Inverter With SUB function

[steka]

Hello Friends,

I live in Lebanon where electricity is basically inexistent ! My brother bought Growatt SPF 5000 ES (mppt range starts at 120v), it comes with a very nice option SUB, where the utility will provide the rest of your consumption if solar is not enough. Following my brother good experience with solar energy I bought growatt spf 3000tl hvm-24. I didn't get the new model (like my brother) since I have very limited space for solar panels and the mppt range of model that I bought the starts from 30v.
I did a lot of research and I couldn't find any inverter with sub option with low range mppt voltage. I was wondering if somebody can help me out by pointing to a brand that have these 2 qualities. Choices are somehow limited in Lebanon, we have the brands growatt, must, sako, sorotec and of course unknown chinese brands). Also another thing I didn't like about growatt spf 3000tl that if my batteries are full or near full, the energy provided from solar panel will be low so the battery will contribute to the load and discharge even if the is a lot of sun outside, the only way to fully benefit from solar is to put a big load on the inverter, so solar will kick in fully.

Thank you,
Regards,
SK

 

[400bird]

I'm not going to be much help with giving you options. But I'm not sure that's much of a feature. It seems like standard operation for most grid tie inverters. I wouldn't buy one that functions otherwise.

If you have 500 watts coming in from solar with an 800 watt load, the utility will support the rest.

 

[timselectric]

I'm not going to be much help with giving you options. But I'm not sure that's much of a feature. It seems like standard operation for most grid tie inverters. I wouldn't buy one that functions otherwise.

If you have 500 watts coming in from solar with an 800 watt load, the utility will support the rest.

Actually, not all AIO 's can load share.
They don't have the ability to sync with the grid.
This allows them to be less expensive.

 

[12VoltInstalls]

not all AIO 's can load share

I just installed an MPP Solar AIO
I can’t decide from the instructions/manual if it does that but it appears to.

 

[timselectric]

I just installed an MPP Solar AIO
I can’t decide from the instructions/manual if it does that but it appears to.

As far as I know, MPP can. It has a lot of internal systems in common with Growatt.
It would be "SUB " , in setting #1 probably.

 

[12VoltInstalls]

would be "SUB " , in setting #1 probably.

I believe your correct
Menu 16 is troubling my mind though

 

[timselectric]

I believe your correct
Menu 16 is troubling my mind though

Not sure what 16 is.

 

[12VoltInstalls]

Not sure what 16 is.

In the manual it lists the customizable menu items. Page 18 (pdf pg. 20) for ‘solar first’ etc.
I have other menus set for ‘grid’ charge to start at 12.5V and cease at 13V.
I set the ‘charging’ amps to 10A but that doesn’t seem to pull the ~2A @ 120V I’d expect. Gotta play with it.

The programming buttons work fine but the case stickers are wrong: up is down and down is up which seems like a very protracted error I can’t believe made it to shipment.

Menu items 16 I don’t know why aren’t making sense to me. I know what their text says; but “solar first” or “battery first” are like the same thing in my mind!

 

[400bird]

Actually, not all AIO 's can load share.
They don't have the ability to sync with the grid.
This allows them to be less expensive.

Wow, that's scraping the bottom of the barrel Really sounds like poor costs saving choices.

 

[12VoltInstalls]

Wow, that's scraping the bottom of the barrel Really sounds like poor costs saving choices.

When the only decent 12V AIO game in town is MPP Solar at only $630 and a good fan base- I’m not sure what real savings there are to be had out there. The unit I have is apparently configurable to be stacked up to 9 units.

 

[timselectric]

When the only decent 12V AIO game in town is MPP Solar at only $630 and a good fan base- I’m not sure what real savings there are to be had out there. The unit I have is apparently configurable to be stacked up to 9 units.

9 units stacked in 12v.
That's a lot of DC amps. lol

 

[12VoltInstalls]

9 units stacked in 12v.
That's a lot of DC amps. lol

I know! I can imagine 2 - maybe.
If I needed that much power I think I’d probably lose my affinity for 12V or at least develop a separate 24- or 48V system. Geesh.

Menu 16 is troubling my mind though

Not sure what 16 is

I think it was just past my bedtime- it makes sense tonight LOL

 

[abhelou]

I have the SPF 5000ES. using in SUB mode, which should use utility when solar energy isn't sufficient. unfortunately, it doesn't function as it intend to. when solar energy is enough, on screen it mention 0 Amps drawn from utility, but in fact if you use a clamp current meter, you will see that continuously it is drawing 1.5-2 amps from utility.

 

[abhelou]

Hello Friends,

I live in Lebanon where electricity is basically inexistent ! My brother bought Growatt SPF 5000 ES (mppt range starts at 120v), it comes with a very nice option SUB, where the utility will provide the rest of your consumption if solar is not enough. Following my brother good experience with solar energy I bought growatt spf 3000tl hvm-24. I didn't get the new model (like my brother) since I have very limited space for solar panels and the mppt range of model that I bought the starts from 30v.
I did a lot of research and I couldn't find any inverter with sub option with low range mppt voltage. I was wondering if somebody can help me out by pointing to a brand that have these 2 qualities. Choices are somehow limited in Lebanon, we have the brands growatt, must, sako, sorotec and of course unknown chinese brands). Also another thing I didn't like about growatt spf 3000tl that if my batteries are full or near full, the energy provided from solar panel will be low so the battery will contribute to the load and discharge even if the is a lot of sun outside, the only way to fully benefit from solar is to put a big load on the inverter, so solar will kick in fully.

Thank you,
Regards,
SK

be careful if electricity is expensive, i have spf 5000es, while it shows that it isn't using from utility when solar energy is sufficient, in fact it always draw 1.5-2 amps. you can check that at you brother place using a clamp multimeter to measure drawn current from utility

 

[RCinFLA]

If I understand your question, you are looking for a hybrid inverter that has low voltage PV inputs and allows AC input to supplement AC output.

On your inverter, you might take a look at program setting 12. You might be able to raise the battery voltage trigger point causing inverter to switch over PV supplementing source to AC input at a higher battery voltage.

Most Chinese HF AIO inverters do not have a true bi-directional battery to high voltage DC converter. They have a parallel buck HV DC to DC converter to charge battery. This requires a mode change that takes a small amount of time so they cannot jump between charging battery and supplying inverter AC output quickly.

Due to this limitation of battery to HV DC converter they have to make a choice on how PV power is supplemented. Either disallow charging and supplement AC output demand from inverter/battery when PV cannot meet AC output demand, or with AC input, use AC input to supplement AC output, but this only allows charging of battery along with supplementing AC output (no load shaving function since it requires quick change over from charging to inverting).

These two choices go hand in hand with being called an off-grid model or a grid tied model. The model you bought is considered off-grid version, so it selects battery to supplement weak PV available power to meet AC output demand instead of AC input for supplementing AC output demand.

Both units synchronize their inverter to grid input when AC input is available. There are some cheaper, cheap units that only use rectifiers from AC input to produce HV DC. when AC input is available. The difference is the latter has poor charging power factor from AC input.

There is really no reason, other than firmware, that the AIO has to be fixed one way or the other. It could change its method based on if AC input is present or not. It may confuse the user on how SOL functions as its fall-back PV supplementing would depend on if AC input is present or not. Some users may not want AC input to supplement unless battery is low.

PV charge controller is a DC to DC boost converter that pushes PV power to the HV DC point in inverter. The DC-DC voltage boost converter is dependent on particular module used. Off grid PV arrays are usually lower voltage arrays while on-grid arrays are usually higher voltage arrays. This is really the only reason why one unit model has a lower PV voltage range than another model. Both boost converters convert PV voltage to HV DC internal to inverter. The efficiency of the DC-DC boost converter gets a bit better when the PV array voltage is closer to the inverter's HV DC voltage.

120vac model AIO inverters have a lower PV input voltage because their internal HV DC is a lower voltage. This might be an option.

If you are stuck with what you have, you can always add a direct to battery MPPT charger.

 

[timselectric]

The SPF-5000-ES, when set to SUB. Uses solar to power the loads, first priority. And uses utility to supplement the needs of the loads. If there's more solar than needed for the loads, the batteries will charge if they need it. The only time that the inverter uses battery for the loads. Is if both solar and utility are unavailable.

 

[timselectric]

SUB, is like having a grid tied inverter(zero export) with a battery backup in power failure.

 

[abhelou]

The SPF-5000-ES, when set to SUB. Uses solar to power the loads, first priority. And uses utility to supplement the needs of the loads. If there's more solar than needed for the loads, the batteries will charge if they need it. The only time that the inverter uses battery for the loads. Is if both solar and utility are unavailable.

what you say is what it is supposed to do. but use a clamp multimeter on utility cable to measure the current. even when there is enough solar to power loads and charge batteries, it is drawing 1.5-2 amps from grid while on inverter it shows 0 amps from utility.

 

[timselectric]

what you say is what it is supposed to do. but use a clamp multimeter on utility cable to measure the current. even when there is enough solar to power loads and charge batteries, it is drawing 1.5-2 amps from grid while on inverter it shows 0 amps from utility.

Yes, this is normal.
We have tested it before.
While in SUB mode, it's constantly connected to the grid. Matching voltage, and frequency.

 

[abhelou]

If I understand your question, you are looking for a hybrid inverter that has low voltage PV inputs and allows AC input to supplement AC output.

On your inverter, you might take a look at program setting 12. You might be able to raise the battery voltage trigger point causing inverter to switch over PV supplementing source to AC input at a higher battery voltage.

Most Chinese HF AIO inverters do not have a true bi-directional battery to high voltage DC converter. They have a parallel buck HV DC to DC converter to charge battery. This requires a mode change that takes a small amount of time so they cannot jump between charging battery and supplying inverter AC output quickly.

Due to this limitation of battery to HV DC converter they have to make a choice on how PV power is supplemented. Either disallow charging and supplement AC output demand from inverter/battery when PV cannot meet AC output demand, or with AC input, use AC input to supplement AC output, but this only allows charging of battery along with supplementing AC output (no load shaving function since it requires quick change over from charging to inverting).

These two choices go hand in hand with being called an off-grid model or a grid tied model. The model you bought is considered off-grid version, so it selects battery to supplement weak PV available power to meet AC output demand instead of AC input for supplementing AC output demand.

Both units synchronize their inverter to grid input when AC input is available. There are some cheaper, cheap units that only use rectifiers from AC input to produce HV DC. when AC input is available. The difference is the latter has poor charging power factor from AC input.

There is really no reason, other than firmware, that the AIO has to be fixed one way or the other. It could change its method based on if AC input is present or not. It may confuse the user on how SOL functions as its fall-back PV supplementing would depend on if AC input is present or not. Some users may not want AC input to supplement unless battery is low.

PV charge controller is a DC to DC boost converter that pushes PV power to the HV DC point in inverter. The DC-DC voltage boost converter is dependent on particular module used. Off grid PV arrays are usually lower voltage arrays while on-grid arrays are usually higher voltage arrays. This is really the only reason why one unit model has a lower PV voltage range than another model. Both boost converters convert PV voltage to HV DC internal to inverter. The efficiency of the DC-DC boost converter gets a bit better when the PV array voltage is closer to the inverter's HV DC voltage.

120vac model AIO inverters have a lower PV input voltage because their internal HV DC is a lower voltage. This might be an option.

If you are stuck with what you have, you can always add a direct to battery MPPT charger.

no u haven't understood the question*

Yes, this is normal.
We have tested it before.
While in SUB mode, it's constantly connected to the grid. Matching voltage, and frequency.

it isn't normal to draw 2 amps from grid, when there is enough solar energy for load and charger, and showing on inverter screen that it is drawing 0 amps from utility grid.