|Dear Paul Gilman,
Thank you for offering to test the Beta version of SAM’s new battery model for grid-connected photovoltaic systems.
Please download and install the Beta version for testing:
As with the current version of SAM, when you first start the software, it will prompt you for an email address and SAM registration key. Please use the key you used to register the current version of SAM to activate the Beta version. (If you do not have or remember your SAM registration key, start the Beta version of SAM, and when you see the Registration window, enter your email address without typing a key, and click Register to have your key sent to you.) The Beta version will not interfere with any other versions of SAM installed on your computer, as long as you install each version in a different folder. When you are finished testing, you should remove the Beta version from your computer.
To provide feedback on the battery model, please post your comments and questions to the SAM support forum, or, if you prefer, email us.
We also invite you to register for a free webinar for Beta testers introducing the new battery model on Thursday June 4 at 1 PM MDT. The model developers will introduce the model, and give you an opportunity to provide feedback and ask questions.
To test the battery model, start the Beta version of SAM, and create a case using the detailed Photovoltaic performance model and either the Residential or Commercial financial model. On the Battery Storage input page, choose Enable Battery from the list at the top of the page. To set up the battery, choose a battery configuration, specify the desired bank size and voltage, choose the battery chemistry, and specify a cell capacity. When you choose a battery chemistry, SAM populates input variables as appropriate for the chemistry you choose. If you are experienced with battery characterization and familiar with these properties, you can change the values from the default, otherwise, use the default values.
You will also need to tell SAM how to operate the battery using the Manual Storage Dispatch Controller inputs. If you are tailoring battery dispatch to take advantage of a time-of-use electricity rate structure, you may want to modify the dispatch inputs to match the rate structure on the Electricity Rates page.
If you want to estimate battery replacement costs, on the Battery Storage page, use the Battery Lifetime and Battery Bank Replacement inputs to specify battery replacement timing and costs. Then, on the Lifetime input page, choose PV simulation over entire analysis period. Note that the analysis period is on the Financial Parameters page, and the battery installation cost is on the System Costs page.
This is a Beta version, and has not been fully tested or validated, so please do not use results from this version for any of your work. The final version that we release with the next version of SAM will include changes to both the internal code and user interface to fix problems we discover during this testing period.
This Beta version includes:
- A new battery model for lead-acid and lithium-ion batteries in grid-connected photovoltaic systems with storage. The model accounts for storage capacity, terminal voltage, temperature, and capacity fade.
- A detailed manual dispatch controller allows custom tailoring of how battery energy is discharged to meet a building or facility's electric load. We hope to add automated and optimized dispatch controller strategies in future versions of the model.
- A new lifetime analysis mode makes it possible to run year-by-year simulations over the analysis period at hourly or sub-hourly (down to one minute) time-steps. This mode is particularly important when analyzing battery systems to properly account for the effect of cycling on battery life and battery replacement costs.
The SAM Team