So today I went out for a trail run and took my backpack and 7m mast w/Slim G in the car with me to do a bit of 270 afterwards.
I took my new to me MML 144/25 with me to try and give the FT-65 a kick up the bum with a bit of power.
I hooked up the LA to a 12v 20ah LiPo and it didn’t power the amp. I later copped in small font it says it needs 13.8v to work. Argh!
The amp does work though as I tested it with a PSU at home to see was it all ok. Just wondering what I could use to power the amp outside of one of those Jackery things that cost about €927,604 (ex VAT)?
For my amplifiers I use 4.2AH LiFePO4s. Much better than LiPOs, which I personally only use to power rigs such as the 817 and KX3 running at 2.5w output, the drive level for my amps. At one time I did use 3S LiPOs with a single cell NiMH in series to power my amps, but that was down to the cost of LiFePO4s… now somewhat better.
Perfect! Thanks chaps. I shall investigate a LifePo battery so. The LiPo powers my 891 really well so I figured it would do for the amp. I just didn’t cop on to the MML needing a bit more welly.
Looking forward to giving my HT’s a bit of a shot of adrenaline! Next step after that is to build a Yagi and a Cubical Quad. 2 of each, 2 for 2 and 2 for 70. Then with the Slim G and the 270 Moxon I should have a good spread of toys to try!
I don’t think you can get hold of LifePo4s via Hobby King anymore which is a shame because the batteries were excellent (although no BMS so unprotected).
I noted in the UK that eBay has a seller with a variety of battery sizes and weights at reasonable prices: DC HOUSE UK | eBay UK Stores
They have balance charge leads though. Let the charger do the protecting. It’s also possible to fit a small LCD voltage monitor to the balanced leads, which will alarm if any cell drops below a preset voltage when under load.
Shame you can’t get them any more. I have a 4200mAh and 8400mAh, weighing just 500g and 1kg respectively. They are great batteries.
I think generally the issue of supply has been a thorn in the side in the UK. I have 3 LiFePO4 batteries, each 4200mAH sourced from Hobbyking, but they have been like rocking horse droppings over recent years. The situation may be better for you inside the EU. As Fraser says, they have a balance connector and I use an Imax B6AC charger for both them and my LiPOs. I never charge at a rate greater than 1.5A.
Yes… don’t do what I did. All my packs are fitted with fused leads terminated with powerpoles and I use a 4mm to powerpole adaptor to fit to the charger. Once I absentmindedly unplugged the 4mm end first… plugs touched, extremely loud bang, whistling ears, blown fuse. No harm done, but I aim not to repeat. Even though the LiFePO4s have a lower power density than LiPOs, they still have a huge capacity for their size.
And to think many years ago I used to drag a 12AH sealed lead acid battery around the hills.
There’s a drone and RC shop in Dublin I might look in on soon. They might do some batteries along the lines of those Zippy ones.
Hopefully that 12.8v 20ah one will do for POTA and BOTA (beaches) on the linear MML and the 891. No use in a backpack though. Hoping to get a little time soon to get up and summit soon and it would be nice to take the MML up to give 2m some extra POW! 70cm will have to be at 5w on the Quansheng.
You can obtain LiPo 18650 and 21700 cells easily but LiPo is somewhat pish compared with LiFePo4 technology.
However, there do seem to be a fair number of 26650 and 32700 cells available on eBay. e.g 32700 sized (32mm diam 700mm long) 6Ah LiFePo4 for £7.70 + p&p. These have M4 threaded connectors. You would need to wire them up yourself and also 3d print a carrier. But for about £30 you should be able to make a 4S 6Ah pack with leads to connect to a Imax B6 type charger. Obviously it will cost a wee bit more if you want to add a BMS to the pack.
I’ve seen one recently but wasn’t quick enough. Definitely on the wish list though. Then, with both MLL’s, decent batteries, a bunch of cubical quad antennas and a Quansheng at my disposal, 270 utopia will be reached!
…this is all well and good until you leave said monitor plugged into your brand new 8400maH battery over the weekend which knackered the one cell that it was powered off.
I also recently killed my longest running 4200 battery (to be fair it was getting on for six years old) as I left it plugged in to the IC-705 which then slowly killed it over the course of a few days.
I’m not rigorous with procedure enough to not occasionally make mistakes unfortunately!
Investing in amplifiers, antenas, batteries and then using quasheng on big antenas is not a good idea. Yes, it is cheap but his receiver is garbage
Buy ft817/818 and have everything you need.
I made an experiment two years ago. 10, 15 meters above me was commercial antenas for all bands from 2m to microwaves. I just need to put my hand on the cover of my ft818. He need some “ground” and received 1W beacon on 2m crystal clear 200 km away.
Buy 4s LiFePo4 battery. You can find them from 7Ah, 15Ah, 50Ah ….. Some of them also have build in BMS. It is normal that voltage drops bellow 13V with higher currens. My battery 3 years old 70% full is 13,2V
