What would you do to upgrade my SPF 3000TL LVM-24P based system to handle more panels?

[oregonsun]

I have 9 440w panels I want to use but my Growatt spf 3000tl lvm 24p only handles 2kw input.
(I bought 10 panels but one died in shipping)

My batteries are 4x amperetime 12v200ah in 2s 2p

I need 120v output.

If I add another growatt of the same model I'll only be able to use 8 of them, effectively right?

Would you switch to another all in one inverter charger, if so which one?
I think this growatt has high idle power consumption, I'm guessing two of them would be even worse and having lost one panel to shipping damage I'm not sure what would be the best route to get the most from what I have.

 

[DThames]

Do you want a larger inverter or just want to charge faster?

If just charge faster, get another charger like a EPEver, and create an array for each charger.

 

[oregonsun]

I don't necessarily need a larger inverter but I want my solar system to be less gasoline powered during the winter in oregon where the sun is poor much of the time, and I want to be able to dump extra solar into tiny house heating and cooling when batteries are full. Only 18x15ft living space to heat and cool.

I may be doubling my batteries soon.

I bought an emporia gen 2 view smart energy monitor with 16 sensors plus 8 emporia smart plugs to smarten up the system and allow me to trigger dump loads when there is extra solar, haven't tried it yet but they claim it can do that, dump extra power into some electric heaters would help greatly to offset my propane heating costs.

Maybe I need a mini split upgrade from propane heat.

I don't know... help me figure this out.

My electric usage currently is under 2.5kw per day with no electric heating or a/c and using propane for cooking, the goal is to use less propane and gasoline in a fully off grid setup and to be able to at least get the 2.5kw each day even in poor winter oregon weather. Whatever I get needs to be optimized for the lowest light days to try to stay off of gasoline in the winter, but also let me use all the extra solar power for heating and cooling when the weather permits.

 

[SignatureSolarAdam]

The SPF 3000TL LVM-24P are generally used in systems that have limited space for their PV array. An external charge controller can help you ensure that your battery bank gets recharged efficiently. A second SPF 3000TL LVM-24P would do that, and add usable wattage to your current system.

The idle consumption very low on these units.

 

[DThames]

EPEver 60amp

 

[MichaelK]

Since you have 9 working panels, one option that might work for you is to wire them 3S3P, but point each string in a different direction. One Southeast, one South, and one Southwest. On bright, sunny days, that will tend to dampen the noon peak, but spread out the lower peak for a longer part of the day.

On cloudy days, when production drops down to 10% the extra panels will be putting out about the same power because the light though lower is more scattered.

Here's some pics of my first generation, V1.4 design. It holds three panels of the size you are working with.

 

[schmism]

My electric usage currently is under 2.5kw per day with no electric heating or a/c and using propane for cooking, the goal is to use less propane and gasoline in a fully off grid setup and to be able to at least get the 2.5kw each day even in poor winter oregon weather. Whatever I get needs to be optimized for the lowest light days to try to stay off of gasoline in the winter, but also let me use all the extra solar power for heating and cooling when the weather permits.

Just add more pannels. you can overpannel, just dont over volt. Or you could add a second SCC to run a second set of panels.

 

[DThames]

The SPF 3000TL LVM-24P are generally used in systems that have limited space for their PV array. An external charge controller can help you ensure that your battery bank gets recharged efficiently. A second SPF 3000TL LVM-24P would do that, and add usable wattage to your current system.

The idle consumption very low on these units.

I think mine draw about 60 watts internal load.

 

[oregonsun]

I've been using 4 of the panels 2s2p, the VOC on them is 52.6v ea, max working voltage is 44.3v ea.
The growatt says max input voltage is 145
It seems 3s3p is just barely out of reach with these panels and this inverter.

Maybe I should switch to SPF 3000TL LVM-ES
It says it can take 120v to 250v solar input and handle 4kw of panels.
That's almost the same input ability as upgrading to SPF 6000T DVM-MPV which costs twice as much but still only max input of 250v and 5kw max panels.

This growatt might be a bad match for these panels, just too limited. Maybe I'm getting poor performance in bad weather because I'm running below 100v input. Sometimes I only see 5-10w middle of the day if the clouds are in the way, is that because the voltage drops too low to work?

 

[oregonsun]

If 60w is the idle consumption on this then it's the largest consumer of energy I have, that's more than my apartment size fridge draws and three times my tv or laptop. Most of the time my average power consumption for everything I power is 100W combined, varying from 70 to 130w.,

 

[DThames]

If 60w is the idle consumption on this then it's the largest consumer of energy I have, that's more than my apartment size fridge draws and three times my tv or laptop. Most of the time my average power consumption for everything I power is 100W combined, varying from 70 to 130w.,

Which would be a good reason to just add another charger. Note on your previous post about panel match.....I bought 60cell panels so I could put 3 in series and stay under the 145v max input.

Edit...the manual says "<50w" on idle consumption. I think mine is a bit higher.

 

[oregonsun]

Which would be a good reason to just add another charger. Note on your previous post about panel match.....I bought 60cell panels so I could put 3 in series and stay under the 145v max input.

Edit...the manual says "<50w" on idle consumption. I think mine is a bit higher.

I think you are right on 60w idle consumption because every day I charge 2x as much as what I've discharged since the last time it was full. When discharged number shows 1.3kw my batteries aren't full until they get 2.6kw of sun. Since I have installed this growatt it says 666kwh total charged and 447kwh total load consumption and 347kwh discharged. There has to be a good amount of loss in here somewhere the numbers don't add up.

When the sun is strong I can refill batteries in 2hrs at peak sun with 4 panels, but on a dark day I can see as low as 500W solar charge from the entire day off >1600w of panels.

I made a mistake when I bought the panels, some vendors list this growatt as 150v max input when the manual says 145 and I only saw the panel working voltage was 44 so I thought I had a good match for 3s, I didn't know about VOC being 52.6.

I really like the web based monitoring on an all in one unit, where I can see the full input and output, if I add another solar charger then I would be missing some info. I'd prefer another all in one that can just handle more panels, then I can sell this one. Ideally I'd like something with faster update rate on the wifi monitoring so I can get more real time info, rather than the every 5 minute refresh of this growatt.

 

[DThames]

I think you are right on 60w idle consumption because every day I charge 2x as much as what I've discharged since the last time it was full. When discharged number shows 1.3kw my batteries aren't full until they get 2.6kw of sun. Since I have installed this growatt it says 666kwh total charged and 447kwh total load consumption and 347kwh discharged. There has to be a good amount of loss in here somewhere the numbers don't add up.

When the sun is strong I can refill batteries in 2hrs at peak sun with 4 panels, but on a dark day I can see as low as 500W solar charge from the entire day off >1600w of panels.

I made a mistake when I bought the panels, some vendors list this growatt as 150v max input when the manual says 145 and I only saw the panel working voltage was 44 so I thought I had a good match for 3s, I didn't know about VOC being 52.6.

I really like the web based monitoring on an all in one unit, where I can see the full input and output, if I add another solar charger then I would be missing some info. I'd prefer another all in one that can just handle more panels, then I can sell this one. Ideally I'd like something with faster update rate on the wifi monitoring so I can get more real time info, rather than the every 5 minute refresh of this growatt.

Have you considered 2s3p on your panels?

 

[oregonsun]

Have you considered 2s3p on your panels?

I considered 2s4p just so I could get a decent charge on dark days but then thousands of watts would be wasted on good days that could have gone to offset my propane heating costs, and with the cost of propane what it is now the calculation has totally changed, need to reduce these high heating costs. I'm spending over $200 a month on gas and propane, I'd rather put that into solar, I feel like I'm just burning dollar bills every month when I should instead just be adding more panels.

2s3p would be close to ideal for this growatt most of the time, but then it's not going to do what I'm hoping for on dark days and we have a lot of them in a row in oregon. I really need all 9 panels if I want to stay off generator as much as possible in the winter, if not more. If I could go back in time with 1.21 jiggawatts I'd buy a full pallet of 31 panels even if I didn't need them all and go to larger all in ones that are stackable I think.

 

[WYtreasure]

It sure seems like a second charge controller would be a simple fix, as has already been suggested.

 

[oregonsun]

It sure seems like a second charge controller would be a simple fix, as has already been suggested.

Would that shorten the expected lifespan of my growatt if I'm pulling close to max off the 3kw inverter and heating with it? I've never pulled that much power for long periods of time from it, not sure it's built to handle that long term.

 

[MichaelK]

Would that shorten the expected lifespan of my growatt if I'm pulling close to max off the 3kw inverter and heating with it? I've never pulled that much power for long periods of time from it, not sure it's built to handle that long term.

Redlining any equipment is hard on it and the electronics are no exception. I've always recommended selecting 2X capacity for whatever I buy, be it inverters, or my pickup truck.

 

[WYtreasure]

Would that shorten the expected lifespan of my growatt if I'm pulling close to max off the 3kw inverter and heating with it? I've never pulled that much power for long periods of time from it, not sure it's built to handle that long term.

I have to agree with what @MichaelK said.

I also believe, by adding the appropriate charge controller and managing loads, you will be able to reduce the charging load and inverter load of your growatt. Having a second charge controller on hand always seems like a good idea.

The less you spend on a product, the farther you should stay from the recommended limits.

 

[oregonsun]

Ok thanks guys. Problem solved now.

I just bought a spf3000tl lvm es from signature solar they had open box, with the credit I had from a broken panel on my last order it was $410 shipped and I can sell the growatt I have for more than that so free upgrade. That's enough to run 8 panels for now and I'll keep heating limited to 1500w so as not to push it too much, later I can add another if I get more panels.
It says it supports 4kw of solar and 250v max input, so it's a step up from the other one even though both are 3kw inverters.

 

[DThames]

I have to agree with what @MichaelK said.

I also believe, by adding the appropriate charge controller and managing loads, you will be able to reduce the charging load and inverter load of your growatt. Having a second charge controller on hand always seems like a good idea.

The less you spend on a product, the farther you should stay from the recommended limits.

While this..."The less you spend on a product, the farther you should stay from the recommended limits.", may very well be true, we should demand that products meet their rating. If I buy a 1 hp electric motor, I expect it to deliver 1 hp for years under rated conditions. I shouldn't have to expect to derate an inverter to make it last a normal lifespan. Just saying.