Just thought I’d start this thread. Seems a few people are getting interested in using this type of battery chemistry.
It APPEARS that it has a lot of advantages, but as always it seems to depend on what you read.
I have HEARD that they are 1/3 the weight of equivalent 12V same Ah SLABs.
They have a very flat discharge cycle, keeping their voltage high until almost discharged.
They hold their charge happily for months on end and don’t mind being stored fully charged.
A 4 cell version produces around 13V fully charged and is therefore ideal for use with 12V transceivers and doesn’t require any regulation.
They are relatively safe when compared to LiPo. Much less likely to go on fire during charge or discharge unless VERY abused.
You can charge with a standard 12V SLAB charger.
OK, so thats the hype.
What is the real world experience and where are people getting these from and how much are they paying?
I am very satisfied with my batteries, yes they were expensive but they should last many times longer than a slab without losing capacity. Mine are made by tracer power.com and can be found on Ebay. I found a retailer near Rotherham so I went to their shop to avoid paying shipping - I drive past it every week. My batteries are supplied with a custom charger and have an offset spring loaded bayonet fitting so you dont mix up the polarity which results in smoke (Brian).
When I weigh up all the advantages, I think it was money well spent. My particular brand of battery starts at 16Ah so a cw operator would probably need something smaller.
In reply to MW0WML:
Thanks for starting this thread.
Could someone tell us if LiFePO4 batteries have a minimum voltage below which they cannot be re-charged?
A source of reliable information?
www.HobbyKing.Com have a range of batteries, some available from their UK warehouse. When I bought my existing LiPo’s through them, they didn’t have a UK outlet, so price comparasons could be misleading.
Hi Don’t run them down below 3.8 each cell you will not get then to charge up again, you can get motinters to set so they sound an alarm when they get to 3.8v and i no i’ve been there.
In reply to G0VWP:
Not sure the arithmetic works out here. For a 4-cell battery (12.2V nominal?), 4 X 3.8V = 15.2V - more than it’s maximum voltage.
The booklet with my IMax B6 charger gives the nominal voltage of LiFePO4 batteries as 3.3V per cell, with the max as 3.6V. This gives a nominal 14.4V for a fully charged 4S battery.
The spec for the FT857 supply is given as 13.8 +/- 15% (ie 11.7V - 15.9V), which is why the LiFePO4 is so attractive.
Regards, Dave, G6DTN
I have a monitor for my LiPo’s, set at 9.6V. Even with 'phones on it makes you jump!
Even if you accidentally discharge a LiFePO4 cell well below the recommended minimum of about 2.5 volts, you can still safely recharge it. It may have lost some percentage of its capacity in the process. This cell chemistry is much more tolerant of slight overcharge and overdischarge than regular LiPo. LiFePO4 batteries are still optimally charged per cell with a balance charger, but I have used low current series charging without apparent ill effect or cell mismatch, though I would still balance charge it every once in a while.
In reply to AE5KA:
Hi Harold (or is it Chip - looking at your QRZ page)
What make/model do you have and where did you source them?
It is this much more tolerant nature that attracts me to these batteries, plus the flat discharge curve from around 90% full to 10% full. Can you confirm this in real world use.
Also, I’ve read that these work from 0C upwards, whereas standard LiPo’s can operate down to -20C. Anyone got any low temp experience? I often operate below freezing in Winter (“Quick QSO’s please” is often my call).
What make/model do you have and where did you source them?
I should also ask what you use to charge them. Some of the 12V packs are advertised as being chargeable with a standard SLAB charger (as long as it doesn’t trickle charge).
I took delivery on Saturday of 2 Zippy Flightmax 4S 4200 LifePo batteries. Sourced from Hobbyking.com (they have a UK warehouse too on same site), along with an Turnigy Accucell6 charger.
Coming in at in impressive 485g for a 4.2Ah battery and delivering 13.2V when charged. I cant obviously give an long term impressions having used them once but pretty impressed so far.
I have had great experiences both with large experimental cylindrical LiFePO4 cells I got from a now defunct electric car company as well as prismatic LiFePO4 cells I ordered special from batteryspace.com into a 4s 20ah pack.
The cylindrical cells seemed to get a bit low in voltage under load a bit early, however they were used in an experimental fashion by the car company, so I cant say that speaks to their quality.
The prismatic cells are phenomenal, and I got something like this
but also with balance leads that I don’t use .
I have drained 15amp hours out from this pack with my Icom 706mkIIG and sometimes an elecraft k3. I haven’t taken the pack beyond 15amp hours drained in total, but all the way to that point I could put out 100w from the rig without any issues in all temperature conditions. Its really an amazing pack…I have never bothered balancing it.
I do treat my pack with caution, and I transport it to the summit in a small case surrounded by some foam but again I have never had a problem. You may be able to see the pack in action in some of my SOTA pics/videos.
In reply to N2YTF:
I use a 6.6ah pack that comes from the same company Tom linked to above. This particular pack is attractive as it comes in a tough extruded aluminum case so I dont have to worry as much about damage to the internal cells. It also has a built in regulator board to protect the cells from over charge / discharge. I added Anderson Power Poles to the bare leads to make it friendly with my other equipment.
As to performance, I’ve recently used it for 4 days worth of activations without charging it and it held up fine with 5w out of a KX3. Its routinely 13.8V right off of the charger. I’ve not run it down to battery cutoff yet. The KX3 is happy with it. Time will tell if it lasts as long as a lead acid pack.
I haven’t used these cells in below freezing conditions so can’t speak to their performance there.
I had a 4S pack that I bought on Ebay for my K2. Composed of cylindrical cells, not A123, but it gave a good 2 Ah and fit in the position for the SLAB that normally comes with the K2 battery kit. A second one I bought, maybe not from the exact same vendor, had a weak cell.
I have also purchased LiFePO4 4S1P packs (Zippy brand) from Hobbyking. Half of them had a bad cell, but two are still much cheaper than one from Buddipole. Even a “good” one always seems to come in at 10% to 15% under rated capacity with a discharge test - even a fairly slow discharge test. Others recently seem to be having better luck than I did a couple years ago. Usually the cost and hassle of returning a bad battery isn’t worth it to me! The Zippy prismatic batteries could use a more robust wrap to protect from drops and abrasions. I used disposable plastic water bottles - they act just like heat shrink tubing and make a nice armor when shrunk around the battery.
Finally I purchased some genuine A123 cells from Hobbyking and made up my own batteries. These have been the best so far. Heavier than prismatic, but meet their rated capacities. More expensive than Zippy, but about half what Buddipole charges for their batteries - but you have to fashion your own interconnects and pigtails w/ fuse. If you go this route be sure they have solder tabs already on them, it is difficult to solder to a bare A123 cell without damaging it.
You probably can’t go wrong with the Buddipole batteries, but you pay. Other options depend on your tolerance for making your own batteries, carrying more weight, or maybe getting some duds from Zippy in order to save some money.
I use a Cellpro Multi4 charger myself. Great little piece of kit, but there are less expensive options in balance chargers that seem to do the trick too.
There are some very interesting recent regulations relating to the carriage of lithium batteries by Royal Mail services (effective from 14 January 2013). Basically, it is now against the law to send lithium batteries by First Class or Second Class mail except if they are installed in equipment (or in certain very limited circumstances, as spares “with equipment”).
The tightening of regulations is well overdue. A UPS or FedEX cargoflight was lost due to a fire in consignement of batteries. My own LiPOs were shipped from Honk Kong in an envelope. No not a padded envelope or JiffyBag but a plain brown paper envelope! They came in the normal post. Unbelievable!
As an engineer, I find the advances in battery technology over the period I’ve been licenced to be truly fascinating. We’ve moved from NiCd to NiMH to LiIOn to LiPO. LiFePO4 cells are obviously the current future technology. They’re just a little more expensive than LiPO cells right now but that will change. Their greater safety will drive the adoption.
There are quite few portable radios that are less dependent on final voltage and so 3S LiPO remains a cost effective choice. But if you need something near 13.8V and want a stable voltage then they do appear a good choice.
Of course those with wallets that are harder to open will welcome the arrival of LiFEPO4 cells as that and the more stringent requirements on shipping LiPO should drive down the LiPO price as the market flushes out them out of the system to make way for the newer tech.
In reply to MW0WML:
Thanks for all the comments and observations everyone. All VERY interesting. I think this type of battery may be the way to go for me.
However… they only have the 20Ah version in stock in the UK. If I want the smaller ones they need a minimum of 10 to order of one size.
I was thinking of the 5Ah, which weighs 1Kg. They cost £55.54+VAT, plus £12.30 carriage (per address delivered to). I would probably want two. They do a charger for £28.00+VAT, this is in stock in the UK. They will deliver to separate addresses even if we get an order for 10 together. Delivery is estimated at five days.
Anyone interested in taking part contact me by email gerald dot davison at gmail dot com.
Hope this isn’t classed as advertising - it’s not intended that way. I couldn’t think of a way of getting a large enough order together. If a moderator doesn’t like this please just delete it.
This is what I have used for some time now, comes complete with charger, VAT inc. 12 volt 9.2 Ah in it’s own waterproof case, weighs 700 grms from a British based company that has a proven track record.
As you know at the moment I’m using an FT817 for activations (using ssb/FM) and this battery has given me hours of trouble free use during a day out on the summits. It certainly lightened the weight in my rucksack as opposed even to a small slab. I bought it locally which did not incur any postal charges.
Yes, it is more expensive than most of the batteries discussed by others but it fitted my criteria for a battery for activation and I hope it will give me many years of service, fingers crossed
