Got a new 100a battery shows like 12.2-12.4 when the pump has filled the system
When the pump is running and filling the system its really low to the point it will almost cut out around 11.4 then when i connect the pole to the hose it works around 11.7 - 11.8 has it got anything to do with micro bore or pump being 2 years old I do these days have to use it at almost max around 90
A battery following a full charge will register between around 12 - 13 volts. As you place a load on the battery in this case switch your pump on the voltage will fall off in your case between 11.4 and 11.8 and will likely hold at that point for a few hours.
What you are seeing is the normal operation of a circuit the volts are carrying the current (amps) to the pump the volts return back to the battery with the amps being used by the pump. Think of the Volts being a carrier belt.
At the start of the day you have a 100 amps during the day the amps fall and by the end of the day will be lower.
How many amps you use will depend on the pump motor efficiency, water flow rates and how much pressure is required in your system to get the flow you want.
Running the pump at 90 you are probably using around 6 - 7 amps an hour I would guess you are getting around 6 hours or so if work out of your battery a day. 6 x 6 + 36 amps used a day. Your battery now has around 64 amps left.
What will happen is that while the amps in the battery are high the volts in the battery stay constant. After 3 - 4 hours use as the amps drop you will see a sudden fall of in volts as well. this is normal and as long as you recharge the battery at the end of the day replacing both Volts and Amps no problem.
Fitting a split relay can help, however how much the amps are replaced will depend on how much driving you do the battery will still need a bench charge every couple days or so.
Volt drop could also be an issue try to ensure that cables are as short as possible and replace any worn/rusted connectors or damaged cable.
http://www.springltd.co/node/133To answer the other points yes your pump will not be as efficient as it was possibly the motor brushes are worn or just full of dust. a 6mm hose will create higher restriction in the system also meaning the pump has to work harder to get the water to the brush head. Very good article explaining this in July WCM.
Out of interest what is the calibration level on the control