JCPowerPit

MattBarnesJCKS

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Joined
Aug 26, 2018
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8
I guess I will settle camp here. This is intended for (mostly from me) questions and (hopefully from all of you) answers regarding my power-bricks. The chosen name of a 'power-pit' is mostly inspired by brick, wood burningpit-grills and pork fat.

I am currently at 3s60p 18650'sto power a single120V circuit from a12V 1000Winverter. There is a need for solar panels I have yet to fill.

Plans for the future:

-Attempt to create aDIY BMS, similar toStuart Pittaway, with Raspberry PiSBC's,
- Find and configure some sort of software solution (web GUI preferred) for cooperative operation and management,
-Collect many, many more cells,
- Make the move from proof-of-concept to permanent install in some fashion
- Possibly move to 4s, but I need to do more research for that

Thank you!
 

MattBarnesJCKS

New member
Joined
Aug 26, 2018
Messages
8
I am wondering what general opinion(s) is/are for 4s to 12V instead of 3s. Is there too much power loss stepping down?
 

Redpacket

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Joined
Feb 28, 2018
Messages
1,279
You can use buck (step down) converters from 4s to 12V for small loads but for an inverter's input it'd be too hard/too lossy.

You're better off planning for 24V which is a good match to 7s battery packs. The losses in your inverter are also much less at 24V.
You can still use one bit or several smaller 24V to 12V buck converters for 12V devices.
 

MattBarnesJCKS

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Joined
Aug 26, 2018
Messages
8
I received a '96 model Liebert UPStation S. This is capable of 3.6kW and is a beast!

It looks as if it was wired directly from the supply AC to a breaker panel, and the old batteries looked to be in a 24V setup.

Will this, in theory, operate similar to a normal battery/inverter setup? Battery to inverter, solar charger to battery, etc? It's more than I've ever tried to tackle before.

Thanks to all!

Matt


MattBarnesJCKS said:
I received a '96 model Liebert UPStation S. This is capable of 3.6kW and is a beast!

It looks as if it was wired directly from the supply AC to a breaker panel, and the old batteries looked to be in a 24V setup.

Will this, in theory, operate similar to a normal battery/inverter setup? Battery to inverter, solar charger to battery, etc? It's more than I've ever tried to tackle before.

Thanks to all!

Matt

Edit: Nope, I was all wrong. Got a pdf copy of the manual.This beast has a nominal battery voltage of 192VDC. This really isn't something I want to play with using a 48s setup, or more. Is it?
 

jdeadman

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Joined
Mar 28, 2017
Messages
937
A UPS is an inline backup What it does is take in line power to run the devices connected to it and charges the battery if needed.

192V is a bit high and you do need to be extremely careful with that much voltage. there is lots of potential arcing. but most of those systems have anti Arc Connectors built into them so as long as you use the connectors that are there it should not be a huge problem. Just get the High Voltage Gloves that Electricians wear.

Also if you are trained in electricity I would not tackle this!!!! I have 4 years of schooling including High Power systems and I would think about it but there would have to be lots of planning and designing the safety features before I would even touch it
 

Redpacket

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Feb 28, 2018
Messages
1,279
I'm with jdeadman - I would not do a 192V system, too dangerous.
 

MattBarnesJCKS

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Joined
Aug 26, 2018
Messages
8
Agreed. Seems too much for a consumer. I'm going back to using my APC BR1500... lol. Anyone wanna suggest a price or make an offer? :cool:

Thanks to all! I genuinely feel welcomed here.
 

MattBarnesJCKS

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Joined
Aug 26, 2018
Messages
8
Reverted back to a 3s80p brick for a 12V inverter. 4x4 grid of 20 cell holders (20 columns 16 rows)to allow for 2 empty rows between each pack of 80. Found a solar controller that will operate at both 12 and 24V. It's capable of threshold adjustments for the battery and charging voltages. I figure low end at 10.2V and upper at 12.3V for some head room.Seems a pretty viable setup. My inverter operates with 10 - 15.5VDC, so it shouldn't stress the battery pack too much? Hopefully allows fora longer life. I do need to bottom balance this brick when complete, right?What do you all think?

Thanks for the help.

m@
 
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