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Author Topic: NiMh Battery packs  (Read 3387 times)

Guy

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NiMh Battery packs
« on: February 20, 2008, 10:49:07 am »

Hello again,

As you guys were so helpfull last time I thought I would try another question.

My twin MFA 400 motors currently run from a NiCd 7.2v 2000mah pack. But MFA tell me i should try running a 12v pack for the two motors. However the weight is on the limit using the 7.2v pack so an alternative needs to be found.

I have done some research and found (on the hobby stores or ripmax web sites) these lovely NiMh cells which are much smaller allowing 12v from a pack smaller and lighter then the standard 7.2 NiCd's and roughly the same price. Great!!

However they only seem to be available in around 1100mha. Will this affect my runtimes much?

Also charging these cells seems to require an expensive charger...
Does anyone out there have any experience with these cells?
And can anyone recommend a supplier of cells and chargers?

Thanks
Guy
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malcolmfrary

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Re: NiMh Battery packs
« Reply #1 on: February 20, 2008, 11:32:24 am »

If the boat is performing up to expectations, why change?
Dropping to 1100mAH will reduce your run time, increasing the voltage will increase the current drawn, and will further drop the run time, but will increase the performance.  A reduction in overall weight will also improve performance and possibly offset the loss of run time.
If your current charger is not a fast type, it might be able to handle 12 volts.  Otherwise, getting the appropriate charger is usually the best bet for anybody who isn't used to handling electric bit'n'pieces, and ultimately a lot cheaper than re-buying replacement batteries.
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DickyD

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Re: NiMh Battery packs
« Reply #2 on: February 20, 2008, 11:33:42 am »

 Component Shop for all batteries and chargers. Excellent prices and service
Their website will answer most of your questions.  O0

http://www.component-shop.co.uk/html/large_packs.html
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Guy

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Re: NiMh Battery packs
« Reply #3 on: February 20, 2008, 11:51:23 am »

Thanks.

The Boat is a little slower then was hoping. I was originally trying to find replacement propellers but these are impossible to find for the M2 shafts i have and possibly not the solution when the motors should be running a higher voltage.

The current 2000mha battery's give a very very very long running time so i am not too concerned if this reduces. However i dont want to find i only get 10Min's out of it now after spending a load of cash, hence the questions.

The motors only draw 0.8 amps each with this twin motor set up according to the man at MFA! Im not so hot on my electronics....

Thanks Guy
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BarryB

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Re: NiMh Battery packs
« Reply #4 on: February 20, 2008, 11:52:11 am »

I've been into LiPo batteries now for nearly a year - Lightness is good if you want speed - Sometimes you want the weight for ballast, so I stick to 12v Gel batteries then.

Charging LiPo batteries - I got myself a small balance charger which croc clips on to a 12v supply (eg the 12v Gel above) - cost was about £8.00
Thsi will charge (believe me on this) 2S or 3S LiPo from as little as 11.5V
E-Sky EK2-0851

Barry
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Guy

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Re: NiMh Battery packs
« Reply #5 on: February 21, 2008, 11:21:57 am »

Hi,

Just to let you all know i have ordered a 12v 2400mha NiMh pack with AA size cells (very small and light). This is from the Component Shop (thanks for the link DickyD) at about £10....

Also a peak detection charger for the same company at about £15. So all nice and cheap compared to Hobby Stores minimum charger of £60 and cells at £25!!!

If anyone is interested i will post the results of the test run with these cells as opposed to a standard 7.2v NiCd pack.

Also the people at the Component Shop were very helpful so i strongly recommend them...
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tony52

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Re: NiMh Battery packs
« Reply #6 on: January 30, 2009, 05:25:52 pm »

Richard, found this posting from last year

Component Shop for all batteries and chargers. Excellent prices and service
Their website will answer most of your questions.  O0

http://www.component-shop.co.uk/html/large_packs.html

Ordered battery pack, to my spec, leads and charger and I must say their service is EXCELLENT. postage rates are very reasonable, technical help available.

Thanks for the link,
Tony.

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DickyD

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Re: NiMh Battery packs
« Reply #7 on: January 30, 2009, 06:04:38 pm »

Nice to know you are on the ball Tony :}
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Popeye

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Re: NiMh Battery packs
« Reply #8 on: January 31, 2009, 12:25:37 pm »

ModelPower - www.modelpower.co.uk  - 01827711501, offer a vast range of batteries  and accessories. Give 'em a ring; you'll find 'em very helpful and will give good advise in respect of your particular needs. They also participate in the 'big' model shows, Wings n Wheels, Weymouth, Warwick, Ally Pally etc.

Their service is excellent and they're my first choice for my battery etc. requirements.

Definitely a  :-))
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