How much MAH lipo batt I can use to replace the NICAD batt for my RDS8000?

Why? There are alot of ther options which will give you more flight time thatmake more sense.Do some research on higher capity Nicad or Nimh packs.

I am running an upgraded nimh pack in mine.  I have replaced (3) so far.  I have had good luck with the High Energy from Hobby People.  I picked this up on sale for $20.00

http://www.hobbypeople.net/gallery/233832.asp 

I just did a slow charge discharge cycle on them and they work pretty well.

In the RDS8000 thread, they list the lipo battery.  I did not search there.


Dru.

I have a 1600mah NIMH battery in mine, from RadicalRC.com. I can fly all day on a charge, actually two days without recharging.

Radios have some kind of witchcraft circuitry built in between the charge jack and the battery, and the battery is reversed polarity from other brands and batteries. I'm not sure but this might make charging and discharging a lipo much more of a chore than a simple NIMH replacement with which you could use your regular fast charger.

Just my personal thoughts. I hope you find something that works for you.

I've used six of these on different TX's, some JR, one Futaba, one Hitec, one Polk.

All have worked great, and it is wonderful needing to charge the battery once every two weeks and then in an hour using a computer controlled LiPo charger.

See: [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7346&Product_Name=Rh ino_2620mAh_3S_11.1v_Transmitter_Lipoly_Pack]Click me![/link]

What type of connector does the NICAD battery for the RDS8000?  I would like to charge the battery using my Hyperion charger but I couldn't any adapter for it?  The battery on mine only last 1.5 hr and 12 hours to charge with provided charger.

old style Airtronics, be careful, the polarity is reversed, hot is on the outside instead of the middle. Max products( MPI)should have the correct connector.

Sounds like this is definitely worth a shot. Ididn't realize you could get a TXlipo for so little.

Is it a problem charging lipos through the radio or you you have to take it out?

You should take it out and charge it with a good lipo compatable balance charger.  I would never use the standard NiCad wall wart charger for a lipo.  The voltage is wrong and it could cause damage.  Aways be very cautious with lipo batteries.

Correct.

While the wall wart will not harm the LiPo battery ( the wall wart current is way too low and the incorrect voltage doesn't help either... ), it also will not charge it fully nor balance it properly.

The best thing to do is to hook up one of these to a LiPo balance charger.

I recently gave one of these battery packs to a friend as a gift, and I took a balance charger and wall wart 12v supply that came with an EDF and threw that into the box.

He has been quite pleased with the results.

I usually charge mine by removing the backplate from the TX, and with the battery still in place, I charge it through the balance jack using a TC-1030 Team Checkpoint ( aka ICE Intellipeak ) charger.

With an intelligent charger I charge up my packs in far less than an hour and I'm good for the next two weekends.

He is talking about the RDS8000 which is NOT the old style. The below is a screen capture from the RDS8000 manual.

CGr.

The connector on the battery pack is the Airtronics Z connector. You can make a connector for your charger using a servo extension. The Airtronics Z connector is almost identical to the Hitec S and JR connectors.

<< edit to add >> If you want to make something to connect your charger through the plug on the side of the transmitter, this is available for $3.00
http://www.hobbypeople.net/gallery/477037.asp

I know receiver connector is called Z connector. Not sure about the transmitter connector.

Before I wrote the reply I looked up the replacement transmitter battery on the Hobby People web site and it says the connector on the actual battery pack is the Z connector.

I don't know the connector names, but the battery is definitely reversed polarity from everything else, such as the receiver. Airtronics changed the polarity of new receivers, new servos, etc. but NOT the battery in the radio.

Yes, that is correct. A standard "Z" connector will work, but you have to swap positive and negative on the connector. Although it's a quick and easy switch to do.</p>

Ken</p>