If you perform different tests between the batteries other people sell and your own batteries then you cannot compare the results. It’s possible those doing the tests didn’t realise they were performed differently, a genuine mistake. Being a cynic, I see the tests as being harder on the batteries they don’t sell, which makes me think they were deliberately giving their own products and easier time. Result in my cynic’s mind: don’t buy from these people, they are trying to con me. And if they are genuine fire service staff and not male strippers in their firemen’s clothes, then why did they allow the tests to be performed differently?
So the whole thing is like those videos of BMW X-drive vs Audi Quattro cars on snow/ice where one brand of AWD massively outperforms the other. Till you notice one brand of cars are on summer tyres and have drivers who cannot drive inside them compared to the other brand with snow tyres and competent winter weather drivers.
The video is, as we say up here, complete and utter pish.
And finally, have you ever seen what happens when someone accidentally drops a 15mm combination ring spanner on the live terminal of a car battery and the chassis? Oh the spanner gets so hot so quickly it sets lots of plastic parts, wires and stuff in the engine bay on fire faster than you would believe. Luckily this was 40 years ago and there was a BCF Halon extinguisher to hand to put out the flames.
Should we not allow cars to have lareg lead acid car batteries? Especially as not everyone working on a car in a garage has an extinguisher to hand. The poor video merely shows stored energy is dangerous.
I have 2 LiFePo4 battery packs with 12Ah each. The older one, I purchased as a kit with single cells without BMS, lately I got a Eremit 12Ah pack with integrated BMS.
I only use them during QRO activations with my FT-891. For the old pack, the TRX acts as a deep discharge protection: Discharge voltage of the battery pack is 10V, while the FT-891 switches off at 11V. When the TRX shuts down, I switch it on again, reduce thepower to 20W and finish the pile up..
With the Eremit battery, I had issues with the BMS protection during a activation in ZS: Temperature was around 35°C, the battery stood in the sun and after a few QSOs, the BMS shut down. Probably overtemperature protection, whwn I reduced the power to 50W and put the battery in the shade, it didn’t happen again.
With 100W output of the TRX, both batteries last for around 3 hours. I can extend this to 4-5 hours when reducing output power to 20W or so.
Ok. So to make the move to safer LiFePo4 from Li batteries for my back-country setup I need:
Battery.
Option A:
12.8v 30-60Wh power pack. Talk about hen’s teeth! Zero in-country. LiFePo4 batteires for sale start at 100Ah vehicle starter batteries and go up from there to something to power your house.
I assume that international air-freight do not carry LiFePo4 batteries, so I cannot order internationally? Or is LiFePo4 not caught up by the air-freight Lithium battery rules?
Option B:
4x26650 cells plus holder. $25 per cell for 3000mAh batteries.
No 4x holders available, so build my own by glueing together 4x single holders and cabling up. Say $24 plus some phaffing around.
Home charger
Assuming I go with individual cells: only thing in-country seems to be $30 LittoKala 4-slot Intelli-charger which covers this battery type. Looks cheap, nasty, budget-Chinese stuff. So will look overseas for something better.
Suggestions for a good home 4-slot 26650 LiFePo4 charger?
Portable charger
Ideally a lightweight 26650 LiFePo4 (1), 2 or 4 slot charger that runs off USB or 12v ciggy lighter for charging at camp or in vehicle. Portable, lightweight. Extra points if it has USB out to charge a USB device from the cells. Similar to the Nitecore 4x18650 I have for Li-ion. Do they exist? None spotted so far …
Then I just need a torch that takes 26650 and I’m fully converted.
Or are there other / better ways of doing this that I’ve not considered?
You spurred me to have another search - Google AI this time (I’ll do my penance later) rather than Qwant. I see several that did not come up in a simple keyword search - e.g. Jaycar go down as far a 7Ah.
However, at 7Ah, 700g is a lot to be carrying around on multi-day tramps, or in my work day-pack ‘just in case’ for opportunistic activations. 3500mAh has served me well for up to 7 day trips, and so that’s roughly what I’d like to stick with.
…as I work from my car chasing portable, I have got a 60ah LifePo4 battery and a Blue Smart Victron charger (12v 15A) that runs from 240v. I charge after I get home from a park.
I build lots of packs up mainly to show others what can be achieved. With LiFePo cells, I bought some secondhand 26650 cells (ex vehicle) that were nominally 2500mAhr but were down to 2300mAhr. They work as expected for low current use (KX2 etc.) but being designed for vehicles can provide 50A without distress but not for long of course! I have some myself, the rest went on to locals in the Edinburgh area.
You can buy dual 26650 holders from AliExpress and these photo shows a number of homebrew “proof of concepts”
LifePo cells, Hobbyking, Eremit and 4x26650 with 2x holders on a piece of stripboard. (AA for scale)
LiPo: 3x21700 (green), 3x 18650 (lilac), 3S2P ex-vape and AA. The 18650 holder shows 2 cells and a piece of ribbon used to make removing cells easier. The ex-vape pack is so light, it’s the backup KX2 supply and will run it at 8W or so for an hour.
As DH1WM already suggested, we avoid connecting batteries in parallel, but we can connect them using this little toy. Power will automatically switch to battery number 2 when battery 1 drops below the threshold.
The same happened to my 8Ah Eremit battery about a week ago when I was activating POTA from the car. I has suspected the heat in the car was relevant, but wasn’t sure if the issue was the radio or the battery. It seems the BMS in the battery is the problem. After opening the car windows and leaving the car to cool for 5 minutes, everything worked again.
I also bought some of these from your favourite auction site, to make another battery pack.
4 cells with 100% capacity for just under £15 and free delivery.
I’m having difficulty selling stuff on there right now… lots of people looking, nobody buying :-(:
I think mine were somewhere between £2.00 and £2.50 each. I must go and check the actual cost. ISTR I got 24 and sample tested them for endurance. i.e. BMAX charge and discharge runs and seeing how much went in and how much I could get out… all were good for 2300mAhr capacity. Not brilliant but for c. £10 for a pack including cell holder and leads is OK. Yours sounds a bit better of a deal at £15.
Today the 8Ah LiFePO4 battery from Eco-Worthy arrived. The 10Ah version was out of stock, but I think this one has the right weight and capacity for the use I need it for. I charged it using the current specified in the manual; it arrived at 60%, and drawing 8A it reached 100% without getting warm.
This week I won’t be able to test it during a SOTA activation, but hopefully I’ll manage next week. I’ll make a short report with my first impressions of LiFePO4 batteries
