Hello Mike Then,
You’re welcome.
Have you tried to adjust the Adjust voltage potentiometer?
If not, please tried to adjust the voltage potentiometer, clockwise for increasing, counter-clockwise for decreasing.
Hope this can help you.
Best regards

Hello Harry,
The output current just need to be set once and then the value of the output current can be stored.
And the product cannot be connected to a load when you adjust the output current.
As your description, your application needs 4A constant current.
You can finish setting the output current firstly, then connect the product to the Raspberry Pi.
Best regards

Hello gregg,
Thank you for writing in.
Could you please tell us your order ID or the link of your little green LED panel meter?
Waiting for your reply.
Best regards

Hello Clay,
Thank you for writing in.
Have you tried to adjust the CV potentiometer?
If not, please try to clockwise adjust the CV potentiometer until the output voltage reach 56V.
Hope this can help you.
Bets regards

Hello Mark,
Thank you for writing in.
Do you mean you want add one more this product to your speakers so that one more phones can control the speaker at the same time?
Or do you mean you want to one more Bluetooth devices (phones) to this product at the same time?
Best regards

Hello Nilo Provera,
Thank you for writing in.
We have consulted your problem to our technician that this product cannot utilize instead an external controller, i.e. Arduino or Raspberry.
The terminal points (Vcc-Gnd,Tx,Rx) is the marks for the program of this product.
Hope this can help you.
Best regards

Hello Harry,
Thank you for your quick reply.
Here is the adjusting mehtod for you:
Firstly, in case without load, adjusting the output voltage of the product to 42V, then counter-clockwise adjust the CC potentiometer to min.(the end), connencting the 42V battery and a ammeter, then gradually clockwise adjustthe CC potentiometer until the output current is 4A.
When the charging voltage of the 42V battery increase, the charging current will decrease.
And when you set up the output current of the product to 4A, the output current will be bot over 4A.
Please note that before connecting the battery to the product, the output current of the product must be set to be the min.(counter-clockwise adjust the CC potentiometer to the end), otherwise, the module will be burnt.
And it is recommended that you can apply a fan to dissipate heat.
Hope this is helpful to you.
Bets regards