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SAM PV Battery System
28 Jun 2021 14:27 - 30 Jun 2021 15:19 #9751
by craigrichards
SAM PV Battery System was created by craigrichards
Hi,
I am trying to model a residential hybrid PV system in SAM and am just struggling to get the battery part of the simulation to give the results I expect. I am modeling a 15kW system with a 14.8 kWh 48V LiPO4 battery. When I input 14.8 kWh as my battery size, it seems to me that the battery is actually way below this capacity and charges/discharges far quicker than it should and as a result the battery hardly gets used at night. I was just messing around and instead used a battery capacity of 1474 kWh and that gives me results more in line with what I expect. I have attached my project file to reference, any help would be appreciated.
I am trying to model a residential hybrid PV system in SAM and am just struggling to get the battery part of the simulation to give the results I expect. I am modeling a 15kW system with a 14.8 kWh 48V LiPO4 battery. When I input 14.8 kWh as my battery size, it seems to me that the battery is actually way below this capacity and charges/discharges far quicker than it should and as a result the battery hardly gets used at night. I was just messing around and instead used a battery capacity of 1474 kWh and that gives me results more in line with what I expect. I have attached my project file to reference, any help would be appreciated.
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30 Jun 2021 18:35 - 02 Jul 2021 15:57 #9760
by craigrichards
Replied by craigrichards on topic SAM PV Battery System
Hi Paul,
Thanks for getting back to me. I picked up the inverter mismatch after I posted and changed the panel layout and inverter so that I had no losses coming from inverter clipping. The problem remained and the think I found the problem in the "Battery Cell and System" settings. In the original I had set the nominal cell voltage to 51.2 V, when I changed this to 3.4V, which was more in line with the electro-mechanical properties in the "Battery Voltage" section, I got results more in line with what I expected. Below are two plots made using the original model I uploaded (so inverter is still clipping and I am wasting a lot of power), the first plot with the initial battery settings and the second one with the new battery settings. As you can see, the battery is working in the second plot more or less how you would expect it to - I am not sure if what I have done is correct but it seems to be working.
Thanks for getting back to me. I picked up the inverter mismatch after I posted and changed the panel layout and inverter so that I had no losses coming from inverter clipping. The problem remained and the think I found the problem in the "Battery Cell and System" settings. In the original I had set the nominal cell voltage to 51.2 V, when I changed this to 3.4V, which was more in line with the electro-mechanical properties in the "Battery Voltage" section, I got results more in line with what I expected. Below are two plots made using the original model I uploaded (so inverter is still clipping and I am wasting a lot of power), the first plot with the initial battery settings and the second one with the new battery settings. As you can see, the battery is working in the second plot more or less how you would expect it to - I am not sure if what I have done is correct but it seems to be working.
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