Charging Battery Pack

[martinjr]

Equipment: Queen Bee Thunderbolt Remote Control Helicopter 110 V
Charger - AUTO 300VA Transformer, portable UK to USA Transformer (Maplins)
This helicopter uses a 7.2V AAA650 mAh NiMH battery pack. I am hoping that the above information is sufficient to ask the question: how long should it take to charge this battery pack using the above charger/transformer, please? If further info required please let me know. The RC helicopter was bought about 10 years ago whilst on visit to Seattle in Frys Store (Renton).The unit has been used very little and battery pack now not charging so I acquired a replacement pack. martinjr

[Old_Geezer]

Trying to picture this, you're plugging the transformer into 230v, getting 110v out which then powers the US charger ?

I'm unsure there's enough information.

Transformers transform only so doubling pd halves current and vice versa. Shouldn't make a difference to time taken.

How much current does the US charger supply at 7.2v ? Knowing that you have a fighting chance to work out how long it'd take to supply 650 mAh.

[martinjr]

Input Max Current 1.3A. Freq: 50Hz
Max Current:Output Max Current: 2.7A, Freq: 50Hz

[Old_Geezer]

Hmmm, maybe try it and see. I'm probably being naive here but I'd figure 0.65 Ahr ÷ 2.7 A = 14.5 minutes, which seems too fast and implies max output current doesn't occur, or RMS can't simply be converted as DC.

[bhg481]

Just because the charger CAN supply x amps doesn't mean that it WILL. Think about your car, where the alternator will supply a very large current but he charge rate is limited by the circuitry to avoid "boiling" the battery. The same will apply to your helicopter battery; I know cras have a lead-acid battery and your helicopter will be lithium or similar but the same principle applies.