Dongguan Lighting: Purchase 280AH LiFePo4 cells. Purchase & Review

[LukeVader]

Hey shouldn't one of the leads be on the opposite end of your stack of cells? Seems like you will front load the one cell by connecting to both terminals of the same cell?

Yeah, in post #15 I said I changed that lead..... so far its been 34 hours of charging and its at 3.313V now. Still putting out 6A

 

[Jeremiah]

I'm super stoked about these cells. I hope they still have inventory when the lockdown ends here in 18 days.

 

[LukeVader]

Yeah, the timing on ordering these cells and charger have been really lucky timing for myself. It's like I have something to do right now. Cells are now at 3.314 after 10 more hours. ?

 

[Jeremiah]

Yeah, the timing on ordering these cells and charger have been really lucky timing for myself. It's like I have something to do right now. Cells are now at 3.314 after 10 more hours. ?

That's what stinks here, all shipping is practically banned now. SO not only are ALL the stores closed except for grocery (where you have to wait outside for 1-2 hours in the sun as they allow limited numbers inside), but they also stopped the deliveries. At least I can research the stuff and if I order I can time it for the end of the month when our lockdown is supposed to ease up.

 

[LukeVader]

So how odd is this? @Sgt Raven got me thinking about my attachment to the PS so I made my own set of cables with what I had laying around. I put these on my PS and the amperage went down to literally 0.053a? They meter just fine.

 

[Sgt Raven]

Meh, I kept charging lol. 6 hours 19 min so far and the multimeters reading 3.308 on the copper bar and the ps is reading 3.65v and 6.504A. I also changed my negative charge lead to the opposite end for the heck of it.

I really am fighting the urge to stop charging at 3.350 90% SOC

I don't have my 150W adjustable Constant Current Electronic Load Battery Tester yet so I wont be able to release any power from its high state of charge. Will I hurt the cells if I stop at 3.350 then let them rest for a week or however long it takes to get my equipment then charge them the rest of the way when it shows up?

The cells are not even close to being warm at all and the PS has slight warm air coming out of the back from the fan.

It shouldn't hurt the cells to be charged to 3.65V for the short time you're gonna have them there. It's real long term with them sitting there you don't want. As in months or years sitting fully charged. It sounds like you're talking about weeks, not months.

Hey shouldn't one of the leads be on the opposite end of your stack of cells? Seems like you will front load the one cell by connecting to both terminals of the same cell?

Yes, you want the leads at the far end from each other.

 

[Sgt Raven]

Yeah, the timing on ordering these cells and charger have been really lucky timing for myself. It's like I have something to do right now. Cells are now at 3.314 after 10 more hours. ?

Pretty soon they should take off and the volts start going up real fast compared to what they have been. Going from 3.29V to 3.4V seemed like forever. From 3.4V to 3.65V was lighting fast compared to earlier.

 

[Sgt Raven]

So how odd is this? @Sgt Raven got me thinking about my attachment to the PS so I made my own set of cables with what I had laying around. I put these on my PS and the amperage went down to literally 0.053a? They meter just fine. View attachment 10832

Try hooking the leads together and reset your amps to max output. Then unclip them and reset your volts to 3.65V.
The other thing you can do, turn off the PS and let it turn completely off. While it is off, turn the volt knob all the way up. Then turn it back on. On some PS they go into a over-voltage protection mode and that is how you reset it on my PS. Don't know if yours is the same. But it's something you could try.

 

[LukeVader]

Wouldn't connecting leads together cause a spark?

I would have tried that if the original leads wouldn't have worked when I put them back on but they did? I ordered those silicone leads anyway lastnight and they showed up this morning already. I tried them and they still do the same thing. You just touch the wires and the amperage goes all over the place. Maybe it's the connectors on the PS? Anyway, those new leads you can plug in another banana plug into it so I got the silicone one on the far ends from each other on the copper bars and the original set plugged into them on the opposite ends. The amperage went up when I added the 2nd set of cables. lol

As of 10AM this morning after 68 hours of charging the cells finally meter says 3.320V nothing warm or pillowed yet.

 

[LukeVader]

Live and learn right? I've been reading here and decided to strap the cells to limit expansion, hopefully this is good enough. I'm sending the extra battery leads back cause they didn't really help. I put a box in front of the leads coming out of the PS which keeps the rotating banana plugs tighter and happier I guess. Without something pulling on the wire the amperage goes down into the 4 to 5 amp areas. After 76 hours of charging the multimeter is reading 3.234V now

 

[JoeHam]

Most banana plugs can be “smushed” out to make the fit tighter.

Just deform them to decrease length and increase girth a little bit.

 

[Sgt Raven]

When it's all over, if you're brave enough. You could open the case of your PS and check the connections on the back side of the banana jacks. See if one of them is a little loose. I contacted the importer/seller of my PS and they said there is a blue trimpot on the backside of the display board to adjust the meter"s readings. I'll have to see which type it is and get a "Diddle Stick" for that type.

 

[Jeremiah]

When it's all over, if you're brave enough. You could open the case of your PS and check the connections on the back side of the banana jacks. See if one of them is a little loose. I contacted the importer/seller of my PS and they said there is a blue trimpot on the backside of the display board to adjust the meter"s readings. I'll have to see which type it is and get a "Diddle Stick" for that type.

Haha "diddle stick"

 

[Sgt Raven]

Haha "diddle stick"

That's what the old Electronic Technicians called them, back when things like TV sets had tubes in them. There was lots of trim pots to adjust under power. You don't want to stick something conductive in there, if you can avoid it.

 

[LukeVader]

Ok, I'm going to be busy for a bit and cant really babysit the cells the way I want to for the last 90-100% leg so I JUST took them off the charge.

3.351V took 95 hours 45 minutes from the delivered 3.29V.

3.65V @ 7 amps average I would guess was the charge parameters.

They are still all connected in parallel and I'm going to just let them rest like that for about 1 week.

 

[LukeVader]

Hey, quick question for all of you with lifepo4 280ah cells........... lets say you charge your batch to 3.35V and then let them rest, has anyone checked their rested voltage 1 day later, 2 days later, etc? What would you expect your voltage to be? Can we use the voltage to figure out the soc? I still don't have my load tester yet

SOC Cell V 12V setup 24V setup 48V setup
100.00% 3.650 14.60 29.20 58.40
99.50% 3.450 13.80 27.60 55.20
99.00% 3.375 13.50 27.00 54.00
96.00% 3.363 13.45 26.90 53.80
90.00% 3.350 13.40 26.80 53.60
80.00% 3.325 13.30 26.60 53.20
70.00% 3.300 13.20 26.40 52.80
60.00% 3.275 13.10 26.20 52.40
50.00% 3.263 13.05 26.10 52.20
40.00% 3.250 13.00 26.00 52.00
30.00% 3.225 12.90 25.80 51.60
20.00% 3.200 12.80 25.60 51.20
14.00% 3.150 12.60 25.20 50.40
9.50% 3.000 12.00 24.00 48.00
5.00% 2.800 11.20 22.40 44.80
0.00% 2.500 10.00 20.00 40.00

 

[Sgt Raven]

Hey, quick question for all of you with lifepo4 280ah cells........... lets say you charge your batch to 3.35V and then let them rest, has anyone checked their rested voltage 1 day later, 2 days later, etc? What would you expect your voltage to be? Can we use the voltage to figure out the soc? I still don't have my load tester yet

SOC Cell V 12V setup 24V setup 48V setup
100.00% 3.650 14.60 29.20 58.40
99.50% 3.450 13.80 27.60 55.20
99.00% 3.375 13.50 27.00 54.00
96.00% 3.363 13.45 26.90 53.80
90.00% 3.350 13.40 26.80 53.60
80.00% 3.325 13.30 26.60 53.20
70.00% 3.300 13.20 26.40 52.80
60.00% 3.275 13.10 26.20 52.40
50.00% 3.263 13.05 26.10 52.20
40.00% 3.250 13.00 26.00 52.00
30.00% 3.225 12.90 25.80 51.60
20.00% 3.200 12.80 25.60 51.20
14.00% 3.150 12.60 25.20 50.40
9.50% 3.000 12.00 24.00 48.00
5.00% 2.800 11.20 22.40 44.80
0.00% 2.500 10.00 20.00 40.00

I started my test at 13.9V. 6.5 days later I finished my test at 12.7V. Starting I set my Smart BMS to 280AH as pack capacity. After the test, the BMS says my capacity is 308AH. Don't know what it would say if I went down to 11.5V The last whole day the dashboard said I was at 0% left for 24 hours. What does it all mean? Your guess is as good as mine...

 

[Jeremiah]

Hey I know with Lead acid the AH ratings are usually for 20 hour period or 10 specified on the battery but if you drain slower you get more Amp Hours out of it; what is the standard time for rating AH on LiFePO4? 20 hours/ 10 hours? I haven't seen that anywhere.

 

[LukeVader]

I started my test at 13.9V. 6.5 days later I finished my test at 12.7V. Starting I set my Smart BMS to 280AH as pack capacity. After the test, the BMS says my capacity is 308AH. Don't know what it would say if I went down to 11.5V The last whole day the dashboard said I was at 0% left for 24 hours. What does it all mean? Your guess is as good as mine...

Thanks for the reply, you did a load test or a real life test? I'm talking about a resting test. Charge the cells to 90% soc then just leave them for 6 hours... a day..... 2 days.... a week and check your resting voltage. Did it change? Should it change? I would think grade a cells shouldn't change voltage right? Wouldn't this be what's called a storage retension test?

 

[Sky-HHI]

Both of my batteries, a 24v BYD battery and a 24v sinepoly. while at rest after a full charge will settle around 3.35 volts - 3.34 volts. That seems to be the average voltage for these batteries at rest after a full charge. The BYD is used and the sinepolys are new.