Ampere/hour battery rating.

[Derlyn]

Am I right so far.
Not worried about charging the batteries YET.

Calculating how many batteries I need to pull 2A for 24Hrs.

on 24V side current is 20A

20A for 24 Hrs = 480Ah.

Now we dont want to go beyond 30% DOD so the 480Ah is 30% of the total battery capacity.

If 480Ah is 30% then 100% will be 1600Ah. ( 19.2Kw )


16 of 100Ah batteries should suffice.

That's a giant battery bank. Are my calculations correct ?

PS. We will worry about the charging later.


Don't know if it's worth it after reading the following.
https://mybroadband.co.za/news/energ...ity-eskom.html

[GCE]

Am I right so far.
Not worried about charging the batteries YET.

Calculating how many batteries I need to pull 2A for 24Hrs.

on 24V side current is 20A

20A for 24 Hrs = 480Ah.

2 Amps at 240V = 480Watts
For 24 hours you will need 24 x 480watts = 11 520 watthours or as we are used to 11,5KWH

From Battery side
24V x 20 amps will give 480watts/hour x 24Hrs = 11 520 watt hours capacity = back to amp hours will be 11520/24 = 480Amphrs or 11520/12= 960Amphrs

Amp hours is similar to watts - The amp hour is what is available if used in an hour and then the DOD comes in and the C rating comes into play.

If you going gel batteries you are going to need lots of them - As a thumb suck I use 360watts or amp hours usable per 100amphr battery for each hour which will mean around 32 batteries 100Amphr or 16 x 200Amp hour batteries

Besides charging you need to think of gas build up and ventilation

Lithium is the only way to go.

Don't know if it's worth it after reading the following.
https://mybroadband.co.za/news/energ...ity-eskom.html

Sometimes think My Broadband should stick to IT issues and not create panic - It is not so much the extra cost that comes into play it is how you manage it - The majority of extra cost is due to TOU tariff

[Derlyn]

2 Amps at 240V = 480Watts
For 24 hours you will need 24 x 480watts = 11 520 watthours or as we are used to 11,5KWH.

If you going gel batteries you are going to need lots of them - As a thumb suck I use 360watts or amp hours usable per 100amphr battery for each hour which will mean around 32 batteries 100Amphr or 16 x 200Amp hour batteries

Thanks GCE.

Somewhere I'm making a mistake with the number of 100Ah batteries needed.
Maybe you can help me.
I come up with 16 of 100Ah batteries needed. You say 32 batteries needed.

We both agree that 480Ah is whats used over the 24 hr period.
You should then have 70% of your total battery capacity left if you disregard any charging during that time.

My maths is as follows: 480 = 30%
Therefore X = 100%

Therefore 30x = 48000

Therefore x = 48000/30

Therefore x = 1600

Therefore 100% battery capacity = 1600Ah

1600/100 = 16 of 100Ah batteries.

Where am I going wrong ?
Big difference between 16 and 32 batteries.

[GCE]

We both agree that 480Ah is whats used over the 24 hr period.
.

did some changes to calculation in original post I made - Our difference is due to battery voltages - you using 24v which means 100amphrs needs 2 batteries
Still think I could be confusing myself , will need more coffee and a couple of cigs to wake up completely

[Derlyn]

Morning brother.

I also need some coffee and gwaai's to wake up in the morning, otherwise I'm still

You are correct

Batteries in series do not increase the Ah rating. Only the voltage.

My battery bank has just increased from 16 to 32.

Will have to buy a new house now.


Now to start working on how to charge these things. That should be fun.

[Dylboy]

Hello !

Didn't even know there was another section hahaha.

If it is 12V and 100AH that is then 1200WH or 1.2KWH

Then if

24 V and 100AH that is then 2400WH or 2.4KWH

Is that correct ?

Sent from my CPH2197 using Tapatalk

[GCE]

Hello !

Didn't even know there was another section hahaha.

If it is 12V and 100AH that is then 1200WH or 1.2KWH

Then if

24 V and 100AH that is then 2400WH or 2.4KWH

Is that correct ?

Sent from my CPH2197 using Tapatalk

That is correct -
Battery in parallel - voltage will be added , amp hour stays the same
In series - voltage stays constant , amp hours is added up

2 batteries in Series = ( 2x12v) x 100Amphr = 2 400Whr

2 in Parallel - = 12v x ( 2 x 100Amphr) = 2 400whr

As a quick rule I just use a 100Amphr battery using only 30% will give me 360w usable energy - If the client wants to run a 1 Kw load for 2 hours then I say he needs 2Kw of energy divide by 360W = 6 Batteries - The configuration of batteries to suit the inverter voltage all works out the same , The bucket of water is still the same size.

[Derlyn]

That is correct -
Battery in parallel - voltage will be added , amp hour stays the same
In series - voltage stays constant , amp hours is added up

2 batteries in Parallel = ( 2x12v) x 100Amphr = 2 400Whr

2 in series - = 12v x ( 2 x 100Amphr) = 2 400whr

Hmmm ..... Regarding series and parallel batteries, I think the above 2 statements are the wrong way round.

[GCE]

Hmmm ..... Regarding series and parallel batteries, I think the above 2 statements are the wrong way round.

You are correct did an edit on previous post- Still confusing myself even with coffee and cigs

[Dylboy]

Awesome ! That is how I have done it and always understood it but had to make sure as the above stuff has me questioning my self. Albeit I did read it quick but still.

Appreciate it as always

I like your rule of thumb for the 100AH and 30%.



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