The beginning of my powerwall

resonance

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Jun 15, 2018
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6
Hello guys

I need advice it's my first attempt oncell and battery arrangement but my goal is to form an off grid solar power wall with Yilong 40ah lithium Titanate battery lto for off grid purpose ,i need help calculating the number of battery cell required in producing 4000 watts energy to power atleast a 1.5 horse power ac during sunlight hours and off peak period either one, 800watts ac or fridge plus bulb of 450 watts tv 3 phones one laptop for at least 18 hours.

I apologize if my post is in a wrong thread am still trying to figure out how to create a thread for my personal post.

thanks for your contributions in advance would really appreciate it.
 
Moved to proper location. To create a new thread, just click the button at the top of the forum that says "Post Thread".
Also, please read the FAQ as it will have a lot of information that you are asking about listed.
And please read of others build projects as there are lots of ideas on designs. These will point you in the right direction as well.
 
resonance said:
Yilong 40ah lithium Titanate battery lto....


image_tgwwpn.jpg


I think this is the cell size .... many capacities , all @2.4V ... you are using 40Ahr which can store ...2.4x40= nearly 100WHr

So 10 of these will store 1KWHr (after losses 800wHr?).... enough to run a 800W appliance for 1hr .... of a 80w light for 10 hrs

Calculating power storage required for solar is not easy ... I've just had 4 gloomy rainy days with hardly no power from panels ...to have power for those very rare occasions you need a big powerwall ...

I would start with a 100 or 150(perhaps about$8,000 new), you can always add more later if it's not enough ...
 
Korishan said:
Moved to proper location. To create a new thread, just click the button at the top of the forum that says "Post Thread".
Also, please read the FAQ as it will have a lot of information that you are asking about listed.
And please read of others build projects as there are lots of ideas on designs. These will point you in the right direction as well.

Thanks for the advice and moving my thread to the right location.
 
I've been looking more at this battery type ... totally different from Li-ion and not suited for solar applications...

It definitely would not be a good idea to by these new for use as a solar powerwall .... if you come by them cheap , used , they will be OK.

They have about 4 times the weight of Li-ion for the same capacity ...energy density they are the same as lead acid....

Their outstanding features are high charge/discharge current and cycle life ..."more than 30,000cycles " !!! this is what you are paying for , a solar application would never use all those cycles it would take over 100 years so the battery would probably deteriorate from old age . before cycle life achieved .

These cells are suitable for something like a buggy at an amusement park , clients drive around for half an hour , return for rapid re-charge for the next customer ... 15 charge/discharges per day the battery would still last 6 years .
 
ozz93666 said:
resonance said:
Yilong 40ah lithium Titanate battery lto....


image_tgwwpn.jpg


I think this is the cell size .... many capacities , all @2.4V ... you are using 40Ahr which can store ...2.4x40= nearly 100WHr

So 10 of these will store 1KWHr (after losses 800wHr?).... enough to run a 800W appliance for 1hr .... of a 80w light for 10 hrs

Calculating power storage required for solar is not easy ... I've just had 4 gloomy rainy days with hardly no power from panels ...to have power for those very rare occasions you need a big powerwall ...

I would start with a 100 or 150(perhaps about$8,000 new), you can always add more later if it's not enough ...

This piece of advice comes in handy and helpful as a guide for beginners like us ,i can't tell you how much i appreciate it,now my question is this if i make a pack of 10 cells if am correct that should be 2.4vx 20=48 volts @ so 20 cells x 40ahr =800whr so would i be correct if i say 300 cells would power a 800 watts appliance for for 10hr.

Am in Africa and we do have alot of sunlight and when it rains we hardly use the air conditioner this helps on reducing power consumption .

The grid power comes in at 220-volts do the rating on these appliances like air condition matter some of them state 220 volts on their power cords.
 
Yes, you can use 20 cells for the 48V setup. If you did 1p (parallel), then you still get 30Ah. So, 20s1p = 48V @ 30Ah or 1440Wh.
As you add cells in parallel, for example going from 20s1p to 20s2p, you double the capacity. 20s3p would triple the capacity.

220V AC is not the same as 220V DC. Any device that runs on AC (mains grid power) will need to have the power inverted from DC to AC (there are few exceptions, but beyond this scope atm). Also, anything that runs on induction will need a pure sine wave inverter, not modified. Otherwise you will get a lot of hum from those motors and shorten their life span.


What size battery is that? It can't be an 18650 size as I see those are only around 5200mAh. Where's the stats 30Ah cells?

Ok, found one on Aliexpress. That joker is expensive!! $40USD per cell. sheesh. Well, it is 30Ah :p Better than a car battery on capacity, size, and weight.
 
ozz93666 said:
I've been looking more at this battery type ... totally different from Li-ion and not suited for solar applications...

It definitely would not be a good idea to by these new for use as a solar powerwall .... if you come by them cheap , used , they will be OK.

They have about 4 times the weight of Li-ion for the same capacity ...energy density they are the same as lead acid....

Their outstanding features are high charge/discharge current and cycle life ..."more than 30,000cycles " !!! this is what you are paying for , a solar application would never use all those cycles it would take over 100 years so the battery would probably deteriorate from old age . before cycle life achieved .

These cells are suitable for something like a buggy at an amusement park , clients drive around for half an hour , return for rapid re-charge for the next customer ... 15 charge/discharges per day the battery would still last 6 years .

This is a very rare featureTheir outstanding features are high charge/discharge current and cycle life

Why would you not recommend a newlithium Titanatebattery? i need to know before i place an order for my project.


Korishan said:
Yes, you can use 20 cells for the 48V setup. If you did 1p (parallel), then you still get 30Ah. So, 20s1p = 48V @ 30Ah or 1440Wh.
As you add cells in parallel, for example going from 20s1p to 20s2p, you double the capacity. 20s3p would triple the capacity.

220V AC is not the same as 220V DC. Any device that runs on AC (mains grid power) will need to have the power inverted from DC to AC (there are few exceptions, but beyond this scope atm). Also, anything that runs on induction will need a pure sine wave inverter, not modified. Otherwise you will get a lot of hum from those motors and shorten their life span.

I need more insight on this new calculation how long would a 800watts appliance last @ 30Ah or 1440Wh thanks for yourexplanation much appreciated.


Korishan said:
Yes, you can use 20 cells for the 48V setup. If you did 1p (parallel), then you still get 30Ah. So, 20s1p = 48V @ 30Ah or 1440Wh.
As you add cells in parallel, for example going from 20s1p to 20s2p, you double the capacity. 20s3p would triple the capacity.

220V AC is not the same as 220V DC. Any device that runs on AC (mains grid power) will need to have the power inverted from DC to AC (there are few exceptions, but beyond this scope atm). Also, anything that runs on induction will need a pure sine wave inverter, not modified. Otherwise you will get a lot of hum from those motors and shorten their life span.


What size battery is that? It can't be an 18650 size as I see those are only around 5200mAh. Where's the stats 30Ah cells?

Ok, found one on Aliexpress. That joker is expensive!! $40USD per cell. sheesh. Well, it is 30Ah :p Better than a car battery on capacity, size, and weight.

https://evlithium.en.alibaba.com/pr...0AH_Lithium_Titanate_Battery_LTO_Battery.html


I need more insight on this new calculation how long would a 800watts appliance last @ 30Ah or 1440Wh thanks for yourexplanation much appreciated.
 
1440Wh / 800W = 1.8 Hours or 108 minutes
 
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