LiFePo4 Battery Build using LiitoKala 32700 cells

Рет қаралды 5,029

Күн бұрын

Based on a series of tests done over at the electronicsNmore channel ( • High Capacity LiFePO4 ... ) I decided to build myself another battery for ham radio use.
These cells are marked 7000mAh, but their spec sheet says 6500 and that seems to be more realistic. The spec sheet also says 30A continuous discharge, so that's what I built the pack for BUT check the tests over at electronicsNmore before you rely on this value. I think 20 is more realistic. My Yaseu 891 draws 18A on full power transmit, so it's an almost perfect match.
Discussed a few safety points about battery building that I think are often overlooked. Especially when using budget imported cells and BMS boards, you really need to go the extra mile to take any reasonable precaution that you can.

Пікірлер: 24

@DK5ONV 3 жыл бұрын

Cool! I put 40 LiFePo4 in my outdoor hardcase for amateur radio portable in the Fields. 3,36V-DC/29000mAh a piece. Built a inlaying bed out of foam pads I bought at amazon, did the wiring inside, drillied 5 holes on the sides of the Hardcase. 4 outlets for 13,8V-DC and 1 line in for charging the LiFePos with Turnigy Charger Balancer (300W/20Amps) which gets hooked to a Hama Notbook Switching Supply (for 15 or 19V-DC). Took me good 2 hours being busy with getting everything soldered and finished up ready to use it. This happened 3 years ago, the LiFePo4's are still working fine and delivering hours of fun on my activations outdoor. I love this documentary video and the excellent job you do. 73's from SW-Germany. DK5ONV Uncle Guenter

@alexandres8846 3 жыл бұрын

lifepo4 a wonderfull battery. safety stronger. long life and low cost.

@pmwilliams123 2 жыл бұрын

Excellent detail and explanation of reasoning. All the good stuff in a very practical build, with comparison notes on performance parameters that competent operators desire to know. Thanks.

@ericklein5097 11 ай бұрын

That 40 second delay in the BMS cutting off the pack is likely due to the minimum cell voltage being under 2.5V on the BMS. LiFePO4 in general can go down to 2.00V without really damaging it so long as its not a regular thing. For a capacity test or rare BMS cutoff situation its fine. Also many BMS's have a delay time for that protection to kick in. Usually 3 seconds to 30 seconds. So maybe 10 seconds after that second to last measurement you hit 2.5V even across all 4 or one of them hit 2.3V (a common min voltage number used on el cheapo BMS's). That means 30 seconds later the BMS tripped the protection. So fairly standard behavior all the way around. Hell you can go down to the 1.7 1.8 volt range and they'll still recover fine. A123 cells go down below a volt and act like nothing happened. 0V cells can be recovered in ok shape. With how little energy exists down there its best to probably use 2.7 to 3.50 or 3.55.

@imperialsecuritybureau6037 2 жыл бұрын

Excellent battery pack. I really like the attention to safety! If this was going to be mounted in a vehicle I’d maybe suggest some battery brackets/holders for the ends of the cells in order to keep them structurally held together nicely, but this is so robustly constructed it would probably be redundant anyway. Nice job!

@zonta71 2 жыл бұрын

Spot on. Your build details simple with specifications. Am looking at building a standby 12v unit for my remotely parked motorcycle with a tracker and its bother to keep visiting every 2-3wks to ride. I wish I had the time tomride more but life as they say...

@KevinW8BRY 3 жыл бұрын

Thanks Matt. Enjoyed the build. I build mine for sure! Most recent build was a solar generator. Still need to get my solar panels to completer the build and will be doing so soon. I have been looking for a more lightweight battery for summits on the air. Think this build may meet those specifications. Kevin

@MattHeere 3 жыл бұрын

This would be a great size for a solar setup. The 32700 size cell seems to be the smallest you can go and reliably get the continuous current rating needed to run a 100W radio at 100W. If you can manage the capacity limitations through a combination of output power selection and solar recharge, you're golden.

@kitamuram4389 2 жыл бұрын

Very easy to understand pictures, thanks a lot.

@anonymousgeorge4321 3 жыл бұрын

Great video. Thanks.

@glock35ipsc 3 жыл бұрын

As always Matt, great video. I do want to get a welder, as I have a bunch of tab-less cells to play with. Bob, W0BNC.

@lookoutleo 2 күн бұрын

I would like a 30a 36v ebike battery . My bike only uses 15amps at highest setting so maybe 2 p 12s? What you think ?

@ValenteEspinosa 3 жыл бұрын

Nice setup, what bms are those? and where can we get those? Thank you

@joatmofa0405 3 жыл бұрын

I see below there are a few requests for the parts list? May I add my request to that ever expanding list?

@kodyeliason1389 3 жыл бұрын

What’s the part number or link for the bms

@ericklein5097 Жыл бұрын

How can the two center cells create a short circuit if the can of both is negative?

@ammocraft 3 жыл бұрын

Any chance you could pop up links for the parts you used? Avoids playing the Ali Express seller lottery. 👍

@ericklein5097 11 ай бұрын

One person can get brand new A grade cells from a seller and 2 months later after they have a good reputation they pull out the Grade Garbage for everyone else.

@qplaqpla 2 жыл бұрын

Hi matt, I'm making my own lifepo battery pack. What are you using to charge the battery? good day to you.

@MattHeere 2 жыл бұрын

I use a benchtop power supply that regulates both current and voltage. I set the voltage to 14.8V and the current to 3A. It runs 3A for most of the cycle until it hits the 14.8V limit and then the current starts dropping until the pack is charged.

@charlesaec442 3 жыл бұрын

What is the maximum voltage Lii-70A Liitokala 4S 32700 14v oke

@ericklein5097 Жыл бұрын

14.6V if charged up to 3.65V however many charge to 3.5 or 3.6

@davidleaghty2943 3 жыл бұрын

Might be something if your running QRP.

@MattHeere 3 жыл бұрын

2 hours at 50W is a lot of possibilities for POTA/SOTA, and I did buy the parts to make two of them. But yeah, it'll run the KX2 for a long, long time.