How to adjust the Luna charger (mini and advanced)

[Sebz]

Charger fine tuning basics

Example of adjusting a charger

How to adjust the Luna charger

They all have 3 potentiometers in them, we will call them P1, P2 & P3

• P1 is CV (Constant voltage) adjustment. turning this pot will change the final voltage.
• P2 is CC (Constant current) adjustment. turning this pot will raise or lower the max current in the constant current phase.
• P3 is the current cutoff at the end of the charge cycle. Basically what will terminate the charge. turning this pot will change at what amperage the charger will stop. Normally is will cutoff at around 5% of the max amperage. So a 300W set at 5amp will cut the charge to .25amp (regardless of the amperage switch position).

This is a simulated charge cycle of the Shark 13.5ah GA 52V on a 3amp charger set to 100% charge.
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On the left the latest Luna mini charger with the 2 rotary knobs (either 48V or 52V)
On the right the first generation 300W advanced 52V with the red toggle switch (80/90/100%) and the recessed amp switch (3-5amps).

NOTE: the 300W advanced with the 2 rotary knobs is the same as the first generation charger.


To adjust P1, you will need a multimeter set in the right VDC range plugged in the output of the charger (AC plugged in). No battery connected.

Be careful not to touch anything else but the potentiometer!

• On the mini turn clockwise to raise the voltage and counter-clockwise to lower the voltage.
• On the 300W advanced, it's the opposite, CW to lower and CCW to raise.

Note: On mine I had to set the unloaded voltage higher than the 58.8V because it was cutting short, this can happen du to resistance in the wiring. I did set it to 59V on both charger to get 58.8V at the end.

If you are patient you could tune it better with a battery connected when the charger is actually in the CV part of the charging phase when the current is close to the cutoff. But you will require a amperage meter hooked in between the batt and charger (batt-man, watt-meter, cycle analyst) to do a good job. I find that just setting the voltage unloaded and test and adjust later is better and easier.

NOTE: Do not raise the voltage if the charger is outputting the correct voltage (unplugged from the battery) but cutting short like a few volts off.. that can be the BMS cutting the charger due to a detected problem. Only tune it if you tested the BMS and know the pack is balancedd and the charger is slightly off track!

[Sebz]

For advanced users ONLY. If you don't know how to hook up a amperage meter in-between the charger and battery you should not try this.

Also you will need to make sure that your battery is good and balanced before adjusting the the potentiometers...

To adjust P2, the CC (max current) .

Well no real need to adjust this one.... going over the limit will end badly. So a 300W advanced at 5amp 52V is already 294W... so only use it to lower the amperage if needed... Lets say you have the older V1 300w advanced with 2 position switch and would like 2and 4amp instead of 3 and 5amps... you can use it for this.

You will need a discharged battery (or at least below the 80%), an amperage meter hooked in between the batt and charger (batt-man, watt-meter, cycle analyst, multimeter).

Plug your meter in between and start charging, move the pot to the desired amperage.

• On the mini turn clockwise to lower the amperage and counter-clockwise to raise the amperage.
• On the 300W advanced, it's the opposite, CW to raise and CCW to lower.

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To Adjust P3, the current cutoff.

The only reason I see that you should play with this one is that you have adjusted the P1, and the cells are balanced and you still don't get the 100% you wished for... The charger is maybe cutting too soon in the CV phase... not charging long enough at low amps.

I found that my older advanced 300W shifted a bit and was cutting at 0.6amps (over the 10%) So I set it back to 5% current (0.25amp) and charging took a couple minutes longer but actually got the 58.8V.

You will need a almost full battery (or at least close to 99%), an amperage meter hooked in between the batt and charger (batt-man, watt-meter, cycle analyst, multimeter).

Plug your meter in between and start charging, monitor the amperage and see where it's cutting the charge.

If it's too high, unplug the charger from the battery, turn the pot in the right direction to lower the threshold and plug back the charger in the battery, it will resume charging. see where is stops... you will have to do that a couple times to get the right setting.

If it's too low... well, it's fine at 3% so I doubt yours is lower than this, but if it is: You will have to discharge the batt a little before you can start the cycle again, unplug the batt from the charger and just put the batt on the bike and make the rear wheel spin a little. Unplug the batt from the bike, turn the pot in the right direction to lower the threshold and plug back the charger in the battery, it will resume charging. see where is stops... you will have to do that a couple times to get the right setting.

• On the mini turn clockwise to lower the amperage threshold and counter-clockwise to raise the amperage threshold.
• On the 300W advanced, it's the opposite, CW to raise the amp threshold and CCW to lower it.

Hope that helps

NOTE: If your charger differs from the pictures shown, please send me a picture of yours and were the right potentiometers are and I will add it to this post!

[Sebz]

Note:

The 80 and 90% switch is not affected by the P3, The charger simply cuts at the right voltage, the charger will not go into the "CV" mode as the voltage will never reach the CV threshold.

The amperage switch is not affected by the P3, The charger simply cuts at the right amperage based on the max amp it can deliver regardless of the switch position.

BUT! changing the P1 will raise or lower the 80 and 90% setting as they are linked to the 100% setting.

Soooooooo You could change a 48V charger to be a 52V charger.... just remember to lower the amperage to 2.5A instead of the 3A limit of the 48V Mini. it's only 150W max!!! Nad might be a good I idea to reduce it too on the advanced to be sure.

But warranties are voided when you mess with it, so ask your supplier before!