Elliot Howells reviews a clever unit - 4/3/10
Big and clever - the new Jeti Max BEC 2D
|Jeti's Max BEC 2D is a linear voltage regulator offering power inputs for two 2S Li-Po batteries. It's fair to say that 2.4 GHz technology is now well established and firmly loved in the field of model radio control. It's advantages are almost too many to list however, as yet, few companies seem to exploit fully one of the biggest strengths available, that of telemetry.
When I was looking for a 2.4Ghz solution for my radio (a Graupner MC24), Jeti’s Duplex seemed the best choice for several reasons, but the most salient was the inbuilt facility in each and every receiver to alert the modeller, using an alarm in the transmitter module, to low receiver voltage via telemetry.
I've found this insurance a great comfort when flying any model of a value greater than a few pounds, indeed even my park-fly models benefit from this enhancement. This battery voltage reporting function was only previously available to me by using an expensive (circa £2-300) vario module with it’s associated hand held receiver.
The fly in the ointment appeared when I applied this new technology to my glider tug and large scale gliders. The problem was that in these larger more complex models, most modellers including me use some form of battery redundancy - my current setups run a pair of 2S 5000mAh Li-Pos. The receiver will now of course see the regulated voltage (selectable between 5 and 6v usually) and report this figure back. Now I expect you’re ahead of me here, because you’ll see that clearly by the time a 7.4v Li-Po reaches this voltage we’re in the soup and all our telemetry based smugness has evaporated!
That was until Jeti released the Max BEC 2D. Building on the success of the rugged and appealing Max BEC 2, the 2D now features battery voltage monitoring with alarms and a temperature sensor to alert the user if the BEC becomes too hot. Alarm values are easily set using the Jeti Box programming/display tool and these are fed back into the receiver for transmission via it’s EXT port. So now we have almost total peace of mind, safe in the knowledge that our radio is keeping a careful eye on itself.
The icing on the cake, and something that will always appeal to big kids like me is the magnetic switching. The first Max BEC 2 used a removable plug to arm the receiver, complete with a neat ‘Remove before flying’ pendant, the 2D however goes another step by using a magnetic switch which is operated by holding a magnetic ‘wand’ on the switch - this in turn operates an electronic switch within the BEC itself. This switch will remain in its set state regardless until you use the magnetic wand again to switch it back. You can disconnect and re-connect the batteries and the switch will still be in the same state.
The LEDs provide battery state info
The body of the BEC uses high power LEDs to show battery health visually, if you don’t wish to be able to view these from the outside of your model or your installation is such that it’s not viable, then you can mount just the switch unit on the side of the fuselage for example, and still be able to monitor battery state by the single high power by-colour LED next to the magnetic sensor, green is good, red alerts the user to an alarm status.
The 2D does not come with battery connectors, just high quality silicone wire with tinned tips, the power supply end has a Multiplex green six pin connector, which conveniently plugs straight into the larger Duplex receivers and also some of the smaller ones which are designated EPC (Extended Power Connector), the unit is rated to 20Amps which should be more than ample for all but the most giant scale applications. Jeti supply the BEC with a mounting kit and female MPX socket should you wish to make up a lead to use a non-Jeti receiver.
As you might have guessed by now, I am a bit of a Jeti fan; their products are of the highest quality (although they've yet to develop a system that monitors and rejects duff stick inputs) and very reasonably priced too. A Max BEC 2D will cost around £75; I have mine in a 1/3 scale aerobatic glider, paired to a Jeti 14-channel receiver and the magnetic switch is mounted in the instrument console - not quite scale but it makes me smile. The original Max BEC 2 is doing sterling service in my tug and costs £60.
It’s also worth noting that Jeti are very well supported in the UK by at least two suppliers. I’ve used (both excellent) and they offer the highest level of service should you ever require it.