JON:
Now that we have parameters I can see you problem well.
You are producing the voltage expected at the RPM the generator is rotating.
You forgot to include the pipe size and pipe length to give you a bit more accurate power calculations.
The power available
- l/s
- meter head
Gross Power watts = 12 * 10 * 9.81 = 1177 watts
RPM for peak power
Maybe around 700 to 900 watts available depending on the efficiency of the overall system ( includes pipe losses, Banki and generator efficiencies)
Water velocity = Square root ( 2 * 10 * 9.81) = 14 m/s
RPS = Rev Per Second
Banki Peak RPS = 14 / 2 = 7 m / s = 700 cm/ s
Generator RPM with a banki 25 cms
RPM = (RPS / PI * diameter ) * 60 = (700/ 3.14 * 25)* 60 = 535 RPM
You can not slow the Banki down like in a wind mill because the power will go to nil, and a way to use the present banki would be to have a voltage conversion to the 12 volts you aim to have as a bank.
You have a BAD marriage, let's try it does not go into a divorce and getting a new replacement.
What solution you may be able to use.
You can not use a MX60 since the voltage generated will be much higher than its capabilities.
You could get a PWM switching power supply WITH PFC input and wide range ( 85 to 240 AC) and the 12 volts output adjustable to the 15 volts for the C60 to operate properly.( may be a bit costly and, as well, you will need a good ELC = Electronic Level Controller to keep the Gen RPM to a safe value).
Change the generator to a 6 poles motor and convert it to a generator with capacitors and get transformers to convert to 15 volts nominal for the C60 operation, you could use the available AC power (800 or so watts ) directly and a smaller charger for the battery bank.
You will need an ELC.
You could start cold again and design the system to produce the watts that the water source is capable in a way that is practical for you and your use.
Lastly you could use a pulley RPM conversion to attain the low RPM needed for the generator to produce the peak power available in the Banki.
YOU WILL NEED to define the Voltage Versus RPM of the generator ( the info in the site is for wind mills and the loading effects of the load on the wind mill blades, which is represented as a curve for the generator) WHICH in reality is the impedance curve of the wind mill blades.
Let me know
Nando