diy solar

diy solar

Your preference, DIY or rack?

Ronnie B

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Jun 11, 2021
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If you were to buy batteries today for your system, which would you buy and why?
 
Rack.

More expensive, but in theory, if warranty is needed, someone else is holding the bag.
 
This thread is probably the answer to your question.

 
Probably a rack if you have room for a rack cabinet, and any desire to expand. I'll be getting a full height with my next battery purchase that will hold 10 5KWH rackmount batteries for 50KW. That will enable me to get 100KW in two racks of space, 4ft x 7ft x 4ft. Similar capacity with something like the wall mounted 15KWH units would take 7 units that you have to find a place on the wall to mount. I guess if you had a lot of wall space that might be better. My final plan is to have space for 3-4 racks, a total of 200KWH. That will take 8x7x4ft of space.
 
I haven’t measured both but, a16s 280ah diy would give you 14kWh and cost less. You may not be worried about cost and the rack batteries would look good.
 
DIY or Powerpro is my preference. I don't want to mess with 100Ah's anymore although I don't mind having my one of them as an auxillary battery.
 
To me, at some point the compactness, simplicity, and flexibility of a pre-built 51.2v/100AH rack unit simply outweighs the cost differential. I just don't want to build a bunch of custom stuff with BMC's and bus-bars to save a few thousand dollars. My time has value, I'd rather spend it in a different place that saves more money, by building out mounts and an out-building for my back yard. I'd rather be outside laying block for a building that will become my workshop, than assembling a bunch of batteries into a custom racking system. Everyone keeps telling me that they keep putting all these DIY systems together for next to nothing, but everytime I start adding up the stuff I want, the price difference drops dramatically. Not to mention the weight aspect of a 15KWH/300AH set of prismatics.
 
I wonder if they are sturdy enough to stack 4-5 high?
I was wondering that myself but you would want them on separate shelves to begin with so that if you have to pull the bottom one you don't have to unstack all of them. Was thinking some kind of heavy duty metal shelving system like 4ft wide Dewalt one. People who get multiple PowerPros seem to have issues with spacing since they are designed to just be placed vertically on the floor more or less.
 
I wonder if they are sturdy enough to stack 4-5 high?
They look it I have four of the 8s 24 volt boxes in the garage and waiting for four more. But I am installing them in U27 server racks, four to a rack.

So my vote would be DIY server rack.
EB81FB34-813C-40AF-BFAC-FAFC4CCC550B.jpeg609CE5C8-28B6-4A0B-B42A-C8F11E7F5763.jpeg2A2DE108-C019-4B78-AAD9-A7600F1136B4.jpeg3833FD95-6B90-4ED9-80F4-0BFE6CE4AA48.png
 
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why you dont want to mess with 100Ah small capacity?
Just because to me each battery is something I'm going to give a bit of individual attention, check its interface and cell voltages, etc. and so for a big battery I can get 3x the capacity for the same amount of baby sitting.
 
To me, at some point the compactness, simplicity, and flexibility of a pre-built 51.2v/100AH rack unit simply outweighs the cost differential. Everyone keeps telling me that they keep putting all these DIY systems together for next to nothing,

57Kwh for less than $8000 is my current build I'm getting ready to build when the cells arrive. It will be compact, like this.

1711567783579.png

but everytime I start adding up the stuff I want, the price difference drops dramatically. Not to mention the weight aspect of a 15KWH/300AH set of prismatics.
I don't have a problem lifting each cell one at a time into the bank.......
 
If you were to buy batteries today for your system, which would you buy and why?
DIY every time for me, even if it cost $1000 more per 15kWh. I like the control of my DIY BMS to Inverter software and knowledge of how it all works.

More expensive, but in theory, if warranty is needed, someone else is holding the bag.
Disagree. My DIY batteries come with a 5 minute SLA response time, 24/7, 365 days per year. If something ain't working, I would want to resolve it now, even if it's me in my pyjamas :).... I hate trying to convince some spotty teenager that something is wrong with their product and they need to fix it.

the rack batteries would look good.
Quite happy with my hand-varnished plywood box!

I don't want to mess with 100Ah's anymore
why you dont want to mess with 100Ah small capacity?
for a big battery I can get 3x the capacity for the same amount of baby sitting.
(y) why manage 3 packs when you can manage 1 :)

It will be compact, like this.
1711567783579.png
:love:
 
Zwy has a great custom rack.

7000 60KW of 300AH batteries
0500 4x 100A BMC
0030 standoffs and mounts for the BMC's
0400 6x4ft Threaded rod + Bolts washers etc
0015 2x8ft 1/2" PVC pipe
???? Interesting cabinet
???? 300A BUS WIRE/Infrastructure . . 4/0? $8/ft paired 2/0 or 1/0?

Realistically closer to $9-10K, with the cabinet but still a big savings. Kind of, tough to move around. Weak aesthetics not that that really matters.
 
If you were to buy batteries today for your system, which would you buy and why?
After eight years with ihree iterations of DIY batteries and three different inverters I finally went with Pytes rack batteries. A lot of my motivation was the fact that I had been running those systems without a building permit and I finally wanted to have a UL listed system so I could pull a permit. The cost was close to $400 per kWh including the UL listed enclosure, compared to the DIY batteries which cost less than $100 per kWh.
 
After eight years with ihree iterations of DIY batteries and three different inverters I finally went with Pytes rack batteries. A lot of my motivation was the fact that I had been running those systems without a building permit and I finally wanted to have a UL listed system so I could pull a permit. The cost was close to $400 per kWh including the UL listed enclosure, compared to the DIY batteries which cost less than $100 per kWh.
It's good to have the option to get a permit if needed someday. I see alot of people say they will never get a permit, but unfortunately sometimes the AHJ forces you to get a permit or tear out your system
 
Zwy has a great custom rack.

7000 60KW of 300AH batteries
0500 4x 100A BMC
0030 standoffs and mounts for the BMC's
0400 6x4ft Threaded rod + Bolts washers etc
0015 2x8ft 1/2" PVC pipe
???? Interesting cabinet
???? 300A BUS WIRE/Infrastructure . . 4/0? $8/ft paired 2/0 or 1/0?

Realistically closer to $9-10K, with the cabinet but still a big savings. Kind of, tough to move around. Weak aesthetics not that that really matters.
Next build is as follows.

Cells $91 each from Luyuan includes shipping- $5824
4 JK BMS with screens, includes shipping- $585.55
4 T Class fuses with holders from Don Rowe- $239.96
Cabinet- $200
Copper busbars 1/4" x 1" x 48" - $150 includes shipping

That comes to $6999.51. I will need 4/0 cable and some 1/0, maybe some 1/8" x 3/4" wide copper bar (which I already have left over). I don't use breakers on the bank for each battery, instead I use T class fuses. I will need some square tubing for the shelves, sixteen 5/16" redi rods and some pvc for covers (I have a pile of scraps), 4 end plates from 1/2" aluminum plate (I have a pile of 3/4" I might use instead I gave $40 for the whole pile). Luyuan free gift of the cell separator panels which I might use instead of poron.

Can I build it for under $8000? I sure hope so. This build is to see how cheap I can build it unlike my first build which used the Batrium and cells cost more then. That one went $11K but the Batrium Core, expansion board and 4 K9's don't come cheap.
 
Premade batts are getting more affordable. I can get 6 x 10,24kWh = 61,44kWh under 7700e (~8300$) including rack with wheels, 24% VAT and delivery. This is just as my friend is a vendor and he sells these without profit to me. I bet big vendors are getting their batts 80-90e/kWh already.

With this price I seem to get working warranty, but rack has no busbars on it and BMSs are equipped with ~50mA passive balancers. I think I paid 60e for two big copper busbars and made bushings out of POM for it with my lathe. Then need to open up every batt and install Neey balancer wiring harness on them (11e). Only one actual Neey 4A smart balancer (80e) is needed as it is only needed for few days max on each battery per year.
 
With this price I seem to get working warranty, but rack has no busbars on it and BMSs are equipped with ~50mA passive balancers. I think I paid 60e for two big copper busbars and made bushings out of POM for it with my lathe. Then need to open up every batt and install Neey balancer wiring harness on them (11e). Only one actual Neey 4A smart balancer (80e) is needed as it is only needed for few days max on each battery per year.
Sounds very good price, but I would have thought that opening up the packs and installing a 3rd party balancer on them would void any manufacturer warranty? :unsure:
 
Sounds very good price, but I would have thought that opening up the packs and installing a 3rd party balancer on them would void any manufacturer warranty? :unsure:
Might be true, but my vendor friend handled my one warranty matter so far and they didn't ask any specifics or pictures. I think my friend buys enough from them so little things like replacement cells + postage don't matter. They did offer free change of those cells too, but I wanted to see how these batts are constructed and did it myself. Now I'm sure I could DIY 16S battery if needed, but with these prices I see no point in that. Actually I did order 2 x 10kWh more of these batteries week or two ago.

I don't think these batteries are "top of the line" even they claim using A grade cells. Probably these are B grade and BMS is only 100A with shitty passive balancer. They are not properly top balanced out of the box for sure but even still seem to deliver >100% of promised capacity.

I also work at least 85 hours every week, so finding time to DIY build batteries is difficult for me. It almost killed me to DIY my current solar setup (not joking) and there's still a lot to do.

EDIT. Just got my rack batts full from being around 5% (averaging about 3,05V) this morning. Got 81,5kWh into them while having only 76,8kWh nominal capacity. These have 2P16S configuration with unknown blade style cells so maybe they have 105Ah or something instead 100Ah promised. Only one out of nine is correctly top balanced so far.
 
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I chose to go with rack batteries, at present I have two SOK 48v100aH and two EG4 48v100aH,
The SOK were out of stock, but I have no complaints about the EG4.
My choice was the shipping times of "Rack batteries" verse "DIY Batteries" and then finding a BMS and flexible clamps to connect the batteries together. Time is a valuable and my wife HATES the time I spend tinkering with solar and batteries. If I were a single man I would "maybe" go the DIY route.
 
I'm happy with my rack setup. My only regret is not starting out with 280ah cells. My first battery was made with 230ah cells and space for that build was limited to a wall mounted truck toolbox. As I built out, it seemed logical to continue with them, even though I have plenty of room now for the larger cells. Cost savings were significant compared to the same kwh hours with commercially made batteries.


3.0 Rack Front.jpg
 
I'm happy with my rack setup. My only regret is not starting out with 280ah cells. My first battery was made with 230ah cells and space for that build was limited to a wall mounted truck toolbox. As I built out, it seemed logical to continue with them, even though I have plenty of room now for the larger cells. Cost savings were significant compared to the same kwh hours with commercially made batteries.


View attachment 206130

Similar to me
I got a deal on some 200ah Lishen cells that were getting old sitting on a shelf when 280ah cells were new and all the rage.
At $50 each I was able to build (2) 24v batteries pretty cheap
A year later I scored another 16 SOK 206ah cells pulled from batteries with defective BMSs for the same price.

I wouldn't hesitate to build more with some 280s or 304s these days with the prices dropping
BUT I'm looking to add more to my array and upgrade to a good 48v AIO before adding more capacity to my battery bank
Kind of sucks having a limited budget

(SOK cells in the foreground)
batteries.jpg
 
Similar to me
I got a deal on some 200ah Lishen cells that were getting old sitting on a shelf when 280ah cells were new and all the rage.
At $50 each I was able to build (2) 24v batteries pretty cheap
A year later I scored another 16 SOK 206ah cells pulled from batteries with defective BMSs for the same price.

I wouldn't hesitate to build more with some 280s or 304s these days with the prices dropping
BUT I'm looking to add more to my array and upgrade to a good 48v AIO before adding more capacity to my battery bank
Kind of sucks having a limited budget

(SOK cells in the foreground)
Yep. The original batch of 230ah cells I bought was to replace the declining lead batteries on my then 24 volt system. It was a small 1500 watt inverter with an AC charger, intended to run the freezer and refrigerator, also the tv for the warden and a few lights without running the generator all night if the grid was down.

While waiting for the cells to make it here from china, I bought a couple 8 cell BMS’s and started spending more time reading posts on this forum. Wait…what’s this Growatt thing I see people talking about? The warden had got interested in prepping and when I presented this as a solution to running the well pump on the batteries I’d already bought, the additional funding was approved.

We paid off the loan on the grid tie system last year so that freed up some cash and the trip down the rabbit hole just took off from there. Let’s add some solar panels since the Growatt could do that. Then the number of batteries increased, and now I’m doubling my solar capacity.

It has been fun and I’ve learned a lot. It’s taken most of my free time and attention away from my other hobbies which include amateur radio and astrophotography.

Saturn and Jupiter from my back porch using a Celestron 8” SCT



53DB971B-88D0-485D-AB1A-4FDDCA065839.jpeg642B1919-6DF4-4E39-ACB0-BE918C00CCCB.jpeg
 
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