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BenandAmber
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Joined: 16/02/2019
Location: United States
Posts: 961

Posted: 07:20pm 10 Dec 2020

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I am tinkering around trying to make a high input inverter

I am using a PJ short board with the ben and amber little mosfet boards kent made for me

I am trying to finger out the mosfets to use

For now i am thinking about using hy5012 300amps 125 volts 2.9 m ohms

The voltage my be to low for 8 12 volt batteries

Sould I work on a even higher input voltage maybe as high as a ev battery so ev battery could be used as is insead of having to break it down to a lower voltage

I will be needing to step down battery voltage for the control board is there a buck that has a very large input voltage all ready made like the postage size ones warp speed speaks of

Like always I dont have enough know how to do this but thats never stopped me before thanks to you guys

I am also stocking up on mosfets for 48 volt inverters

I have been using 200 amp 80 volt hy4008 2.9 m ohms thinking of trying out the 360 amp 80 volt hy5608 1.5 m ohms this time

Any advise on all of the above or any other topic would be appreciated

be warned i am good parrot but Dumber than a box of rocks

BenandAmber
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Joined: 16/02/2019
Location: United States
Posts: 961

Posted: 02:57am 14 Dec 2020

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Hope every one is doing well �not much going on on the shed anymore

I am keeping the voltage high input inverter under 150

Still trying to finger out a cheap 247 style mosfet to use

I talked to a friend and he said hy5608 should be ok for the 48 volt inverters

He also said that the 300 plus volt inverter my not need the expensive big tranny

I don't like the idea of not having the big tranny even if it is just for isolation

With my very limited knowledge and understanding it seems to me no matter the voltage the magnetic flux stored in the core would be needed for start up loads

My friend is a very gifted EE and programmer he is wise beyond his years and a incredable person

I could have misunderstood what he was saying it wouldn't be the first time

I think he will BE making a big splash and will be well known in the EE crowd VERY soon

I have also been chasing what most think are ghosts but i just know they are there

I am talking about me by ignrants accidentally finding ac on my inverters battery input cable

For those that haven't hear get ready for a laugh i was for a very long time using a AC clamp meter on DC

Yes it says ac on the screen and on the clamp its self yes also on the selector for the different functions yes a few of you guys tried to tell me

I spent countless hours winding and unwinding every material known to man and all numbers of turns on each trying to make the very best choke

I did learn that the lower the ac reading on the dc input the cooler the mosfets and the inverter will run flawless even if you are pushing to way to hard just to watch it blow

So the ac is the ghost i am tring to catch and get rid of completely

I my be getting a scope very soon i think it will give me a greater understanding of it all

I am also wanting to get started on my warpspeed inverter soon

so if any one has any parts they dont need and want to sell or trade please let me know

I have two finished nano control boards not programed and many other inverter stuff

I hope every one is doing good just to busy to entertain my shenanigans

Thanks for your time and god bless
Edited 2020-12-15 04:48 by BenandAmber

be warned i am good parrot but Dumber than a box of rocks

Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 1024

Posted: 11:39am 17 Dec 2020

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Even a high voltage inverter with a transformer for isolation purposes, is still going to be a big transformer, depending on the amount of kw's you want to put through it.

Without the isolation transformer, a blown up mosfet or IGBT could let DC rail voltage (whatever high voltage that is) through to all appliances that are running from the inverter and cause damage.

A way of stopping that, might be to to have a relay/contactor capable of breaking a high voltage DC ark without damage, The contactor would be powered from a small transformer (12v or so) with a small dc rectifier to power the contactor.

The transformer runs off the inverter output when AC is present and closes the contactor, if something blows up and DC is present, the transformer want work and the contactor will open, there is a bit more in it than that but thats my theory anyway.
I don't know what the grid inverters use, talk to your friend and have a look inside 1 or 2 or more.

Just a thought.

I'm busy with other things.

Cheers Aaron
Off The Grid

mab1
Senior Member

Joined: 10/02/2015
Location: United Kingdom
Posts: 209

Posted: 07:37pm 17 Dec 2020

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I'm not sure what voltage you have in mind, but, if you want a high voltage inverter, you could go for >170v (you're US 120v AC yes?) and connect your battery directly to the HV DC buss of a cheap HF sinewave inverter as that would be circa 170v dc anyway.

I have heard of someone connecting solar panel strings with VMP 170v direct to the dc buss of a HF inverter without a battery and running appliances including washing machines off the inverter AC. The sinewave generator regulates the output even though the buss rises to Voc and as long as the PV can provide enough amps it works fine.

Just make sure the H-bridge FETs/IGBTs and caps are rated > Voc (or max battery volts).

An isolation transformer would still be advisable if you're doing it with a battery though. And do be careful: HV DC is not to be played with lightly.

BenandAmber
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Joined: 16/02/2019
Location: United States
Posts: 961

Posted: 07:03pm 19 Dec 2020

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thanks revlac and mab1

revlac a small step down transformer ran from inverter to contractor makes really good since

mab1 i have also heard of people not using batt and some no inverter either both are very interesting

and you are right about high voltage dc i have been jolted from my 48 volt battery bank and warpspeed tells of being in water and getting a jolt from 12 volts

thanks two both of you for the advice hope you are busy with something cool revlac

be warned i am good parrot but Dumber than a box of rocks

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