IFR 26650 Powerbank

[Stefaan De Ridder]

isn't 8x8=64 instead of 36?

 

[Dennis Van Hoek]

yes all confused. its 6x6

 

[miu]

Remember to adjust the Opus to the correct charge voltage, since these cells are only 3.6v, and not 4.2v...!

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Ups, old thread...

 

[Dennis Van Hoek]

@miu Please see the first post where I set my OPUS to charge 3.7V max (these 26650's are nominal 3.3V).

small progress:
The new fusebox is installed so my spot welder is working good.




So I started to make squaretwisted busbars




The 300Wiron +flux are working well....I soldered the busbar to the nail.. twice .




4x2for the 12VRV pack 4S 36P

 

[Dennis Van Hoek]

small update:


Harvesting cells goes one slowly but steady.
My bike is up and running itneeds a BMS/charger.
for the 56V pack.





I'm going to place 36P 4S in my camperbusfor a 12V utilitybattery.

For my tiny house I'm working on a 108P 4S


I will keep my 2 AGM 270Ah battery's and place the26650 batterynext to it.
A friend of mine offered to design a BMS so I'm looking forward to the result.

It should look something like this:




The big orange pack is for my house the small green one for my campingbus.



in the front a 18650 next to a 26650 for reference/scale.

today will be spot welding time for the negative side.
I still need to order fuse wire.. still unsure whats good
the cells can discharge 70A continues, or 120A peak..
But I will never use it so I take a weaker fuse to be safe.
I will be using my victron inverter that gives3000vA and peaks 5000vA.
But might want to get another one in parallel one day.. (electric shower heater/electric cooking)

3000VAx 0.8/1000 =2.4kW

2.4kW/108 cells= 22W per cell

22W/3.3V=6.7A per cell

So I guess a 15A fuse wire will do the job?(in cease I want to use 2 inverters one day)

 

[Dennis Van Hoek]

Next step:Fuse wire.
I bought 0.2mm tinned,copper wire.
It's rated 5 Amp continuous.
But its actually burning at 9.32 Amps





For me thats no problem since the cell's should be able to discharge continuous at 60Amps and peak at 120Amps.
I will not be asking this much fromthe power wall. The fuse wire will burn before the cells are anywhere near there peak.

I made the packs 72 Parralel so it canpeakaround 700Amp.... thats enough

Now I have to find some time for spot welding and get a BMS for LIFEPO.

 

[Dennis Van Hoek]

My pack for the RV is ready for testing.


I only need a BMS and isolation/protection

 

[Dennis Van Hoek]

I installed the testing power wall in my camper van 36S-4P.
Idecidedto use doubleheat shrink for isolation.
There won't be any big discharges so i'm not afraid for overheating.

I use a Chinees LIFEPO4 100A 4sBMS
https://www.ebay.nl/itm/4S-Balance-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649




heat shrink test fit its really cool how it first looks terrible and becomes nice and tight when the process is fully finished





I used 125A fuses between every pack just to be sure.
Thepeak load is normally25A maxwhen the diesel heater is starting up.
so I think this should be fine




the set-up ready for testing and it works (Y)




installing the BMS and wiring in the battery box




the final instal in the battery box under the seat
it has a 30Wp solar panel on the roof for day charging
I have a 220V charger for gritpower (which is not installed yet).

The only thing I wonder if the BMS is capable of charging/balancing from the solar panel and supplying power at the same time to lights water pump etc.
The light are always working so that part works for sure..
I just don't know whats happening with the BMS..
I monitor the voltage all the time with gives a steady 13.3 V for the last week.
So I guess the panel is not doing a lot with the marginal sun during the winter time...

 

[KaminoReal]

The only thing that 6$ BMS may do is to kill your batteries, at least get one with communication so you know when your batteries will die(j/k).
My advice: buy a proper BMS or don't use.

 

[Dennis Van Hoek]

thanks for the advice.
The best BMS is the operator in person!
I'm monitoring the voltage all the time when the battery is in use.
The BMS is working well. It is cutting of the power when it drops below 11V and I have a charger with LIFEO4 charging cycle that goes up to 14.4V (3.6V max charge per cell).
The voltage drops back to 13,4V when the charger stops.
This is exactly the nominal voltage of the cells( 3,3V) so the BMS is doing a good job

For a bigger system I like to have a monitoring system like Batrium of course.

 

[KaminoReal]

The best BMS is the operator in person!
I'm monitoring the voltage all the time when the battery is in use.

I don't want to be rude but that task is almost impossible, unless you are using the batteries on your free time.
If the BMS's where that good, especial the cheap one' we wouldn't have what to recover from dead batteries packs, other then good BMS and bad cells......

 

[Dennis Van Hoek]

All testedcells have been resting for 3-6 months.
All the self discharging cells have been removed and anything under 2450Mah is not included in the build.
Generally the cells are2500 mAh (2.5Ahcapacity spec as new).

144P A123 26650 in each pack.
4S to create a "12V" Pack

A friend of mine is working on a can buscontroledboard to use the Mitsibitie Outlander BMS for my packs.
Hopefully they will be controlled up and running end of this month.





double sidedfoam tape to isolate and keel the busbar in place





5 string 1.5mm2 wire twisted








2 more to go



















the 2,5mm2 wire will be fused between the packs with a 125Afuse




the packs are cover in Nano Diamond Thermal pads (p300) that where left over after salvaging the packs.

 

[Dennis Van Hoek]

boxed up the packs.
between the packs is a delrin 3mm plate









all connected with 125A fuses





closed box




now I only need to hook up the BMS and place the first pack in our tiny house:

https://www.nrc.nl/nieuws/2018/10/14/een-expeditie-kost-al-snel-10000-euro-a2517979

 

[Mazlem]

How much does each pack and the whole box weigh?

 

[camthecam]

$18 iron did 1000's of soldiers only thing that failed was the tips (from burning off the old winding wire i was using for fuses)

Where did you get your new fuse wire (the tinned one. I think I saw you had found some. I bought some enameled wire from jaycar but the burn off looks like hard work!)

 

[Dennis Van Hoek]

$18 iron did 1000's of soldiers only thing that failed was the tips (from burning off the old winding wire i was using for fuses)

Where did you get your new fuse wire (the tinned one. I think I saw you had found some. I bought some enameled wire from jaycar but the burn off looks like hard work!)

I bought the fuze wire from the UK:
https://www.ebay.com/usr/wirescouk?_trksid=p2060353.m2749.l2754

specs:
36 SWG Tinned Copper Wire 500g FUSE WIRE 5 AMP 0.20MM

works great tested at 8-amp effectivly

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How much does each pack and the whole box weigh?

Yesterday we moved the box to a friends place to place the BMS.not an easy task..its 62KG!!

Here we are testing the Outlander BMS with a costume control unit for my powerbox

 

[Dennis Van Hoek]

The first 140P 4Spack was used for 6 months with a BMS monitoring system.
It was working fine so I was not worried.
But I never installed a relay to cut off in case of under voltage (over charging is prevented by my Flexmax80. it charges the pack up to 14.6V and floats on 13.8 when stuff is in use. and will completely shut down when there are no users.

So I managed to kill the first pack

I tested a small Daly BMS for the last 2 years on a portable pack that worked very well.






In the mean time i changed to a smaller design 100P4S with copper pipe bus bars.





So i installed this 3.3Kwhwith a 100A Daly BMS to be sure i would not drain it.









another side project 36700 LIFEPO4 cells

 

[Dennis Van Hoek]

I started my own design for 26650 cell holders.
5x5 with busbar holder integrated





version 1.0 is ready v2.0 is printing. with 40 Grams PLA and 1KWof electricitythis costs me around 0,08 for a 5x5 holder.
The electrics not included since I'm fully offgrid on solar charged

8 of these units go in a pack (100P) with copper 6.5mm copper tube busbars on top.