Receiver pack question
#1
Thread Starter
Tech Adept
Joined: Jan 2003
Posts: 107
From: Sydney
Hi All,
I was wondering what is the best way to go regarding a receiver battery pack on a nitro car.
At the moment I'm using the old standby of 4 AA batteries in a holder but would like to use the best possible option to power the electrics.
Does using a 7.2V pack make much difference to the speed and efficiency of the servos or does the receiver only supply them with 6V?
It was mentioned to me once that this could be an issue.
I'm happy to pay up for a good NiMh 7.2V pack if it's for the best, or am just as well using 4 AA's? (they are alkalines not Nimh so I am at least getting 6V not 4.8)
How does one recharge these packs if they are using the tiny little connectors to hook up to the receiver?
Do I need to get a special charger or just bodgy something up?
Thanks heaps
marty
I was wondering what is the best way to go regarding a receiver battery pack on a nitro car.
At the moment I'm using the old standby of 4 AA batteries in a holder but would like to use the best possible option to power the electrics.
Does using a 7.2V pack make much difference to the speed and efficiency of the servos or does the receiver only supply them with 6V?
It was mentioned to me once that this could be an issue.
I'm happy to pay up for a good NiMh 7.2V pack if it's for the best, or am just as well using 4 AA's? (they are alkalines not Nimh so I am at least getting 6V not 4.8)
How does one recharge these packs if they are using the tiny little connectors to hook up to the receiver?
Do I need to get a special charger or just bodgy something up?
Thanks heaps
marty
#2
You wont notice much difference in speed weather you use 7.2 v or 6v
I dont think a 7.2 nimh battery pack would fit on a nitro car. Just get a decent 6 volt NiCd pack. They all generaly use 5 cells so they are 1.2v each cell.
Usually when you buy the pack the shop will sell you a charger with it weather it be 12 hour or some fancy one
If you have a decent 7.2v charger they can charge reciever packs... that is if it has that function etc.
I dont think a 7.2 nimh battery pack would fit on a nitro car. Just get a decent 6 volt NiCd pack. They all generaly use 5 cells so they are 1.2v each cell.
Usually when you buy the pack the shop will sell you a charger with it weather it be 12 hour or some fancy one

If you have a decent 7.2v charger they can charge reciever packs... that is if it has that function etc.
#3
Joined: Sep 2001
Posts: 7,016
From: Mongville
Depending on your car get either a hump or flat pack receiver battery, Orion make a great one with 1100mah capacity, will keep you going longer. Usa a peak charger to charge the pack, on about 1 amp, with a low voltage cutoff. Some chargers have a special mode for nimh receiver packs
#5
RX & servos are designed to run on 6V. If you run them at 4.8V they'll be sluggish and will perform slower than their advertised specs. 6V is what they ask for.
However if you run them with 7.2V and your RX is a "BEC" unit, it'll have a voltage regulator inside to drop it down to 6V - so it'll makes no significant difference.
(running non-BEC gear on 7.2V will toast it)
Your best bet is a pack of 5 NiMH cells. Work out what the RX's current drain is & what is your usual running times and work out how much capacity you need to last all day.
NiMH can be trickle charged using your standard TX/RX chargers, just account for the higher capacity (ie charge longer).
However if you run them with 7.2V and your RX is a "BEC" unit, it'll have a voltage regulator inside to drop it down to 6V - so it'll makes no significant difference.
(running non-BEC gear on 7.2V will toast it)
Your best bet is a pack of 5 NiMH cells. Work out what the RX's current drain is & what is your usual running times and work out how much capacity you need to last all day.
NiMH can be trickle charged using your standard TX/RX chargers, just account for the higher capacity (ie charge longer).
#6
Tech Master
Joined: Jan 2003
Posts: 1,296
From: NSW Australia
I am sure I have seen 4.8V only servo's? hmm cant remember...
Anyway for 7.2V servo's they wire the power in from battery and not RX unit (by-passing regulator), only the signal comes from RX unit.
My Ko Propo servo did come with 6V and 7.2V instructions but I didnt take much notice of the 7.2V stuff, but it was a lot more then just plugging it into a receiver.
6V Vs 7.2V KO Servo:
PDS-2123 FET 7.2 V 131.9 oz. 0.06 S @ 60°
PDS-2143 FET 6 V 111.0 oz. 0.08 S @ 60°
Anyway for 7.2V servo's they wire the power in from battery and not RX unit (by-passing regulator), only the signal comes from RX unit.
My Ko Propo servo did come with 6V and 7.2V instructions but I didnt take much notice of the 7.2V stuff, but it was a lot more then just plugging it into a receiver.
6V Vs 7.2V KO Servo:
PDS-2123 FET 7.2 V 131.9 oz. 0.06 S @ 60°
PDS-2143 FET 6 V 111.0 oz. 0.08 S @ 60°




