diy solar

diy solar

Like to see what AIO can AC charge from a cheap generator

Guda

Superstrut Strut
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Nov 19, 2019
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All these new AIO units with pretty cool features. My MPP is super picky about AC charging. It would be a awesome feature for a AIO to be ok with cheap generator power. Kinda like the Growatt can go to 450v saves $ on combiner box itams. Not needing a inverter generator to AC charge can save big $. Maybe there is already a AIO that does this?
 
I'm confused.

You appear to be discussing both AC charging the high PV input voltage. They are not related. The growatt capable of 450V PV input must be DC, not AC.
 
I'm confused.

You appear to be discussing both AC charging the high PV input voltage. They are not related. The growatt capable of 450V PV input must be DC, not AC.
Yeah, he said kinda like. As an example of a feature, not that they are related to the generator question.
 
Op, it is doubtful a cheapo generator would provide clean enough frequency to charge... the motor rpms change too much to be stable. Maybe fully loaded, the speed would be stable, but most likely, it would drop out frequently at best, or damage the unit at worst.
 
Thank you all! Sorry to confuse! It would be nice to be able to use a AC charge with cheap genny. I bet they could do it if they wanted to. Maybe they haven't thought to do it. Maybe some kinda qizmo that plugs inline to clean up the power. Transistor maybe?

I got over my irrational fear of generators & was like "sweet no more truck genny" But then it didn't work. So bummed. But I bought it to weld & it does that on propane so its awesome. I just like things to have more than 1 job.
 
In my defense. My 1st system was 12v RV & I had 2 different AC chargers both worked on cheap generators.
 
I'm in the same boat. I have a victron multiplus ii that won't play nice with any of my cheap generators. I believe the multiplus does some clever stuff where it actually synchronises itself to the input from the generator (or grid) and so it can charge and simultaneously supply the load from both the generator and the batteries. So it needs to to see a nice clean and stable waveform from the generator to do that.

I'm thinking about building a big, dumb and cheap 48v charger so I can charge my battery bank directly off my cheap generators.
 
Indeed. Not sure about lithium - although they shouldn't have a problem - but lead-acid, you can charge with anything.
Do you think a car alternator's regulator is anything more than a rectifier bridge? Car lead-acid batteries basically charge on pulse current.

A big enough (for your desired current) transformer and a bridge will do. Or get a truck regulator, cheap enough.
You might want to add a couple of capacitors (one big, one small) on the output to smooth things out a bit, probably not even necessary, the battery itself will. I may be wrong here (correct me if I am) but honestly...

Now, I believe AIOs won't accept "malformed" AC because they mostly run in "bypass" mode. They power your delicate and fussy AC loads first, what's left they charge the batteries with.
 
My guess is the AIO units employ Power Factor Correction circuits and they cant sync to a crummy wave forms. Just a guess, I might be wrong, won't be the first time.
 
By the time you add in devices to filter for frequency and waveform and to provide voltage regulation, it's just more stuff to go wrong.

I guess you could run power through a decent UPS but one with that level of capacity to cleanly transform and pass through power, it's probably cheaper just to get a decent inverter generator or hook it up to a different charger which can cope with the dirty waveform.

I already had a Yamaha inverter generator and my AIO works fine with it.
 
Indeed. Not sure about lithium - although they shouldn't have a problem - but lead-acid, you can charge with anything.
Do you think a car alternator's regulator is anything more than a rectifier bridge? Car lead-acid batteries basically charge on pulse current.

A big enough (for your desired current) transformer and a bridge will do. Or get a truck regulator, cheap enough.
You might want to add a couple of capacitors (one big, one small) on the output to smooth things out a bit, probably not even necessary, the battery itself will. I may be wrong here (correct me if I am) but honestly...

Now, I believe AIOs won't accept "malformed" AC because they mostly run in "bypass" mode. They power your delicate and fussy AC loads first, what's left they charge the batteries with.
A car alternator's regulator is definitely more than a rectifier. It varies the current in the field windings of the alternator to vary the output voltage.

I have an old microwave oven transformer that I removed the HV secondary winding from and wound a new LV secondary. It outputs about 28v now, which would probably fine for a 24v bank with just a rectifier. But since my bank is 48v, I plan to connect the (rectified) out put from the transformer to one or two boost converters I already have, to step up the voltage for the battery bank and give me CC/CV control of the charging.
Hopefully it should be able to give me about 500w of charging from a small 2 stroke generator.
Not the most efficient way to do things, but since I need it so rarely I don't care.
 
I'm in the same boat. I have a victron multiplus ii that won't play nice with any of my cheap generators. I believe the multiplus does some clever stuff where it actually synchronises itself to the input from the generator (or grid) and so it can charge and simultaneously supply the load from both the generator and the batteries. So it needs to to see a nice clean and stable waveform from the generator to do that.

I'm thinking about building a big, dumb and cheap 48v charger so I can charge my battery bank directly off my cheap generators.
Does anyone know if the signature solar 48v chargers work on cheap power? I would assume they do, most power supplies for computers and phones eat cheap power just fine. (It's because they internally convert to DC right away then back to AC at high frequency then a transformer, then back to DC, with multiple filter circuits)
 
Does anyone know if the signature solar 48v chargers work on cheap power?
I do not consider generators as cheap nor necessarily clean in the sense of providing a clean enough sine wave. It might be sufficient to charge a battery with an external power supply if an AIO will not do it.
 
I do not consider generators as cheap nor necessarily clean in the sense of providing a clean enough sine wave. It might be sufficient to charge a battery with an external power supply if an AIO will not do it.
Sure. One way to set it up would be to put the battery charger on the generator itself and have the generator output feed a transfer switch.

Aka 240 generator-small panel with one receptacle-generator breaker on main panel-intetlock kit.

This way if your batteries run low or your AIO is toast your generator powers your place directly. And some of the power goes to recharging the battery. You use either an automatic transfer switch ($$$) or a manual interlock kit (under 60 bucks).
 
Sure. One way to set it up would be to put the battery charger on the generator itself and have the generator output feed a transfer switch.
Why would you need a transfer switch to run DC from the charger to the batteries? I think connecting the charger to the generator is a good workaround to resolve the dirty sine wave from the generator. Most power supplies in chargers should be able to deal with a dirty sine wave.
 
Why would you need a transfer switch to run DC from the charger to the batteries? I think connecting the charger to the generator is a good workaround to resolve the dirty sine wave from the generator. Most power supplies in chargers should be able to deal with a dirty sine wave.
To take full advantage of high output cheap generators that give dirty 240v power. Just power everything direct. This also gives you a backup if your complex Chinese brand aio fails.
 
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