Do you remember punched cards? That's how I learned to program.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
My understanding is that few prebuilt batteries have any "compression". Rather, they just tape the cells together or use foam between the cell and outer case to hold the cells "securely" in place. Consequently, if you are happy with that level of prebuilt "compression", no need to worry about proper "compression".I'm trying to figure out the correct torque figure for the battery fixture I created.
I hated fortran and punch cards!Do you remember punched cards?
The case/rack, bus bars, fuses, cables, switches, terminals. Perhaps most importantly, your time. I enjoy doing this stuff, but if I take my "hourly rate" into account, I have a really, really expensive battery (and overall solar set up), and it's not even done yet!What am I missing here?
Battery prices are dropping quickly so people may be using last year's prices who knows? But yes in my case diy was less than half the price of prebuiltSomething I don't really follow is that people keep mentioning that DIY batteries are only 10% cheaper than pre-built ones... how is this the case?
For reference, I can get 600ah of pre-built batteries in a rack for $7,700
96 prismatic 105ah cells (16s x6 for 605ah total) is $4,000 shipped. 6x 100amp daly 16s BMSs is a total of $459 shipped.
Grand total to DIY the batteries without any enclosures or racking after taxes and shipping is $4,459
... this is ~46% cheaper for 5% more capacity (630ah vs. 600ah)
What am I missing here?
Wood case $12The case/rack, bus bars, fuses, cables, switches, terminals. Perhaps most importantly, your time. I enjoy doing this stuff, but if I take my "hourly rate" into account, I have a really, really expensive battery (and overall solar set up), and it's not even done yet!
Man, I was just planning on using no compression and laying the cells out on a HD rack (like that dewalt one). It's gonna look ugly af, but I know I am no carpenter.Even for pro-level handymen, to do this right, with all the research required, the fixtures and compression and flexible busbars and sizing and building the box and top balancing and the BMS and the fuses and wiring... etc. etc. this is a really big project. For the record, I happen to be a pretty crappy handyman. So maybe for some of you this is a walk-in-the-park.
As long as you definitely don't get earthquakes.Man, I was just planning on using no compression and laying the cells out on a HD rack (like that dewalt one). It's gonna look ugly af, but I know I am no carpenter.
And have no mice.As long as you definitely don't get earthquakes.
Four of these, 48V 280Ah for $2156.Something I don't really follow is that people keep mentioning that DIY batteries are only 10% cheaper than pre-built ones... how is this the case?
For reference, I can get 600ah of pre-built batteries in a rack for $7,700
96 prismatic 105ah cells (16s x6 for 605ah total) is $4,000 shipped. 6x 100amp daly 16s BMSs is a total of $459 shipped.
Grand total to DIY the batteries without any enclosures or racking after taxes and shipping is $4,459
... this is ~46% cheaper for 5% more capacity (630ah vs. 600ah)
What am I missing here?
Balancing nightmare though.If you can handle the balancing of the much cheaper 12Vs there's big savings to be had.
FWIW, I've never seen any of the plastic case batteries Will or anyone else has torn down with any sort of precisely calibrated compression mechanism in them. I've built several batteries over the years that have run very well without ever sweating over compression. If I were you, I wouldn't worry too much about it. Just my opinion.@42OhmsPA or anyone else who might know torque on these bolts...
Thanks for your feedback. Just wanted to clarify, it's the torque on these bolts, the ones that add compression, that I'm asking about, not on the battery terminals. (Note this is not a picture of my battery, it's a picture I found on this forum).
(Note this is not a picture of my battery, it's a picture I found on this forum)
What am I missing here?
Can put a balancer on each series, tho they may emit a 12kHz whine when running.Balancing nightmare though.