During my last activation, I used a new type of battery for the first time. Since the climb was not foreseen to be a huge physical effort and I only had one type available, I took with me a 20Ah battery. I am more than happy with performance and I believe I will not transmit portable without it anymore.
I used a RELiON 2V 20Ah LiFePo4 or LFP battery promissing a higher usable capacity and cycle life than lead acid alternatives. 14.6 V is the recommended charging voltage and the LiFePO4 technology maintains consistent power even if you only charge it partially. Weight of the pack was 2,55Kg and am looking out to purchase the 5Ah and 10Ah versions as the 20Ah was admittedly a bit of an overkill for the summit activation.
Has anyone had SOTA experiences with these Lithium Iron Phosphate batteries over the regular LiPo’s? LFP batteries should be inherently safer. Has anyone used them for a longer period? Thanks for sharing your up side/down sides.
during my 10 years of portable activities I have passed the usual way from SLAB to LiPo to finally LiFePo4.
I am still using 4200 mAh LiPo (3S) to feed my 2M FM handie on the highest summits, but 4200 mAh LiFePo4 (4S) feeds my KX3 on tne medium ASL summits or by my WWFF activations since two years ago. I use the battery from HobbyKing charged by IMAX B6 and have absolutely no problems with the combo.
I have been using a 4Ah LifePo4 for about two years now, I am very pleased with it.
There are lots of comments about them on this reflector, and I think the key points are: Do not run it down below minimum voltage. Do not store it fully charged. Do not charge it fully in a warm house and then take it out into sub zero environment (either charge it to 90% or keep it insulated)
Having a properly designed charger is important too.
Yes Gert I’ve been using them since summer 2014 when I met DF2GN/P Klaus in the DM/BW area and he showed me his in use. Since then I’ve bought 2 X 7 AH Ultra Max hard case units and 2 X 4.2 AH shrink wrapped Zippy type. I’ve never looked back.
I’m using a 12.6V 6.6 Ah LiFePo4 from I-tecc for more than 2 years now. It weighs only 738g and has a built-in Battery Management System for charging and balancing, as well as over- and undervoltage protection.
This battery runs my KX3 and - if needed - my HLA-150 amplifier all day long on the summit. Also no problems with low temperatures in winter.
This battery was perfect for our Iceland 2017 SOTA Expedition.
I am sold on LiFePO4 batteries. A 3Ah one from Bionics will give me a few activations easily with a KX3. Safe and convenient. If you have a 857 and like to operate at 30 to 50 watts, a 6Ah or so battery might be appropriate for an activation. On the other hand, the internal Lithium Ion battery in the KX2 will give me 2 or 3 activations and is even more convenient.
What is your point of reference for this Adrian? I have read instructions from several manufacturers that have indicated that it is okay to store them fully charged which would provide the advantage of the kit being ready to go. Not as though it affects me at this time as I am still “wearing out” my 2009 vintage LiPOs.
For shorter hikes, or when wanting to be a relatively big-sig, will use a 100-watt mobile rig, with a 19 AH LiFePO4 battery with built-in 30A safety current limiter. Batt weighs 4.8 pounds, and absolutely delivers the goods, with a 22-Amp key-down current. I store it fully charged, and top it off before activating, because it does self discharge over several months.
Well, it is an inference rather than a clear reference, though I think I did read it somewhere when researching where to buy - my charger has a “storage” setting, which charges (or discharges) the cells to a point less than full. That isn’t proof, of course, but it seems that the designers thought it a good idea. There is also anecdotal evidence on this reflector which suggests that cells deteriorate if regularly stored fully charged, though I can’t just find any of them to quote!
I’m willing to be corrected, though.
I don’t find it a nuisance. I only have a 4Ah battery, and charge it at 2A. It is never stored fully discharged, so it takes typically an hour to fully charge before an activation. I either do that the night before, or whilst eating breakfast / packing gear etc.
I can see that if I had a larger battery, or plans were more time critical, it would be worth finding out for certain, but in my case it is a potential risk easily avoided…
I have been using a LiFePO4 for a couple of years after the SLABs I inherited from MM0DHY had to go to the scrap yard. The battery I use is a small, 3 cell 2.1AH which, when fully charged, allows my FT817 to put out 4.7 watts. The battery weighs 210 grams. The battery allows up to three activations, preferably two, and I have balance charged it every time. I usually keep it fully charged. The only problem has been one of the leads on the balancing plug for charging the battery got broken in the rucksack, but has been successfully repaired, a number of times now.
In fact there is a second problem, airport security! The battery is quite often examined and I have been told it is not allowed. But I tape the connections and carry a copy of the regulations and so far, I still have it.
Thinking about this now, it occurs to me that you can get LiFePO batteries for motor bikes, and possibly cars too. These will spend almost all of their life fully charged.
Does this suggest that there is no problem with fully charged storage of LiFePO cells in general, or is the chemistry slightly different? Or the management firmware? How long does a cell have to remain with no discharge current for it to count as “storage”?
“This study presents the ageing results of 27 commercial graphite/LFP cells stored under 9
different conditions of temperature (30°C, 45°C, and 60°C) and nominal state of charge
(SOCnom 30%, 65%, and 100%). The extent of capacity loss was found to be directly related
to the storage temperature. It is most prominent for the most severe ageing condition (T = 60°C
and SOCnom = 100%). Storage SOC also influences the capacity loss, though it is of secondary
importance compared to storage temperature”.
So, it would seem that the state of charge during storage over a period of months does affect the capacity, but only by a few percent. I’d guess that most activators don’t store their cells for months at a time on a regular basis anyway. If you are planning to do that, it is probably good practice to draw off some of the charge, and keep it somewhere away from heat.
Strangely Colwyn, I’ve never had my LiFePo4 checked by airport security. I keep it in my carry on luggage and leave it in the luggage for scanning. I always expect that they will check it but it’s always just sailed through!
I’ve only flown with it 7 times now so maybe I’ve just been lucky?!
Yes James. I must have had well over 20 flights with the battery. On only one occasion, at Heathrow actually, did a young and enthusiastic security operative insist it wasn’t allowed. However, at my insistence, the supervisor was clearly irritated to be called over, perhaps not for the first time that shift, and nodded me through after a cursory look.
I have the battery in a transparent accessory bag (map case) which is often examined as it had leads and wires so it may be coincidence.
Got mine from HK last year brill little battery. But best make a case to protect it in and carry about as i have down with a strong sandwich box allowing leads to pop out and keep the voltage meter with it. Don;t let Voltage drop too low and if in long term storage set charger to storage setting on charger. But prior to going out recharge.
I use a FT450AT lasts me about 4 to 5 hours on 10w TX
PS when on there page don’t buy straight away sometimes a pop up comes up on screen offering discount got 10% off mine as advised by a friend
whenever I plan to do more than just the required 4 contacts, I take a 4s 2300m Ah LiFePo4 with me as a backup for the internal batteries of my KX2, TH-72D and mobile phone. Or, depending on the duration and nature of the activation, whenever I want to spot my track via APRS or have extended emergency capabilities.
btw: In my home shack I am using 200 Ah LiFePo4, solar charged.