Author Topic: My battery system  (Read 1404 times)

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paara

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My battery system
« on: March 16, 2017, 01:44:10 PM »
 I have a 5kw solar panale system on my garage roof. 21 245w panels.. 5kw inverter. South faceing. During pring, summer and autumn I produce more during the day then I use. I am at work most of the productive time anyway, but partly compensate for that having
my water heater on timer.

I got hold of the batteries from a citroen zero. It was in an accident, actually minor damage, but was not economical to fix apparently. 2 years old. It is a 14,5 kw lithium battery. 80 cells. In the car all 80 cells are connected in series for around 300v (80 x 3,7v). The picture with meter saying 160v is only half the series. It cam almost fully charged at 4,0v.  First I had to disassemble the battery. I consist of 10 packages of  2 modules, each with 4 cells. Then I opened each module and rotated 2 of the cells so everyone has the same polarity on same side. In 6 of the modules 2 are one side and the other 2 the opposite. This is so I can easily connect 6 and 6 together in parallel. Then I connected 13 in series. total 78 cells used (2 as spare). This will give me approx 48 (54,6-40v) and 250ah.
I will only charge it to 53,3v (4,1 per cell),because it is charged this way in the car. This will hopefully prolong battery life. The battery is conntrolled by a 30a BMS (to small for the battery since balancing currint is only 40ma), but hopefully the bank is well balanced.I have connected a 40amp fuse. the charger is 25ah. I can adjust voltage and has set it at 53,3v. I could increase voltage closer to 54,6v for faster charging and higher capacity. 

I will charge the batteries by day. I use a timer to control this. It is now set to start charging at 10 am to approximately 4pm. I will adust this as summer approach. The inverter(s) are set to start discharge the battery fro around 5pm to 8am. I have set it this way due to shading on my garage this early in spring.  I use timers so i wont need an expensive inverter. Like the synnyboy battery inverters ($$$$). I have 2 small grid tied inverters that are meant to be used with batteries (locked at 75% load). They will produce 500w and 400w. This way I can adjust the charge and discharge rate during summer. I will have to adjust the timers and 1 or 2 inverters during the year, to compensate for more or less sun. max 900w and minimum 400w. Now, when I have the 500W inverter on during night for approximately 14h I will save maximum 7kwh, but probably less since it will not cover higher load then 500w. I use approximately 24kwh per day, or 1kw per hour. And probably a base load of 800w with shorter peaks when water boiler and other high power utilities are on. But hope to be able to use more of my own power. :)

Of course there are limitations with this setup, but it is easy to build and relatively cheap. What remain is tidying up the cables

(dont know it the pictures work. Usless tread without pictures )
(some of the pictures are rotated, I am not able to correct that. Sorry)













































« Last Edit: March 16, 2017, 02:59:03 PM by paara »

Harold in CR

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Re: My battery system
« Reply #1 on: March 16, 2017, 02:45:35 PM »

 Pics that show look good. Please fix the rest. Very interesting thread. I am going with Chevy Volt/Altera and or Nissan Leaf battery modules.

SparWeb

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Re: My battery system
« Reply #2 on: March 16, 2017, 11:12:18 PM »
Hi
I'm keen to see more of your photos, but most of these will not load.
I've mentioned the problem to the site administrators to look at what happened.
If all you need is some help with re-sizing pictures we can tell you what to do.

What kind of BMS do you have?
I've recently been learning about BMS that "bottom balance" LiPO cells. 
With lead-acid batteries, equalizing was sufficient to balance a bank, most of the time, but this is proving to be bad for LiPO banks.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

paara

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Re: My battery system
« Reply #3 on: March 17, 2017, 09:04:08 AM »
i am sorry that some pictures are not loading. I have uploded them to dropbox, but have experienced problem before as well. Dont know how to fix it.

I use a regular bms suited for lithium batteries. Max 30amp charge and discharge. Balancing current 40mah (approximatly 1ah per day). I checked all cell before connecting them. All where in balance. Hopefully it is enough to prevent overcharging of 1 "cellgroup". Having 6 and 6 in paralell will also "dilute" a bad cell if there is or will be one
I sont think there will be any negative effekt using a bms. But my bms may be to small. But time will show.
« Last Edit: March 17, 2017, 12:45:49 PM by paara »

SparWeb

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Re: My battery system
« Reply #4 on: March 17, 2017, 01:09:04 PM »
I can see them all now.  Great!
That's a very nice system you've built there.

Can you describe a cell in the bank?  How big are they?  Is anything printed on them?  Any indication where they come from?
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

paara

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Re: My battery system
« Reply #5 on: March 19, 2017, 01:44:29 PM »
I can see them all now.  Great!
That's a very nice system you've built there.

Can you describe a cell in the bank?  How big are they?  Is anything printed on them?  Any indication where they come from?

The cells are LEV50. I believe they are made by Lithium Energy Japan for citroen, peugot and mishubitsi

Specifications
Type                                      LEV50   LEV50-4
Nominal voltage(V)              3.7   14.8 (4 cells in series)
Capacity(Ah)                       50   50
Dimensions(mm)   
Length                               171   175
Width                               44   194
Height                             115   116
Mass(kg)                            1.7   7.5


Mounted a battery meter.
« Last Edit: March 19, 2017, 01:57:58 PM by paara »