What type of batteries are best?

[Billy BobParticipant @billybob24045]

Hiya guys,

There are many types of rechargable battries, Ni-mh, Ni-cad, and so on!

Some are low drain/ high drain and are all dependant on the mAh size of the cell…

My question is what kinda battries would you guys surggest for Rc boats. Do I use a different type of battery say for the rx and servo pack in my boat, to the ones in my control box?

The last thing i want is an out of control boat due to a bad jugment of  power serve choices.

Billybob…(newby)

[Jake KnightParticipant @jakeknight71345]

ok billy bob

i use standard duracell battries in my rx and in my handset the reason why is that they never go wrong 

it doesnt really matter

you can by recharable packs (which are a sealed unit) which go inside the handset

they are also very good and save money

hope this helps

[Len OchiltreeParticipant @lenochiltree67043]

Hi Billybob,

I tend to build fairly slow boats,Tugs mainly,and I use sealed lead acid,also called Gel cells in 6v or 12volt and one charge will keep the boat going for most of the day.

If you use a speed controller with BEC you only need one battery in the boat.

I am using Nicads in my Tx,because they were in it.

I use nmh in my Yachts and Thames Sailing Barge.

I hope this helps.

Len.

[ashley needhamParticipant @ashleyneedham69188]

Hi Billybob. Personally, I use NiMh batteries, ordinary AA size in my transmitter, and Gel lead-acids in most of my boats except for a couple of ligh ones which have NiMh packs. all my speed controllers are BEC equipped so I dont need a seperate battery pack for the boat reciever. Its always handy to have a set of duracell AA in youe pocket for the transmitter, just in case.(I find from experience!) Ashley

[60wattParticipant @60watt]

Hi Billybob,

 It’s a while since your original post  but my experiences with alkaline batteries give me good reason to contradict Jake’s recent post on 17th.

 Three times I’ve been asked to sort a problem where a servo has not worked. Each time there was a giveaway clue like "brand new batteries" to enable a diagnosis of the problem without getting off my seat.  Each time the problem was caused because a Futaba receiver could not operate a different brand of servo at alkaline voltage levels. Each time my suggested fix of using Ni-Cd worked ( Ni-mh didn’t then exist ) and was proved by the fault returning with the original ,full-capacity battery……Can any bright sparks say exactly what is in the receiver or servo which is stopping it from working at high alkaline levels?   No prize other than congratulations,well spotted.

I therefore say:  Avoid alkaline batteries unless radio instructions say it’s o.k. to use them,  O.K. "they don’t go wrong"  but many radio control sets are not designed to work at alkaline voltage levels.The instructions on my radio sets all say Use rechargeable batteries only ,not alkaline types.…….

 On high drain Vs low drain batteries…….High drain have a lower internal battery resistance than the same sized same capacity low drain cell . The resistance parameter is an issue only in high-current motor drive applications where a pack discharges in minutes rather than hours.

 If a transmitter  instruction sheet says current draw 108 mA off a 10.8 volt  Ni-Cd then that is equivalent to100 ohms …..an old 8 pack of high resistance sub-c cells would have an internal resistance of 8 x .05 ohms or 0.4 ohms ……..That would mean an efficiency of over 99.5 % The efficiency and recoverable energy for bog standard batteries is not noticeably different at that rate of discharge………Only when the maximum recommended current is reached or the load resistance is less than 20 times the internal battery resistance should you worry about cable size or consider upping battery specification.

 In a receiver pack,there would be no great benefit in using 3 milliohm cells either if the standard switch harness and battery tails add to over 1 metre of low gauge cable. (equivalent to 0.1 ohm).

That’s enough arithmetic on SCE and SCR cells for today! Anyone want to do show the algebraic equations showing how efficiency and output voltage tails off at high discharge rates?….No?

 Since high drain batteries are not needed and Ni-mh are cheap (via E.B.A.Y.) in 2.4Ah AA size there goes the one and only argument in favour of NiCd over Ni-mh.

Don’t get me started on Lithium batteries…..They’re coming to RC equipment though,like it or not ….I have two relatives abroad who had phones with UK sim cards which they only use here….blah…blah ….blah…….the instructions recommend….for optimum lifetime ….each time they vist I have to remove and jump start battery……blah….blah…..old trick learned for Ni-Cd’s …..I can just imagine ,in a few years from now, the phone calls asking for help and the queue of pensioners every Sunday……

Is that what it’s like in model aeroplane clubs?

[Billy BobParticipant @billybob24045]

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