ibow24

My Feedback: (10)

Hello,
I'm getting back into building/flying after many years away. I have several BRAND NEW but obviously OLD DS8611 and DS8611A servos.
I would like to use these in a TF Giant Corsair I'm building.
Question: I tried to do some research and the best I can find is the 8611A is an 8611 with an upgraded case and slightly stronger motor.
will both these servos run on the new LIFE battery packs? will they need a regulator?

When I quit flying Lipo's were just becoming popular but I was still using Nicad… yeah, I'm a dinosaur

thanks for your help
Steve

Zeeb

My Feedback: (41)

Hmm, they're oldies alright. You still see some 8611A servos around in fact I still use several of them in various models including one of my jets. I don't remember ever even seeing an 8611 in the 11 years I've been flying RC. I think the major difference is the A version has a higher torque rating as you noted and I believe they are faster as well. So you cannot pair them e.g. use an 8611 and an 8611A for dual elevator servos.

As for the voltage; those servos were rated for 6 volts which is the nominal voltage of a five cell NiCD/NiMH battery. Those batteries as well as the A123/LiFE come off the charger at about 7.2 volts and if you run those NiCD/NiMH batteries down to 6.0 volts, they're dead. The A123/LiFE batteries will drop rather quickly into the 6.6 volt area and remain there for pretty much most of the time you're flying. The A123/LiFE batteries are a great solution for our models but it will require a new charger for you with that chemistry in the software and you will have to get used to charging by flight time as you cannot effectively volt check those batteries, the discharge curve is just too flat.

There are lots of threads on those batteries here and on other forums, I suggest you do some reading to familiarize yourself with them before diving into using them. For all intents, NiCD's are no longer available for environmental reasons and the NiMH's are not much good for todays higher demand electrical systems. They have a pretty low discharge capability, they false peak on charging especially if you run over a 1/10C charge rate which means overnight like you're used to doing with the old stuff. The self discharge rate on those batteries is pretty significant as well except for the Eneloop type batteries which work well for tx's but not for rx packs. A123/LiFE's will charge in about 20 minutes with a virtual zero self discharge while they sit.

ibow24

My Feedback: (10)

wow…great response. Thanks so much for the info. I Have (5) of the 8611A's brand new in the package so I was thinking (2) ailerons, (2) elevator and (1) rudder. Then using the (2) 8611's for the flaps.
I'll be doing a lot of reading on the A123/LIFE's before I dive in but obviously they seem to be the way to go now. Just took all my Nicad's to recycle.
thanks again

tomfiorentino

I have found the narrative and Q&A parts of the www.hangtimes.com website to be very helpful in understanding A123's. There are set-up tips in there as well and they are wonderful to deal with should you decide to buy batteries from them.

You will see a set-up and charging tip that involves modifying a heavy duty switch that allows for balance charging the pack through the switch port using standard 3-wire servo connections. That is what I have been doing on my models and it works beautifully! On a larger set-up where I may be using a powersafe type receiver...I just pull the canopy off to charge the batteries and don't have any charge ports cut into the fuselage that way, and the receiver comes equipped with a soft switch for power. Works great...lots of guys doing that type of thing.

Many of the guys on RCU know this stuff inside and out so the forum is a good place to turn as well.

Have fun and good luck to you as you get back into things...

Tom