diy solar

diy solar

New System Design - 40kw / 80kwh / 20kw

deal-breaker for me at this price point is no UL listed components for NEC residential install. i know SOK batteries are, so you would need to come up with something other than victron. sorry; but at that pricepoint i'm paying someone to install it/support and doing it legally.

i specd out a very similar system for a good friend using SolArk AiOs and made sure all was UL components so he could get it approved. $90k. he decided against it as it would be far cheaper for him to get a backup diesel generator and a few thousand gallons of fuel which would then allow him to install a much smaller PV array. being in Michigan, we get zero sun from November through February so he couldn't justify the cost. he said he's going hybrid wood boiler/diesel genset/PV for under $40k and thinks it's a better balanced setup for him as he has a diesel tractor he needs to power, anyway.
 
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When you get to this size system, it is vital to customise precisely to individual needs.

All my off-grid systems now are dual systems. A primary for general household and critical (eg. refrigeration/supply water pump), then secondary for heat pump / workshop / non- critical.

Generator able to supply either system for backup, and secondary able to transfer to primary.

I have found this to be more effective than one large system, the components can be more easily matched to the requirements which saves on unnecessary expense.
 
deal-breaker for me at this price point is no UL listed components for NEC residential install. i know SOK batteries are, so you would need to come up with something other than victron. sorry; but at that pricepoint i'm paying someone to install it/support and doing it legally.

i specd out a very similar system for a good friend using SolArk AiOs and made sure all was UL components so he could get it approved. $90k. he decided against it as it would be far cheaper for him to get a backup diesel generator and a few thousand gallons of fuel which would then allow him to install a much smaller PV array. being in Michigan, we get zero sun from November through February so he couldn't justify the cost. he said he's going hybrid wood boiler/diesel genset/PV for under $40k and thinks it's a better balanced setup for him as he has a diesel tractor he needs to power, anyway.
Good luck to him getting all of that installed for $40K. I harvested 130kWh two days ago in Kentucky. All it takes is 35kWp and 165kWh battery to store it in.
 
Dexter, could you speak as to how important using this wiring is method us versus the package you supply on your website? This is from the Victron book if I'm recalling correctly. I just a bought a few of the 5 battery stacks and had wondered about it doing this way but with everything else I never circled back to it. Obviously I want the best performance and life from my battery bank and now is the time to change things up.

Thanks!


View attachment 126985
One customer did it this way while the rest do it opposite corners.

In the real world, the customer that did it this way has no better balance than the others.

Some analysis on this forum has indicated that this is better, but there is no way to do this configuration with 5 batteries...it only goes in qty of 2,4,8,16,32,64...

From my perspective, there are far more connections and points of potential failure from a bad connection. In a perfect world sure it's better, but opposite corners is perfect enough while keeping practicality in mind.
 
Dexter, could you speak as to how important using this wiring is method us versus the package you supply on your website? This is from the Victron book if I'm recalling correctly. I just a bought a few of the 5 battery stacks and had wondered about it doing this way but with everything else I never circled back to it. Obviously I want the best performance and life from my battery bank and now is the time to change things up.

Thanks!


View attachment 126985
This is interesting. Little different than how I have mine.
Maybe try it and see how it works..
 
I came up with a concept for a massive system, that I'm considering having pre-designed for customers. Based around LF quattro inverters, the goal on this is for someone off-grid that is unable to reduce their system demand and is wanting to run everything electric. Supports adding a generator quite easily also.

Having 20kw of solar for an 80kwh battery bank, the thought is this should be sufficient to recharge the bank within 4 hours of sun, which is pretty average across the board.

40kw of inverter in split-phase +parallel to give some major output capability.


View attachment 95620

16 SOK 48v server rack batteries = ~80kwh battery
4x Victron Quattro 10k's = 40kw (120kw surge)
4x Victron MPPT RS 100a = 20kw solar
3x Lynx Distributors with a bunch of fuses
1x Cerbo GX

A few notes:

  • Victron requires all cables to the Quattros be equal length when used in a multi-inverter cluster. We dispersed the battery interconnections within the inverter connections so that we could reduce the load on the busbar and avoid having 1200a through a single point.
  • The SOK's have internal shunts/monitoring, so that would handle the SOC% and current measurement calculations
  • Solar panels are TBD, I just pulled in a standard block from a different diagram I made
  • Equal length battery cables for even current sharing. 4/0 to Lynx (400a max of batteries), 1/0 from group 1-2 to group 3-4 (200a max), 2awg from 1 to 2 and 2awg from 3 to 4 (100a max)
With solar panels included this has a pricetag in the range of $75,000 for everything included.

What stands out to you?
Looks good to me.

Is Racking and panels included in that price?

If so price is within reason.
 
One customer did it this way while the rest do it opposite corners.

In the real world, the customer that did it this way has no better balance than the others.

Some analysis on this forum has indicated that this is better, but there is no way to do this configuration with 5 batteries...it only goes in qty of 2,4,8,16,32,64...

From my perspective, there are far more connections and points of potential failure from a bad connection. In a perfect world sure it's better, but opposite corners is perfect enough while keeping practicality in mind.
I'd imagine you could do groupings and then hook them into a bus bar.

For example, I picked up a pallet of SOK batteries (12) from Watts247. My plan was to do racks of 4 and hook each rack into a lynx distributor.

Will it be perfectly balanced? No. But I think it will be better than the racks of 5 connected at opposite ends based on some other analysis done on the forum.
 
Where did you see a 3x surge on the quattros? The data sheet only shows 2x (for 0.5 seconds).
 
I'd imagine you could do groupings and then hook them into a bus bar.

For example, I picked up a pallet of SOK batteries (12) from Watts247. My plan was to do racks of 4 and hook each rack into a lynx distributor.

Will it be perfectly balanced? No. But I think it will be better than the racks of 5 connected at opposite ends based on some other analysis done on
Go for it. Wont hurt anything.
 
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