Using Lipos and Stock 7cell NIMH?

[spiderhole]

I've have the SC and two stock 7cell NIMH packs, but I plan to start using some of my 3s 2100 Lipos since I already own a few. I bought a pigtail PZ style battery connector to make a PZ-to-Dean adapter so I can easily swap between the Lipo and NIMH without having to solder the Cub's or connectors or those on the NIMH packs.

From what I understand by reading other posts is that if I remove the voltage jumper, the cutoff will be raised to ensure the lipos don't get drained to the point of damaging them. However, I assume this new higher cutoff will cause the 7cell NIMH to stop working way before they're depleted resulting in super short flight times? If I decide to leave the jumper ON, then I need to be very careful not to drain my Lipos too far, but the NIMH will work the same as before.

I've looked into the jumper switch mod others have done, but it looks like a lot of trouble. My inclination is to leave the cutoff jumper as is and just be careful, taking notes on a couple of test flights using my voltage meter to come up with safe flight times.

A couple of other things I'm wondering....

- After removing the jumper, when low voltage causes cut-off do you still maintain servo power?

- In same circumstance as above, can you get another burst of reserve throttle by resetting the stick (like with most "real" speed controllers)?

Thanks,
m

[flydiver]

FWIW the majority of ESC have inadequate LVC and cannot be trusted to 'take care of your lipo'. Fly by time.
Yes.
Yes. It's just a battery. All you've done is change the LVC. No other feature is changed.

You absolutely will want to prop down to a GWS 10x6 HD or APCe 10x5. You are significantly upping the voltage, the RPM's and therefore the load on the motor. Scotty-she won't take it.

Dump the Tamiya connectors. Seriously, they are poor. Do NOT make connectors. Learn to solder Deans. Tamiyas suck, suck, suck.....clear enough?
You risk complete electrical disconnection and loss of any control from whatever altitude you happen to be flying. You will not like it. I have been there so know of what I speak.
If you can't/won/t solder get Anderson Power Poles-expensive crimper but no soldering hassle.

fly

[spiderhole]

fly,

Thanks for the response. Yeah, I forgot about the prop part of the equation. It's sounding more and more like using both Nimh and lipos in the same Cub is too much to ask.

[flydiver]

May 29, 2008 5:52:18 GMT 1 spiderhole said:

It's sounding more and more like using both Nimh and lipos in the same Cub is too much to ask.

If you are doing both for the same session it would be a nuisance. Have to keep changing the prop or be careful to keep your thumb out of the throttle and fly it like it was on 7-cell. But then, what's the point of that?

It seems, once you've been bitten by lipo the NiXX kind of go away or are reserved for dedicated planes.

fly

[spiderhole]

Ok, everyone was right. I did a quick mod and flew lipos last weekend and WOW! Don't think I'll ever fly nimh in the cub again. I even helped another guy at the field cut a hole in his battery compartment and loaned him a lipo...he was instantly hooked too