Hey everyone! I'm looking for advice on how much extra battery capacity I should have for my off-grid setup. Here's the situation: I have an 8 kW solar array paired with an EG4 indoor battery that holds 14.3 kWh. My off-grid inverter is also EG4 and has a 3K capacity. On a typical day, I draw about 10 kWh from the battery, which usually gets recharged in about 3-4 hours since I live in the Caribbean. However, the infrastructure here is a bit unreliable, and I'm concerned about what would happen if I couldn't use AC or if the solar panels don't generate enough power. I'm thinking about getting another 14.3 kWh battery to double my capacity, which could last me around three days if needed. I'm open to other suggestions too! Thanks for your input!
2 Answers
I’d definitely recommend getting another 14.3 kWh battery or a similar DIY battery. I have a very similar system with one 14.3 kWh battery and an EG4 6000XP inverter, and I find I can't go two days without sun, especially with only 4 kW of panels. It's all about your daily usage and how many cloudy days you can handle. A generator could be a good backup to charge your batteries if you do hit a stretch without sun!
The amount of backup battery capacity really depends on how long you expect to go without power. If your setup can get you through a night and recharge fully each day, you might be fine. However, keep in mind that bad weather can reduce solar generation, so if outages could be related to storms, you might want to plan for longer periods without sun. For serious outages, investing in a generator might be more cost-effective. Propane can store for long periods without degrading, which could be beneficial for you. Just remember that if you add batteries, especially lithium, you'll need to use them regularly to maintain their health.