Dai Phan

My Feedback: (2)

Hello all,

Over the weekend I went to a local battery shop and had a replacement made since my original battery does not hold power after charging. The new battery has the original leads and I was advised the new one has the same specs as the old. However after a full day of charging, the maximum voltage indicated on the front panel is 9.7V rather than the full bar of 11.1 with my original battery. I look at the specs on the replacement and it says 9.6V. Should I return the battery and ask them to remake it with 11.1V? I don't feel comfortable flying with half empty juice. But yet, there are replacement batteries online for 9303 that says 9.6V. Thank you for addressing my confusion and concerns. Dai

MX240

My Feedback: (4)

Yes, I have also tried the "local" battery store with your same results.
Go to Horizon and order a JR 2500ma battery.

mikmerl

Dai, it is likely that they will claim the rated 1.2V per cell (1.2V x 8cells = 9.6V)

I recommend you change to LiFe batteries for your Tx (and RX)

I did so some years ago and have never looked back

http://www.hobbyking.com/hobbyking/s...ter_Pack_.html

The one above fits your Tx perfectly and you will literally forget to charge your Tx………..it will amaze you how long a charge lasts and you can recharge in an hour.

You will need a balance charger capable of charging LiFe packs.

mike

Dai Phan

My Feedback: (2)

Hi all,

I called the battery place and I was advised to bring the battery back so they can make it into 11.1 V. The replacement battery on HH indicates it is a 9.6 V so I am pretty confused here. I tried to call HH but the wait time is too long. Dai

mikmerl

An 8 cell AA size NiMh pack is rated at 9.6 volts because each cell is rated at 1.2V.
Depending on the quality of the cells and their condition a fully charged cell may “offer” up to 1.4V for at its initial discharge.
I don’t know how the battery shop intends to boost your pack to 11.1V.
Potentially with a few charge – discharge cycles the pack will approach 10.5-11V when fully charged.
mike

Dai Phan

My Feedback: (2)

So a 9.6 V pack should eventually get to 11 V when charged/discharged a few times? Perhaps I didn't charge long enough? I gave it a 24 hour charge. I wanted to buy the battery you suggested but it is out of stock in US warehouse. Dai

mikmerl

24h is possibly too long…………but that depends on the capacity of the battery pack in mAh and the rate of charge from your charger. Or you have a smart charger that detects the pack has peaked and switches to trickle mode.

Common practice for Tx type applications is to charge at 1/10 (0.1c) the capacity of the battery (unless the batteries are of the fast charge variety). So if your batteries are 1000mAh you would charge at 100mAh. Usually 12-14 hours should do it for a healthy pack.

Yes……………you should see an improvement in a new pack after a few charge/discharge cycles. When discharging don’t allow the cells to drop below 1.1V per cell (8.8V for the pack)

mike

A.T.

What chemitry was the original? NiCD or NiMH and what was the replacement.
A typical 8 AA cell NiMH battery is rated at 9.6V but under full charge will display aprox 11.1V on a transmitter meter.
However, it does take at least three full cycles to reach full capacity and this is at the "slow" charge rate
- never use a fast charger to break in a new battery pack.

This is explained under directions for a different brand of TRX:
. Aurora 9 - Battery is not charged. Charge before first use so as not to damage battery. Battery is 1300 mAh_charge rate is 80 mAh
(to minimise damage if left on to long at any time) = 19-20 hours for first full charge - please read the further details.

. Transmitter - Voltage Display - How To Read & Interpret Remaining Battery Time

Much more information available under sub sections
"Battery Care, Performance & DIY Battery Packs."
and below
"Radio Systems, Accessories, Alterations and FAQ" at
Alan's Hobby, Model & RC FAQ Web Links

Alan T.