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INA 2.5A oder 5A?

The Welder spot is more a hobby than controlled work ...
take one of your cells and measure how much capacity they actually have.
Why don't you use 21700 (LG Chem INR21700-M50T - 5000mAh) cells if you build the battery yourself anyway?
The cells are also a little less sensitive and would work with your BMS.
Unfortunately I don't have any BMS sources for end customers.

Before you build your next battery, fully charge all cells, measure, wait 24 hours, measure again and only use cells where the voltage has not changed.
 
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Hi all, have to scheme in here as I got the same situation. Batteries outside the Ardumower are much faster charged than by the PCB1.4 with the same power supply (29.4V, 4A e-bike charger for Li-Ion). I got a self-welded 7S3P battery pack with 21700 Samsung 50E cells and BMS ~ 10Ah.

With the PCB1.4, charging starts at 3,5A and ends with 27.0V and 0.4A (0.4A are set in charging threshold in config.h). While charging, amps go down to ~1A when cells reach ~26V and it takes 2-3hrs to get to 27.0V. Never even close to 28.8V.

Without discussing about the battery specs, are there any settings in the battery or config file (CURRENT_FACTOR?) that could tweak that behavior and keep up the Amps longer?

As said, directly connected to the battery pack the charger charges to 28.8V in ~1,5hrs, with PCB1.4 in ~5hrs to 27.0V only.

Any idea?
 
It's rather the current that bugs me. I understand the CCCV process, however, the current is dropping too fast.
Any way to tune the charging curve?
 
During charging with mower on, you loose some half an amp compared to direct charging. You cant tune the curve.

You can Check If sunray reads the voltage true.

The original charger is very weak and cheap, i accidently ordered two. One had 1.2 max amps, the other 0.7. Now I am using a 5Amps quality charger, and it puts out 5amps, Problem was solved. I Had the Same Problem with 14h charging, because of a 260wh battery Pack.
 
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I am using a 4A quality CCCV eBike charger.
Again my question, any way I can keep the amps up for longer?
There is the "CURRENT_FACTOR 2.941" setting in the config.h - would that have any influence on the charging curve?
 
No. You cannot influence a charging curve, only by overvoltage. And that is No good and Dangerous
You should Check If sunray gives you true Data in voltage and current. Measure it, there might be an Offset.
 
Maigold schrieb:
Hi all, have to scheme in here as I got the same situation. Batteries outside the Ardumower are much faster charged than by the PCB1.4 with the same power supply (29.4V, 4A e-bike charger for Li-Ion). I got a self-welded 7S3P battery pack with 21700 Samsung 50E cells and BMS ~ 10Ah.

With the PCB1.4, charging starts at 3,5A and ends with 27.0V and 0.4A (0.4A are set in charging threshold in config.h). While charging, amps go down to ~1A when cells reach ~26V and it takes 2-3hrs to get to 27.0V. Never even close to 28.8V.

Without discussing about the battery specs, are there any settings in the battery or config file (CURRENT_FACTOR?) that could tweak that behavior and keep up the Amps longer?

As said, directly connected to the battery pack the charger charges to 28.8V in ~1,5hrs, with PCB1.4 in ~5hrs to 27.0V only.

Any idea?
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@AlexanderG or @Fürst Ruprecht - Do you know any other way to increase the amps while charging?
Got another 29.4V 5A CCCV e-bike charger that does not make any difference.
 
I think the cause of the slow charging with PCB is the additional voltage drop from charging terminal to battery terminal. If you are using a BMS then a standard charger is not actually required. The BMS must control and adjust current and voltage for the cells (for each cell). The standard charger also does this, but only for all cells in series. With BMS you should be able to increase the voltage of the charger or just the voltage of a power supply. You can try this with a power supply that allows you to adjust the voltage and limit the current. I would check what the voltage drop across the PCB is. The PCB 1.4 has a semiconductor as a switch (PCB1.3 has a relay)? Possibly the semiconductor does not switch through properly, I had that with my self-built PCB too. If you increase the supply voltage slightly, you have to pay attention to the PCB. You're right, the loading time is way too high.
 
You need to Check the basics. If the voltage isnt going to your battery, then you wont have the amps! For example, If you have a Bad Connection or too think wires, you get hot wires or Connection resistances, wich will lead to lower amps. You need to measure where the Problem is. It hast nothing to do with Code or a current_factor for calculating the amps.
 
I have almost the same situation and problem as this post. Similar cells, but 7s5p and a 30a lithium ion BMS from batteryhookup. It charges very, very slowly with the charger that came in the kit. I see 0.6a max as well, even at lower voltages. Maybe these chargers are worse than rated?
 
Yes, the chargers are very very shit. As stated, I Had 2 of them.. one did Charge 0.8A and the other 0.6A. Add 0.4 idle consumption of the electronics to this value to get the Output amps of the chargers. Die Not search the mishap at your Side.
 
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