Are 48V chargers necessary if owning HYBRID LV6048?

[MichaelK]

LazyDragon,

I looked up Voc in my manual. I'm going to paste it here as I want to make sure I fully understand. VOC=Volts on Charge VDC=Volts of direct current. What is the difference or are they the same? Here is my midnite solar specs: I don't think I did it right. Definite beginner, thanks for your patience.

Nope, you are getting that wrong. Voc means the open circuit voltage, the voltage of the panels went the wires are physically disconnected from anything else. If you plug your multimeter probe tips into the sockets of a disconnected solar panel, the voltage you are reading is the Voc. The voltage under load, when the panel is actually making power is the Vmp, or the maximal power point voltage.

The Voc comes into play when the battery bank is full, and the controller shuts off current flowing to the battery. As soon as current stops, the voltage raises up to the Voc, just like water pressure raises when you shut the valve. When the controller however senses a battery drain and closes the current flow circuit again, all the electronics are briefly exposed to the full Voc. It might only be milliseconds, but that's enough time for excessive voltage to damage the electronics.

BTW, You've typed the wrong parameters into the string calculator. You can't have a Vmp of 91V and a Voc of 435V?

 

[LazyDragon]

in the winter as my property is limited with sun due to mountains blocking the sun at this time of year.

I'm in a similar condition, but for me in winter it is the trees that block the sun. My 4kw array generates about 90 watts when the sun only gets halfway up the trees lol. I am working (on paper) on a trailer with panels that I can roll out to a spot that has better southern exposure since the state logged it last year. But it makes for a really long wire run back to my power shed. 300+ feet. I'm still considering my options for how to handle that. This past winter, I was running my small gen, charging at 40A on 48V, about 3 to 4 times per day for about 45 minutes each run.

My only concern with using the shed is the length of the wire needed to get to my camper. How far away would you place the shed from the camper?

Depends on where you want to put the inverter. If the inverter is in the shed, you'll be running 120/240V to the camper. At 240V, you really don't need to worry about the length of cable. Use 6 or 8 AWG (or higher) copper depending on what your eventual house size will be.
Other factors like propane lines will be a more important consideration for where to place the shed. Power lines are easy.

 

[LazyDragon]

But I am unable to justify a 48v only gen. I would rather have the dual use as a failback
How can we make autostart a reality? Lets do this.

That 48V charger looks nice, but as you say, it is pricey. You can buy 2 inverter generators for the price of the 1 48v charger. It also seems like it would be pretty loud.
It also wouldn't work for my batteries, which are 40V to 49V. "Capable of charging any battery chemistry between 48-59v"

My "autostart" setup is a real frankenstein LOL.
The Switchbot is epoxied onto the generator to provide the button pushing. This is really the crux of the system. I can push the button over the internet from anywhere on my property, or in the world. Switchbot also has smart features where I can push the button and it will run for a specified amount of time, then push it again automatically to turn it off.


For an autostart function, you need battery voltage monitoring (not too hard), but then you have to get that information into the home automation system that controls the generator. In my case, that is Switchbot. I'm not enough of an automation guru to connect different systems programmatically, so I brute forced it. I have a voltage controlled relay that turns on for 5 seconds when battery V hits 45.0. I wired the relay to the switch of a little flashlight, so the flashlight turns on for 5 seconds.
Switchbot has a couple of devices that include light sensors. That is the white box you see underneath the flashlight. When the flashlight turns on, the light sensor sees it and signals the switchbot environment, which can then trigger other events, such as turning on the generator, turning on an outlet, etc.

 

[MichaelK]

I'm in a similar condition, but for me in winter it is the trees that block the sun. My 4kw array generates about 90 watts when the sun only gets halfway up the trees lol. I am working (on paper) on a trailer with panels that I can roll out to a spot that has better southern exposure since the state logged it last year. But it makes for a really long wire run back to my power shed. 300+ feet. I'm still considering my options for how to handle that. This past winter, I was running my small gen, charging at 40A on 48V, about 3 to 4 times per day for about 45 minutes each run.

Another alternative is running a high voltage DC array line. With a really high-voltage controller like a MorningStar TS-60-600V controller or an Outback Flexmax 100 FM100-300, you might wire six grid-tie panels in series to get 240VDC. Position the solar array in the optimal sun location, then run the 240VDC back to where you want the power to be. At 240V, you would only be getting ~2% voltage drop at 300'.

 

[LazyDragon]

Another alternative is running a high voltage DC array line.

I've thought about that, but the higher arc potential of the DC makes me nervous. I'm in the national forest. If "something happens", I think I would prefer 240VAC.

I've been considering using 2 of those 4-to-1 microinverters to give me 8 panels with 240AC output for transmission. I certainly lose some efficiency, going from panel DC to microinverter AC to battery charger DC. The microinverters would be useful anyway, since there is still 1 tree standing in the field where the array would be pointing.
I can use the same Growatt SPF3000 I use for generator battery charging to also charge from the 240VAC input.
I've got my eye on a dump trailer frame which could provide both my transport, the base for the panels, and the panel elevation, all at once.

 

[buck4424]

Thank you guys for all your help. I really appreciate it.