Battery advice for my solar system?

ismaildoganw

Member
Joined
Jun 22, 2017
Messages
53
Hello there. The solar system that I use at home is working with the acid battery. Its performance is lower than that. I want to build a battery pack of 18650 batteries.

How many cells and series do I need to make?
Do I need to use the BMS system?

I need your advice in this regard.

System features;

2x250 watt solar panel
4x90Ah Acid battery
3200 watt inverter (chargeable)

Devices I use
A refrigerator
Washing machine
Dishwasher
Lambs
Small household appliances

Thank you for your answers already
 
A refrigerator, Washing machine & Dishwasher require high amount of power needed. With 2x250w solar panel, it may not be fast enough to charge up the battery within a day. Moreover, if days or cloudy or raining.. you do not have enough backup. An estimate if you're able to run you appliances using 3.2Kw inverter, you should require double or triple the power of battery needed. At the same time, increase the solar panel as well....
 
Dam Lim Thank you for your reply. I just started this business. I'll have 2 solar panels. I have a lot of sunlight in the area. I live in Hatay, Turkey. Do you have any suggestions on the battery? How much cell and serial combination do I have to make?

There are 14 likely to be serials. How many cells I want to learn will be regular, in parallel?
 
Series depend on the inverter and charger.
Paralell depends on type of cells and how much stored eneegy is needed and also the max current.

On mobile so cant add numbers now but someone else can
 
Inverter device 3200 watts. It can charge between 1 ampere and 50 amperes. I can choose how much current flows.

It will not be standard since the cells will be from old laptop batteries.
Daily consumption 5kw
The maximum load is 1.5kw

Inverter device

3YCCcTZBBF0qDpUa-38ZtPkj04f6btoIvOgK63dz93GL47ckdnWGH7EHdx94hLzeeoe_8bR4Y1sErzP3qYc1qEbxvdP4CgCuKM4Q_XLqeS1ysFtwYAoeM4N1IYvLm2Veq4bSWISDh0bfYbCF6lRA3a4s1G1-kwsyaqINOs7tg0-PNM_rFL6B_uGtmHYF4Ce4DvK1p6mmJ7UxcP_d9UXWWICNtQq_He6sFFIreIuvMx2Smcs6WedpiFzAD6vt_BAhcey-aFffwdEyEJdPg_QrpcevnLyCTJ58V9TfRIOtGdjgNNlqbQNSTMYuNII_eKs7r13aaKhX7bFjFk5csXKTxd4uOuUrXdeTxrNOv1iGOD-EvTpqjtXUlh24yMQ_FGpF4uksGUjVxR4Q6VoyuP99LUlejUe1volQDIVYOxiGiK7nJfpXNJa0yk27UOgq_AL7wb6OWHi83JzgpJi9uYTZ9sJ4ej6k3xXTTyf7gc0AYHURiwpS1v28R_7TowlCaIJ6I0fKszP1AT6b5LS6Ynny7pazvFXC4IvneE5kirK15k4qITMnZWan5sMDPN0HGtF4y3DvPdXhP-j5sMPTSo6MgYJBdY_mB0zp6BrxPi0cRURoHJdPXeSx9jGtiB4tSWoCOLdJNvt8DMTHd5j189UhSM53NLAbchFBK-qPRCzmjEs=w275-h379-no
 
Looks like a MPP clone.

For only 2 panels you will not be able to charge much per day at all. But on the other hand its better to have more cells per pack than to few. Dont go below what you have today that is 45Ah. (50% of the Lead acid)
That would be 14s20p with 2.2Ah cells. BUT I personally dont recomend more than 1A per cell to not stress them. (Same as you tested with) And that would be 1kw max useage. On inverter side perhaps 800w.

So to get 1.5kw i would recomend 14s40p at minimum!
 
Since you have Inverter onhand, firstly you need to determine what Voltage is best for your inverter, 24V/48V. This decision has to be made before you start putting all the cells together... a 14s will give you 14x3.7V= ~51V-55V. After that you need to calculate the power (Watts). Assuming each battery is 2A, 20p = 40 Amp / 40p = 80 Amp.... You use the final ampere x 3.7V, that will give you the total power you need. The more the better as Daromer mentioned. In this configuration you need at least more than 5 panels of 250W to power your inverter and charge the battery...
 
Thank you for your dan lim and daromer answers. I think I'll start with 14s and 50 cells in the first place. This battery is assumed to be 1 amp power, how many watts of power it contains. For now the refrigerator and the lights are enough for the nights. We do laundry and other heavy work daytime.


Write power calculation formula in watts


14s*50cell*1amp=700amp*4.2v=2940 watt

This account is correct?


Can we use all 2940 watts?
 
Averaging 18650 around 2-2.3Amp, the better ones are 2.6-3Amp.... just take "2A"...
Not correct, as you're connecting in series (14s), the voltage will increase, the power remain the same...
so, for 1s = 50cells x2A = 100Amp.
P= 100A x 51V(14s) = ~5100W.
Should be enough to power your inverter.
Total you need 50cells x 14 = 700cells
With this you need more solar panel to charge up this amount of battery...
solar panel = 250 watt x 10 = 2500w.. At least it can charge 50% of your battery..
 
Dan Lim said:
18650 civar?nda ortalama 2-2.3Amp, daha iyi olanlar 2.6-3Amp .... sadece "2A" al ...
Do?ru de?il, seri (14s) ba?lan?rken gerilim artacak, g Ayn? kal?r ...
yani, 1s = 50cells x2A = 100Amp iin.
P = 100A x 51V (14s) = ~ 5100W.
?nverterinize g vermek iin yeterli olmal?d?r.
?htiyac?n?z olan toplam 50 hcre x 14 = 700 hcredir
Bununla bu miktar? ?arj etmek iin daha fazla gne? paneline ihtiyac?n?z var ...
gne? paneli = 250 watt x 10 = 2500w .. En az?ndan pilinizin% 50'sini ?arj edebilirsiniz ..

Is not that much for this battery with 10 250 watt solar panels? The sunshine calendar we have here is here.

http://www.eie.gov.tr/MyCalculator/pages/31.aspx

2x250watt'l?k gne? panelim gne?li bir gn iin asit sigara iiyor. ?ki tane daha gne? panelim olacak. Toplam 4x250 watt olacakt?r. Bu 14sx50 hcre iin yeterli de?il mi?
 
?lk amatr pil grubum. Elektrikli bisiklet iin yapt?m. 16sx6cell. BMS yaptm, fakat bir dizi mavi pil kt gitti. San?r?m bu yzden BMS bozuldu. Asl?nda bu ok amatrce idi. :)Bu yzden daha teknik bilgiye sahip oldu?u iin gne? sistemimde yeni bir pil grubu kullanmak istiyorum.


yhNYgzN4IzAmpsV4W1Ia8lDQfyQmeDwZwFZDzdncS_rmK2PtKF6UTKiVGNp_G1UNKVuJmdICZ1xqba5fnw8kM4XMyXgxLFWct6M9qv0PZePOc7xjlR48xHV0wCHDQt6f3KxufbOHozaojUlFHhZvIlapz5Dd9L34BG5sajK6IDA_d86lyKjpnkCN_q380LegD8-w5RJhGn5Zo23KomlSbwAVG8o4bP8HXiAdl2m9VNLVuZ_-gmjqCnEEBBpTqUP6-QM58oVYdrEqu4L5ZYfrilHjdekLdgMsBzgZSvRt6tShhYSSBEUB9YO1ThjNWG04Ru3bteZPdQ15ES1TA1efRMGXwnL1-wrpcS2MuCJLo2hUV3cHNi-ss9bGFj1s3ChFlEyhraMSVyW_SAZeyGAnE3by8iXIXaRwCt9WW60MvMZ9cSWv1TGq74DzTfE3wvN3FWwD0QuyvrBCNm8sCJb75DS1_eAEmWq6ALhoXQPc5bN2yCHzyb5u65N7WU3nyVdWonUM0zvPXLeEy-fjTlP5PwBxjie1XRl46NQLGBHNJnhcg1E_O9dtuQzO85tFv3aJ5jcexx1AM0zXlbrQhX9cV8TktO0HQwD31Ketw1n5MfjJNS-MOpdmkQ=w634-h845-no
 
?smaildoganw said:
?lk amatr pil grubum. Elektrikli bisiklet iin yapt?m. 16sx6cell. BMS yapt?m, ancak bir dizi. Mavi pil kt gitti. San?r?m bu yzden BMS bozuldu. Asl?nda bu ok amatrce idi. :)Bu bir daha iyi teknoloji bilgisi olana?? iin gne? sistemimde yeni bir pil grubu kullanmak istiyorum.


yhNYgzN4IzAmpsV4W1Ia8lDQfyQmeDwZwFZDzdncS_rmK2PtKF6UTKiVGNp_G1UNKVuJmdICZ1xqba5fnw8kM4XMyXgxLFWct6M9qv0PZePOc7xjlR48xHV0wCHDQt6f3KxufbOHozaojUlFHhZvIlapz5Dd9L34BG5sajK6IDA_d86lyKjpnkCN_q380LegD8-w5RJhGn5Zo23KomlSbwAVG8o4bP8HXiAdl2m9VNLVuZ_-gmjqCnEEBBpTqUP6-QM58oVYdrEqu4L5ZYfrilHjdekLdgMsBzgZSvRt6tShhYSSBEUB9YO1ThjNWG04Ru3bteZPdQ15ES1TA1efRMGXwnL1-wrpcS2MuCJLo2hUV3cHNi-ss9bGFj1s3ChFlEyhraMSVyW_SAZeyGAnE3by8iXIXaRwCt9WW60MvMZ9cSWv1TGq74DzTfE3wvN3FWwD0QuyvrBCNm8sCJb75DS1_eAEmWq6ALhoXQPc5bN2yCHzyb5u65N7WU3nyVdWonUM0zvPXLeEy-fjTlP5PwBxjie1XRl46NQLGBHNJnhcg1E_O9dtuQzO85tFv3aJ5jcexx1AM0zXlbrQhX9cV8TktO0HQwD31Ketw1n5MfjJNS-MOpdmkQ=w634-h845-no

My first amateur battery group. I did it for the electric bike. 16sx6cell. I did BMS, but a series. The blue battery went bad. I guess that's why the BMS broke down. Actually, it was very amateurish. :) I want to use a new battery pack in my solar system for this better technology information facility.
 
I don't know why, but I cannot see your images. I see the urls are coming from a google.com page, but i can't see them. All that is visible is a gray circle it wit a - in it.
 
Thats because he most likely copied a search image from google and they dont allow that.

ismaildoganw: Coppy the real image address and insert here. This thread at the moment is not understandable.
 
Your solder joints are too cold. And it looks to me like several cells are corroding (especially the ones toward the bottom). What kind of solder did you use?
 
Korishan said:
Your solder joints are too cold. And it looks to me like several cells are corroding (especially the ones toward the bottom). What kind of solder did you use?


Hello I was not online because of Ramadan festival. I could write now.
I used standard solder. I do not know the technical specifications. But the soldering machine I used when I soldered the first time was weak. I soldered very hard. I think it was cold solder. What do you suggest I do?
 
Cold soldering refers to the parts being soldered not getting hot enough to keep the solder in liquid form. Your soldered joint shouldn't look pale or hazy, but should be more glossy.

Please watch this video:
 
Back
Top