S.B.D wrote:Why is the third "float Pot" needed? Is is used to allow a larger output voltage change than the stock pot?
No idea with regard to the first question, but the third pot is the one that controlls the 'float voltage'
This three pot design, has current limiting adjustable as per the single pot design.
The board then monitors the output current as the charge progresses, and due to the battery becoming charged and its voltage rsisign to meet that of the charger, the current flow drops.
The second pot sets the threshold current where the board kicks the PSU from charge mode in to a lower voltage 'float mode'
All float mode is, is the board lowering the output voltage of the charger to a little below that of the battery, and changing the bi-colour LED rom Orange to Green.
The second pot, sets the current threshold when this change over occurs. Seem to remember from about 1 amp and below. So the board monitors current, and when it drops below the value set by the second pot, the LED changes colour and float mode 'kicks in'
It is the third pot that controls the amount the PSU drops its voltage by.
So in practice, you break the 'Float enable ' jumper, set the PSU via its own on board pot, to the voltage you require for your fully charged battery.
You then install the Float Enable Jumper. This (with no battery connected) kicks the board in to float mode. This pulls the output voltage of the charger down. the amount it pulls down is determined by the third pot. Range is only a volt or two, but enough to stop the charge current flowing to the battery.