Transmitter battery question

[Jetgirl]

or a transmitter general question.

I have a hitech eclise7 radio. I have noticed I have to keep charging the transmitter battery. It seems that the times between charging get shorter and shorter. Dunno if I am flying more or if the battery is going bad.

Question to the group:

Do you have more than one transmitter battery, if not, how often do you charge your transmitter battery :?:

forgot to add:

where do I get another battery if I need one? The battery I have is 600mAh 9.6 V NiCad, 3 7/8"-1 1/6" 0 1 1/16' (dimensions) wth the white 2 pin connector. I have seen them at tower hobbies but where else?

edit to change the subject line of the post

[helirook]

hey jetgirl,

it may be that your battery is starting to get old. i use the same radio and typically i can make it 2 or 3 flights between charges. i only have the one battery. you can get a new one through servocity.com they have some pretty reasonable prices. also, you can order a larger mah if you like, or even a lipo....

[Logan826]

Jetgirl,
Go to http://www.commonsenserc.com/index.php and get the 2500 lipo for your radio. You'll have to solder your own leads on, but it's well worth it. Also you will have to make up an end to end for your lipo charger, you can not charge these from the tx charger. You can go a whole weekend on a charge.
Dan

[BarracudaHockey]

Jetgirl you don't need to make things more complicated than you have to.

Goto http://www.hangtimes.com/txpacks.html and get a 2000 mah 9.6 volt Nimh pack, I can fly all weekend without recharging and thats taking two nitro helis and an airplane or 2 to the field.

[angelob]

The only problem with going NiMH, and it might be a non-issue, is what kind of charger are you using or planning on using to charge the battery. If you are using the stock wall charger, it might not be rated to charge Nimh and you might need to purchase a different charger.

Angelo

[Jetgirl]

Good thing to keep in mind. I will have to check my chargers to see if I have something that will charge NiMH. I may have one for when I use to race my T-3 truck.

[Rick Rotorhead]

Could be and aging Nicad pack (most Nicads are good for between 500 and 1000 cycles), but could also be the infamous NiCad 'Memory' effect. Do you use the packs full capacity (or nearly so) before recharging or just give top-up charges? Topping up Nicads is bad because it will eventually reduce their capacity to maybe 1/4 of their rated capacity, but can often be fixed by using a Nicad cycling charger/discharger. I think NiMh do not exhibit 'memory' effects and can be topped up without a problem, plus they have like three times the capacity of the same physical size of Nicad, so that would be a sensible move. I'm not totally sure charge rate wise, but a Nicad wall plug type trickle charger should be fine for NiMh cells, but they will need proportionatly longer to charge if they have greater capacity than your nicads. One warning - act soon because nicads have a habit of going from a 'noticeable drop in performance' condition to practically no capacity in a very short time.

[Jetgirl]

I don't pop charge my transmitter battery. I have been using it until I get the 'beep' stating battery is low or until it gets to 9.3/9.4 on the radio. It will beep soon after.

mmmm thanks for the 'warning' as to what the batteries can do.

[Rick Rotorhead]

Thats interesting Jetgirl, I've been using my new Fut 9c on the XTR sim until the voltage goes under 9v and it still has not cut out yet, I think this Tx has a cut off at 8.5v (I'll re-check my manual) - I could be over discharging mine...gulp!
I can give an example of my 'warning' with an old mobile phone I have: This phone is Nicad powered and seems to charge up quite fast, but once charged it only last for two days on standby (instead of 4 or 5) and if a call is made or recieved it cuts out totally after about 1 minute. Now, imagine that was your Tx batt - appears fully charged for quarter of an hour, then goes totally flat in 5 mins - you might not even be lucky enough to spot the voltage reading dropping rapidly away. Anyhow, don't wanna scare you, thats worst case scenario for a well worn out nicad pack, but the writing is on the wall as they say....... Rick

[DavidH]

Usually the low battery warning will beep at 8.5 volts. The transmitter will not turn off until the battery is dead. I have repeatable used my 9Z transmitter till the low battery warning goes off. Then I land the model and pop in another battery and go back to flying. Put the low battery on charge and then use it again when needed. Your in the best part of the battery when the voltage is between 9 volts and 9.8 volts.

David

[Rick Rotorhead]

Thanks DavidH, will I do any long term harm to my Tx batts by discharging them to under 9v?

[Jetgirl]

I have only ran out of juice twice. I hope I didn't damage the batteries. My boyfriend had some NiCad or NimH lying around and made me a battery pack. We shall see if they work or not. :)

I will keep all the advice in mind!

[Seeker]

You won't harm NiCad or NiMH by discharging too far down. As a matter of fact, it's good for them to get completely discharged once in a while (monthly maybe?)

Lipo's are another issue... those you don't want to discharge too much.

[z11355]

well, you dont want to bring the individual cells to < 0.9v each, thats pretty much thelower limit

[Rick Rotorhead]

Hmmmm, Ok. So thats 7.2v across an eight cell pack (nominally 9.6v). Well, I'm plenty above that and the 9c Tx power cut off will keep the lower voltage limit safely high. I take it that means 0.9v per cell under load, i.e. Tx switch on.
I'm gonna use it on my sim until it does cut out and see what voltage it terminates at.

[Steve Rogers]

Jetgirl you don't need to make things more complicated than you have to.

Goto http://www.hangtimes.com/txpacks.html and get a 2000 mah 9.6 volt Nimh pack, I can fly all weekend without recharging and thats taking two nitro helis and an airplane or 2 to the field.

This is the way to go. I use a 2300 NiMh in my 9Z & I get somewhere in the neighborhood of around 4 hrs actual flying time before I have to recharge. This is of coarse over a few days but I NEVER let the battery set more than a week without a good charge due to NiMh having a higher dissipation rate while setting than NiCds. NiMh retains no memory due to "topping off" and since a normal weekend of flying for me is only around 1 or 2 hrs of time the voltage is still well above 10 volts & when I get home I simply plug in the Tx on about a 50 to 75 Milli amp constant trickle & it will be topped off in a few days. A stock wall wart that comes with the Tx is great for this assuming your using a large pack. There again if you are going to be flying sooner top it off with a good charge or use a little higher rate. This is a plus to the larger NiMh because they can be completely charged with a 50 to 75 mill charge rate if left on there long enough (3 or 4 days) but that rate is not enough to hurt a large pack (1500 Mah or larger) if left on there for a few weeks. Longer than that could cause bridging of the cells since the trickle is a constant one but I have left mine on for as long as 2 months & all was well. This method allows me to come home from a weekend of flying stick the Tx & Helis on a good constant trickle & if I get to fly sometime through the week I know the packs are up to snuff without missing a day because they weren't charged or abusing them with a fast charger. Fast chargers only charge your packs to around 80 or 90% compacity.
I build all my own chargers with simple stuff from Radio Shack & still do the ole 16 hr thing on a completely discharged pack & in the many years of flying I have yet to have it let me down. Sure its not as "convient" as ripping a battery & go fly but it allows me to pay more attention to one of the most important things in the heli! I'm no battery genius but I have experimented alot to find out what works best with my stuff so if I can help in anyway just holler.

Oh yea, my first computer Tx. was the Eclipse & what I did was get a 1650 NiMh pack from tower & if you look inside the battery compartment of the Eclipse (if they havent changed) there is also a provision for a battery that has stud connections rather than pin connections. Remove the back of the Tx case & solder a standard plug that a battery, will plug into in the corresponding place (it will be easy to figure out once you look) rout the plug through one of the small openings to the battery compartment & you wont have to worry about finding a pack with the proper connectors, all will be standerd then.

Hope I've helped & not confused,
Steve

[Rick Rotorhead]

FYI - used my Fut 9c on the XTR sim until a low batt alarm(very audible) cut in.
Voltage read 7.4, Tx still operated. Thats about 0.9v per cell.