adanny01:


I asked this question some comments back.

Tell me if am right or wrong.

24v with 400Ah will be connected in series. The battery Ah of the bank will be 200Ah. That will be 24 x 200 = 4800wh. Also 200Ah/20A= 10hrs right?

12v with 400Ah will be connected in parallel. The battery Ah of the bank will be 400Ah. That will be 12 x 400= 4800wh. Also 400Ah/20= 20hrs right ot wrong?

I thougt before that it beats my common sense and every imagination that same charger will not be able to charge same batteries just because of the connection. Please help me clarify cause i have been doubting these logical calculations.

This is the reply i got before.

the simple logic is that tho both is 20A charger but the volts are different. 24V and 12v
that is to say in series 20A charges at 24v (double)
and in parallel 20A charges at 12v (single)

yahyamay:


the simple logic is that tho both is 20A charger but the volts are different. 24V and 12v
that is to say in series 20A charges at 24v (double)
and in parallel 20A charges at 12v (single)

chris81964 do you agree cos that seems to be the logical case?

Used 75amps external charger for sale, call 08117398294 or email Info@monzpowersolutions.com

adanny01:


Thats my point. In every individual use case has its positives and negatives. As a system planner you have the responsibility to balance the negatives and positives.

In the case you cited above, assuming it has a 20A charger. The system should fully charge in 400/20= 20hrs.

At the point of purchase, if you had opted for the 24v inverter with same charger, charging time would not have been that long but 10hrs.

Every system has its advantages and disadvantage.

A 24 volt Inverter for example will require two 12 volt batteries connected in series to generate the required 24 volts. In order get decent run time we are talking two 200ah batteries. These two batteries have a combined capacity 400ah, but if there are connected to a 24 volt Inverter the capacity will be 200ah. Total cost N135,000

A 12 Volt Inverter connected to a signal 12 volt 200ah battery , will give you the same run time and backup capacity as two 12v 200ah batteries connected to a 24v Inverter. Total cost N80,000

In reality my 12v Inverter with a 400ah capacity battery bank takes less than 12 hours to fully charge on most days, How? On any given day i only use half the capacity of the battery bank, and before it gets to half NEPA usually brings light and charges the bank back to full.. Now it does not always work that way because sometimes NEPA can take light for days, in such worst case situations it takes less than 16 hours to fully charge. It will never take the 20 hours suggested by the formula 400/20 because it is assuming that the battery bank is fully discharged, which my Inverter will never allow. When it it gets to a certain rate of discharge the alarm goes off.

12 hours may be considered to long for some, as many have already elucidated , the long charging hours are easy to mitigate , by buying an external charger , in which case 12 hours could easily become 6 hours or less and you will still be spending less than you would on a 24v system.

adanny01:


chris81964 do you agree cos that seems to be the logical case?

I am not going to teach you something you don't want to know.

chris81964:

I am not going to teach you something you don't want to know.

Oga, i asked a simple question over and over again just to satisfy my curiousity. My room mate in the university for 3yrs and currently flat mate who is an electrical engineer has not been able to answer this question for me. I came here wanting to know from those who have the experience, if you dont want to share you knowledge, just say so.

I have had two answers to my question. One is yours and out of the people who said otherwise i quoted one for you. I am lost but more inclined towards your answer using my common sense, but as i have been thought how to logically calculate it, i arrived at a different answer. How can i know which is absolutely correct if you dont expantiate so i can understand more. I just wonder how you came of the impression i dont want to know.

Let me rephrase the question incase you change your mind.

Would the charging rate of a 20A charger be the same under a 24v series or 12v parallel system connected to 2 x 12v 400Ah battery bank?

Those who said no gave their reasons using the numerous same calculations above.

You seem to say yes. Can we learn from your experience. I want to know.

spinola:


Every system has its advantages and disadvantage.

A 24 volt Inverter for example will require two 12 volt batteries connected in series to generate the required 24 volts. In order get decent run time we are talking two 200ah batteries. These two batteries have a combined capacity 400ah, but if there are connected to a 24 volt Inverter the capacity will be 200ah. Total cost N135,000

A 12 Volt Inverter connected to a signal 12 volt 200ah battery , will give you the same run time and backup capacity as two 12v 200ah batteries connected to a 24v Inverter. Total cost N80,000

In reality my 12v Inverter with a 400ah capacity battery bank takes less than 12 hours to fully charge on most days, How? On any given day i only use half the capacity of the battery bank, and before it gets to half NEPA usually brings light and charges the bank back to full.. Now it does not always work that way because sometimes NEPA can take light for days, in such worst case situations it takes less than 16 hours to fully charge. It will never take the 20 hours suggested by the formula 400/20 because it is assuming that the battery bank is fully discharged, which my Inverter will never allow. When it it gets to a certain rate of discharge the alarm goes off.

12 hours may be considered to long for some, as many have already elucidated , the long charging hours are easy to mitigate , by buying an external charger , in which case 12 hours could easily become 6 hours or less and you will still be spending less than you would on a 24v system.

Now i understand that you are a user. My guess is that is the Mercury 2.4kva 24v inverter with 20A 3 stage charger connected in series to 2 12v 200Ah batteries. I am also a user of the 1.2kva 12v inverter coincidentally with the same 20A charger but just 1 12v 200Ah.

You mentioned 16hrs to charge even when it wasnt fully discharged. My system takes about 8hrs. This is very interesting because by the formular i have come across for calculation of charging time 10hrs is the calculated charging time for your system just like mine. The 10hrs is because 2 batteries in series still maintains 200Ah.

Of course there are losses. Aside the losses, there is Depth of Discharge (DoD) or its alternate, State of Charge (SoC). If am not wrong, manufacturers of inverters program a cut off at a certain DoD to protect the batteries. So when your inverter goes off, it doesnt mean that the battery is 100% depleted. Our inverters might have cut off at 80% DoD (or what ever the brand might have set). 20% is now the battery's SoC in which charging takes off from. That only explains why you will not take the 20hrs as in the simple theorithical calculations.

A 12 Volt Inverter connected to a signal 12 volt 200ah battery , will give you the same run time and backup capacity as two 12v 200ah batteries connected to a 24v Inverter.

This cant be exactly as your system has 4800wh storage capacity and the mine 2400wh. Runtime with same load will be twice as much as mine.

adanny01:


Oga, i asked a simple question over and over again just to satisfy my curiousity. My room mate in the university for 3yrs and currently flat mate who is an electrical engineer has not been able to answer this question for me. I came here wanting to know from those who have the experience, if you dont want to share you knowledge, just say so.

I have had two answers to my question. One is yours and out of the people who said otherwise i quoted one for you. I am lost but more inclined towards your answer using my common sense, but as i have been thought how to logically calculate it, i arrived at a different answer. How can i know which is absolutely correct if you dont expantiate so i can understand more. I just wonder how you came of the impression i dont want to know.

Let me rephrase the question incase you change your mind.

Would the charging rate of a 20A charger be the same under a 24v series or 12v parallel system connected to 2 x 12v 400Ah battery bank?

Those who said no gave their reasons using the numerous same calculations above.

You seem to say yes. Can we learn from your experience. I want to know.

I will ask you a question too. I have 12 200 AH 2 V batteries on a 12 V system or 3 400 AH 8 V batteries on a 24 Volt system.

They both have 20 A chargers which would charge faster and why?

The buckets are the same size and the rate at which I can fill it is the same. Which one will I fill faster?

No need to over complicate a matter. Serial or parallel the size of the buckets are the same and the rate I can fill it is the same.

chris81964:


I will ask you a question too. I have 6 400 AH 2 V batteries on a 12 V system or 3 400 AH 8 V batteries on a 24 Volt system.

They both have 20 A chargers which would charge faster and why?

The buckets are the same size and the rate at which I can fill it is the same. Which one will I fill faster?

No need to over complicate a matter. Serial or parallel the size of the buckets are the same and the rate I can fill it is the same.

At first sight of the configurations, i assumed the first will charge faster.

However, i need to calculate it to know for sure. Let me get on with the calculations as best as i know it.

1. 6 x 400Ah x 2v all batteries must be connected in series to have a total of 12v 400Ah (current remains same on series connection).
Total power is 12x400=4800wh
Charging time is 400/20=20hrs

2. 3 x 400Ah x 8v all batteries must also be connected in series to have a total of 24v 400Ah (same reasons as above)
Total power is 24x400=9600wh
Charging time is 400/20=20hrs

At the end, if the calculations are right, they both should charge at the same rate. From your analogy, the first system is like a 48 litre jerry can and the second is like a 96litre. Using a 12mm diameter nozzle (12v) to fill the 48L and a 24mm dia (24v) to fill the 96L with water flowing at the same rate of 20L/min (20A charger). Both may fill up same time.

In this case, the bucket or jerrycan are not the same size because the actual size of a battery in a bank is the total power it can store. Another example with exactly same bucket but different connection will be closer to my question.

adanny01:


At first sight of the configurations, i assumed the first will charge faster.

However, i need to calculate it to know for sure. Let me get on with the calculations as best as i know it.

1. 6 x 400Ah x 2v all batteries must be connected in series to have a total of 12v 400Ah (current remains same on series connection).
Total power is 12x400=4800wh
Charging time is 400/20=20hrs

2. 3 x 400Ah x 8v all batteries must also be connected in series to have a total of 24v 400Ah (same reasons as above)
Total power is 24x400=9600wh
Charging time is 400/20=20hrs

At the end, if the calculations are right, they both should charge at the same rate. From your analogy, the first system is like a 48 litre jerry can and the second is like a 96litre. Using a 12mm diameter nozzle (12v) to fill the 48L and a 24mm dia (24v) to fill the 96L with water flowing at the same rate of 20L/min (20A charger). Both may fill up same time.

In this case, the bucket or jerrycan are not the same size because the actual size of a battery in a bank is the total power it can store. Another example with exactly same bucket but different connection will be closer to my question.

The charge time is resolved. Now which has more stored? You answered it. The 12 V equivalent to the 24 volt system will be 800 AH.

chaiiii battery bank calculator guys dey here ooooo...oga pass oga 4 nairaland.....everyone always proof they know something,some claim they know everything.God go help us

chris81964:

The charge time is resolved. Now which has more stored? You answered it. The 12 V equivalent to the 24 volt system will be 800 AH.

That has been answered already. 1st system has 4800wh when full and the 2nd has 9600wh when full.

If to say the second inverter was 12v, there is no way to connect 3 x 8v batteries. The same thing goes to the first inverter if it were 24v, 6 x 2v batteries will not work. Thats why i prefered an example of a battery bank that can be connected in both 12v and 24v systems. Besides both cases are series connections which is not the case i am trying to compare.

adanny01:


That has been answered already. 1st system has 4800wh when full and the 2nd has 9600wh when full.

If to say the second inverter was 12v, there is no way to connect 3 x 8v batteries. The same thing goes to the first inverter if it were 24v, 6 x 2v batteries will not work. Thats why i prefered an example of a battery bank that can be connected in both 12v and 24v systems. Besides both cases are series connections which is not the case i am trying to compare.

Since you know what you are looking for. Answer your own question then. When that fails Google it.

chris81964:


Since you know what you are looking for. Answer your own question then. When that fails Google it.

A simple 'i dont know' should suffice or better still no need to throw attitude by keeping it to yourself instead of throwing questions to the same person who asked in the first place.

After the wild goose chase for no apparent reason, you send me back to google! If i had the answer i was looking for from google i wont be asking you. I blame myself for playing nice even when it was clear you had no idea.

adanny01:


A simple 'i dont know' should suffice or better still no need to throw attitude by keeping it to yourself instead of throwing questions to the same person who asked in the first place.

After the wild goose chase for no apparent reason, you send me back to google! If i had the answer i was looking for from google i wont be asking you. I blame myself for playing nice even when it was clear you had no idea.

I was being polite. You are obviously challenged. Use Google or go to school to learn it like others before you.

Hi everyone....plz am new here and i love this thread of inverter stuff so am intrested in having one in my apartment to power my ps2 50watt and 21"tv 90watt,ceiling 50watt and cfl bulb of 10 watt plz can i use '650va ups' to power them with maintiance free car battery......

chris81964:


I was being polite. You are obviously challenged. Use Google or go to school to learn it like others before you.

Unless the word polite has a new meaning in English. I just wonder why a polite person instead of either contributing to a solution or keeping quiet would choose to send someone on a wild goose chase. At the end someone who wants to know is told by you to go back to school. Even if i will go back to school, i wont study electrical engineering. Infact, when i was about to go to the university, i had 2 admission offers and one was electrical engineering but i turned it down for my current profession. It doesnt stop me from desiring to know some certain aspects of it especially for my personal use.

Next time, when a general question is thrown, you dont have to answer or take it personal. If you dont know, its not by force to answer. I didnt call on you to answer until you gave yours. There is no crime in asking for clarification of your answer. If the question was beyond you, it was better to gracefully walk away.

Besides, i love my profession, if i would go back to school for my Ph.D, its going to be within my profession.

temizeee:
chaiiii battery bank calculator guys dey here ooooo...oga pass oga 4 nairaland.....everyone always proof they know something,some claim they know everything.God go help us

Even if those some people claim they know everything, i know that they dont.

adanny01:


Even if those some people claim they know everything, i know that they dont.

abeg answer my question na

officialfestus:
abeg answer my question na

I would have loved to since i dont believe in hoarding but afraid that some may not be comfortable.

I have fairly use inverter battery and New battery
I want to no maybe, I can connected the two battery together. in series ?

adanny01:


Even if those some people claim they know everything, i know that they dont.

mr @adanny01 you don't have to take what I said as a weapon against another nairalander........i don't fight or like to argue online......i commented abt some guy having 4 ba3 bar blinking ish some times ago and you see i backoff...not becuz i totally agree but i don't argue online.
also this mr @chris81964 you are talking about is who i can call a professional installer in solar power (chk diz page u will see some of his recent installation www.nairaland.com/390522/solar-energy-complement-fta/126) ....he had knowledge in this system so i don't know d boss or who is right....my point is what i said abt knowing everything,isnt about him...... i just talked generally.

temizeee:
mr @adanny01 you don't have to take what I said as a weapon against another nairalander........i don't fight or like to argue online......i commented abt some guy having 4 ba3 bar blinking ish some times ago and you see i backoff...not becuz i totally agree but i don't argue online.
also this mr @chris81964 you are talking about is who i can call a professional installer in solar power (chk diz page u will see some of his recent installation www.nairaland.com/390522/solar-energy-complement-fta/126) ....he had knowledge in this system so i don't know d boss or who is right....my point is what i said abt knowing everything,isnt about him...... i just talked generally.

Thanks @Temizeee. Thank you for coming to my defense. There is an expression in Ibo that says when you have asked and received the head of the dog what will you do with the chin? I am sure I butchered the translation.

People who have way more time on their hands like to waste the time of others on hypotheticals. That is what school or Google is for.

Thank you once more. We try to learn and help others who have a system perform better. I am always happy to contribute my two cents.

temizeee:
mr @adanny01 you don't have to take what I said as a weapon against another nairalander........i don't fight or like to argue online......i commented abt some guy having 4 ba3 bar blinking ish some times ago and you see i backoff...not becuz i totally agree but i don't argue online.
also this mr @chris81964 you are talking about is who i can call a professional installer in solar power (chk diz page u will see some of his recent installation www.nairaland.com/390522/solar-energy-complement-fta/126) ....he had knowledge in this system so i don't know d boss or who is right....my point is what i said abt knowing everything,isnt about him...... i just talked generally.

I am not a new person here, i have watched his videos and seen pictures of his installations. When he first dropped his comment here, i thought he would be of help.

adanny01:

Oga, i asked a simple question over and over again just to satisfy my curiousity. My room mate in the university for 3yrs and currently flat mate who is an electrical engineer has not been able to answer this question for me. I came here wanting to know from those who have the experience, if you dont want to share you knowledge, just say so.
I have had two answers to my question. One is yours and out of the people who said otherwise i quoted one for you. I am lost but more inclined towards your answer using my common sense, but as i have been thought how to logically calculate it, i arrived at a different answer. How can i know which is absolutely correct if you dont expantiate so i can understand more. I just wonder how you came of the impression i dont want to know.
Let me rephrase the question incase you change your mind.
Would the charging rate of a 20A charger be the same under a 24v series or 12v parallel system connected to 2 x 12v 400Ah battery bank?
Those who said no gave their reasons using the numerous same calculations above.
You seem to say yes. Can we learn from your experience. I want to know.

adanny01:


I am not a new person here, i have watched his videos and seen pictures of his installations. When he first dropped his comment here, i thought he would be of help.

Can I Try to answer this? Can we look at it from a point of how much power (voltsX current) we can put back to our battery bank ? The current plus the volts you are using that current matters. A 12V 400amp system has the same TOTAL capacity as 24V 200 amp system = 4800Watts all things being equal in a perfect system. However, 12v 20amp system will deliver 240w power back to my battery bank per hour while 24v 20amp will deliver 480w, cutting the charging time by half.
Hope this helps.

durodee:

Can I Try to answer this? Can we look at it from a point of how much power (voltsX current) we can put back to our battery bank ? The current plus the volts you are using that current matters. A 12V 400amp system has the same TOTAL capacity as 24V 200 amp system = 4800Watts all things being equal in a perfect system. However, 12v 20amp system will deliver 240w power back to my battery bank per hour while 24v 20amp will deliver 480w, cutting the charging time by half.
Hope this helps.

Initially, i thought otherwise that a 20amp charger for example will deliver the same power in any voltage system and would naturally take longer to charge when battery bank is increased. I have realised that thats not the only case since when voltage increases, power delivery increases proportionally. I arrived at a conclusion in this post below.

I get the point.

Example: there is this certain inverter of Prag brand in 2 variants both 4kva with 30 charger and cost the same 165k. The only difference is one is 24v the other is 48v. Lets say i have 4 12v batteries of 200Ah.

1. 24v will give 2S2P arrangement to get 24v 400Ah. This will take 13.3hrs to full charge and store 9600wh

2. 48v will give 4S arrangement to get 48v 200Ah. This will take 6.7hrs to full charge and store 9600wh

Am I right to say there is no point or benefit of buying the 24v inverter when it simply slow down charging. It also means as much as possible we should avoid connecting batteries in parallel as it will take too long to charge. It also means if am to advise a user who already has a 48v inverter and plans to upgrade the battery bank to 8 12v batteries to better plan for a 96v inverter too.

This is interesting.

I got this reply from Chris which got me a little confused and sought to get some more explanations leading to the exchanges.

You are not quite correct. I have a 24 V 6 kw inverter with a 140 Amp charger. What determines how quickly you charge is the battery bank and the size of the charger.
You can do parallel connections as long as you don't exceed (recommended that you don't exceed) 4 banks. You can avoid multiple banks by purchasing higher AH batteries. You can find 2V 4700 AH batteries in the market if you so desire

Thank you for your contribution. I now understand why Mercury 1.2kva 12v and 2.4kva 24v inverter have the same charging current of 20A but same charging time even with the 24v having twice the battery bank.

adanny01:


Initially, i thought otherwise that a 20amp charger for example will deliver the same power in any voltage system and would naturally take longer to charge when battery bank is increased. I have realised that thats not the only case since when voltage increases, power delivery increases proportionally. I arrived at a conclusion in this post below.



I got this reply from Chris which got me a little confused and sought to get some more explanations leading to the exchanges



Thank you for your contribution. I now understand why Mercury 1.2kva 12v and 2.4kva 24v inverter have the same charging current of 20A but same charging time even with the 24v having twice the battery bank.

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Good Day Guys,

I wanted installing an inverter in my apartment but something came to mind when going through some inverter catalogue. Let say, I settle for a 5KVA inverter:

1. How much power will the inverter consume for charging (Does it use the entire 5KVA to charge)?
2. What is the implication of the inverter on my meter tariff: e.g I have a load of 4.5kw and the inverter is rated 5KVA, will the 5KVA load add to my tarrif charge making it (4.5KW + 5KVA)

Good explanation shall be highly appreciated..........

ajk42:
Good Day Guys,

I wanted installing an inverter in my apartment but something came to mind when going through some inverter catalogue. Let say, I settle for a 5KVA inverter:

1. How much power will the inverter consume for charging (Does it use the entire 5KVA to charge)?
2. What is the implication of the inverter on my meter tariff: e.g I have a load of 4.5kw and the inverter is rated 5KVA, will the 5KVA load add to my tarrif charge making it (4.5KW + 5KVA)

Good explanation shall be highly appreciated..........

Very good question for those who are installers. I am interested in knowing.

I can only estimate that from the sound of my 2kw gen when different loads are plugged on to it. I have a 1.2kva inverter and i can guess it draws less than 1kw since i have a 1kw pressing iron to compare the gen's sound when plugged.

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