Futaba RX power & battery type

[HowardParticipant @howard79726]

Hi there,

This is probably a matter of terminology. The instructions for my new Futaba R304SB receiver ask for a power supply of 4.8 to 7.2v but NOT 'dry cell' batteries. This is for is an IOM running a Kingmax sail winch rated at 6v max, and I am currently using a NimH battery pack (5 x AAA size) which performs well, but does this mean I should upgrade to LiPo at 7.4v for the new RX, which may be ambitious, or does the term 'dry cell' not apply to pre-made packs?

Howard

Edited By Howard on 16/05/2021 10:30:37

[HowardParticipant @howard79726]

[Chris FellowsParticipant @chrisfellows72943]

Seems a rather odd instruction as it's only lead acid that are "wet" I would have thought?

I'd be wary of using 7.4v LiPo though as fully charged they are well above that voltage i.e. 8.4v.

In my yachts I use 6.4v LiFe Rx packs if you want something smaller than the NiMh pack.

Chris

Edited By Chris Fellows on 16/05/2021 10:45:03

[HowardParticipant @howard79726]

My thoughts also Chris. My other yacht has an RMG winch and I use a 2S Lipo in that which, as you say, shows 8.4v on a full charge. I may well try LiFe if it works for you!

Howard

[Tim RoweParticipant @timrowe83142]

Hello Howard

It could simply mean don't use the old style "dry cell". Often it is stated to use alkaline batteries (which seem to be more or less standard) if you are not using rechargeables.

Tim R

[HowardParticipant @howard79726]

Thank you Tim, I also wondered if that was the true meaning. Instructions can be ambiguous at times I find, and second opinions often help.

Howard

[Colin BishopModerator @colinbishop34627]

Alkaline should be fine. In some of my TXs I use the low disharge NiMH cells – best of both worlds?

**LINK**

Colin

[Kev.WParticipant @kev-w]

I sail an IOM with a Futaba sail winch, I use a LiFe 2 cell with no problems, I also use a LiFe 2 cell in my DF65 V6, this is the recommended battery for the boat, so you should have no problems.

Prior to this, I used a 5 cell NiMh & a 4 cell alkaline "dry cell" in the IOM, no problems encountered.

Edited By Kev.W on 16/05/2021 20:43:05

[Malcolm FraryParticipant @malcolmfrary95515]

A LiFe cell has a nominal voltage of 3.3, so 2 of gets 6.6 volts. I would be cautious about using LiPo cells, the seemingly small increase in voltage might not be good for the electronics.

One of the most common queries for DF65s was " do I have to replace my dead steering servo with a Joysway one or can I use something costing less". This was usually from users who had maxed on the battery voltage.

Dry batteries are normally single use non rechargeable types and are suitable for low drain applications, but are incapable of supplying high currents and maintaining their voltage. Rechargeable batteries are to all intents and appearances as dry as anything else, but inside are as wet as so called dry batteries. They do have the merit of delivering heavier current while maintaining their voltage.

"Dry", when applied to batteries just means that you can't pour the wet stuff out, as opposed to leclanche cells that could be re-enlivened by dropping a few sal ammoniac tablets into the visible liquid, and repeated until the electrodes dropped to bits. Just a case of the wrong words from past technology sticking.

[HowardParticipant @howard79726]

Thanks Malcolm, Kev and Colin, all very helpful. That's answered my queries and misgivings so I can happily go ahead and set up the new transmitter/receiver combo. Great stuff!

Howard

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