In reply to G4OIG:
Gerald is right, buy today, other than LIPOs battery is worthless. If someone wants to carry more weight on top, they will improve their antenna.
This is not advertising, perhaps it will help someone:
They have a large variety LIPOs and chargers. And the prices are very good.
Tested several times, all came within ten days in order.
73! Petr OK1FFU
In reply to G3CWI:
Well, I could say that I’ve got the T-shirt, but the truth is that the XYL is the driver and my walking partner and her knees have had it:-(
73
Brian G8ADD
In reply to OK1FFU:
That’s a great price, what kind of charger would you buy with that ?
Andrew
K1YMI / GM1YMI
In reply to KC2EUS:
I use this
with these
The same cells are used by several SOTAists.
SLABs are so last century 
Well that’s not fair. They’re simple to charge and if you don’t intend to carry them far then the weight is less of an issue. Once you start walking more than a few kms and climbing over a few hundred metres the weight advantage of LiPos becomes apparent.
Andy
MM0FMF
In reply to KC2EUS:
Hi Andrew
Dan, OK1HRA use this:
I have a very similar, all are copies of a proven product. Charging takes about 1.5 hours, I set charging current 3.5 A. Service is not complicated and can be recharged almost all types of batteries.
As the power supply you can use anything that can 5 A/12V. Or buy
73! Petr OK1FFU
In reply to KC2EUS:
Andrew,
I use the same batteries and charger-balancers as Andy - they only charge the 4AH batteries at 800mA which is 0.2C, so take 5 hours to charge from fully discharged. However, the chargers are so cheap that I have several and so I can charge packs simultaneously. I would advise that these charger-balancers don’t charge the 4S packs and a more comprehensive charger will be required for those. The subject has been discussed before on the reflector, so you may wish to do a search to see the comments that have been made.
LiPo batteries are now affordable - for a long time they were too expensive for most to consider. The other issue is that the one-time myth that the batteries did not produce a voltage suitable for standard rigs has been well and truly dispelled. A 3 cell battery typically gives 12.6V fully charged and 11.1V when discharged. I have taken my cells below the quoted discharged voltage without any ill effect.
The 5AH 20C battery on the website quoted certainly looks good. The extra weight relative to the 4AH 10C batteries appears to be due to the heavier grade of construction required to provide not only the additional capacity, but also the discharge rate. Of course for the average amateur radio set up, 10C batteries should suffice… mind you I wouldn’t mind one of the larger ones to power my 180W 2m linear!
73, Gerald
In reply to G0WBR:
Tim, this question has been asked here numerous times and I suggest you search the old threads. I have two FT857s, an 817 and a 706 mkIIG and have used them all on the hills. In the shack the 706 is a better rig than the 857 but on the hills the 706 is heavier both in weight and on batteries. The 857 will run fine on lower voltages and for much longer from the same battery. The current draw on RX is the first problem as it can almost zap the battery before you even make a contact. The RX current draw seems to be to do with the DSP circuitry but turning DSP off makes no difference. There is a further problem, the 706 goes into self oscillation as the voltage drops and your transmitted audio comes back through the speaker in the rig. If you were to use LiPo batteries as some are suggesting you will really have problems due to the lower starting voltage, the rig will be unstable from the start. It will be fine with SLABs but you will only get around half the QSOs you would using an FT-857. There is a lot more info on this subject that has been posted to this reflector so it is well worth having search through the archives.
Steve GW7AAV
In reply to LA8WF:
Dear Jon!
Let me add arguments to my statement above, as I dealt some time (by profession) with UPS-es and batteries several years ago.
In case of batteries the basic arithmetic 2x2=4 is not really applicable. Let’s assume that a battery of capacity C loaded with I current. Based on the thumb rule it provides t=C/I operation time. However loading it with I/2 current does not result in 2¤t operation time but more! The lower the loading current is, the more the difference is from the calculated t=C/I value! That is, the t(I) diagram is non-linear, but somewhat resembles to the function y=1/x !
This is the reason, why I suggested using a higher capacity battery instead of 2-3 lower capacity ones.
73: Joska, HA5CW
In reply to G0WBR:
Tim,
I have had a 706MKIIG for years now and have taken it up several hills. Its not a bad SOTA rig, but I have found that the RJ45 based mic connector fails every couple of years because it does not have a molded stress connector. This is a reall bummer if it happens to you while on a summit as I expereinced this year.
I have since replaced the mic cord with the stock cord from an FT-817 which has a nice, protected connector.
Also my 118t? Touch Tone Icom mic for the 706 had poor quality UP/DOWN mic buttons. Those buttons which are used for CW are not rugged at all, and one has failed me.
All that being said, I have used my 706 with a LiFePO4 homebrew pack with nice results. I suggest you consider LiFePO4 cells instead of the traditional lithium technology as these are much more rugged in terms of balancing and fire hazard, yet have a comparable power density to traditional lithium and have provide many more cycles then either lead acid or traditional lithium. You can find the cells at batteryspace
or Buddipole
If you are really going to only use the 706 for 20w, there is a mod out there for the 817 for 10w+ if you really want to push your luck. You could trade back to an 817 and save yourself a bunch of weight and some bulk over the 706 and loose only about 3db vs 20w.
73,
Tom
Thanks guys for all your help and information.
I think for the extra weight of the radio and batteries I need to trade in the 706 for, probably, an FT817. I have used one when out portable on a number of occasions and had a lot of fun with it so will probably go for that. It would be nice to have the extra power of the 857 but can’t stretch to that amount of cash.
Cheers again.
73
Tim
G0WBR
In reply to G0WBR:
I’m more than happy with my FT817 (weight 1.17 kg inc internal NiMH battery pack), Tim. I used mine at 5 watts on 2m in the VHF Fun Day yesterday, and that was enough to enable me work almost every station I could hear on the 3 el SOTA-beam. (Only 2 got-aways.)
For what it’s worth, yesterday I was using a 3.3 AH SLAB (weight 1.3 kg) which was fully charged at the start. I operated fairly intensively for just over 3 hours and at the end of that time the “lower power” indicator on the 817 was just beginning to flash. I have become aware that the one thing that DOES pull the battery down with the 817 is transmitting on FM at the 5 watt level. Yesterday, almost half my contacts were on FM and that did put a heavy drain on the battery.
73,
Walt (G3NYY)
In reply to G0WBR:
… I need to trade in the 706 for, probably, an FT817.
maybe you should consider buying an icom ic-703! i use it for my sota-activations and i am 100% happy with it. it has a built-in atu and has 10watts power. but it’s only 0.5 kg lighter than the ic-706.
vy73 de martin
www.oe5reo.at
In reply to G3NYY:
is transmitting on FM at the 5 watt level
FM isn’t known as feeble mode for nothing! It does hammer whatever batteries you have on the 817. However, my VX-170 handheld appears to have a Tardis for a battery. No matter how hard you abuse it at the 5W level it just keeps going. Best of all you can knock tent pegs into hard ground with the VX-170 and as long as you’re careful you wont damage the tent pegs! The VX-170 battery is a 1400mAhr NiMH pack and so is the FT-817 internal pack yet the VX-170 just keeps going.
Andy
MM0FMF
In reply to OE5REO:
In reply to G0WBR:
… I need to trade in the 706 for, probably, an FT817.
maybe you should consider buying an icom ic-703! i use it for my
sota-activations and i am 100% happy with it. it has a built-in atu
and has 10watts power. but it’s only 0.5 kg lighter than the ic-706.vy73 de martin
www.oe5reo.at
Built in atu is good but only trouble with the 703 is that it doesn’t cover 2m
Martin. Otherwise yes I did consider one of those.
73
Tim - g0wbr
In reply to G0WBR:
I will add me 2 pence worth here, My two main radios are a Icom-706 MK2 and a FT-817ND. The 706 i find eats battery life and for this reason i wouldnt use it /P, At the moment nearly all my operating is either mobile or portable so the 817 dominates the 706 and being interested in QRP the 817 is the radio of choice for me.
If i was to choose from the 817 and a 703 i would go for the 817 as it has the extra 2 bands, yes there is a 3db difference but operator skill in choice of aerials and/or band for time of day/year along with modes one can over come if not better this difference. Sean M0GIA
In reply to M0GIA:
I might be slightly arrogant here, but I reckoned when I was active that the chaser end had to find the better kit, and I travelled light. I did have a 706 some years ago, and never even contemplated taking it /P - the 817 is just so much lighter, smaller and neater. My only quibble with it is the size of the buttons, which are inoperable with gloves, and even difficult without.
Then there’s the RX current draw.
In reply to G0WBR:
Hi Tim, I just see this thread so back to your original post : I have been an user of a 706MKII for ALL my SOTA activations. (I sold it for an ICOM 7000 now)
It was used with about 30W, battery was a 9Ah, and worked perfectly all the activations during (even with some SSB QSOs)(CW will let you use the battery more time). All my SOTAs were filmed and online on Youtube if need…
Hope it helps !
73 QRO de Chris F8DZY.
In reply to MM0FMF:
Andy,
I’ve had a look at the batteries etc in your post and quite right they look very small compared to my 7ah SLAB. So tell me what connectors and configuration do you use. Do you put any sort of protection in line for getting wires the wrong way round etc.
If you have details of parts etc even pictures anything would help as I haven’t seen these in action or used by anyone yet.
Thanks for any advice
Regards
Brian (M0OYG)
In reply to 2E0OYG:
I used Tyco/Amp FASTIN-FASTON 250 series connectors for the simple reason that I had some in the junk box. I wanted a connector that was impossible to connect back to front. Also a connector such that you would have to try very hard to accidentally contact the terminals on the battery side. The 250 series does that but there are others. As I said, I happened to have some 250 series lurking. Anderson Powerpoles are probably as good.
The requirements are:
The rest was simple commonsense to make sure the wires can’t become disconnected easily (heatshrink, cable ties etc.) It’s probably taken longer to type all this than it did to fit the connectors and make everything ship-shape.
Andy
MM0FMF
In reply to 2E0OYG:
Hi Brian
I can recommend the Anderson Powerpoles - they have all the desirable attributes listed by Andy in his posting, and are easy to use even with gloved hands. I have now standardised on the 30A pattern for all my power supply leads in and out of the shack. There is a conventional configuration - see RAYNET-UK | Technical Team - RAYNET Power connector
I fix a pair of powerpoles to the flying leads from the LiPo and tape them to the battery for strain relief, then use a short lead with a fuse in (3A for the '817) for onward connection.
(Quick query for those cleverer than me - I have occasionally seen recommended using a fuse in both positive and negative leads. Why on earth would you want to do that other than to increase the profits of the fuse manufacturers???)
I use 2200mAh LiPo’s with my '817 and get some 3hrs of sideband operating with one charge. So no need to lug those oh-so-heavy 4000mAh LiPo’s up the hills
73 de Paul G4MD