19" DIY Power Packs

schmue

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Jul 16, 2018
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14
Hi@all,

sorry for my poor english skillsI'm from Germany.

Today, after month of reading, watching, colecting an testing, I've started some prototyping my first power pack.

But at first. Thank you to this great community that has first impressed me and then inspired me to start my own project.

The PV
Off Grid 4*175W and 16*185W(3.6kwp) with room for another 9 Panels.

The Inverter
PIP4048GE

The Plan
I've some small 2HE19" Cases in Stock

image_liokba.jpg

For a 48V System I plan to build a 30p14s Setup.

image_kqhumu.jpg

2 drilled 2*2,5mm copper busbars, XT-60 connections for each block and kapton tape for insulation from the steelcase.

image_frcrqh.jpg

image_amlnpp.jpg


All in all I plan to build 5to 6 19" batteries. And put them in a rack in my garage.

Questions
I still have no idea about the bms/balancer..
Each batterie should have about 3kwh.
Of course Batrium is a great BMS but with 84 Longmons it is a little bit expensive.
But what about connecting all blocks parallel before I put them in series to balance them and balancing them monthly again.
If this is enough, I will go for a china smart bms und build an external balancing unit and connect on demand to the batterie that have to be balanced.
Did someone try this before with recycled cells?
Every tip and best practices are welcome. :)
 

daromer

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Welcome!

You can use a couple of china BMS yes or you just build bigger packs and then you only need 14 longmons instead of 84. 1longmong can do up to 400-600Ah packs so no problem. I highly recommend it if you plan on going the pro route.
 

Korishan

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Interesting design using the cases as the holders. Pretty good ingenuity.

Work a little more on your solder skills. You have a few balls of solder on cells that aren't quite solid. Most look good, just have a few that stand out. Remember, if they look like balls sitting on the cell, then they aren't connected as good as if they look like pancake sitting on the cells.
Nice job on the twisting of the bus bars. Make sure to solder the connection where it loops around and wraps around the other end of the wire.

If you plan on using the XT60 to use both terminals of the plug as Pos or Neg (meaning two connectors per pack), then that would be fine. But if you plan on using 1 XT60 connector per packs, 1 lug for Pos and 1 lug for Neg, then I would recommend going up to the XT90's. They can handle the current a lot better (90A constant load for the XT90 vs the 60A constant load of the XT60's)

Not sure where you get 84 longmons from. If you go 14s30p, that's only 14 longmons. If you go 30p14s, then that'd actually be 420 (30 rows of 14s), but I dont believe you mean this. Also, I believe you meant 14s30p as you have 30 cells in parallel, which are then connected 14 in series. A 30p14s would be 14 cells connected in series, then 30 of those connected in parallel. Make a big difference physically when connecting them together. Electrically they are the same. The pack design you have in the picture is 30p, so I would assume you meant 14s30p.
Unless for the 84 longmons, you mean you have 6 cases that you will be connecting together. In which case, that would be correct. And, really, if you want proper monitoring of the whole system, then the 84 longmons would be the way to go. They can all connect up to 1 watchmon (I believe this is correct as long as they are all the same chemistry and the banks are connected in parallel. I hope someone will correct this if I am incorrect)

You could do the whole balancing thing manually if you want. It does involve a lot more wiring and making sure everything is absolutely correct. Completelycharged has a project where he's doing just that. There's also a few others as well.
 

schmue

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Jul 16, 2018
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Thanks Daromer,

I have thinking about building bigger packs.
But I want to have the batteries as modular as possible so I canwork on it easy without deactivating the whole system.

@Korishan

Thank you. I'll work on my soldering skills ;)

Your right. I'm building 14 packs in series and each pack has 30 cells. So there are 420cells per pack and I need 14 longmons per case.

When the system is running I'll add morePIPs to feed all the 3 phases in the house and I calculated with max 2A per Cell. Willthis work with a single XT60 and 6mm wires?
I have looked for the XT90 and the bigger XT150connectors. But I don't find themfor case mounting.

The rack for the cases will have massive busbars, I think I'll adopt owittes idea and use copper tubes, andI thought about mounting the cables to them with terminals
and connecting the battery case with a XT60.
Any other Ideas?

@BMS,
84 longmons+shunt+watchmon....that's much more my gouvernment, my lovely wife :p , will approvefor this project.
That's why I'm thinking about what are the main features of a BMS,
1.watching at the voltages and temps of the battery
2.prevent packsfrom over- & undervoltage
3.switch of the battery when any of the parameters is out of range
4.balancing


and how do I need this functions.
1-3 should be monitored in realtime but 4 only when neccesary right?

Thats why I'm thinking about building an, let me call it external balancing modul,and connect it to all batteries at intervals.

But, I'm a noob in batteries, please let me know when this is a bad idea ;)
 

wim

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Apr 6, 2017
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560
schmue said:
...I have looked for the XT90 and the bigger XT150connectors. But I don't find themfor case mounting.

Look for Anderson plugs ... Average Joe is using them also for his "server rack" powerwall.
 

Korishan

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XT60 are rated as 60A continuous for short periods, like maybe 30mins to an hour, maybe. The Anderson 50A can sustain the 50A for a longer duration.
Also, the Anderson plug itself has a through hole for mounting, or other versions have a slide catch on them.

The Andersons are a lot more rugged and durable. These are what are used on electric forklifts, pallet jacks, etc. They are highly durable and lock together very well.

There are far more fake XT connectors out there than there are the Anderson plugs, meaning that the XT casings could melt under heavy load as was experienced by another member here.

As far as those selling, there's lots on eBay: Anderson SB50

It's also worth noting that you could potentially get housings and lugs/contacts separate and get a better deal. 10 lugs for 30AUD is pretty decent. And housings 8AUD per.
 

schmue

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Jul 16, 2018
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I think about the Andersons SB50 for connecting the Case to the Rackbusbars. But I'm afraid that there will not be enough room inside to use them to connect the packs. So I will go to use two xt60 in the first version.

Yesterday evening, I tried to solder on XT60 direkt to the copper busbar....that was a mess and I haven't manged it to work. Think my Solderingiron was not strong enough(48W)....bought a 100W today ;)

What about soldering the 6mm cable direct on the busbar? Saw this somewhere in the www...
.
image_hpeiws.jpg
 

Korishan

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Yeah 48W is a bit weak, specially when dealing with the heavier wire. The XT connectors will probably be fine as long as you don't plan on pulling a continuous 60A for longer than 30mins or so. And if you used 2 XT's per pack, then that'd be 120A capable, though I think that's a little overkill considering your size of your setup. XT90s would work just as well, too.

100W iron will do a lot better. Which one did you get?

Not sure what you mean about soldering direct to the busbar. Do you mean not using fusing and going straight from cell to bus bar? If so, and if using reclaimed cells, not recommended
 

schmue

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Jul 16, 2018
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Just a normal 100W from a local store.
Link

I mean, I could not manage to solder the xt60 direct to the busbar. Maybe the 100W Iron will do this.
But last night I thought about soldering a 6mmwire to the busbar and the xt60 to the wire..maybe this is a little easier for my poor soldering skills
 

Charly144

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Nov 22, 2017
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287
Go for a TS100 with a big tip. It is one of the most versatile soldering irons you can imagine...

Regards
Karl
 

Korishan

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Yeah, it's a good iron. I use mine for pcb work. Altho, mine has the really small tip. I've seen some of the reviews with the larger round tip and they did pretty decent work with it.
 

schmue

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Jul 16, 2018
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Sorry guys. Progress is not so fast as it should be. I had towork on other projects...
Today I was able to spend some time to test the new soldering iron and build a new version of my busbars.
As Korishan said, I use one XT60 per busbar.
What do you say?

image_vvogka.jpg

image_mhjopp.jpg

And I got 2 of this 8s BVMs to see if the cells are drifting.
image_mofcqx.jpg
 

Riplash

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May 27, 2018
Messages
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schmue said:
Sorry guys. Progress is not so fast as it should be. I had towork on other projects...
Today I was able to spend some time to test the new soldering iron and build a new version of my busbars.
As Korishan said, I use one XT60 per busbar.
What do you say?

image_vvogka.jpg

image_mhjopp.jpg

And I got 2 of this 8s BVMs to see if the cells are drifting.
image_mofcqx.jpg

I like how you used the the XT60's per busbar. I am going to use split bolts on my full size 48S x1sx140p battery, as shown in the top module (Prototype 2)but XT60's will work great on these smallerexperimental 1s x 40p battery packs where I will be attaching them and disconnecting them a lot.I might be soldering XT60s on Prototype 3 and Prototype 3revA tonight.


image_kkrrrm.jpg


-Ryan AKA Rip
 

schmue

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Jul 16, 2018
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Nice woodwork Ryan :)
Soldering XT60 is not as easy as it sounds.
Because I am a noob in soldering my first and my second try was a disaster.
I think I need a solderingbootcamp

Regards Stefan
 

Redpacket

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Feb 28, 2018
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Riplash said:
I am going to use split bolts on my full size 48S x1sx140p battery, as shown in the top module (Prototype 2)but XT60's will work great on these smallerexperimental 1s x 40p battery packs where I will be attaching them and disconnecting them a lot.

Just watch for possibility of shorting, the split bolts look pretty big in the pic - might be the camera angle? Could do it nicely with crimped eye/loop terminals as well (probably cheaper too!).
 

Riplash

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May 27, 2018
Messages
66
Redpacket said:
Riplash said:
I am going to use split bolts on my full size 48S x1sx140p battery, as shown in the top module (Prototype 2)but XT60's will work great on these smallerexperimental 1s x 40p battery packs where I will be attaching them and disconnecting them a lot.

Just watch for possibility of shorting, the split bolts look pretty big in the pic - might be the camera angle? Could do it nicely with crimped eye/loop terminals as well (probably cheaper too!).

I haven't decided 100% on the size of bus bar wire or battery module to battery module bus wire for the full size finished product. Right now it looks likeI will be using 4 AWG as the battery pack bus wire, and possibly 2/0 or 4/0AWG as battery module to battery module cable, so Crimped and soldered eye terminals are a possiblity. I will just have to see what works out the best when I get there. I will be pulling 100kW of power at peak for a short timeand I can pull about 54 kW of power continuous. The exact Amps willdepend on which motors and controllers I go with.No matter what method I use, these electrical connections will look like electrical tape covered golf balls when they are finished. And will they willbe treated like High Voltage connections as much as I can. (Hard to turn off the batteries when you work on them...They are always on)
 
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