Deciding to DIY my solar battery was one of my worst mistakes ever

[upnorthandpersonal]

many quarters in the arcades

The local university where I also teach has the largest Arcade and Pinball collection in Finland.

Vaasan yliopistolla on ainutlaatuinen retropelien kokoelma â âMikään hieno ei tule helpollaâ, huokaisee kokoelman koonnut Teemu Närvä

Tuhansittain kävijöitä houkutteleva Vaasa Game days -tapahtuma on yliopistolle keino olla näkyvillä yhteiskunnassa. Teemu Närvä on koonnut yliopistolle suuren, harvinaisen pelikonekokoelman.

yle.fi

Article in Finnish, but you can translate...

 

[Sanwizard]

The local university where I also teach has the largest Arcade and Pinball collection in Finland.

Vaasan yliopistolla on ainutlaatuinen retropelien kokoelma â âMikään hieno ei tule helpollaâ, huokaisee kokoelman koonnut Teemu Närvä

Tuhansittain kävijöitä houkutteleva Vaasa Game days -tapahtuma on yliopistolle keino olla näkyvillä yhteiskunnassa. Teemu Närvä on koonnut yliopistolle suuren, harvinaisen pelikonekokoelman.

yle.fi

Article in Finnish, but you can translate...

Sweet! Brings back fond memories.

 

[ksmithaz1]

LOL... lucky you... I had to use a soldering iron to build my first computer. Not just for connecting bits together, but soldering all the components to the PCB... Yes, I am that old

H-8, H-19, H-89, Wire-wrapped SRAM for the H-8, my design, discrete logic, lot's of LS240's,. Re-built an ADM-3A for fun, pretty bad input device. Owned an actual VT-100 . . . It does not have a backspace key, total garbage why it became an the basis for ANSI standards is beyond me. Wy-50 was really fast. Wy-150 was a workhorse.

I would not consider a BMS based battery bank "trivial". I would consider it tedious, and you really need to have something in mind on how you plan on stringing and "racking" it. My problem is I'm ANAL, so a plywood box, some threaded rod, with some standoffs somewhere mounting the BMC and wires everywhere is just gonna give me the willies. By the time I have it assembled in something I can live with, I'm just not that far off buying a pre-assembled rack unit.

Part II is scaling. I'd really rather have 5KWH chunks of 48v cells 100AHx16. DIY is going to put you in 15KWH chunks 300AHx16 to get the cost benefit, It's just not as mobile, even if it ends up in an equipment rack. To max out savings you going to end up with something that cannot be easily moved or disconnected. For some folks here on the forum with lot's of space to put all this stuff, and more time than $$$ it makes sense but I need my stuff to be somewhat more mobile, and I want it in a standard rack.

 

[ksmithaz1]

Do you remember punched cards? That's how I learned to program.

80 or 96 column? (Hollerith is 80, later IBM liked the smaller 96, then punch machines went straight to 8" floppy with 96 column record lengths) Paper tape? punch boards even, punch the program and plug in the board(s)? Punch board machine was obsolete but fun to learn on, Sperry or something. Monroe had a programmable calculator that was interesting that had if-then logic. 3B2/VME changed the game, and led the smaller non mainframe. Most of that stuff is way more complicated than wiring a 16S BMC.

 

[ksmithaz1]

3.11 for Workgroups for life!

Meh, MP/M-86, or Xenix-86. Hand build your parallel cables on CEN50 connectors, and hand code the self-modifying assembler for the driver, with hard-coded wait loops to slow things down, and take everyone out when you print.

 

[1201]

I thought we were supposed to be keeping topics on topic?

 

[Supervstech]

I thought we were supposed to be keeping topics on topic?

OP brought the topic into the conversation.
If the OP wants topic cleaning, a simple report gets it done.

 

[ksmithaz1]

Circling back on topic then, DIY 16S harness has 16 sensor/charge wires each need to go to on battery. A ground, and the primary connection thru the relay. A couple of control pins maybe 24 or so pins with RS-422/CAN you have to pin out. Back in the day a CEN50, you soldered down onto the pins and clamped it in maybe 12 wires, 8+4 control if uni-directional. The BMS harnesses are kind of annoying if you need to extend the sensor/bleed wires, but you should be able to get away with some crimp connectors and heat-shrink tubing. The issue with DIY is where to put the BMS. For a 15KWH setup with ~300AH batteries, you may want a 300A BMS, this makes for bigger wires, but interconnect FTA you can probably get away with a pair of #1/0 or something. Now you have to mount this bad-boy on something strong and clamp all the high current bus wires to something strong as well. If you are like some of the guys above with small machine shops, and tools, and can source raw materials easily it's not a problem. If you don't, then you have a tendency to spend quite a bit more than you realize on do-overs and waste. 1/0 is around $4 to 5 per foot. Waste 4 feet, you are out $20. It just adds up when you build it out. Now if you already figured all this out so it would scale, adding additional capacity would get much cheaper, because you know exactly what you need, so if you have the space and can engineer it to scale out, you will benefit greatly if you DIY it. The last part is you are going to want to make sure you decide how you want to communicate with the BMS system(s). Most of them will now talk to the bulk of the larger scale systems, but you are not going to get the integration of say an EG4 AIO with EG4 batteries. Back to the computer analogies, your going to have a custom SCSI card that runs your drives, that might create boot problems if you don't get out in front of it.

Definitely not for everyone.

 

[1201]

Waste 4 feet, you are out $20. It just adds up when .

Considering that buying prebuilt batteries would have cost me about $9k more, a couple of hundred Dollars of waste is not so bad, I think.

Also by using the savings on extra battery you can reduce the size of wire in most cases.
Example I have 4x 280ah batteries with 12kw inverter. The most one battery will ever see is around 60a. Wire size for that is reasonable

 

[Brett V]

Considering that buying prebuilt batteries would have cost me about $9k more, a couple of hundred Dollars of waste is not so bad, I think.

Also by using the savings on extra battery you can reduce the size of wire in most cases.
Example I have 4x 280ah batteries with 12kw inverter. The most one bms will ever see is around 60a. Wire size for that is reasonable

That was how I designed my battery rack. With 4 batteries each having a 100 amp BMS and breaker, I used #2 wires to the bus bar and 4/0 to the 12k inverter. Theoretically it’s still ok if 2 batteries are off line for any reason.

 

[Sanwizard]

Circling back on topic then, DIY 16S harness has 16 sensor/charge wires each need to go to on battery. A ground, and the primary connection thru the relay. A couple of control pins maybe 24 or so pins with RS-422/CAN you have to pin out. Back in the day a CEN50, you soldered down onto the pins and clamped it in maybe 12 wires, 8+4 control if uni-directional. The BMS harnesses are kind of annoying if you need to extend the sensor/bleed wires, but you should be able to get away with some crimp connectors and heat-shrink tubing. The issue with DIY is where to put the BMS. For a 15KWH setup with ~300AH batteries, you may want a 300A BMS, this makes for bigger wires, but interconnect FTA you can probably get away with a pair of #1/0 or something. Now you have to mount this bad-boy on something strong and clamp all the high current bus wires to something strong as well. If you are like some of the guys above with small machine shops, and tools, and can source raw materials easily it's not a problem. If you don't, then you have a tendency to spend quite a bit more than you realize on do-overs and waste. 1/0 is around $4 to 5 per foot. Waste 4 feet, you are out $20. It just adds up when you build it out. Now if you already figured all this out so it would scale, adding additional capacity would get much cheaper, because you know exactly what you need, so if you have the space and can engineer it to scale out, you will benefit greatly if you DIY it. The last part is you are going to want to make sure you decide how you want to communicate with the BMS system(s). Most of them will now talk to the bulk of the larger scale systems, but you are not going to get the integration of say an EG4 AIO with EG4 batteries. Back to the computer analogies, your going to have a custom SCSI card that runs your drives, that might create boot problems if you don't get out in front of it.

Definitely not for everyone.

Or you could just buy the cells you want, and purchase a vertical wall mount or horizontal server rack kit ( like a Seplos Mason) which includes the BMS and everything you need for a few hundred bucks plus shipping.

 

[SoggyShoes]

I'm old enough to remember punch cards and being so excited to get an 80 column graphics card.
But all this talk of remembering back about building computers does remind me of the classic Monty Python skit about "back in our day" (which I am so guilty of).

Oh how times have changed. My kids equivalent to "when dinosaurs roamed..." is "the olden times like when phones were stuck to the wall."

Back on topic. For me, I really enjoy the discovery and tinkering of DIY.

 

[Sanwizard]

I'm old enough to remember punch cards and being so excited to get an 80 column graphics card.
But all this talk of remembering back about building computers does remind me of the classic Monty Python skit about "back in our day" (which I am so guilty of).

Oh how times have changed. My kids equivalent to "when dinosaurs roamed..." is "the olden times like when phones were stuck to the wall."

Back on topic. For me, I really enjoy the discovery and tinkering of DIY.

Love that skit. Is that from "Secret Policeman's Other Ball"?

 

[SoggyShoes]

Love that skit. Is that from "Secret Policeman's Other Ball"?

I think it is from Live at the Hollywood Bowl.

 

[OM617YOTA]

A lot depends on time and circumstances as well. I DIY'd my batteries from individual cells, and at the time it was absolutely a mistake. Health issues were very severely limiting my physically functional time, and DIYing my own batteries probably added a year to the project. Should have just bought off the shelf batteries and been done.

If anyone else is in the same situation, don't beat yourself up or worry about it, just buy the off the shelf solution and carry on. On the other hand, if you enjoy this kind of thing, then definitely build your own and enjoy it.

Going forward, now that I'm getting on top of my health and back on my feet again, and already having the experience and tools to build batteries out of individual cells, future batteries will absolutely be DIY for the cost savings. Trade a few hours work to save thousands, yes please. The only thing I'll do differently is buy cells from more reputable vendors.

 

[SeaGal]

LOL... lucky you... I had to use a soldering iron to build my first computer. Not just for connecting bits together, but soldering all the components to the PCB... Yes, I am that old

Do you remember punched cards? That's how I learned to program.

Embarrassingly, yes. At school we learned FORTRAN; handed in punched cards which were sent away to a PDP11 somewhere and got a print out / result a week later - frustratingly slow, especially if you made a typo and it didn't run!

H-8, H-19, H-89, Wire-wrapped SRAM for the H-8, my design, discrete logic, lot's of LS240's,. Re-built an ADM-3A for fun, pretty bad input device. Owned an actual VT-100 . . . It does not have a backspace key, total garbage why it became an the basis for ANSI standards is beyond me. Wy-50 was really fast. Wy-150 was a workhorse

LOL - sounds similar era to my Z80 based computer, with lots of TTL chips and about 8k bytes of static RAM.

 

[ksmithaz1]

Or you could just buy the cells you want, and purchase a vertical wall mount or horizontal server rack kit ( like a Seplos Mason) which includes the BMS and everything you need for a few hundred bucks plus shipping.

MMM, "A few hundred" meaning ~ $600 + shipping from Alibaba or something. This of course includes no cables

https://www.amazon.com/LiFePO4-Bluetooth-Appliances-Off-Grid-Maintenance-Free/dp/B0C4LB48MV $700 thru amazon. + shipping

I did look. I've bought a few e-device batteries from aliexpress, < $100, but I'm hesitant to send > $500 to some place in china. Also this results in a extremely heavy 300-odd pound cabinet. If someone made a DIY "Shelf" or battery cabinet similar to some of the stuff these guys are making, with a bus bar, BMS mounts and wiring channels with fitment for the 280AH/305AH profile I'd re-consider. Something with 6-8 shelves engineered for it. Some of these folks have made some pretty impressive mounts/racks.

 

[SilverbackMP]

Or you could just buy the cells you want, and purchase a vertical wall mount or horizontal server rack kit ( like a Seplos Mason) which includes the BMS and everything you need for a few hundred bucks plus shipping.

Unless you have slightly oddball cells like me (230AH) and your master BMS expects all of the same capacity batteries.

 

[Sanwizard]

Unless you have slightly oddball cells like me (230AH) and your master BMS expects all of the same capacity batteries.

I use a seperate BMS for each battery, so every cell is monitored, I can remove an entire battery for maintenance if needed, and I can mix battery sizes (like 135AH in parallel with 280AH) on the same busbar.

 

[Sanwizard]

MMM, "A few hundred" meaning ~ $600 + shipping from Alibaba or something. This of course includes no cables

https://www.amazon.com/LiFePO4-Bluetooth-Appliances-Off-Grid-Maintenance-Free/dp/B0C4LB48MV $700 thru amazon. + shipping

I did look. I've bought a few e-device batteries from aliexpress, < $100, but I'm hesitant to send > $500 to some place in china. Also this results in a extremely heavy 300-odd pound cabinet. If someone made a DIY "Shelf" or battery cabinet similar to some of the stuff these guys are making, with a bus bar, BMS mounts and wiring channels with fitment for the 280AH/305AH profile I'd re-consider. Something with 6-8 shelves engineered for it. Some of these folks have made some pretty impressive mounts/racks.

My Seplos Mason 280AH kits were around $400 shipped. I also lucked out and bought four of the complete 135AH kits (which included the cells) for $1000 each introductory offer rate.