what battery is best to power my radio,want to use a small mobile transceiver.would motor bike battery be ok

In reply to M3PPQ:

What is your radio and what power do you wish to run? 10 watts max. I presume you mean for /P operation.
Simple maths really 10 watts, 12 volts, so just under 1 amp on transmit. Some radios like the FT-857 or IC-706 can draw as much as 2 amps just on receive.
Most ops use a SLAB (sealed lead acid battery) which come in different sizes, the likes of the FT-817 will do a few activations on a 3ah SLAB whereas the bigger radios would require a 7ah SLAB.
SLABs are readily available on ebay and quite inexpensive.

73 Mike GW0DSP

In reply to M3PPQ:

what battery is best to power my radio,want to use a small mobile
transceiver.would motor bike battery be ok

Hi there,

If its for SOTA I would have thought that the best option has to be
the sealed lead acid battery (Gel Cell) commonly known as a SLAB. I
believe that there 2 types, one of which is normally used in Alarm
systems and is float charged, and the other which is suitable for
deep discharge and which would be preferable. The same difference
as you would find between a vehicle battery and the deep discharge
type of ‘wet’ leisure battery. I would think you would run the risk
of accidental leakage from a motorcycle battery (I am assuming they
are still the ‘wet’ type as my motorcycling days finished many years

Kind regards

Dave G0ELJ

In reply to M3PPQ:

What kind of radio do you want to run?
How long do you want to run for?
How much do you want to spend?
How much weight are you prepared to carry?
How far do you intend to carry your gear?

A little more info on your intentions and you’ll get lots of suggestions. You can also use the search facility to look back through the prvious threads as this subject is discussed very regularly.


In reply to MM0FMF:
want to run a kenwood tm 241,run it for less than 2 hours.will spend up 2 £30.will be carrying up mountains,not hills,so cant have any thing that will le3ake…thanks

In reply to M3PPQ:

Hmm, an interesting choice of radio, not one I would carry up a hill never mind a mountain!

Easiest point first, mustn’t leak. So a sealed lead acid (SLA) or NiMH pack or LiIon/LiPoly pack.

Mustn’t cost more than £30. So that rules out NiMH and LiIon/LiPoly packs.

TM241 on high power draws 11A on TX. Probably about 4A on medium and let’s assume 2A on low power. It wont be frugal on RX so we’ll assume 1A. Well 50W is a non-starter, so we don’t need to worry about providing power for that. For anything approaching 2hours operation you’d be pushing your luck with a 2.8AHr SLA so probably a 7AHr SLA would do and would allow some operation at medium power with a comfortable margin.

A 7Ahr SLA weighs 2.65kg and you should be able to get one for around £14 plus p&p.

Personally, I’d look for a cheap FT290Mk1 and a small linear. You can get 290’s from £65 and MM 25W linears for around £30. Although you’d have to drop the drive to the linear to keep within the 10W limit. That would give you the big advantage of SSB where your battery will last a hell of a lot longer than on FM.

Shame you sold that 290mkII a few weeks back, that would have been ideal.