24v all in one mop unit, wiring details plz..

[Jtp.PlzAndThankYou]

So I bought the mppt 24v system from @Will Prowse reccomended sight. Trying to wire six Solar panels(12v100w,2 rich solar and four hqst) can I do three pairs in series(3 sets of 24volts right?) and then parallel them? Would I still need a combiner box for this method? Or what type of fuse would you recommend from panels to all in one unit and from battery’s to all in one unit?(I have 4 battery’s but was planing to do 2 to make sure I don’t blow all my investment) Thanks for any help I can repay it if needed.

 

[tictag]

can I do three pairs in series(3 sets of 24volts right?) and then parallel them?

Yes and no. Firstly understand that the '24V' is the output to the battery, the input is from your PV panels. A 100W panel would typically generate around 22V (open circuit) so three in series would be 66V ... this is oft called the 'system voltage' and must be supported by your charge controller (most offer up to at least 75V). Paralleling these two series connected strings would double the available current whilst maintaining the same system voltage. A 300W series connected panel string would generate around 6A (at 66V) so doubling up would be 12A (at 66V).
So, yes, you can connect your panels in this way, but no, they would not make 24V. Clear as mud?

Would I still need a combiner box for this method?

Not sure what you mean.

Or what type of fuse would you recommend from panels to all in one unit and from battery’s to all in one unit?

Imho, you don't need to fuse PV lines so long as you have spec'ed the PV cable correctly, though adding an isolation switch is a good idea.
After making sure that the cable from controller to battery and battery to load is spec'ed correctly*, you should fuse the controller to battery line (at just above max current your controller is specified for) and from battery to load (at just above max current for expected loads). Remember fuses are just there to protect the wiring from short circuit overloads; the devices they connect to have their own protection. It is also a good idea to have a battery isolation switch.

Will's website has a load of good blueprints for typical installations: https://www.mobile-solarpower.com/

*To spec wire:
(1) Ensure the cable is capable of supporting the maximum expected current
(2) Ensure the cable run (i.e. there and back) does not drop more 3% of the supplied voltage across it
(3) Ensure the cable (and connector) specs are suitable for the intended use e.g. use dedicated PV cable for PV runs, automotive cable for internal runs, tinned copper lugs etc.

Other installation considerations:

• Keep the PV cables long to ensure controller and battery cables are short as possible in order to reduce resistive losses.
• Use a proper crimp tool and good quality terminals for battery and load terminals - you don't want these arcing or corroding.
• Over-spec'ing cable just adds weight and cost to your project without any appreciable benefit.
• It's a general rule of thumb to spec your battery bank to provision 3 days expected daily usage and your PV array to replenish daily use per day. For example, Daily Usage = 1,200Wh, spec 300AH battery bank (1,200Wh x 3 days = 3,600Wh / 12V = 300AH) with 240W total panels (240W x 5 hours sun = 1,200Wh per day). Remember though that depending on your latitude from the equator, solar energy reduces. I live in England at 55o latitude, my rule of thumb is 80% efficiency in Summer dropping to 20% efficiency in Winter.

I hope this helps,
Regards,
David.

 

[Jtp.PlzAndThankYou]

Dave thank you so much! The info you have provided is enough to finish my system I believe, so would you recommend

So I bought the mppt 24v system from @Will Prowse reccomended sight. Trying to wire six Solar panels(12v100w,2 rich solar and four hqst) can I do three pairs in series(3 sets of 24volts right?) and then parallel them? Would I still need a combiner box for this method? Or what type of fuse would you recommend from panels to all in one unit and from battery’s to all in one unit?(I have 4 battery’s but was planing to do 2 to make sure I don’t blow all my investment) Thanks for any help I can repay it if needed.

@tictag t

Yes and no. Firstly understand that the '24V' is the output to the battery, the input is from your PV panels. A 100W panel would typically generate around 22V (open circuit) so three in series would be 66V ... this is oft called the 'system voltage' and must be supported by your charge controller (most offer up to at least 75V). Paralleling these two series connected strings would double the available current whilst maintaining the same system voltage. A 300W series connected panel string would generate around 6A (at 66V) so doubling up would be 12A (at 66V).
So, yes, you can connect your panels in this way, but no, they would not make 24V. Clear as mud?

Not sure what you mean.

Imho, you don't need to fuse PV lines so long as you have spec'ed the PV cable correctly, though adding an isolation switch is a good idea.
After making sure that the cable from controller to battery and battery to load is spec'ed correctly*, you should fuse the controller to battery line (at just above max current your controller is specified for) and from battery to load (at just above max current for expected loads). Remember fuses are just there to protect the wiring from short circuit overloads; the devices they connect to have their own protection. It is also a good idea to have a battery isolation switch.

Will's website has a load of good blueprints for typical installations: https://www.mobile-solarpower.com/

*To spec wire:
(1) Ensure the cable is capable of supporting the maximum expected current
(2) Ensure the cable run (i.e. there and back) does not drop more 3% of the supplied voltage across it
(3) Ensure the cable (and connector) specs are suitable for the intended use e.g. use dedicated PV cable for PV runs, automotive cable for internal runs, tinned copper lugs etc.

Other installation considerations:

• Keep the PV cables long to ensure controller and battery cables are short as possible in order to reduce resistive losses.
• Use a proper crimp tool and good quality terminals for battery and load terminals - you don't want these arcing or corroding.
• Over-spec'ing cable just adds weight and cost to your project without any appreciable benefit.
• It's a general rule of thumb to spec your battery bank to provision 3 days expected daily usage and your PV array to replenish daily use per day. For example, Daily Usage = 1,200Wh, spec 300AH battery bank (1,200Wh x 3 days = 3,600Wh / 12V = 300AH) with 240W total panels (240W x 5 hours sun = 1,200Wh per day). Remember though that depending on your latitude from the equator, solar energy reduces. I live in England at 55o latitude, my rule of thumb is 80% efficiency in Summer dropping to 20% efficiency in Winter.

I hope this helps,
Regards,
David.

@tictag
For four of those batteries do I need the four isolator switches, two or would they all go to one, I was going to wire for 12v 135ah battery’s in parallel with two groups of two for the 24v?
thanks a lot for your help David

 

[tictag]

For four of those batteries do I need the four isolator switches, two or would they all go to one, I was going to wire for 12v 135ah battery’s in parallel with two groups of two for the 24v?

You generally only need one battery isolator to cut the battery bank off from the rest of your system and one PV isolator to cut the panels off from the controller. There are so many potential designs, it's best to just work to two principles:

(1) For series connections, connect +ive to -ive and add battery voltages together e.g. 12V + 12V = 24V



(2) For parallel connections, all current paths to every terminal must be identical to avoid dissimilar cable voltage drops. For example, Battery 1 gets 14.4V, Battery 2 gets 14.2V because Battery 1 cable run is 1m, whereas Battery 2 cable run is 1.2m.



For example:



Tip: Battery isolators are relatively cheap (e.g. £15) but you might want to consider one of Victron's Battery Protect modules. They offer convenient low voltage disconnect protection together with switchable isolation in one package. And, no, I am not employed by Victron! I just like their gear.

RE recommending any particular system, if Will has a system documented on his website, I would recommend it; the man is clearly a genius.

I hope this helps.

Regards,
David.

p.s. Sorry for crude drawings, I never was much of an artist!

 

[Jtp.PlzAndThankYou]

You generally only need one battery isolator to cut the battery bank off from the rest of your system and one PV isolator to cut the panels off from the controller. There are so many potential designs, it's best to just work to two principles:

(1) For series connections, connect +ive to -ive and add battery voltages together e.g. 12V + 12V = 24V

View attachment 4582

(2) For parallel connections, all current paths to every terminal must be identical to avoid dissimilar cable voltage drops. For example, Battery 1 gets 14.4V, Battery 2 gets 14.2V because Battery 1 cable run is 1m, whereas Battery 2 cable run is 1.2m.

View attachment 4583

For example:

View attachment 4584

Tip: Battery isolators are relatively cheap (e.g. £15) but you might want to consider one of Victron's Battery Protect modules. They offer convenient low voltage disconnect protection together with switchable isolation in one package. And, no, I am not employed by Victron! I just like their gear.

RE recommending any particular system, if Will has a system documented on his website, I would recommend it; the man is clearly a genius.

I hope this helps.

Regards,
David.

p.s. Sorry for crude drawings, I never was much of an artist!

Drawings are awesome,
I don’t know if it’s encouraged or approved

You generally only need one battery isolator to cut the battery bank off from the rest of your system and one PV isolator to cut the panels off from the controller. There are so many potential designs, it's best to just work to two principles:

(1) For series connections, connect +ive to -ive and add battery voltages together e.g. 12V + 12V = 24V

View attachment 4582

(2) For parallel connections, all current paths to every terminal must be identical to avoid dissimilar cable voltage drops. For example, Battery 1 gets 14.4V, Battery 2 gets 14.2V because Battery 1 cable run is 1m, whereas Battery 2 cable run is 1.2m.

View attachment 4583

For example:

View attachment 4584

Tip: Battery isolators are relatively cheap (e.g. £15) but you might want to consider one of Victron's Battery Protect modules. They offer convenient low voltage disconnect protection together with switchable isolation in one package. And, no, I am not employed by Victron! I just like their gear.

RE recommending any particular system, if Will has a system documented on his website, I would recommend it; the man is clearly a genius.

I hope this helps.

Regards,
David.

p.s. Sorry for crude drawings, I never was much of an artist!

Hey David this is incredible help thanks a lot his videos Is why I’am here, and your drawings are amazing as well can you size up fuses/relays/isolator switches for my system I hope I’am not abusing guidelines when I say I can pay you for your help (not a lot cuz I ain’t rich) but something for your time if you can give me the missing ingredients, he don’t recommend much on his blueprint as far as isolator switches. Thanks for all your help again

 

[tictag]

My help is free

I'm assuming the attachment is from Will's website? It's time for me to get some shut-eye (yes, I know it's actually 0855hrs here in the UK and I haven't been to bed yet!!). I'll take a look later when my eyes uncross ;-)

 

[tictag]

Hey, @Jtp.PlzAndThankYou, I've been looking at Will's website, are you planning your project based on: https://www.mobile-solarpower.com/all-in-one-solar-power-packages1.html ?

If so, couple of questions:
- Are you planning on using all described components? If not, what's different?
- Are you planning on the same capacities described on that page and in his associated videos? If not, more/less?
- Are there any other design considerations? Boat, RV, house, remote location, limited space, cheap v best, minimal weight, remote control, analytics, alarms needed, ingress protection etc
- Are you looking for general design advice or a parts list you just add to your shopping basket?
- Where are you physically located (approx)?

Regards,
David.

 

[Jtp.PlzAndThankYou]

Yes, I have the mpp all in one, not the hybrid version the one from his video and his setup,or a similar model.(specs are in one of the attachments)
And my pv cable is 8 gauge instead of the recommended 10.
Yes, maybe even less. I will just run a light and a fan. Not really pushing its capacity. If by capacity we are talking loads.(trying to conserve the cycles in going with the worser choice of acid batteries)
-It’s a house I plan on adding more panels later on to better take advantage of the power in the inverter(as well).
-And either or both would be greatly appreciated, thank you a lot!
- Southern California
I really been doing some research and trying to save you the trouble of replying to me all day, I got a lil close with a Renogy article on how to fuse my system, just hoping to get some verification, and anxiously awaiting to see what you could come up with again thanks a lot David

 

[tictag]

OK, so I've now watched all of Will's videos on this 'all in one' unit ('unit') and reviewed his system blueprint. Some assumptions:

• You have model PIP 2424LV-MSD 'all in one' which can handle a up to 145VDC PV system voltage, has a 2.4KW PSW inverter, 80A MPPT solar controller, 60A 24V 3-stage battery charger, a grid transfer switch and computer communications via USB.
• You have 6 x 100W PV panels for a total of 3,000Wh capacity per day (assuming 5 hours ideal sunshine)
• You have 4 x 12V 135AH VMAX for a total of 270Ah capacity (or 3,240Wh) maintaining the recommended 50% DoD for VRLA batteries.
• Will suggests buying the following, do you have these?
  • Pre-terminated (MC4) PV cable, connecting panel-to-panel and to your unit.
  • Pre-terminated battery cable, connecting battery-to-battery and to your unit.
  • Pre-terminated 110V mains cable, connecting mains to your unit and your unit to your loads
• You have all the required tools e.g. wrenches for battery terminals, screwdrivers for terminal blocks, hammer drill for cable entry etc
• As this is a home build, all components are UL certified and will be installed in accordance with the National Electrical Code (NEC) of the USA

You're going to require a few other parts off the top of my head:

1. Panel mounting scheme (presumably for your roof, or an angled frame for a standalone ground installation)
2. External cable anchors for PV cable runs
3. Foaming sealant for cable entry
4. An independent earth connection e.g. to internal pipework
5. Some form of temperature compensation / overtemp protection for your batteries (the PIP 2424LV-MSD doesn't appear to have this)
6. Sealed DC fuse for battery-to-unit cable run
7. A method of containing and/or expelling battery fumes (in an emergency failure)
8. DC isolator switch for PV
9. DC isolator switch for battery
10. (Optional) A battery state of charge / energy meter can be very useful (the PIP 2424LV-MSD doesn't appear to have this)
11. A consumer unit for AC loads, to include an independent earth, master breaker, a combined GFI/overload breaker
12. A fixed socket outlet

Before I go any further into this design, I have a few more questions:

• Why you are doing this? If this is a home build, I am assuming you already have mains. Is this an 'emergency power' system? If so, do you ultimately intend to supply your entire home?
• Why such high capacity (power & storage) for such a relatively minuscule load i.e. light + fan?
• Do you want to lower your household energy bills by 'feeding back' to the grid?
• Do you want this system to act as an uninterruptible power supply i.e. if mains is lost, backup is instantaneously provisioned

Regards,
David.

 

[Jtp.PlzAndThankYou]

At the moment due too my small pv array and acid agms, I only want too run a fan and a light or two, for about 5 to 600wh for 18 hours 300watts non stop and occasional usage of other 300. (Later on I plan on using about the full 2000 when I better understand the equation and operations.
I hope my size system encourages the homeowner to install a bigger system.

it’s always encouraged or as far as will recommends 24v over 12volts, the 2000wh available I plan on using later on a 960watt air conditioner and a 1000 watt hps light. If my system can cover this later on with a few upgrades I will be so blessed. For now due to lack of funds for a good 6 months I would be happy just running a 200 watt led, and a fan.

it will help my bill extremely running these loads off the sun.