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combined charger / inverter or to separate?
#1
I am in the US.  Looking at something like this

https://www.mppsolar.com/v3/split-phase-lv-series/

However.  I was wondering if it's better to split the charger from the inverter.  I liked this option because it can use the solar, battery and still be on-grid and can pass thru for the grid.  Can charge from the grid if needed.  

Only thing it can't do is grid tie... and well i wouldn't be building batteries if I wanted to feed the grid lol.

Any suggestions or thoughts?  Anyone use the mpp solar split phase units?
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#2
There are several options. Mine is but one of many. But to share - I'm off-grid and producing 9megwatts/year, delivering 240v@50a to the house thru automatic transfer switches. My goal is to double this to 18megawatts/year - e.g. 240v@100a AC available to feed into the house.

I think the scale of your end goals will affect your decision. If you know where you want to wind up, you can plan to get there in an incremental way - and that might answer some of your questions.

In my case, my PV array, Controllers (Midnite Classic), Battery (18650s), BMS (Batrium), Inverter (AIMS), and Transfer switches are all seperate units. This lets me add more PV+Controller or more battery or more inverting or more power distribution - one at a time (as long as the overall system/wiring sizes etc allow).

If you know/share your goals in more detail I think you'd get more helpful advise than my random comments here Smile
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#3
(08-02-2019, 07:07 PM)OffGridInTheCity Wrote: There are several options.  Mine is but one of many.   But to share - I'm off-grid and producing 9megwatts/year, delivering 240v@50a to the house thru automatic transfer switches.   My goal is to double this to 18megawatts/year - e.g. 240v@100a AC available to feed into the house.

I think the scale of your end goals will affect your decision.  If you know where you want to wind up, you can plan to get there in an incremental way - and that might answer some of your questions.

In my case, my PV array, Controllers (Midnite Classic), Battery (18650s), BMS (Batrium), Inverter (AIMS), and Transfer switches are all seperate units.   This lets me add more PV+Controller or more battery or more inverting or more power distribution - one at a time (as long as the overall system/wiring sizes etc allow).

If you know/share your goals in more detail I think you'd get more helpful advise than my random comments here Smile

I have no intention of being off the grid where I am.  However, utilizing as little as possible does appeal.  My goals are the following bullet points

day to day
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  at night pull from the battery until certain point then go to grid.  


since I live in a hurricane/storm area power outages are a concern.  during this time my goal would be.
* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.  

Looking at my power bills.  During the highest bill of the year i average about 60kwh per day.  the daily average over the whole year is about 45kwh.

Hope this provides some additional info to get some feed back Smile
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#4
(08-02-2019, 07:18 PM)CrankyCoder Wrote:
(08-02-2019, 07:07 PM)OffGridInTheCity Wrote: There are several options.  Mine is but one of many.   But to share - I'm off-grid and producing 9megwatts/year, delivering 240v@50a to the house thru automatic transfer switches.   My goal is to double this to 18megawatts/year - e.g. 240v@100a AC available to feed into the house.

I think the scale of your end goals will affect your decision.  If you know where you want to wind up, you can plan to get there in an incremental way - and that might answer some of your questions.

In my case, my PV array, Controllers (Midnite Classic), Battery (18650s), BMS (Batrium), Inverter (AIMS), and Transfer switches are all seperate units.   This lets me add more PV+Controller or more battery or more inverting or more power distribution - one at a time (as long as the overall system/wiring sizes etc allow).

If you know/share your goals in more detail I think you'd get more helpful advise than my random comments here Smile

I have no intention of being off the grid where I am.  However, utilizing as little as possible does appeal.  My goals are the following bullet points

day to day
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  at night pull from the battery until certain point then go to grid.  


since I live in a hurricane/storm area power outages are a concern.  during this time my goal would be.
* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.  

Looking at my power bills.  During the highest bill of the year i average about 60kwh per day.  the daily average over the whole year is about 45kwh.

Hope this provides some additional info to get some feed back Smile

Good info.

>I have no intention of being off the grid where I am.  However, utilizing as little as possible does appeal.  My goals are the following bullet points
>day to day
>*  during they day, i would love to be able to run the house from solar and excess charge batteries
>*  at night pull from the battery until certain point then go to grid.  
>since I live in a hurricane/storm area power outages are a concern.  during this time my goal would be.
>* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
>*  during they day, i would love to be able to run the house from solar and excess charge batteries
>*  during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.  

My 'off-grid' system is designed to meet exactly the goals you list here.  When I say off-grid I don't mean 'no grid'.     It means that the power generation is not 'tie'ed (not connected) to the grid electrically.  When my system has enough power (battery reaches a specific charge level) the inverter turns on and this throws the automatic transfer switch relays so that the inverter supplys power to portions of the house instead of the grid.   When the battery runs down the inverter turns off and grid takes over.    All automatic.   

There are certain 'hybrid' (grid-tie with batteries) that meet your goals as well  - see this link on the site https://secondlifestorage.com/t-What-typ...e-inverter

>Looking at my power bills.  During the highest bill of the year i average about 60kwh per day.  the daily average over the whole year is about 45kwh.
My 24panels = 7kw system produce 9,500kwh / year.   That's an average of 26kwh/day.    Winter is 14'ish kwh/day.   Spring/Fall = 30'ish kwh/day.   Summer is 45'ish kwh/day.
Per your info - 45kwh/day * 365 = 15,425kwh / year.   In southern oregon that would be 11kw PV array.  11,000/300 = 36panels.

My house is wired to consume an average of 2,400 watts/hour which means the 45kwh/day generated is consume as 30kwh of PV directly (during the day) and 15kwh from battery into the night.     

With that kind of profile, at 60% DOD that would be a 25kwh battery.

To recap:
Array size (2kw, 7kw, 11kw) is a key metric to the Hyrbrid or Grid-Tie Inverter or Off-Grid/MPPT-Controller you chose.. and perhaps how many you need in parallel. As I mentioned, to handle 7kw PV array I have 2 Controllers in parallel. The size of your system dictates what you need to purchase. For a larger system you need to purchase large spec equipment or be sure you can parallel multiple smaller ones..

Minimum effective battery size would be relative to your PV array, home power draw, goals. I gave you the example of 7kw PV array, home use of 2400kw/hour, 60% DOD would be on the order of a (minimum) 25kwh battery size.
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#5
(08-02-2019, 09:20 PM)OffGridInTheCity Wrote:
(08-02-2019, 07:18 PM)CrankyCoder Wrote:
(08-02-2019, 07:07 PM)OffGridInTheCity Wrote: There are several options.  Mine is but one of many.   But to share - I'm off-grid and producing 9megwatts/year, delivering 240v@50a to the house thru automatic transfer switches.   My goal is to double this to 18megawatts/year - e.g. 240v@100a AC available to feed into the house.

I think the scale of your end goals will affect your decision.  If you know where you want to wind up, you can plan to get there in an incremental way - and that might answer some of your questions.

In my case, my PV array, Controllers (Midnite Classic), Battery (18650s), BMS (Batrium), Inverter (AIMS), and Transfer switches are all seperate units.   This lets me add more PV+Controller or more battery or more inverting or more power distribution - one at a time (as long as the overall system/wiring sizes etc allow).

If you know/share your goals in more detail I think you'd get more helpful advise than my random comments here Smile

I have no intention of being off the grid where I am.  However, utilizing as little as possible does appeal.  My goals are the following bullet points

day to day
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  at night pull from the battery until certain point then go to grid.  


since I live in a hurricane/storm area power outages are a concern.  during this time my goal would be.
* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
*  during they day, i would love to be able to run the house from solar and excess charge batteries
*  during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.  

Looking at my power bills.  During the highest bill of the year i average about 60kwh per day.  the daily average over the whole year is about 45kwh.

Hope this provides some additional info to get some feed back Smile

Good info.

>I have no intention of being off the grid where I am.  However, utilizing as little as possible does appeal.  My goals are the following bullet points
>day to day
>*  during they day, i would love to be able to run the house from solar and excess charge batteries
>*  at night pull from the battery until certain point then go to grid.  
>since I live in a hurricane/storm area power outages are a concern.  during this time my goal would be.
>* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
>*  during they day, i would love to be able to run the house from solar and excess charge batteries
>*  during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.  

My 'off-grid' system is designed to meet exactly the goals you list here.  When I say off-grid I don't mean 'no grid'.     It means that the power generation is not 'tie'ed (not connected) to the grid electrically.  When my system has enough power (battery reaches a specific charge level) the inverter turns on and this throws the automatic transfer switch relays so that the inverter supplys power to portions of the house instead of the grid.   When the battery runs down the inverter turns off and grid takes over.    All automatic.   

There are certain 'hybrid' (grid-tie with batteries) that meet your goals as well  - see this link on the site https://secondlifestorage.com/t-What-typ...e-inverter

>Looking at my power bills.  During the highest bill of the year i average about 60kwh per day.  the daily average over the whole year is about 45kwh.
My 24panels = 7kw system produce 9,500kwh / year.   That's an average of 26kwh/day.    Winter is 14'ish kwh/day.   Spring/Fall = 30'ish kwh/day.   Summer is 45'ish kwh/day.
Per your info - 45kwh/day * 365 = 15,425kwh / year.   In southern oregon that would be 11kw PV array.  11,000/300 = 36panels.

My house is wired to consume an average of 2,400 watts/hour which means the 45kwh/day generated is consume as 30kwh of PV directly (during the day) and 15kwh from battery into the night.     

With that kind of profile, at 60% DOD that would be a 25kwh battery.

To recap:
Array size (2kw, 7kw, 11kw)  is a key metric to the Hyrbrid or Grid-Tie Inverter  or Off-Grid/MPPT-Controller you chose..   and perhaps how many you need in parallel.    As I mentioned, to handle 7kw PV array I have 2 Controllers in parallel.      The size of your system dictates what you need to purchase.  For a larger system you need to purchase large spec equipment or be sure you can parallel multiple smaller ones..

Minimum effective battery size would be relative to your PV array,  home power draw, goals.   I gave you the example of 7kw PV array, home use of 2400kw/hour, 60% DOD would be on the order of a (minimum) 25kwh battery size.

Great feedback!  I was thinking of going with the pip-lv2424 

https://www.mppsolar.com/v3/split-phase-lv-series/


Starting with 1 and wire it in on 1 side of my breaker box.  Then get a second one on another bank on the other leg of the breaker.  That way i can have 2 sets of solar/batteries/inverters.  

Then using the communication cable between them to do the split phase and give me a 240v for stuff like the AC.  I think this could work, just wouldn't have grid tie, which as mentioned before isn't really an issue for me.  

That 25-30kwh battery size seems about what I figured would be a great goal to shoot for.  

Thank you for the detailed feedback.  This definitely helps Smile
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#6
I have the 2424lv-hs with 1.2Kw of Solar and Running most of my 120V loads Sitting on 10Kwh of Storage and I'm building another 8Kwh of batteries on my bench now and have another 8-10Kwh of loose cells to assemble.   I have purchased a Reliance Controls Manual Transfer Switch http://www.reliancecontrols.com/ProductD...spx?31410B for use with my main Panel so I can switch each of my circuits between Grid and Inverter (gen on the unit)    Right now I'm running My fridge, Freezer, Internet, Battery Bench and a couple computers temporarily and loving how it works.   I have maxed out the inverter/charger/solar charge controllers input of solar (1.2Kw) and whenI get more panels I will be getting a PCM60X but for now the ability to run directly off Solar is Awesome

I also Love the ability to charge the batteries on Schedule (Only with Non MPT software SolarPatrol) so I can have it stop taking from the battery of the voltage gets too low and also charge during off peak up to 60Amps .  but so far since I have started it in June I have generated just over 100Kwh of Solar and used about 9kWh from the grid for those loads.

You can also add separate chargers and solar controllers to the battery   but having the ability in 1 units is great.

Here is my dashboard from SolarPatrol http://216.211.44.63/
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#7
(08-03-2019, 02:17 PM)jdeadman Wrote: I have the 2424lv-hs with 1.2Kw of Solar and Running most of my 120V loads Sitting on 10Kwh of Storage and I'm building another 8Kwh of batteries on my bench now and have another 8-10Kwh of loose cells to assemble.   I have purchased a Reliance Controls Manual Transfer Switch http://www.reliancecontrols.com/ProductD...spx?31410B for use with my main Panel so I can switch each of my circuits between Grid and Inverter (gen on the unit)    Right now I'm running My fridge, Freezer, Internet, Battery Bench and a couple computers temporarily and loving how it works.   I have maxed out the inverter/charger/solar charge controllers input of solar (1.2Kw) and whenI get more panels I will be getting a PCM60X but for now the ability to run directly off Solar is Awesome

I also Love the ability to charge the batteries on Schedule (Only with Non MPT software SolarPatrol) so I can have it stop taking from the battery of the voltage gets too low and also charge during off peak up to 60Amps .  but so far since I have started it in June I have generated just over 100Kwh of Solar and used about 9kWh from the grid for those loads.

You can also add separate chargers and solar controllers to the battery   but having the ability in 1 units is great.

Here is my dashboard from SolarPatrol  http://216.211.44.63/
The 2424 maxes out at 1.2kw of solar?  I thought it could handle higher than that.  I can see why you would want to add the pcm60x.  

I am still leaning towards the pip as it will definitely hit a few of those checkboxes for me.  And the scheduling is icing! Smile
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#8
One more sizing comment.

>pip-lv2424
This is 24v system. For a larger scale power output you might want to think about going 48v from the beginning. I notice that Pip has 48v as well.

To illustrate... it takes (aprox) 48v@250a DC to produce 240v@50a AC. If you go 24v, it would take 24v@500a DC to produce 240v@50a AC. Notice the jump from 250a to 500a between 24v and 48v DC.

From my experience... 48v is the sweet spot of wiring/equipment availability/reasonable-pricing for a system if you plan to produce 'large' amounts of power. For example, try to find a circuit breaker higher than 250a for DC....

Its hard to quantify - but let me pull out this out of the air.. 24v would kind of max out at 6000watt inverter output (e.g. 250amp DC wiring, circuit breaker etc).

------------------------
Don't want to come off as lecturing. We all struggle to make choices for our systems.. and you just have to get started and learn from your own hands-on experience. 24v is perfectly OK starting place - its where I started as well. And for me, I'm mostly doing this for the FUN of it.. and its important to keep that in mind Smile
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#9
Separate charger and inverter, unless you go the hybrid unit route.

Multiple MPPT controllers - one fails you still have some power.
Inverter fails - you still have stored energy to use with DC-DC converters as your battery never ends up with just the inverter connected....

Depends on what you want from your system and if any outages/down time are something you value against.


When you start to get over 100A with any voltage the losses start to pose increased risks as any bad connection becomes a radiant heater and with the heat also comes thermal expansion/contraction cycles, which slowly loosen connections that are not 100% and make the joints higher resistance, more heat, fire or burnout.

The losses in power are Amps x Amps x Resistance. Voltage is irrelevant to losses in term of the heat generated at a point in your system, just current...
50A x 50A x 0.02 Ohms = 50 Watts (picture a small soldering iron sat on your wiring)
150A x 150X x 0.02 Ohms = 450 Watts (couple of very large soldering irons)
300A x 300X x 0.02 Ohms = 1800 Watts (small electric room heater)

Moving 24V to 48V halves your current and reduces losses by 4x (and reduces the risk of hot joint thermal expansion/contraction)

24V (max I would recommend is 3kW)
48V (max I would recommend is 6kW)
Above 6kW split to multiple inverters (because idle losses in relatively low priced commercial units are large)
>12kW you have to go HV DC battery pack and that is not for a typical DIY builder due to the significant risks a HV DC battery pose.

Forgot to add - in terms of charging from grid, consider your full input / output losses as to what your trying to achieve.

Typical input to output losses could be in the order of over 20% (Charger 95% x Battery 95% x Inverter 90%) so you need to consider any price saving on grid charging which is then also on top of what you value your batteries at per kWh of energy put in and taken out.
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#10
The HS version is pwm only and 1.2kw. The mppt version goes up to 2000kw
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