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Author Topic: Battery size/amp for Graupner 700BB 12V 36" Perkassa  (Read 1820 times)

crock

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Battery size/amp for Graupner 700BB 12V 36" Perkassa
« on: April 05, 2013, 04:31:13 pm »

Hi,


I need to buy a battery or two for my 36" Perkassa running on a Graupner 700BB 12V.   Thinking of going for 2 7.2V NiMH batteries but what would give me a reasonable run time on the water ?  I know this is a bit like asking how long is a piece of string but hopefully there are a few Chaps out there with some experience of amperage and times for this combination.  Also a battery charger ?  Component Shop do one for ~£50, ( the cheaper of the Turnigy )  would that do the job.  I need a mains charger as estuary at the bottom of the garden.


Many thanks as usual


Crock  :-)
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essex2visuvesi

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Re: Battery size/amp for graup 700BB 12V 36" Perkassa
« Reply #1 on: April 05, 2013, 04:44:35 pm »

I would say to go for 2 or 3 cell lipos (7.4 or 11.1V) as the Perkassa is a Fast boat and they would give the best "bang per Ounce"


Available in all shapes, sizes and capacities.... I would look at a pair of 2600s or a single 5000


if you don't mind loosing a little runtime then go for a pair of 3 cell 2200s reason being is that this particular size is extremely popular with Heli flyers (most 450 size helis take this size and are by far the most popular sized heli) also a lot of the EPO planes take this size pack therefore they are quite reasonably priced.


You will need a special Lipo charger but these can be had quite cheaply as well
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crock

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Re: Battery size/amp for Graupner 700BB 12V 36" Perkassa
« Reply #2 on: April 07, 2013, 04:38:32 pm »

Thanks but I really wanted to stay with NiMH as I'm familiar with them.  Would there be much difference in going from a 6V 4300mh to a 7.2V 3700mh or even a 7.2V 4300mh or 7.2V 4600mh ????? 


Longer run times but how much longer and at how much cost for an occasional hobby ?????
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imsinking

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Re: Battery size/amp for Graupner 700BB 12V 36" Perkassa
« Reply #3 on: April 07, 2013, 05:08:39 pm »

Thanks but I really wanted to stay with NiMH as I'm familiar with them.  Would there be much difference in going from a 6V 4300mh to a 7.2V 3700mh or even a 7.2V 4300mh or 7.2V 4600mh ????? 
Longer run times but how much longer and at how much cost for an occasional hobby ?????
Hi , I run 2 x 5000 x 7.2 NiMh's in series making 14.4 volts , the 700BB's good for 19.2volts , run time approx 40-45 mins (it's a heavy boat). . . it's a slow reving motor & I drive thru a 2.5/1 gearbox with a 50x prop , I use a SIGMA eQ mini charger , each stick takes about 70mins or so @ 3.00amps (I cant get it any higher for some reason)
The batterys were £25 a stick from component shop  :-))  & the charger was £35 from Phil Greeno  :-))  , you can also charge SLA's & LIPO's  %%  with this , needed a charger harness to fit the DEANs connectors I'm using . . .

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