# Transformerless rectifier AC to direct DC

#### nes2020

Joined Oct 29, 2020
3
Hi All,

I have a solar hybrid inverter in my summerhouse running off grid. During winter times, there can be periods with no sun meaning i have no electricity in the house during nighttimes.

My though is if it would be possible to connect my 2500W 230VAC gasoline generator to the solar hybrid inverter where my DC pannels connect to the inverter. The voltage accepted is anything between 100-600 VDC. - This to charge my battery pack so i do not have to turn on a generator during the evening to power up the house.

Is it possible to just buy a simple 50A rectifier and connect a capacitor accorss the DC side to convert the 230VAC to DC directly and simply connect it to the solar hybrid inverter?

Is it really that simple?

#### Attachments

• 38.6 KB Views: 12

#### Danko

Joined Nov 22, 2017
1,059
Is it possible to just buy a simple 50A rectifier and connect a capacitor accorss the DC side to convert the 230VAC to DC directly and simply connect it to the solar hybrid inverter?
Yes, you can, with solar panel disconnected from inverter.
It is better to use 100A diodes. See I(V1) plot.

========================================================================================================
Or this variant. 1000μF capacitor and 50A or even 25A diodes are good:
------

Last edited:

#### Marley

Joined Apr 4, 2016
408
Use a 240V AC relay on the generator output (before the rectifier) to automatically disconnect the solar panel when the generator is running.

#### nes2020

Joined Oct 29, 2020
3
Great inputs. Just to confirm - is it okay to asume that using a capacitor of 0.14 Farad C = (0.7*I)/(Vpp*f) = 0.7*10/(1*50)= 0.14 farad is a good value?

#### Ian0

Joined Aug 7, 2020
1,537
Great inputs. Just to confirm - is it okay to asume that using a capacitor of 0.14 Farad C = (0.7*I)/(Vpp*f) = 0.7*10/(1*50)= 0.14 farad is a good value?
It’s a very good value. Pity it doesn‘t exist. Why are you aiming for 1V p/p ripple?

Does your solar controller have an MPPT? if so, connecting it to a generator might be a bad idea, as it will try to extract the maximum power from the generator, and will keep increasing the power until it blows up or the generator stalls.

#### nes2020

Joined Oct 29, 2020
3
Correct. It do have MPPT control and proberly it will trigger the circuit breaker on the generator. Hmm might need a 200V DC power supply etc. with current limiting.
Thanks for all the great feedbacks.

#### Danko

Joined Nov 22, 2017
1,059

#### Just Another Sparky

Joined Dec 8, 2019
187
You could probably provide current limiting using some AC capacitors. You can find motor run caps for reasonably cheap at online surplus stores. Be careful to use sufficiently high voltage ratings and install bleeder resistors.