Price per watt hour-diy versus 48V rack battery

[Will Prowse]

Will

Sorry... I was mostly teasing you.. and I fully understand your reply.. and don't expect you to protect idiots who play with batteries from themselves. And in this field I am surely a rookie and sometimes an idiot.

I spent several weeks reading and learning about LiFeP04 Batteries and installed a class T fuse in my RV battery bank, and 8 280Ah Batteries under my steps to replace inadequate 12 wet cells that factory installs. I have watched Andy put the current meter between a full cell and an empty cell and then slowly short them together and demo > 100A flowing from the full battery to the empty battery.. That's kind of scary, and a wake up call to your constant reminding of "don't drop a wrench" on your terminals you won't like the result.

The entire top of the RV battery install is fully covered with a large slab of 1/4 thick G10-FR4 (circuit board insulating material). The 200A BMS is mounted with plastic screws to the G10-FR4 slab and so my exposed terminals are minimized and protected.

With that as background your comments that batteries as you demo in the video, represent a very simple DIY, and are on a metal rack, surrounded by non-flammable materials, and correctly wired, and protected with a Class T fuse.

You also make the point the these batteries (correctly installed and utilized) are about as dangerous as a stack of wood.

I fully agree.. thank you for making that statement. I also agree that my wood stove in the corner of my basement is likely a higher risk to burn my house down, if I forget to clean the chimney, or use a shop vac to suck up burning embers.
Burning embers sucked into shop vac result in a shop vac fire. (Don't ask me how I know).

My option is to place a similar rack in my concrete basement, next to a concrete wall well below my main circuit panel. I could easily place a Wyze observation camera over the unit, and a smoke alarm, and have remote notification if the alarm goes off. (Wyze hears the alarm and notifies me)

This option gets me 30Kw of backup power, is ugly, hidden, but very useful inexpensive and functional.
And as you stated, I doubt you spent more than 8 hours building that bank.

I am not an "influencer" and don't really care what is popular, just a little concerned about doing things safely, and you have addressed that concern.

Thanks for the reply, and sharing.. and sorry if I hurt your feelings.. but I don't think I did.
I appreciate your sharing on your battery and solar adventures.

Cpu

PS.. I have captured a screen shot of your reply for my lawyers when my house burns down.

That last sentence ?? and no worries, I don't take it personally. Just want people to understand the dangers and cost vs risk. Sounds like you know enough to avoid problems, so you should be fine.

 

[michael d]

I am definitely in the group of DIY enthusiasts who believes the time to assemble and make cables etc is the way to go...
I have 64 272Ah Lishen cells and 32 Eve LF280K 280Ah cells in 24 and 48-volt configurations...
DIY lots of research and time,,,
I bought all the LIFePO4 cells from China via Alibaba ... so the slow boat ride method...
all the LiFePO4 cells arrived in perfect condition....no issues other than slow shipping...
about $10000 in cells alone but....
272AH x 64 cells x 3.2 volts per cell = 55,705.6 Watts-Hours for approximately ($5963.99) >>> (1st 32 Lishen cells cost $3063.80) and (2nd 32 Lishen cells cost $2903.19 in the year 2020 ) (I ended up with 64 because the 1st 32 seemed to be lost but did show up - 63 days in transit) (((The wait is tough with long shipping times for a huge chunk of change!!!))) scary long shipping wait time >>>>but use your credit card for a little protection and Alibaba has a certain amount of buyer protection also..... A bit scary and trying investment of your hard-earned cash, for sure!!! i used my credit card with a virtual number so they never get all of the cc numbers....{{{the second batch of 32 Lishen cells showed up in 59 days with 3 major holidays and blizzard weather slowing them down in year 2020}}}
plus an additiional
280Ah x 32 cells x 3.2 volts per cell = 28,672 Watt-Hours for $4243.19 including shipping to my door and taxes; (82 days transit time this batch in the year 2021)
rough figures above (will add better more exact details later - since editing is still available)
but need to add wires and terminals and BMS etc maybe another 1000 dollars and lots of cool tools...
an addictive project >>>> I assure you....

so say $11207.18 dollar investment,,,,,for 84,377.6 Wh or 84.378KWh
$11207.18 divided by 84.377 = roughly $132.82 dollars per KWh going the DIY route with raw cells....

server rack prefab at 300 dollars per KWh would cost >>>> $25,304.4 dollars....
you can buy a lot of really good equipment inverters, tools etc with the DIY method....

lots of time and research to do it yourself.....?

all LiFePo4 batteries are on my workbench at a nice workable height....
the Dewalt commercial prefab rack does look cool though.....??
Off-grid whole house build that is stationary in South Dakota.....in an insulated solar power shed....not in the living quarters....
and yes the server rack batteries would be quick to set up and a very expensive way to go....

each situation will require your own decisions,

 

[Warpspeed]

For any Australians here.....

I ordered eight 280Ah cells from Luyan (Amy Wan) on 15 April. They arrived today Jun 1 so about six weeks total.
Total cost plus shipping came to $1,465 Australian dollars for eight cells.
Amy has been very helpful and a pleasure to deal with.

As these only arrived about an hour ago, I have only been able to give them a visual inspection so far, and they all look 100%.
Plan to charge, top balance, and run a discharge test, and then order another batch if all is well.

I already have a home made individual cell monitoring system with video display of cell voltages (as a histogram display) with overvoltage and undervoltage shutdown on an individual cell voltage basis.

Am currently in the process of home building a high power inductive cell balancer, its much cheaper to design and build all my own equipment, rather than buy commercial products of sometimes doubtful quality and performance. Warranties are fine things, until you try to make a claim.

Its possible to put together a very good system by doing everything myself, and at a much lower cost than buying all commercial black box equipment.

 

[toms]

The only cost worth worrying about is the per kwh price over the life of the system.

Initial purchase price is only part of the equation.

I know more than a few people that are on their 3rd commercial LiFePo4 battery set since i commissioned my system.

 

[michael d]

For any Australians here.....

I ordered eight 280Ah cells from Luyan (Amy Wan) on 15 April. They arrived today Jun 1 so about six weeks total.
Total cost plus shipping came to $1,465 Australian dollars for eight cells.
Amy has been very helpful and a pleasure to deal with.

As these only arrived about an hour ago, I have only been able to give them a visual inspection so far, and they all look 100%.
Plan to charge, top balance, and run a discharge test, and then order another batch if all is well.

I already have a home made individual cell monitoring system with video display of cell voltages (as a histogram display) with overvoltage and undervoltage shutdown on an individual cell voltage basis.

Am currently in the process of home building a high power inductive cell balancer, its much cheaper to design and build all my own equipment, rather than buy commercial products of sometimes doubtful quality and performance. Warranties are fine things, until you try to make a claim.

Its possible to put together a very good system by doing everything myself, and at a much lower cost than buying all commercial black box equipment.

the price of cells has increased a lot in the last 2 years.....maybe close to double....