About 10 years ago I bought a 5000 mAh and a 2800 mAh LiPo batteries. I used them all these years without ever having problems; I was quite active, so they went through frequent charge and discharge cycles.
Recently I’ve been using them less, leaving the batteries at storage voltage for many months and forgetting to recharge them. The result was a critical imbalance of the cells that is no longer recoverable.
I’m thinking of buying a new battery pack. Given the technological developments, would it be better to switch to LiFePO4, or stick with LiPo?
I don’t have any issues with chargers because in recent years I’ve switched to LiFePO4 for my motorcycle battery.
I’d suggest LiFePO4 12.8 volt batteries with integrated Battery Management System. If you have a suitable LiFePO4 charger or current limited power supply, you should be fine.
…I have this type of battery. It is 60a/h and very easy to carry (light). I had to buy a special charger though as the led acid battery charger I had wasn’t suitable. I use it in my car when operating portable with my FT-710. Very happy with the LiFePO4.
Another vote for LifePO4 - 10 years ago, they were horribly expensive when compared to LiPO, so LiPo was the better buy. The Gotcha with LiPo was that you needed a special charger as the charger balanced the cells; there was no BMS inside the cell. With LiFePO4, the battery comes with a built-in Battery Management System (BMS) to make sure that cells are charged and discharged equally. There is no extra lead on a LifePO4 where it would go into the charger, along with (in some cases) the main two leads as well.
There ARE LifePO4 chargers that seem to “talk” to the built-in BMS and hence can charge the battery as quickly as is safe. Simply using a regulated PSU of the correct charge voltage will work, but not be as quick as the specific LifePO4 chargers. If you shop around, the LiFePO4 chargers are not that expensive either.
The key difference of course between LiPO and LiFePO4 is that a LiPO battery will normally supply a higher voltage for the same number of cells, so ensure you match up a suitable LiFePO4 to what your equipment needs. Normally, this will be a 12.6/12.8V 4-cell LifePO4. Ah is whatever you calculate you need for your usage.
I forgot to specify that I would mainly use it to power a KX3 in QRP; I rarely exceed 5 watts. Since it operates at a slightly lower voltage compared to LiPo batteries, I’m not sure I’ll be able to use the KX3 at maximum power, but that’s not very important.
However, the RC packs that we all were buying some years back no longer seem to be available in LiFePo, only LiPo. The big advantage is LiFePo are not the fire risk that LiPo are. I try to avoid buying LiPo now.
One possible source is Eremit.de. They have been selling LiFePo packs for some years and they seem to use the top quality cells. I have a 12.8V 4Ahr pack and with my KX2 on mainly CW it’s good for 6hours of operating. Eremit sells it for €35 including a built in BMS. You will find many satisfied Eremit customers on here. The downside is Eremit only ships to German addresses. You can possibly arrange with some German SOTA friends for them to buy a pack or two and you can meet them and collect the packs. Maybe you meet up midway between Italy and Germany and do some Swiss summits Eremit also sells bare LiFePo cells in 18650, 26650 & 32700 sizes. You can buy holders on AliExpress for pennies if you want to make your own packs up.
Cells are available on AliExpress along with everything else you need to make your own packs. The problem is most vendors ignore the rules on shipping Lithium cells so there is always a change your items will get stopped by your local post office. The Royal Mail in the UK do X-ray some packages and if it looks like batteries inside will destroy the package on “safety grounds”.
There is a huge number of items when you go looking, but if it was me, I would be looking for someone on here who lives in Germany who is going to the Friendrichshafen rally and see if they will buy and bring an Eremit pack to the rally where you can meet up. It’s how I got my Eremit pack a few years back. I wont say which super nice guy did this in case he doesn’t want to be inundated with requests!
If you buy a 4S LiFePO4 battery your kx3 will run very happily on that for hours. I run my kx3 at 15w or 10w depending on what seems to be needed (and the band) on a 4S LiFePO4, which charges to 14.4v and drops down to below 12v after quite a while. Below 12v the kx3 automatically switches to 5w. If using 5w always, the 4S battery will run it even longer. Usually it will do at least 3 activations of 25 contacts, or more.
My LiFePO4 batteries bought from Hobby King 10 years or more back, are just 4 cells connected up in series with a power output leads (red/black) and a balance lead containing a wire for each cell connection and a 5 pin connector. They require a charger with the balancing lead socket as well as the lead used to charge and discharge. Most of us have put a powerpole connector on the charge/discharge wires. But more recent LiFePO4 batteries have the internal battery management system (BMS) to perform the balancing process. They just need a current limited DC source of 14.5v or a little more.
(An extra comment about connecting to these batteries: Due to the thickness of the main power cable capable of producing up to 90 amps, the wires cannot be connected to a 30 amp powerpole pin. But if split into two sets of wires, each half can be connected to a 30 amp powerpole pin, so I have done that with mine. The battery thus has a pair of powerpole connectors and can power two devices. Take care when stripping the wires for that operation, do one polarity first and only strip the second wire when the first one is safely completed and covered with heatshrink insulation. This saves making up separate adaptors to power ATUs or amplifiers from the same battery that powers the radio. )
Last week I ran my KX3 for 4 hours at 10 watts with a 4.2AH LiFePO4. When I charged it, it only took 1.76A to fully charge. I would say something around 2AH should be ample for a couple of normal SOTA activations.
I still have a couple of LiPO batteries, but I will not be buying more as LiFePO4 are much safer. I’ve never had any issues with LiPO, but you never know what might happen.
Eremit also sells bare LiFePo cells in 18650, 26650 & 32700 sizes. You can buy holders on AliExpress for pennies if you want to make your own packs up.