pack to turn the OS50 Hyper?

Does anybody know how many amps the Dynatron will draw for this engine? Or should I go over 100A anyway in case it stalls?

Andy

[cudaboy_71]

you need to anticipate stalls (like a hydro locked engine). if you stall the starter and it spikes the battery pack, you could have a nice little hand grenade in your hands--pull the wand before you chuck it :P

FYI, i'm using a hobbico torqmaster 180 w/ 2 old 3s 2200s in parallel. they were no longer any good for flying my 450, but turned over my hyper 50 every time this season. dunno how long they last on a charge...i usually recharge after about 20 starts anyway.

[Azlum]

I have a dynatron and have tested the amps... however, keep in mind that amp loads vary with voltage.

I run my dynatron on two 7cell 1900mah nicd packs, and on a full charge they deliver just over 20v to my starter. I tested the amps with my packs at full charge.

Dynatron spinning with no load: 17amps
Dynatron in stalled condition: 87amps

I havent tested it "while" starting the helicopter, but I would guess it's around 30 amps, as there isnt much load starting a .50. The big thing to keep in mind is that if the starter stalls and you dont let go of the button fast enough, you WILL damage your pack.

[fiveoboy01]

I don't think you have to worry about drawing too many amps unless you stall the starter. The OS .50 doesn't take that much to turn over really.

I forget that one company, but they make an adapter plate that replaces the backplate on the dynatron, and allows you to snap a makita 18V lithium battery pack from their cordless drills onto it. THAT would be the cat's booty, I might do that, my brother works construction and has several Makita lithium tools:twisted:

[matrix1171]

i happened to see Zak Johns dynatron at my field one weekend and he had 1 5s lipo on his and it had enough to start a buddy of mine 90 heli and it was a flight power he also used to use it to start his 90 when he had one:thumbup:

[frogbmth]

Thanks for all the replies

I think I better get a pair of NiCads or a LiPo with plenty of amps in case it stalls. I'm not so worried about losing the pack, more about having it catch fire in my hand and on top of my heli!

Andy

[Trooper Sam]

I'm nutty...I use my T-Rex 600 packs on my Dynatron. :)

I pull my glow plug each day before flight and spin the engine to blow out any fuel in it before starting, so that I don't wreck my C-Spec with that pack on the starter. :)

[Azlum]

I think most people look too far into it.... truth is, my setup with the two 7cell Nicd's was fairly cheap, and will start a bulldozer!!

Seriously though, my starter will start 90's with EASE, and goes 2 months without needing a charge... you need more than that???????? I didnt think so.

[frogbmth]

Good point, plus NiCads only get hot when overloaded, rather than exploding.

[Pinecone]

I don't think you have to worry about drawing too many amps unless you stall the starter. The OS .50 doesn't take that much to turn over really.

I forget that one company, but they make an adapter plate that replaces the backplate on the dynatron, and allows you to snap a makita 18V lithium battery pack from their cordless drills onto it. THAT would be the cat's booty, I might do that, my brother works construction and has several Makita lithium tools:twisted:

Google is your friend. :)

http://www.afineredgemfg.com/index_files/Page426.htm

Does look like a cool idea.

[EBCooper]

I just got my finer edge adapter, I hope this thing doesn't twist my hand off!!!!!

[IcemanCharlie]

Google is your friend. :)

http://www.afineredgemfg.com/index_files/Page426.htm

Does look like a cool idea.

This link DOESN'T work :-(

[druth]

Been using 2 of these on my Dynatron. Plenty of power and no charge in three months of weekend flying. Plus the price is same as NiCd for NiMH

http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1713

Not affiliated in any way, just pleased with product.
Dave