10kwh 18650 Powerwall in Nigeria

Lawcomleo

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Jul 4, 2017
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I plan to build a 10kwh battery pack from 18650 cells harvested from dead Laptop Batteries.

I believe this is the first 18650 powerwall in Nigeria.

Alreadyhave a solar system (24v)
  • 6pcs of 250W Solar panels (1.5kwh total)
  • 2pcs of 200AH SLA Battery (4.8kwh, which is nearly dead and only has 25% of its capacity left)
  • 1kw inveter (Will change it to a 5kva Hybrid Inverter once the pack is completed)
I will be building the 18650 packs in sets of 1kwh [20p7s].One (1)of them is already completed, Nine (9) more to go.

1kwh pack can currentlyrun my house for for 5hrs@MaxV: 4.0,MinV:3.2. Even though it will stay for 8hours @MaxV: 4.2, MinV: 3.0, I am not willing to do that because I wantthem to last longer.

By the time I get to 10kwh I should have 2 day's worth of storage.

Images will follow in the next post
 
Welcome to the forums. Look forward to seeing how things come along. Being the first in Nigeria, well, that gives you huge bragging rights :p
 
Inverted18650 said:
Dude this is great! What's the 'normal' power bill in Nigeria? I've never been anyway in Africa so I'm totally clueless. Welcome and stoked to see pics.

Thanks. The power bill depends on whether it's for domestic or industrial use. It's is outrageously cheap but the real problem is that you never see the power - In my location for example, I get light from the utility only 100 hrs out of the entire month (and am being fair to them).

The other issue is that power is not metered at the point of usage inmore than 80% of the consumers' houses, so there is something called an estimated bill. The powerdistribution company measures what goes to a particular area for the month and then share the bill amongst the consumers in that area based on the size of your compound. If the compound has several apartments then the landlord shares the bill amongst his tenants.

The retail electricity tariff structure in Nigeria consists of 3 elements.
  • Energy Charge This is for variable costs recovery (N25 to N35 per kWh)
  • Demand Charge This is for applied pressure (load amount) on the power system (Discretion of power company subject to a Multi-Year Tarrif Order implemented by the government)
  • Fixed Charge This is for capital costs recovery. (N750 to N900)
At an exchange rate of $1 to N360 you can see its not too expensive.
A lower-middle classhome like mineconsumes only about 5kWh a day, so even if I had constant power 24/7 for an entire month I would only pay N35 x 5kwh x 30days + N750 fixed charge = N6,000 ($16.67)


Korishan said:
Welcome to the forums. Look forward to seeing how things come along. Being the first in Nigeria, well, that gives you huge bragging rights :p

Thanks for the encouragement. BTW I have always wondered if bragging rights were actually rights. Am looking forward to getting suggestions from you guys.
 
Great explanation. So the primary reason for solar power is not due to higher bills, but lack of quality supply. Very interesting. Do you have a good source for used laptop packs there or do you order them online? If we can somehow manage to get someone to build a wall on Antarctica, then there would be at least one on every continent! That's pretty amazing when you think about on a global scale.

When I was in the military and lived in Germany, the post I lived on did an "estimated bill." I was not very happy, because as you probably know, power in Germany, is extremely expensive and sharing the bill with people who leave the lights on all day and night was no fun. I wish I was into solar energy back then.
 
Inverted18650 said:
Great explanation. So the primary reason for solar power is not due to higher bills, but lack of quality supply. Very interesting. Do you have a good source for used laptop packs there or do you order them online? If we can somehow manage to get someone to build a wall on Antarctica, then there would be at least one on every continent! That's pretty amazing when you think about on a global scale.

When I was in the military and lived in Germany, the post I lived on did an "estimated bill." I was not very happy, because as you probably know, power in Germany, is extremely expensive and sharing the bill with people who leave the lights on all day and night was no fun. I wish I was into solar energy back then.

Exactly! Here we all do solar because of necessity. Most people do not have the initial capital to setup a solar system even if they would really love to and there is no government incentive. You can even talk of net-metering because the system isn't ready.

I get the laptop battery from laptop reapir guys for N300 and it's really stressful because you can only get about 5 from one person at a time. Pete is lucky to get from schools and recyclers. Here school dont even have systems, those that do use desktops.

Now I have a guy that Igive extra N50 (that makes it$1 per pack)so he does the gathering for me and I can get 30 pieces from himat a time after a few days.
 
I took some images when I was taking apart the packs, so I thought I should add it tothis thread


image_gfdkfa.jpg


I also have some images of the first 1kwh pack.

image_babdiz.jpg

image_ewiqxv.jpg

image_ucvzkw.jpg

image_edzjqd.jpg


I used cable lugs on one side of the bus bar and mc4 connectors on the other side.

Here is the pack hooked up to my inverter

image_ahwrku.jpg


But I have noticed that fondling with the busbars sometimes breaks the soldered connections linking the cells to the busbar.
How can I prevent that from happening? Would appreciate any ideas.
 
I just completed and installed my 2nd 18650 Kwh pack last week (8 more to go).


image_rzigpe.jpg


It runs my house for 12hrs (through the night), there is enough sun to run my house throughout the day. So it's safe to say I have 24hrs power on sunny days.

I am already in the process of sorting batteries required for the 3rd Kwh pack.
See image of charged batteries below -


image_cchfcp.jpg
 
I can't exactly tell from the pics, for the connections between packs, are the lugs touching each other and then bolted, or are they connected Bolt-Lug-Nut-Lug-Nut? And, what kind of bolt are those; galvanized, zinc plated, silver plated, stainless steel?
If the nut that is in between the two lugs is silver plated, copper/brass, or nickel plated, then it'll probably be ok. But if they are zinc plated, stainless, or galvanized, then you are going to loose a lot of power right there. If not for differing metals causing electrolysis (moisture in the air contributing), but high resistance in the SS and Galv.

Now, if you connect it so that they are Bolt-Lug-Lug-Nut, then it wouldn't matter what the bolt/nuts are made from as the current would go from lug to lug without effecting anything else.
 
If you have problem with tearing the soldered fuse wires apart when working with it there is 2 things you can do if you ask me:
* Don't hook it up until its perfectly aligned so you wont disturb the fuse wires
* Secure the ends so some movement wont cause any issues or just attach longer wires/busbars so some flex can be given.

I do both here on my packs.
 
Korishan said:
I can't exactly tell from the pics, for the connections between packs, are the lugs touching each other and then bolted, or are they connected Bolt-Lug-Nut-Lug-Nut? And, what kind of bolt are those; galvanized, zinc plated, silver plated, stainless steel?
If the nut that is in between the two lugs is silver plated, copper/brass, or nickel plated, then it'll probably be ok. But if they are zinc plated, stainless, or galvanized, then you are going to loose a lot of power right there. If not for differing metals causing electrolysis (moisture in the air contributing), but high resistance in the SS and Galv.

Now, if you connect it so that they are Bolt-Lug-Lug-Nut, then it wouldn't matter what the bolt/nuts are made from as the current would go from lug to lug without effecting anything else.

Korishan, Thanks a lot for your contribution. The arrangement is Bolt-Lug-Nut-Lug-Lug-Nut. And you are absolutely right about the electrolysis thingy because I can already notice corrosion on the nut in-between (the same nut that I need to take out toimproveconduction).
The reason I added the nut in the first place was to act as a spacer. The lugs on the first pack has very little flex (literally no cable extension - see image)image_mfjqrv.jpg

Without the nut there will be no space in-between the packs. I wonder if I can get a copper or brass nut and I don't have the luxury of desoldering any of those batteries for now.
I will definitely look for a work around.


daromer said:
If you have problem with tearing the soldered fuse wires apart when working with it there is 2 things you can do if you ask me:
* Don't hook it up until its perfectly aligned so you wont disturb the fuse wires
* Secure the ends so some movement wont cause any issues or just attach longer wires/busbars so some flex can be given.

I do both here on my packs.
Thanks Daromer for your suggestions. I will definitely make the busbars longer to have more flex.
 
Yeah, a brass nut, or a brass bushing, would work fine. The bushing would probably be easier and cheaper to get
 
I considered to have something in between to but i skipped it and had the wire to be bent so they fit together without. less resistance and stuff.

But if I would have done it i would have used copper tubing that fits over the nut directly and acts as bus.
 
Installed my 3rd KWH pack some weeks ago. 7 (Seven) more kwH to go.


image_bkoagw.jpg


I finally removed all the nuts in-between. I extended the length of the bus bars to allow for more flex, besides there are six cable lugs between the bolt and nut so the packs have some space in-between.


image_mpvxlt.jpg


My next build will be a 2kwh pack (40P7S) to make my total storage 5 kWh.
 
very nice setup, congrats :) . Why are you using MC4 connectors? From my experience, they're easy to close but hard to open (sometimes even with a special tool) and quite expensive compared to other solutions...
 
Hopefully I am wrong, but why are your Batteries between 4,34V and 4,53V?
max. Voltage for a cell is 4,2V!
 
I have now added more packs to my cells.

image_kgjfai.jpg


Total size is now 5kwh.


image_jjkijn.jpg



owitte said:
very nice setup, congrats :) . Why are you using MC4 connectors? From my experience, they're easy to close but hard to open (sometimes even with a special tool) and quite expensive compared to other solutions...

Sorry for the late reply. I have been offline for a while.

All what you have said is entirely true. I actually used the MC4 Connectors because I have so many of them, no other reason in particular.

I have since resorted to using cable lugs.


PAF said:
Hopefully I am wrong, but why are your Batteries between 4,34V and 4,53V?
max. Voltage for a cell is 4,2V!

You are perfectly correct! It's the mini voltmeters that are giving a wrong reading.

Unfortunately they are not the type that can be calibrated.

They are about 0.3v higher than the actual voltage, so I just use them to have a general idea of where the voltage is.

I have replaced them with more accurate ones that can be calibrated.
 
Now that's something! What did it cost you to get the batteries?
I find its expensive here in Port Harcourt...
 
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