MTK standard battery
The standard MTK battery is a stick of five Sanyo N-50AAA 50 mAh NiCd cells that weighs 19.7 g.
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MTK standard battery |
This pack should be recharged after every 4 to 5 flights, so two packs will fly a contest or, with a field charger, allow continuous practise and trim flying. The batteries should be recharged or replaced as soon as the open circuit voltage falls below 6.2 volts. In the interests of having a fixed pre-flight routine I recharge the flight battery after every flight.
An alternative is to use a 5 cell NiMH rechargeable battery 1.2 V x 110 mAh, which should allow a complete contest to be flown without recharging.
To be sure that the battery is OK before flying, check its voltage with a meter or set the power check mode. If the voltage is less then 6.2 V, replace the battery. The use of two flight battery packs is recommended so one can be charged while the other is in use.
A charging cable and suitable charger will be needed to recharge the flight batteries. MTK timers are supplied with a Futaba two wire red battery connector. The charger must be fitted with the same half of this connector as the MTK timer. This the male side, which has two bare pins inside a hollow plastic housing. This way charging only requires the battery to be disconnected from the timer and plugged into the charger.
I use the Sirius Charge 100 from Peak Electronics Inc. This is a peak detection charger and is well made and housed in a robust cast alloy case. This unit can completely recharge the flight batteries in between 30 and 45 minutes and top off the battery between flights in about 5 minutes.
This charger can be run off a pack of eight 1050 mAh AA size NiCds. A full day's trimming with the flight battery recharged every one or two flights used 25% of the capacity of this pack.
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Sirius Charge 100 with battery pack. |
I use a 2.5mm mini-power connector between the charger battery and charger because that matches my overnight charging systems. You can see the red Futaba connector on the output lead. This charger plus AA battery pack can be strapped together to make a pocket pack measuring 110mm x 50mm x 40mm.