Receiver packs; 4.8v. Or 6.0v.? NiCd or NiMh?

4 vs 5 cells for receiver packs

· 4 cells cost less · 4 cells are more reliable than 5 (more parts/connections = less reliability) · 4 cells give you longer flying time than 5 cells of equal capacity · 4 cells are lighter · 4 cells put less stress on radio and servo components (unless regulator is employed)

· 5 cells give you faster servo response · 5 cells allow for voltage regulation to give you constant servo response. · 5 cells give you a margin of safety if one cell shorts (but this is a rare occurrence in flight - if you don't do an ESV check before you start flying, then you deserve what you get.)

Usually same charger that comes with your radio system will accommodate both

4 and 5 cells, for 5 cells the charge may take slightly longer. A standard Futaba Charger will charge 5 cells at about 40 mA, whereas it charges a 4 cell pack at 55 mA. For 5 cells charge 20% longer.

All present day radio systems seem to accommodate 5 cell receiver packs without problems.

-- Red S. Red's R/C Battery Clinic

us out for "revolting" information.

I would use something like a 1200mAh NiMh on 5 cells (6 v). Maybe even larger with those 7 servos.

Red,

How so? I'd have thought they'd be about the same.

What type of regulator would be needed? --

Jim L.

Using - Virtual Access(OLR), ZAP 4.5, & WinXP Pro w/SP1

Paul,

I'm thinking of going with (5) 2000mAh-NiMh's (AA). --

Jim L.

Using - Virtual Access(OLR), ZAP 4.5, & WinXP Pro w/SP1

We have a batteries plus store here where I live and the guy makes up battery packs for us. These are cheaper than what we can buy OEM and are 1650 mah. I go to the field 3-4 times before I charge my stuff. I have been using the 6 volt reciever packs for about a year with no problems. I use Futaba gear with a little tower and GWS thrown in. You won't regret going to 6 volts. A little more speed and torque. Eddie Fulmer

Not all. It's not relevant to the original poster's situation, but some of the micro-sized gear can't take 5 cell packs. Hitec's HS-50 servos come to mind as an example.

-tih

Higher voltage = higher current draw. Doesn't seem logical does it?

NiMH gives you more flight time with less weight. Requires special chargers to prevent overcharging. Overcharging NiMH is more harmful to the pack than NiCad.

Yes, there are exceptions to all "general" rules. The HS 50 is not usable with 5 cell Ni-Cd packs. This is one out of the 34 +/- servos in the HiTec offering. Thank you for pointing this out even if it was not relevant to the original post.

RS

6.0v, NiCd Dr.1 Driver "There's a Hun in the sun!"

I am with you Driver. I use high capacity (and weight) 1800 to 2000 mah nicad 6V (5 cell) packs in all my large models. I have Futaba Receivers and Hitec Digital servos. I charge with a Tower Hobico DC Quick field charger Mk2. Works Ok for me. I don't trust NiMH and Don't need to save weight in RX packs. I do use LiPoly in my electric models and love the light weight and long run times they give. You need a good charger for them.

Regards

Tom Watson Sydney Australia .

That should do it.

Higher voltage into the same resistance cauese higher current.

A regulator he is talking about is to regulate the 6v down to about 5v so you don't stress the electronics too much on the initial peak of the charge.

And the point of regulating 5 cells to equal the voltage of 4 is what?

Happy Holidays

Mike

The "experts" feel that it gives them more consistent servo response throughout the flight. Unfortunately I'm not a good enough pilot (48 years flying R/C) to be able to detect the difference between 5.2 and 4.8 volts.

-- Red S. Red's R/C Battery Clinic

us out for "revolting" information.

Ah, those must be the same "experts" who can tell the difference flying with a metal or nylon clevis huh?

Happy Holidays Mike

Jim,

I am a guy who puts safety first. My Success story: I fly small planes: up to .91 (15cc) 6 feet span. Maximum of 7 servo's incl

1 digital one (They can consume quite some current) Weight is important on these planes, as is safety. NiMh Cells are the greatest at this moment (weight vs capacity). (note : no memory build up, and with 0.1 C loading an extra couple of hrs loading does not harm the cells) What do I do: I take 2 packs of 5 cells 750 mAh.(AAA) Each pack gets a Diode (just a std 3A one) and gets solderd just before the switch. So I have 2 packs each with a diode and a switch. Each pack gets it own chanell in the receiver. This way: if one pack fails , the other one takes over. (No drain to the bad pack due to the diodes). If one switch fails I still have the other pack and switch. The diode also lowers the voltage by 0.7 - 1 volt. 5 cells * 1.35 (full state) =6.75 volt - 1 = 5.75V Great stuff with 2 small packs: balancing. always space to put them somewhere so you do not have to use lead.

This is simple , cheap and it works. (and no, I am not selling them....) good luck

maarten