It fits internally in the 817, is 3ah, is reasonably priced and works like a charm. I just bought a second as a backup. You can get the proper connectors to refit the dry cell pack connecter from an RC hobby shop.
I use a 6.6Ah (6600mAh) Ultra High Density Lithium-ion battery.
It weighs 6oz (170g) and it is truly tiny:
2.3 x 0.94 x 3.2"
5.8 x 2.4 x 8.1cm
Puts out 12.5V (12V under load).
To charge it I use a Powerfilm 5W panel:
Dimensions:
Folded (closed)
5.5 x 4.5 x 0.75"
14 x 11.4 x 1.9cm
Deployed (open)
25.5 x 11 x 0.06"
64.8 x 27.9 x 0.15cm
0.38 lbs (170g)
But I donāt often pack the solar panel since the battery lasts all day, the solar panel just comes with me on canoe trips charging up the battery as I paddleā¦
Tom, how do you get around the 817ās program that reduces power when using the internal pack?
Iāve been using 3 cell LiPoās for the last year with the 817 but externally. Iām using 2200 packs since I had them on hand for my R/C aircraft. They work great but the Venom pack you found is better solution but I hate to give up my 5 watts for 2.5 watts.
A bit delphic, Andy. Its a slight confusion: as I understand it an internal circuit in the 817 reduces an external supplies higher voltage to match the voltage of the internal pack, and 5 watts is available on either supply - or at least, on mine it is! As a consequence the 817 runs warmer off an external supply because of the voltage drop.
I donāt think so Brian as a brief look at the circuit diagram would reveal.
Follow the battery input through D1084 to TP1078 and then from there follow it back through D0185 to the external DC input. i.e. the power inputs are commoned at the filter.
You know I never really used my 817 from the internal battery pack so I never checked it. There is a reference on page 28 of the manual that indicates the power will be set to 2.5 watts when on internal battery. More careful reading seems to point out you can change this but to be honest it isnāt the clearest of English - even for us Yanks! G4ILO on his review also echoes the āhalf powerā limitation when on internal battery but goes on to say you can set it differently.
My bad, I stand corrected and thanks for pointing that out.
Hey, they donāt call us the āSOTA Jerksā for nothing you know!
I donāt think so Brian as a brief look at the circuit diagram would
reveal.
Follow the battery input through D1084 to TP1078 and then from there
follow it back through D0185 to the external DC input. i.e. the power
inputs are commoned at the filter.
This doesnāt invalidate what I say, Andy, I am no more able to read that circuit diagram than I could read a bowl of spaghetti, at least without a good loupe, but if you look at the block diagram you will see that there are four regulators on the main board giving 3, 5, 6 and 9 volts and another on the PA unit. That these tie down the power output is strongly suggested by the observation that on increasing the input voltage whilst reading the output on a power meter there is little change. I suspect that you thought I meant that there was a discrete unit at the power input to do this job, but the job is actually distributed. And as I said, running the 817 at a higher voltage means more power dissipated in the unit and it operates at a higher temperature.
Iām using my 817 as an Echolink Node at the moment and even at 1W it gets very hot (13.8V). Looks like I need to decrease the supply voltage somewhat (or use a more suitable radio).
Iād have thought any old Chinese junkjob handheld would have done at that power Richard. eBay is full of the tat, JingTong, Baofeng, Magiksun, Ronson, Anytone etc. if you have to buy new.
Youāll probably need a small fan on anything consumer if itās going to be in TX for more than a few minutes at a time.
G4ILO on
his review also echoes the āhalf powerā limitation when on internal
battery but goes on to say you can set it differently.
You can force the 817 to use high power even on internal battery just by pushing the PWR button until the power indicator *))) flashes. Having said that I doubt you will get 5W out anyway. In fact I was checking my 817ND on 30m this morning prior to doing some WSPRing and found that it only puts out 4W on the high setting on an external power supply.
Iām pretty sure that the automatic changeover between 5W and 2.5W setting is done on voltage sensing. If you power the radio from a variable power supply you can see it start behaving as it does on batteries when the voltage goes below 11V-ish.
Presumably the folks who have fitted LiPo packs internally donāt use the built-in timed charging method?
Iām using my 817 as an Echolink Node at the moment and even at 1W it
gets very hot (13.8V). Looks like I need to decrease the supply
voltage somewhat (or use a more suitable radio).
In measurements on my 817s, on the HF bands they gave an essentially constant RF power output with input voltages between 9 and 15, and took virtually the same current. So the extra power in just comes out as heatā¦
On full power, one gives 4.5W on 5MHz, the other 4.8w so the 5W rating is somewhat nominal.
On the higher bands the situation is more complex, with around 12V being required for full output on 144MHz.