During the last weeks bad receiver packs leads to lost of one and near lost of another plane.... Both are 1500mah Ni-Cd packs, failed the first flight after charging....

So makes me look at other alternative of receiver packs....

Some friends had great success with LiPo packs and regulator combo, they even said this combo give them better control resolution.... But someone had a flying fireball with this combo....

I stumbled across the newer Li-Fe cells that each of these cells are at 3.3V flat.... They are said to be much safer than their "poly bag cousins", some even said that due to their better resistance of overcharging there is no need for balancing for a 2S pack. I heard that some even use a 2S Li-Fe pack plugging directly into the receiver without a regulator to substitute a 5S 6V Ni-Cd/Ni-Mh pack. Any of you guys tried this? Will the receiver/servo take a direct connection of a 2S Li-Fe pack without damage?

If both packs failed after the first charge, I would suspect a problem with the charger or the charger settings. As the old saying goes, once is a coincidence, twice is a conspiracy!

I have no experience with and therefore can't comment on the LiFe's...

However, I would never plug a 2S Li-anything directly into a receiver. They are nominally rated at 7.4 volts, but with a fresh charge they are close to 8.4 volts, which over time -- if not immediately -- will damage your receiver. Imagine the amp draw if you are using 6 or 7 digital servos and then do a maneuver, such as a flat spin, where all of them are engaged fully at the same time!![X(]

-- Bob

Hi,

A really good alternative is the Lithium-Ion ( NMP 7.4V 2200 mah) , and the Jaccio reg. (both sold by Central H. ). Several Pattern fliers here in Norway use them with great success ...

Kjell O.

Hello,
in order to really increase the the power plant robustness to failures, the best way is to add redundancy to the system - this is a general engineering principle.

Regardless of the battery type, I suggest you to deploy a dual pack with dual power cords and two switches. This really decreases the probability of a power failure. I choosed that setup, despite the increased weight, when I almost lost my plane due to a pack failure.

Considering the amount of work and price in our pattern planes, I'm willing to have a heavier but safer plane!

BTW, dual lipo with dual regulators weight not that much, after all. And there is another PLUS: more current can be drawn from the batteries!

For more info, check out this good site:

http://www.rcbatteryclinic.com/parallel.html

For the same principle, stay away from those regulators that have two batt inputs "for safety". The regulator itself is not redundant, so our plane is in the hands of some cheap circuit whose reliability is unknown.

I use the exact combo recommended by 67685, and I couldn't be happier. I can get 10 flights in without even thinking about charging (though I wouldn't do that anyway, just saying I could). I picked the NMP over the Duralite because it was less expensive than the 1800mA Duralite, and weighed less, but most of the guys I fly with use the Duralite because they have a 2400mA that gives them a little more time between charges and they also fly in Masters and FAI, which can be demanding on the current draw.

I also use Li-ion (Fromeco 2600mah) and am very happy with them. A big advantage is that they can be charged at the field, and can even be "topped off" between flights. I have a 50cc gasser and although I use a NiCd for the ignition I am thinking about getting a Li-ion for that as well.

I'd be interested to see what Red has to say about the Li-FE battery technology.

Hi,

For those of you considering a LiPo battery system you might be interested in knowing that Emcotec from Germany recently introduced the DPSI Micro family. The "DPSI Micro - DPSI RV" and "DPSI Micro MPS-RV" look interesting for F3A use...

[link=http://www.rc-electronic.com/html/englisch/unten/dpsi/dpsi_micro/dpsi_micro.html]http://www.rc-electronic.com/html/englisch/unten/dpsi/dpsi_micro/dpsi_micro.html[/link]

Instructions can be downloaded here: [link=http://emcotec.e-vendo.de/downloads/pdf/bedienungsanleitungen/Anleitung_DPSI_Micro_RV_EN.pdf]http://emcotec.e-vendo.de/downloads/pdf/bedienungsanleitungen/Anleitung_DPSI_Micro_RV_EN.pdf[/link]