Off Grid 18650 Project

18650mb

New member
Joined
May 11, 2019
Messages
3
Hi all.
Last two years I'm collecting 18650's and finally in past 3 months I was able to create powerwall .
Currently testing and collecting more 18650's

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18650mb

New member
Joined
May 11, 2019
Messages
3
OffGridInTheCity said:
A lot of work but FUN! What are your plans for using it?

Yes fun indeed !
It's currently installed in my off grid house in woods! And I'm using it primarily for lights and some tools occasionally.
I had two 12V 240Ah AGM batteries and one of them died so instead of buying one new battery I went 18650 way and build my one.
The controller is re-branded MPP Solar PIP-HS 1624with PWM charger and 1600W 220Voutput.
Currently the battery is disconnected because I'm scared to leave it unattended. I't has all the BMS-es protection, fuses and ctr. but never the less I'm still not confident to leave it plugged in.
I have in plan to build battery monitoring system so I could remotely check the battery status of each parallel pack. (That is for other thread).
I would like to upscale the system to have 10-15kWh.
 

OffGridInTheCity

Well-known member
Joined
Dec 15, 2018
Messages
1,475
I see 60cells per pack, assuming 2000mah average it looks like you have aprox 120ah @ 24v pack - which is about 3000watts.

You could start with a cheap BMS ($30) sort of like the meter you show in picture but actually will balance without overheating.. ISDT BattGo BG-8S Battery Meter, https://www.amazon.com/gp/product/B07797N9BG/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 This little meter will eventually balance them and will give audio alarm if a pack voltage (settable) goes to low.

A next level (that I purchased) was based on DIY Tech & Repairs youtube - checkout
.

When you reach 10-15kwh you'll probably want to go on up to Batrium BMS (or other) will full control. I know its expensive, but as you grow and work with you're project and it gets bigger and bigger it will make more sense!.
 

18650mb

New member
Joined
May 11, 2019
Messages
3
OffGridInTheCity said:
I see 60cells per pack, assuming 2000mah average it looks like you have aprox 120ah @ 24v pack - which is about 3000watts.

You could start with a cheap BMS ($30) sort of like the meter you show in picture but actually will balance without overheating.. ISDT BattGo BG-8S Battery Meter, https://www.amazon.com/gp/product/B07797N9BG/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 This little meter will eventually balance them and will give audio alarm if a pack voltage (settable) goes to low.

A next level (that I purchased) was based on DIY Tech & Repairs youtube - checkout
.

When you reach 10-15kwh you'll probably want to go on up to Batrium BMS (or other) will full control. I know its expensive, but as you grow and work with you're project and it gets bigger and bigger it will make more sense!.

They are around 1800mAh average. I did test the twice to be extra sure. I used RePackr to sort them.

I have BMS as I mentioned , but I'm still not confident to leave them plugged in. BMS isP7S-20A-20A-B-V13 , they are 3 connected parallel. I did test them on small scale and they do overcharge and over discharge cut off. They also have balancing function.
On top of that I Have Active Balancehttps://s.click.aliexpress.com/e/cTq9QP32that balance the batteries at 1A so they are reasonably quickly balanced but it only works if difference is more than 0.30V.
[img=200x112]https://secondlifestorage.com/attachment.php?aid=1333[/img]

I was relay thinking ofBatrium BMS or [url=https://github.com/stuartpittaway/diyBMS]diyBMS[/url]. Batrium is more than enoughbut too expensive. I think that I will go with the diyBMSwith some things I already use.
 
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