Can the 12vdc output from a generator (20 amps) be wired into the mppt input or combiner box?

notarichman

Solar Enthusiast
Joined
Feb 20, 2022
Messages
82
The idea is to have the mppt regulate the charge on the battery from the generator when the battery is getting low.
load power would still be available. my Kid mppt controller can handle 30amps, 150v pv input.

an alternate choice may not be possible; feed the AC output of the generator to a converter and then to a diode to stop backfeed into the converter.
then to the mppt. the diode would drop the output voltage of the converter about .7 volts, but should still charge low batteries, but maybe not charge
them all the way with no load.
 

camelCase

Solar Addict
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Apr 24, 2021
Messages
240
The DC output on most generators is regulated at a fixed voltage and is of limited amperage. The popular Honda eu2200i, for instance, puts out 8.3 amps at ~13.8 volts which is about 100w. You would be better off charging your bank directly from the DC output, or better yet, using an AC powered battery charger. MMPT chargers are typically designed to step DC voltage down, not up, and most require several volts higher than the battery bank coming from the panels before they will start charging.
 

Biasjo

Renewable energy user - North Carolina
Joined
Dec 19, 2021
Messages
540
The idea is to have the mppt regulate the charge on the battery from the generator when the battery is getting low.
load power would still be available. my Kid mppt controller can handle 30amps, 150v pv input.

an alternate choice may not be possible; feed the AC output of the generator to a converter and then to a diode to stop backfeed into the converter.
then to the mppt. the diode would drop the output voltage of the converter about .7 volts, but should still charge low batteries, but maybe not charge
them all the way with no load.
My understanding of MPPT CC is they vary their ohms (Sweep) to pick the maximum Amps. Normally this doesn't work well with Generators.
One of the guys from Midnight told me this years ago. Weather that is still the case I'm not sure. Some of the electronics guy here could tell you.
 

notarichman

Solar Enthusiast
Joined
Feb 20, 2022
Messages
82
The DC output on most generators is regulated at a fixed voltage and is of limited amperage. The popular Honda eu2200i, for instance, puts out 8.3 amps at ~13.8 volts which is about 100w. You would be better off charging your bank directly from the DC output, or better yet, using an AC powered battery charger. MMPT chargers are typically designed to step DC voltage down, not up, and most require several volts higher than the battery bank coming from the panels before they will start charging.
i'm in the process of buying a 48vdc battery charger to use with my batteries that i pick up on may 2nd. i don't know the ampere output of the charger, but if it is 10 amps; then that's 480watts plus for whatever the higher voltage is for it. maybe i could use it to feed my mppt for my current
12volt battery system? that should be the same as having the variable voltage/current coming from PV panels and be high enough to charge the
12 volt batteries via the mppt. i will first check the amps out of the charger to make sure it isn't over the 30a max. current of the KID mppt.
 
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