For the Xiegu G90 you would be better of with a 3s lipo,
(although lifepo4 4s is better still)
The G90 works absolutely fine down to about 10v so the 11.1 that a 3s lipo will run at for the most of the discharge curve works absolutely fine
1 Like
from the G90 Manual.
For the full 20 watt output, a supply voltage of between 13.8 & 14.3v is required. Running from a lower voltage such as from a 3S LIPO, the output power will be reduced. (and sometimes with some radios other issues can occur).
That can still cause you issues with modulated sidebands at a spacing equal to the fundamental frequency of the buck/boost regulator. They may appear in your transmitted audio, but typically they will be 30-40dBc.
That is most likely what you’ll find. If you study the boards you’ll find most are running the LM25xx regulators. Quite distinctive and work well.
Well, I have found an alternative LiFePo that is available for you to order now, but it’s pretty expensive:
Including shipping it comes to €89. Whilst the capacity is a bit lower than you are looking for, I use the 2400mAh with my KX2 and find it more than enough for several hours use. At 20w, you should get a few hours out of the 3100mAh. On the other hand, it’s probably lighter than the Zippy. The quality is generally regarded as being higher than the Zippy as well, which may or may not help justify the price tag to you. If you want, I have an old Zippy 4200mAh I don’t use anymore. The capacity seems to me a bit lower than it should be, but it will get you on air no problem. PM me if you’re interested.
73 de OE6FEG
Matt
Matt thanks very much for your help. I have ordered a 4s lipo to get me started. At the moment here in the UK it looks like we are headed for a long lock down, so this will get me going. I have a lot of experience with Lipos as I am a photographer and commercial drone operator. I have also set an alert for when the LiFePo’s come into stock with Hobbyking. Just looking for a 10A buck converter now. Thanks again!
Ed,
Does that 10A minimum rating on the power supply really mean it consumes that much when producing 20 watts output? 13.8v at 10 amps is 138 watts, a lot of power required to produce 20w. Of course all the lithium batteries will source much more than 10 amps but this power requirement seems abnormally high.
Is that what you have observed with yours?
Andrew VK1DA/VK2UH
My FT991A takes 6.7A on ssb transmit standby, kicking up to 7.6A on voice peaks at 5W output. I can only imagine that a very high standing current is used in the PA output devices…
Hi Andrew, I posted the page from the G90 manual (obtained online) in response to the suggestion that the G90 could be run from a 3S LIPO at 10-11v.
I do not have a G90, you will need to ask Martin to measure the actual current consumption.
With my X108G, which is the G90’s predecessor (but not SDR and no tuner) I run it at full power (20w key down, probably 30W PEP output) with an 8 amp fuse, I think I’ve run it with a 5 amp fuse as well but wanted to give it a bit of headroom.
73 Ed.
1 Like
When I actually get a battery I will post! It is frustrating having a new toy and no way to power it up! LOL
M7BIA Martin
1 Like
There is also the possibility of using a car booster battery, such as e.g.
https://www.pearl.ch/ch-a-ZX2905-1420.shtml
You’d have to take the power from the outlet intended to start the car. Check the voltages first, though.
73 de Martin / HB9GVW
Indeed.
The radio has a fairly generic user manual with some Conservative power supply figures.
But extensive testing of the G90 by various people suggests that power does not fall away until the output voltage drops below 10.1v
I have certainly run mine at 10W on 11v with no trouble whatsoever and measured the full 10W out.
Can’t currently test it at more than 10W until I take my next exam but I know plenty of owners of the G90 who have.
That’s interesting Dan. The Yaesu FT-817ND was always known to be able to run will at a lower battery voltage with no receive or transmit issues. If the Xiegu G90 can as well, that a plus point for the rig (I have the predecessor, the X108G and it won’t work reliably at 11v - in fact, it displays a warning).
do not have a G90, you will need to ask Martin to measure the actual current consumption.
It is much less than 10A. I do not have exact measurements, Julian OH8STN has done a much better job and done all the measurements:
At about 11:30 min you’ll see the synopsis. Max is 5A @ 20W on 80m.
73 de Martin / HB9GVW
I saw it last week! Arrived and all soldered up!
“Fuse needed in both leads” says the voice of experience.
1 Like
Following with interest as a SOTA newbie with an 817ND (!) How long (roughly of course) could I expect to operate SSB with one of these? (the Zippy Compact 4200mAh) Is there anything I should know about connecting them up, and is there a charger you would recommend? Thanks, and apologies for the many basic questions!
Best,
Gordon MM0GSS
I use mine on a Xiegu G90, after a couple of hours they only loose 15%. I have a Life 4S one and a Lipo 3S.
As to chargers look for a specific one that can be changed between Life and Lipo, the cell voltage is different 3.3 for Life and 3.7 for Lipo. It also needs to be able to balance charge, so that all the cells are charged equally together.
Hi Gordon
For an FT-817 I would recommend these: https://hobbyking.com/en_us/zippy-compact-2100mah-3s1p-30c-lifepo4-pack.html - you can always take more than one battery remember if you need longer operating times!
They a 3 cell rather than 4 cell and a better match for the FT-817’s power requirements. Having said that a 4200 maH 4 cell would last you literally hours and hours and hours, possibly days.
I’ve got one of these chargers: https://hobbyking.com/en_us/turnigy-accucel-6-80w-10a-1-6s-balancer-charger-suitable-for-lihv.html
Works a charm.
1 Like