I am thinking about extending our energy generation on Entropy with a Hydro Generator
to charge our LiFePO4 battery
bank when cruising.
The following question came up after doing some research
on charge controllers for electromagnetic generators such as wind
gens or hydro gens available for boats. Apart from COTS solutions there are some interesting smaller vendors for Hydro Generator
Turbines which I am currently considering for this purpose. Most of them offer a charge controller for the turbine, but this is always designed to charge Lead Acid battery
This got me thinking about obtaining the Hydro Generator 3 phase AC turbine and buying
a suitable charge controller from a different vendor/sector - if such a thing exists at all.
As you may know LiFePO4
like to be charged to a set point voltage and then charging
should stop. There is no need for fancy charging
profiles in this case.
So now I started searching for a magic device which fulfills the requirements for charging a LiFePO4 bank from a generator type energy source. (It should not really matter if this is a wind
or a hydro generator.)
I have identified the following requirements:
- Raw generator AC raw voltage range is not known yet, as I have not chosen the turbine yet, but it will be likely less than 50 V.
- The charge controller should ideally accept 3 phase AC. However it would be possible to add an external rectifier and feed the charge controller rectified AC (i. e. very choppy DC).
- The charge controller should ideally use MPPT and buck voltage regulation for efficiency reasons.
- The charge controller should produce a clean and constant 13.8 V (or better yet, adjustable) voltage when only lightly loaded (i. e. near 100 % SoC of the LiFePO4 bank). There should be no voltage spikes above the voltage set point (which could lead to unnoticed overcharging).
- The charge controller should be resistant to a short on the load side (which is basically what a LiFePO4 with < 100 % SoC is to a charging source) and be able to protect the generator from overload. This basically means that the charge controller should have an adjustable output current limit.
- The charge controller should ideally provide a digital input for shutting off the power output to the main load output, diverting it to a heating element attached to a "dump load" output of the controller. (However, this could also be done by external circuitry such as a make-before-break toggle relay between charger and battery load/dump load.)
If anyone knows if such a miracle device exists it would be great to hear about this.
If nothing is available on the market maybe it's time to eventually get out my rusty EE circuit design skills