sizing batteries correctly with inverter

[jomolu]

hello,pls kindly help me with this connections.
12v200ah batteries 4pcs connected in series to get 48v and then connected with 3.5kva 48v inverter
i intend connecting another same configurations of 4pcs batteries of 12v 200ah in series again to the inverter terminal in other to increase the batteries time usage.
is this connection correct
thanks

[inetdog]

hello,pls kindly help me with this connections.
12v200ah batteries 4pcs connected in series to get 48v and then connected with 3.5kva 48v inverter
i intend connecting another same configurations of 4pcs batteries of 12v 200ah in series again to the inverter terminal in other to increase the batteries time usage.
is this connection correct
thanks

In principle, yes. But be sure to look at the information at http://smartgauge.co.uk/batt_con.html. It sounds like you are intending to use the inverter terminals themselves as your "bus bar" where the leads all come together. This is probably not a good idea.
The DC drain at max output from the inverter will be about 80A total. So taking the tolerable drain for FLA batteries as roughly C/4 (50A with one 200AH string and 100A with two 200AH strings in parallel) your idea of doubling the battery bank capacity is a good one.
If you were designing from scratch, you would probably want to stack eight 6V batteries in series instead of paralleling two strings.

[jomolu]

In principle, yes. But be sure to look at the information at http://smartgauge.co.uk/batt_con.html. It sounds like you are intending to use the inverter terminals themselves as your "bus bar" where the leads all come together. This is probably not a good idea.
The DC drain at max output from the inverter will be about 80A total. So taking the tolerable drain for FLA batteries as roughly C/4 (50A with one 200AH string and 100A with two 200AH strings in parallel) your idea of doubling the battery bank capacity is a good one.
If you were designing from scratch, you would probably want to stack eight 6V batteries in series instead of paralleling two strings.

hello inetdog,thank you for your comment and the link you gave.
however,no references were made to series connection in the link,does it mean that the normal series connection where the top battery connect to the load is okay or we should adopt the 4th and 3rd method in the link to connect to the load?
thanks

[inetdog]

hello inetdog,thank you for your comment and the link you gave.
however,no references were made to series connection in the link,does it mean that the normal series connection where the top battery connect to the load is okay or we should adopt the 4th and 3rd method in the link to connect to the load?
thanks

If you have only one series string of batteries, the connection is just the same as if you had only one battery.
If you have two or more series strings, the connection will be just the same as it would be if each string were only one battery.
For lead-acid batteries there should not be any load, CC or cross connections at any battery terminals in the middle of a string.

[Bala]

this is just a picture I found, not saying it is correct, but i think this is what you are thinking of.

Untitled.jpg

[jomolu]

pls,if i have two or more string of batteries in series,i think they have to be parallel before connecting them to the inverter?in order to maintain the 48v achieved in the strings.

[Living Large]

pls,if i have two or more string of batteries in series,i think they have to be parallel before connecting them to the inverter?in order to maintain the 48v achieved in the strings.

That link only shows how to connect batteries within each of your two banks, not how to connect the two banks together - which I think is your main question. One way would be to connect the positive lead from each bank to one bus bar, and the negative lead from each bank to the another bus bar. Then one lead from each bus bar to the inverter.

[inetdog]

pls,if i have two or more string of batteries in series,i think they have to be parallel before connecting them to the inverter?in order to maintain the 48v achieved in the strings.

Yes, exactly correct. See the post above for more detail.

[jomolu]

That link only shows how to connect batteries within each of your two banks, not how to connect the two banks together - which I think is your main question. One way would be to connect the positive lead from each bank to one bus bar, and the negative lead from each bank to the another bus bar. Then one lead from each bus bar to the inverter.

hello living large,
thank you for ur observation,that is exactly what i mean.that the two string are now parallel together.
whats is bus bar? and is it possible for me to connect the inverter terminal directly to one of the string battery at the top?
thanks

[Living Large]

hello living large,
thank you for ur observation,that is exactly what i mean.that the two string are now parallel together.
whats is bus bar? and is it possible for me to connect the inverter terminal directly to one of the string battery at the top?
thanks

A bus bar is simply a solid piece of metal, used to connect multiple wires together. Here is a link to a page with 4 battery strings paralleled. Scroll down and on the left side you will see batteries and in the background a positive (red cable) bus bar and a negative (black cable) bus bar. Note that the cable going out is much larger than the cables going to each battery bank, since it carries 4 times the current of one bank. Each of the four smaller cables on the bus bar with the large black cable goes to the negative terminal of a battery bank, and likewise each of the four smaller cables on the bus bar with the large red cable goes to the positive terminal of a battery bank.

http://www.oynot.com/customer-installed-systems/2700-watt-xw6048-offgrid-dunlap-ca.html

This may go without saying, but to parallel your two banks, you would connect the positive terminals of the two banks to each other, and the negative terminals to verbosity edit each other. Then connect the junction of each to the inverter.

[jomolu]

A bus bar is simply a solid piece of metal, used to connect multiple wires together. Here is a link to a page with 4 battery strings paralleled. Scroll down and on the left side you will see batteries and in the background a positive (red cable) bus bar and a negative (black cable) bus bar. Note that the cable going out is much larger than the cables going to each battery bank, since it carries 4 times the current of one bank. Each of the four smaller cables on the bus bar with the large black cable goes to the negative terminal of a battery bank, and likewise each of the four smaller cables on the bus bar with the large red cable goes to the positive terminal of a battery bank.

http://www.oynot.com/customer-installed-systems/2700-watt-xw6048-offgrid-dunlap-ca.html

This may go without saying, but to parallel your two banks, you would connect the positive terminals of the two banks to each other, and the negative terminals to h

thank you