diy solar

diy solar

Batteryless Shed operation LV6548 vs Growatt 3000-ES

BlueMarblePA

Solar Enthusiast
Joined
Sep 11, 2022
Messages
417
Location
PA
My shed can only fit 4 panels. I purchased 4 panels used LG 280 Watt 36V 8amps.

I contacted Ian at Watts247, and he suggested I purchase a Growatt 3000TL LVM-ES. However, the startup voltage is 150V for that unit, and with 36Vx4=144V, I won't have enough volts to start charging (although I am running batteryless)

I am also interested in the MPP LV6548 as it can run batteryless. The startup voltage is 80VDc which should work for my small PV system (1120 Watts). However, Ian at Watts247 says he is worried that I also won't have enough watts.

I am not sure why he said that, though. Can anybody help?

Plan to add batteries later.
 
"However, the startup voltage is 150V for that unit, and with 36Vx4=144V, I won't have enough volts to start charging"

Probably, that 150V spec refers to VOC, (open circuit voltage,) which, on your 36V panels is closer to 45V.

4×45=180 volts, so you're okay there.

However, the 280 watts rating of your panels indicates the MAXIMUM output those panels can produce, under perfect, ideal conditions. Looking at that 280 watts spec more realistically, you can expect from 50% to maybe 70% of that 280 watts per panel, in real-world conditions.

Most likely, that real-world factor is what Ian had in mind when he expressed doubt that your panels would perform to your expectations.
 
"However, the startup voltage is 150V for that unit, and with 36Vx4=144V, I won't have enough volts to start charging"

Probably, that 150V spec refers to VOC, (open circuit voltage,) which, on your 36V panels is closer to 45V.

4×45=180 volts, so you're okay there.

However, the 280 watts rating of your panels indicates the MAXIMUM output those panels can produce, under perfect, ideal conditions. Looking at that 280 watts spec more realistically, you can expect from 50% to maybe 70% of that 280 watts per panel, in real-world conditions.

Most likely, that real-world factor is what Ian had in mind when he expressed doubt that your panels would perform to your expectations.
Interesting. He did say that both all-in-one inverters need 160V PV input to "work properly."

Even though the LV6548 says it will work with 90V, I guess the problem is that because these are used panels, and because it will rarely have sun at full irradiance, it may only reach 50%? Voltage thus may only be half -- 72V to 90V and thus may never really charge?

Are there any other options? I just went through the cost of 2s2p wiring - Victron MPPT 100/20 -- Multiplus -- 48V battery, and the prices went crazy, and I can't run it batteryless.
 
With less than ideal sun conditions, the voltage (open circuit) will still be there, but it will be highly subject to load. The charger might easily load it and it fall out of range but the charger should be smart enough to not do that. But you never know.
 
Back
Top