Newbie: 220 V charge controller, battery bank.

[mickyrox]

Hi guys!

I am supposed to design a battery bank with a charge controller of 220 V rating. All i have right now is 12 V, 120 Ah batteries.
If i use 18 batteries in series to make one string i'll have a 12 x 18 = 216 V string.
On the other hand if i use 19 batteries in series to make one string i'll ahve a 12 x 19 = 228 V string.

I'm not sure if it is ok to use a 220V charge controller to charge a 216 V battery bank. Please advice me likewise.

thanks in advance
micky

[inetdog]

Hi guys!

I am supposed to design a battery bank with a charge controller of 220 V rating. All i have right now is 12 V, 120 Ah batteries.
If i use 18 batteries in series to make one string i'll have a 12 x 18 = 216 V string.
On the other hand if i use 19 batteries in series to make one string i'll ahve a 12 x 19 = 228 V string.

I'm not sure if it is ok to use a 220V charge controller to charge a 216 V battery bank. Please advice me likewise.

thanks in advance
micky

One of the problems of trying to store energy in a high voltage battery bank is that you will have a very hard time finding inverters to run off that battery bank (at least ones which are residential size and reasonable cost.)
A 216 volt battery bank is also a very dangerous thing to work with.
You will have an equally hard time finding a high voltage charge controller.

UPS devices intended to supply AC at high wattage rates may custom build a paired CC and inverter to run off high voltage because it is potentially more efficient to use higher voltages to produce AC.

[mickyrox]

One of the problems of trying to store energy in a high voltage battery bank is that you will have a very hard time finding inverters to run off that battery bank (at least ones which are residential size and reasonable cost.)
A 216 volt battery bank is also a very dangerous thing to work with.
You will have an equally hard time finding a high voltage charge controller.

UPS devices intended to supply AC at high wattage rates may custom build a paired CC and inverter to run off high voltage because it is potentially more efficient to use higher voltages to produce AC.

Thanks a lot inetdog!

This is a 20 KW hostel system which runs for 5 hours a day. So we would be requiring a 100000 Wh supply per day. We have a 220V CC available along with a 20 KW inverter. I would like to know if it is fine to charge the 216V battery bank with a 220V CC (I've heard that some manufacturers actually recommend charging upto a voltage higher than float potential).

[inetdog]

Thanks a lot inetdog!

This is a 20 KW hostel system which runs for 5 hours a day. So we would be requiring a 100000 Wh supply per day. We have a 220V CC available along with a 20 KW inverter. I would like to know if it is fine to charge the 216V battery bank with a 220V CC (I've heard that some manufacturers actually recommend charging upto a voltage higher than float potential).

Hopefully the voltage set points for the various charging stages (Bulk, Absorb, Float and sometimes Equalize) will be adjustable enough to work with your batteries. It is not clear just what the output of a "220 volt" CC will actually be.
The voltage of a nominal 12 volt battery will also vary from as low as 10 volts to as much as 14 volts, and the CC has to be able to work with that range.

The 4 volt difference, if there actually is one, corresponds to about .2 volts per 12 volt battery or .04 volts per cell. That is not a lot, but could still cause problems over a long time.

[Sunking]

Why on earth would you use 12 volt batteries on a high voltage system. The whole point of high voltage is high power levels. For those systems you use 2 or 4 volt large AH batteries. What you are doing is a mis-application.