24 Generator Volts

[dede2002]

Thank you Swallowtail for all these details, I learned / understood a lot of things

Your 10% yield is not so bad, given the specific consumption announced of 421g / kWh, at 44 MJ / kg it would make a yield of 19% for the engine therefore more than 50% for the rest.

Questions: how does mppt handle excitement? is the excitation current taken on the 3 small dedicated diodes? What is the resistance of the rotor?

[swallowtail]

good evening,

the excitation is a "remanent" excitation caused by just a flash of excitation of a few seconds by connecting a 12 or 24V batt (the + on the B + alt and the - on the- of the alt)

then it's self-excitement!

the MPPT regulates the voltage given to the batt according to their state of charge (SOC)
, the current I delivered is modulated by choice of engine speed (here 30A at 3000rpm engine or 2000 rpm alt)

I am still in the trials to see the behavior of MPPT in the absorption phase (85 to 100% SOC)
I will keep you posted .....

swallowtail

[dede2002]

You mean that the excitation is connected directly between the output d + (3 small diodes) and the rotor, and that you start by hand?

Please note if the mppt opens the charging circuit during operation, the alternator voltage may rise very high!

[dede2002]

The regulator could simply stop the engine if the batteries are charged, or rather when they can no longer collect 30A at 28V.

That way you don't risk wasting gasoline by finishing the charge with fewer amps.

[swallowtail]

hi from

actually, you had corrected yourself, it's on the D +.

Yes when the MPPT opens the circuit, due to overcharged battery, the voltage goes up, but apparently does not exceed 55V (max voltage of mppt)

for the moment, the mppt does not manage the excitation, and this system works well only for the BULK phase (I cst) this is what matters because, the charge efficiency of the absorption phase is very bad (gassing) , it is therefore preferable to manage it from a PV source rather than petrol !!!!

But you still have to study for the absorption phase,
I have no solution.
swallowtail

[dede2002]

Hi swallowtail,

You are lucky if the voltage does not exceed 55V, in principle you should never open the circuit of a self-charging alternator, even with a regulator.
(it is often written under the hood of cars "do not disconnect the battery with the engine running"), although it does not always blow up.

It would be nice if your mppt cut the excitation instead of the charging current! And why not the engine at the same time.

A+