Gotion 33140 15Ah 3.2V LiFePO4 batteries

The second set of batteries from a mixed parcel sent by one of my readers. This time they’re some nameless (at least to me) Gotion/Guoxuan cells, but as it turned out, they’re actually quite interesting.

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The first thing you notice is the unusual color of the heat-shrink tubing. I’m more used to blue or gray, and here it’s even hard to say exactly what color they are :)


I couldn’t find the datasheet right away. I’ll add it if I find it; for now, here’s a snippet of a description I found on one of the forums.
• Cell type: LiFePO4, size 33140;
• Marking: LiFePO4 Gotion 3.2v 15 Ah;
• Capacity (nominal): 15 Ah;
• Voltage:
- Nominal: 3.2 V;
- Minimum (fully discharged): 2.5 V;
- Maximum (fully charged): 3.65 V;
• Discharge current:
- Continuous: 3C (45 A);
• Charging current:
- Standard charging: up to 0.5C (7.5 A);
- Fast charging: 1C (15 A);
• Internal resistance: 2.5 mΩ (0.0025 Ω) (impedance at 1 kHz).
• Terminals: copper busbar (easy to solder at home, tested)
• Operating temperature: -30 to +60
• Cycle life: 3000 (capacity drops to 80% of nominal)
• Weight: 280 g.
• Size: 33 mm × 140 mm;
• Manufacturer: Gotion (Guoxuan)

There are no markings, except for a QR code on one end. I tried to scan it, but for some reason my phone absolutely refused to do it....
The terminals are insulated from the case and are bimetallic. The outside appears to be copper, while the inside is either steel or aluminum (most likely steel). Tabs are welded onto the terminals.
The copper terminals themselves have a slight bevel, which caused the alligator clips to slip off several times, slightly damaging the welded-on plate in the process :(


They measure 33 × 140 mm and weigh 270 grams—nothing unusual. By the way, I’ve already reviewed a battery of this size


Impedance is about 2.25 mΩ.


Like the previous test subjects, these initially arrived in storage mode at 50% charge, and were very well balanced.


Naturally, I started with a preliminary charge. Both batteries took almost exactly the same amount of energy, which is a very good sign.


As with the previous batteries, I tested charging in two modes: 0.5C and 1C, where C = 15 A. The cutoff voltage was 3.65 V, and the cutoff current was 0.75 A.
At 0.5C, charging took 2 hours and 7 minutes—a good result.


At 1C, charging took exactly an hour less, which is also fine, but I’d recommend charging at 0.5C to extend the service life.


I discharged them in five modes. Actually, I started with four, but the batteries were behaving well, so to make things a little harder for them, I also loaded them at 40 A, almost 3C. In the end, I used 0.2C, 0.5C, 1C, 2C, and 40 A.
In my opinion, for continuous use it’s best to discharge them at no more than 2C. The 40 A discharge graph shows the voltage bulging upward as the battery heats up.


The temperatures at 1C, 2C, and 40 A look perfectly reasonable to me.


The second cell produced almost identical results. We’ll compare it with the first one later.



The residual charge after discharging at 40 A was around 340–350 mAh, which is a very good result. It means the batteries delivered almost all their energy during the high-current discharge. As it happened, I also measured this parameter at 2C: the results were 340 and 390 mAh.


The characteristics match closely at 0.2C, 1C, 2C, and 40 A as well—no complaints there.


But this graph was much more interesting to me. Here I compared the batteries under review with the EVE IFR33140 15Ah cells I tested earlier, i.e. same size, same capacity, but a different manufacturer.
And here I have to say “unfortunately”: I liked the Gotion cells during testing, but the EVE cells delivered better results.


In brief, the conclusions.
Personally, I find these batteries interesting. At least, I didn’t have any complaints about them during testing. But compared with EVE, they came up short in both capacity and heat generation. The difference isn’t huge, but it’s there.

I’ll leave the decision to you. As far as I’m concerned, these are decent batteries.

That’s all for today. Thanks for reading, and as always, I’d really appreciate your comments and support for the blog.