RX voltage differance
 

I have now got my first RX it is a usedfutaba T7CP it has a 9.6v battery, after charging the battery the TX shows a voltage of 10.5v is this normal?
P.s. sorry if that is a stupid question but i dont want to be doing any damage!!

RE: RX voltage differance
 

Yes, 9.6 volts is the nominal volage as each cell is 1.2 volts. fully charged you will see up to 10.6 volts, maybe a bit higher.

RE: RX voltage differance
 

All my Tx batteries show a voltage over 11 volts when fresh off the charger. If you are reading 10.5 immediately after charging the battery may need replacing.

The nice thing is that unlike a Rx/Servos a Tx puts a constant load on the battery. You may want to charge the battery and leave it on for an hour to see how it holds up (well away from anywhere you may interfere with anyone else). If in doubt, replace.

Terry

RE: RX voltage differance
 

If you know someone with a battery cycler it's a good idea to cycle the pack several times even when new. That will bring the pack up to full capacity and give you a base so you can cycle your pack once in a while to see how it is doing.

RE: RX voltage differance
 

was looking for a battery butit isa ni-cd, can only find ni-mh are these ok?</p>

RE: RX voltage differance
 

Yes, it will work too.

Bob

RE: RX voltage differance
 

G'day

NiCd batteries are becoming less common these days and are being replaced by NiMh batteries which are very similar in operation to NiCd. There are differences though but I will not go into them here. They mostly relate to the amount of current the cells can provide and charging needs for fast chargers. They don't affect their performance in our receivers and transmitters.

My transmitter packs measure about 11.4 volts when just off the charger but this falls to about 10.5 after a few hours. The 9.6 voltage is nominal based on the cells having a nominal voltage of 1.2 Volts under load. A fresh battery usually measures something like 1.36 volts or even higher.

I'd second the idea of discharging the battery and noting how long it lasts. Don't over discharge it though. Keep an eye on it. If you go below 0.9 volts per cell, you can damage the battery. A couple of charge/discharge cycles will help the pack sort out its chemistry.

If you need to replace the transmitter battery and if you need to buy a receiver battery, see if you can find packs made from Sanyo Eneloop NiMh cells. They are excellent batteries with a very low self discharge so that after a year they still hold at least 80% charge. I am gradually moving all my packs over to these and am very happy with them.

Cheers

Mike in Oz

RE: RX voltage differance
 

One of the best choices for a transmitter battery is the Sanyo Eneloops. They are a NiMh but newer design where the self discharge rate is very low, rivals LiPo. You can charge them this month, put them away and then fly next month without having to recharge. They are available now in most hobby shops and several on-line sources with the connectors of choice attached; just be sure to ask for Eneloops. You can also get them as individual cells from sources such as Amazon.com as 2000 mah AA cells. Again, make sure they are Eneloops.