24v batteries is series 4vs 48v

[Carlos1975]

Good morning everyone
I trying to increase back up time by adding more batteries to my existing 24v system what is the difference between running 4 200ah batteries in series and a straight 48v bank... my head says that it could be same

Thanks

 

[Sinbad]

You won't increase capacity of a 24V system by going up to 48v, you'll let out the magic smoke.

You need up go with more 24v batteries in parallel

 

[Willie Trombone]

Good morning everyone
I trying to increase back up time by adding more batteries to my existing 24v system what is the difference between running 4 200ah batteries in series and a straight 48v bank... my head says that it could be same

Thanks

Why do you think 48v is the same as 24v?
If the equipment it's connected to needs 24v, then you run 2 sets of (2 in series) in parallel.

 

[Carlos1975]

Thanks for the quick response
So you mean 2 banks of 24v in series and then parallel connect please send drawing ic you can

You won't increase capacity of a 24V system by going up to 48v, you'll let out the magic smoke.

You need up go with more 24v batteries in parallel

 

[Sinbad]

Get someone qualified to help you.

 

[Carlos1975]

Hi I was referring to the backup time and run time of my batteries would it be the same

Why do you think 48v is the same as 24v?
If the equipment it's connected to needs 24v, then you run 2 sets of (2 in series) in parallel.

 

[Willie Trombone]

Thanks for the quick response
So you mean 2 banks of 24v in series and then parallel connect please send drawing ic you can

+ To - is series, + to + and - to - is parallel.

 

[Carlos1975]

Get someone qualified to help you.

This s what you mean

 

[Willie Trombone]

Hi I was referring to the backup time and run time of my batteries would it be the same

It would not be the same if you up the voltage to 48. It would increase if you kept 24v and ran them in parallel (two 24 v strings)

 

[Willie Trombone]

This s what you mean View attachment 808041

That's fine yes.

 

[Sinbad]

That is bad as the batteries will be unevenly used and charged.
Hence get someone qualified.

 

[Willie Trombone]

That is bad as the batteries will be unevenly used and charged.
Hence get someone qualified.

How so? Are you referring to a missing charge equaliser? That's exactly right if you ask me.

 

[Carlos1975]

Thanks alot for the answers so in all fairness
If I draw the same load from a 48v system or 2 X 24 strings there would be almost no difference in the backup time for these

That is bad as the batteries will be unevenly used and charged.
Hence get someone qualified.

 

[Sinbad]

How so? Are you referring to a missing charge equaliser? That's exactly right if you ask me.

No, the bottom bank of batteries has a longer path to the charger/inverter, therefore higher resistance, therefore considerably less current will go to /from it. The top bank will die a lot quicker.

 

[Willie Trombone]

Thanks alot for the answers so in all fairness
If I draw the same load from a 48v system or 2 X 24 strings there would be almost no difference in the backup time for these

The backup time relates to the battery capacity in mAh.

 

[Willie Trombone]

No, the bottom bank of batteries has a longer path to the charger/inverter, therefore higher resistance, therefore considerably less current will go to /from it. The top bank will die a lot quicker.

How far apart do you think these batteries are going to be? I seriously doubt the resistance difference will be anything but negligible unless they're on opposite sides of the house.

 

[Sinbad]

How far apart do you think these batteries are going to be? I seriously doubt the resistance difference will be anything but negligible unless they're on opposite sides of the house.

It's not negligible. Remember you're talking about high currents here.
Looking for the doc, hang on.

 

[Carlos1975]

So I asking picture 1 or 2

Thanks alot for the answers so in all fairness
If I draw the same load from a 48v system or 2 X 24 strings there would be almost no difference in the backup time for these

 

[Carlos1975]

Well the batteries are together

How far apart do you think these batteries are going to be? I seriously doubt the resistance difference will be anything but negligible unless they're on opposite sides of the house.

 

[Sinbad]

So I asking picture 1 or 2 View attachment 808045 View attachment 808047

Neither of the above, although 2 is not going to destroy your inverter like 1 is.

Docs:

https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

Read it. Pay specific attention to chapter 3, but the first chapter explains the concepts you need to understand.