Inverter opinions please

[rayburns]

Question.. I am planning an off grid power system and I'd like inverter opinions. 36 x 460w bifacial solar panels with 1 rack of 6 eg4 batteries. I'm thinking either 4 eg4 6500 inverters wired 2 phase 240v or 1 eg4 18k inverter? I understand that the 18k is actually 12kw in output. I am also considering 2 18k inverters. Last question is what are you alls thoughts regarding 2 x victron 10kw inverters with necessary pv controllers compared to 2 x eg4 18k inverters and saving $ 4k?

 

[rodrick]

victron is great tier one equipment you can’t go wrong with, multiple inverters for redundancy imo is the best way to go you are never totally dark

voltronic equipment is good value products ( eg4, mpp, growatt ect ) and having a spare doesn’t break the bank
I have both victron and mpp both have served me well so far no complaints

if the system is a one time build and forget no further expansions or load changes and you don’t like tinkering go victron but if you like to play and experiment and tinkering is relaxing go with voltronic units and diy your batteries you can save some cash and have some fun

 

[hwy17]

Watch some Schneider overload videos on youtube. Even if you don't think one XW is enough, it's probably enough.

Your design seems a bit panel heavy or battery short, but that's one strategy.

 

[OffGridForGood]

I am planning an off grid power system and I'd like inverter opinions.

There are a great many options, what are you trying to power?
How much energy per day, kWh
How much load all at once kW (instantaneous) how many loads are motors/pumps?

36 x 460w bifacial solar panels

16.5kW say 75% of this on a typical day x 5 hours = 62kWh although this will vary by season.
Going to PV watts, 16.5 kW Hayesville NC set at 35 degrees due South, the calculator shows: March to Oct all about 2000kWh/month (67kWh/day)
and the worst month is Feb at 1390kWh/the short month, 49kWh/day avg. Will you need this amount of energy, if you get three days of cloudy weather where will you get power from.

with 1 rack of 6 eg4 batteries

one rack is 30kWh, if this rack was at 50% SOC as the sun came out on a typical day, it would be recharged full in 2.5 hours (depending on loads) the rest of that day's energy is either used or fed to the grid, or lost opportunity. - you say off grid so use it or lose it. Will you have an EV to use as a place to dump excess power?
If you have three or four poor weather days in a row, where is the power coming from to run your home?

. I'm thinking either 4 eg4 6500 inverters wired 2 phase 240v or 1 eg4 18k inverter? I understand that the 18k is actually 12kw in output.

Two 6500 is 13kW max load, the EG4 18k is 12kW max load (plus some surge for short periods)
Again the question should be - what are you trying to power? what is the max instantaneous load going to be, from what (motors or resistive loads).
The two 6500's will be less $ than the 18k, but will not have the same features.
What features do you want, or need?

I am also considering 2 18k inverters. Last question is what are you alls thoughts regarding 2 x victron 10kw inverters with necessary pv controllers compared to 2 x eg4 18k inverters and saving $ 4k?

Again, before considering what inverter capacity you need, you first need to know what you will be powering. A/C is typically the biggest load people seem to have, or an EV (or two) and knowing the loads will be critical to planning this out.

Saving $4k? your are describing a PV system with about 8-10k of PV plus mounting system disconnects cables, (distance?) Inverters of 5-12k depending which option you go with, about 9k in batteries (which may be only half of what you really need).
All in all, maybe a $40k if you do the labour, I wouldn't worry too much about the 4k difference, focus on what you will really need in this system so you are not stuck.
When you say 'off grid' do you mean totally without an electrical service available, or do you mean utility available, but not backfeeding? There are several definitions of what we mean by offgrid. If you are completely without utility for back up, you will need a good reliable generator, you will find some inverters are less tolerant of generator power than others.

I know Rodrick has both Victron and MPP, and he says they are both Tier One, I don't have (much) Victron, but feel MPP is not Tier One, more like good entry level Tier 2. If you are completely off grid, then reliability is too important for anything but top Tier equipment in my opinion. You are planning a system that will end up costing maybe 50k+ when all is said and done, and then you need to be able to rely on this system. Don't cut any corners if there is no utility to fall back on during winter. Research and planning cost nearly nothing, buying a bunch of the wrong equipment and then having to replace it all/upgrade/fight with it/start over cost plenty.

 

[JRH]

There are a great many options, what are you trying to power?
How much energy per day, kWh
How much load all at once kW (instantaneous) how many loads are motors/pumps?

16.5kW say 75% of this on a typical day x 5 hours = 62kWh although this will vary by season.
Going to PV watts, 16.5 kW Hayesville NC set at 35 degrees due South, the calculator shows: March to Oct all about 2000kWh/month (67kWh/day)
and the worst month is Feb at 1390kWh/the short month, 49kWh/day avg. Will you need this amount of energy, if you get three days of cloudy weather where will you get power from.


one rack is 30kWh, if this rack was at 50% SOC as the sun came out on a typical day, it would be recharged full in 2.5 hours (depending on loads) the rest of that day's energy is either used or fed to the grid, or lost opportunity. - you say off grid so use it or lose it. Will you have an EV to use as a place to dump excess power?
If you have three or four poor weather days in a row, where is the power coming from to run your home?

Two 6500 is 13kW max load, the EG4 18k is 12kW max load (plus some surge for short periods)
Again the question should be - what are you trying to power? what is the max instantaneous load going to be, from what (motors or resistive loads).
The two 6500's will be less $ than the 18k, but will not have the same features.
What features do you want, or need?

Again, before considering what inverter capacity you need, you first need to know what you will be powering. A/C is typically the biggest load people seem to have, or an EV (or two) and knowing the loads will be critical to planning this out.

Saving $4k? your are describing a PV system with about 8-10k of PV plus mounting system disconnects cables, (distance?) Inverters of 5-12k depending which option you go with, about 9k in batteries (which may be only half of what you really need).
All in all, maybe a $40k if you do the labour, I wouldn't worry too much about the 4k difference, focus on what you will really need in this system so you are not stuck.
When you say 'off grid' do you mean totally without an electrical service available, or do you mean utility available, but not backfeeding? There are several definitions of what we mean by offgrid. If you are completely without utility for back up, you will need a good reliable generator, you will find some inverters are less tolerant of generator power than others.

I know Rodrick has both Victron and MPP, and he says they are both Tier One, I don't have (much) Victron, but feel MPP is not Tier One, more like good entry level Tier 2. If you are completely off grid, then reliability is too important for anything but top Tier equipment in my opinion. You are planning a system that will end up costing maybe 50k+ when all is said and done, and then you need to be able to rely on this system. Don't cut any corners if there is no utility to fall back on during winter. Research and planning cost nearly nothing, buying a bunch of the wrong equipment and then having to replace it all/upgrade/fight with it/start over cost plenty.

Very well put …
..J

 

[rodrick]

There are a great many options, what are you trying to power?
How much energy per day, kWh
How much load all at once kW (instantaneous) how many loads are motors/pumps?

16.5kW say 75% of this on a typical day x 5 hours = 62kWh although this will vary by season.
Going to PV watts, 16.5 kW Hayesville NC set at 35 degrees due South, the calculator shows: March to Oct all about 2000kWh/month (67kWh/day)
and the worst month is Feb at 1390kWh/the short month, 49kWh/day avg. Will you need this amount of energy, if you get three days of cloudy weather where will you get power from.


one rack is 30kWh, if this rack was at 50% SOC as the sun came out on a typical day, it would be recharged full in 2.5 hours (depending on loads) the rest of that day's energy is either used or fed to the grid, or lost opportunity. - you say off grid so use it or lose it. Will you have an EV to use as a place to dump excess power?
If you have three or four poor weather days in a row, where is the power coming from to run your home?

Two 6500 is 13kW max load, the EG4 18k is 12kW max load (plus some surge for short periods)
Again the question should be - what are you trying to power? what is the max instantaneous load going to be, from what (motors or resistive loads).
The two 6500's will be less $ than the 18k, but will not have the same features.
What features do you want, or need?

Again, before considering what inverter capacity you need, you first need to know what you will be powering. A/C is typically the biggest load people seem to have, or an EV (or two) and knowing the loads will be critical to planning this out.

Saving $4k? your are describing a PV system with about 8-10k of PV plus mounting system disconnects cables, (distance?) Inverters of 5-12k depending which option you go with, about 9k in batteries (which may be only half of what you really need).
All in all, maybe a $40k if you do the labour, I wouldn't worry too much about the 4k difference, focus on what you will really need in this system so you are not stuck.
When you say 'off grid' do you mean totally without an electrical service available, or do you mean utility available, but not backfeeding? There are several definitions of what we mean by offgrid. If you are completely without utility for back up, you will need a good reliable generator, you will find some inverters are less tolerant of generator power than others.

I know Rodrick has both Victron and MPP, and he says they are both Tier One, I don't have (much) Victron, but feel MPP is not Tier One, more like good entry level Tier 2. If you are completely off grid, then reliability is too important for anything but top Tier equipment in my opinion. You are planning a system that will end up costing maybe 50k+ when all is said and done, and then you need to be able to rely on this system. Don't cut any corners if there is no utility to fall back on during winter. Research and planning cost nearly nothing, buying a bunch of the wrong equipment and then having to replace it all/upgrade/fight with it/start over cost plenty.

Victron is tier 1 equipment also Schneider, outback, midnight ect

voltronic is tier 2 ( eg4, mpp, growatt good quality for the price )

I never said mpp was tier 1 I said good value products

 

[rayburns]

Watch some Schneider overload videos on youtube. Even if you don't think one XW is enough, it's probably enough.

Your design seems a bit panel heavy or battery short, but that's one strategy.

You're correct. I neglected to mention that I have a 2002 37ft Class A motor home with a very large off grid set up. The new "mother" system will also be changing the 19kw batteries in the Class A. I've been using Victron exclusively for many years but have recently been tempted by the cheaper competition. It's rare that I ask for other people's opinions but I guess I just needed to be reminded that it's a gamble straying from a proven product to save 10 percent upfront.

 

[DIYrich]

If the purpose is to charge the 19kwh of batteries in the motor home, do you need AC (inverter?). Why not just get a charge controller, and link the batteries in parallel?