How To Choose The Right Battery Bank For Your Solar Setup

Posted on: 17 September 2021

Solar battery banks are essential to all setups meant to provide backup or all-day power. There are plenty of ways to assemble solar battery packs, and that can create a choice problem. If you haven't made the leap yet, here are a couple of things that may guide your decision.

Type of Batteries

You have four possible options. There is the traditional flooded lead-acid battery, AGM, gel-cell, and lithium.

Flood lead-acid batteries are similar to the ones that companies have used in cars, boats, and even small planes for years. They don't charge or discharge at 100% amperage, and they tend to be high-maintenance. Particularly, you'll need to add distilled water to keep them working. Also, you must store them in a warm place to keep them operating at peak efficiency.

AGM stands for absorbent glass material. The AGM battery is something of a successor to the lead-acid model. The main benefit is they provide full charging and discharging at max amperage. They're also maintenance-free and spill-proof. AGMs tend to be more expensive.

Gel-cell is the most physically durable model. They have similar charging and discharging inefficiencies to lead-acid. However, they are as maintenance-free as the AGMs. Also, the batteries will keep running even if they are physically damaged. Gel-cells are similarly more expensive than the lead-acid models.

Lithium is the same battery type you'll see in many mobile electronics. It tends to provide the greatest recovery of stored electricity, giving back about 8 kWh for every 10 you put in. Lithium batteries tend to be the most expensive, but they're also more compact and efficient.

Use Case

The size of your preferred solar battery banks will depend on your use case. If you're looking to go fully off-grid, you'll likely have more solar cells. That means your solar battery packs must store enough juice to get you through the days and nights during the shortest daylight periods of the year. Folks storing backup power need to have enough for their worst-case power outage scenario.

It's best to attach a wattage meter to every electrical device you intend to tie to your solar battery banks. Use the peak wattage so you can calculate the worst-case scenario. If you need 0.2 kilowatts to run your fridge and freezer, for example, multiply that by 24 hours to determine total needs. That would be 4.8 kWh of juice per day.

You'll need to factor in efficiency. To supply 4.8 kWh on an 80% efficiency system, for example, you'd need 6 kWh of total storage to provide sufficient overhead.

For more information, contact a local company, like Tier 1 Solar.