Just to put this in perspective, for $169 you can get a 1200Wh deep cycle battery on amazon: https://www.amazon.com/Universal-UB121000-45978-100AH-Cycle-Battery

Just to put this in perspective, for $169 you can get a 1200Wh deep cycle battery on amazon: https://www.amazon.com/Universal-UB121000-45978-100AH-Cycle-Battery/dp/B00S1RT58C/ref=sr_1_3?ie=UTF8&qid=1544043381&sr=8-3&keywords=Deep+cycle+100ah https://www.amazon.com/Universal-UB121000-45978-100AH-Cycle-... however, you will only get 300 cycles before the battery performance degrades to unacceptable levels. If you wanted to use this deep cycle battery for 5 years (300X5, 1500 cycles), you would only be able to discharge 20%, meaning you would need 5 of them. So given that you can buy a $169/1200Wh battery right now, and get 300 cycles Or you can consider it a $845 (5 X $169) / 1200Wh given the above explanation regarding cycles. So for $900 you can get a 100 AH 12v lithium battery, which gives you near 1200Wh, $900/1200Wh to give further understanding about the title of the article. The lithium battery should give you the same amount of cycles as the 5 deep cycles. However they are relatively new in this size and unverified, they will probably perform at this level.