The last big storm that came through knocked power out on the North Shore for half a day. Not fun, but if we get hit by something the magnitude of Irma, Harvey or Iniki, the consequences would be grave. If you don’t want to drop the money for a decent gas-powered generator (at least $1,000) and store a bunch of fuel, there are a few fixes that will at least keep small devices like your smartphone, flashlight and radio powered up.

The least expensive way to go is to stock up on batteries. The industry standard for modern flashlights, radios, lanterns, etc., is the 18650 lithium-ion battery. Get yourself a battery charger to keep them topped off.

If you want to charge devices such as tablets, cellphones, etc., you’ll need to get a power bank, which is essentially a battery with ports that allows you to charge any USB-based device.

You can buy them individually or with portable solar panels that allow you to charge them when the grid is down. One such product is the Sunjack 14W Portable Solar Charger + Powerbank.

The solar charger has four panels, and when folded it’s about the size of an Apple iPad. It provides up to 14 watts of 5-volt USB power under a bright sun ideally producing 2,000 milliamp hours every hour. That means you can recharge the power bank that comes with it in about four hours (under a bright Hawaii sun).

According to the experts at Illuminationgear.com, 1.5 to 2 amp hours is the minimum acceptable usable panel output. Otherwise, charging your power bank, or anything else, will take a full day. The larger solar charging unit you can afford, the better. The Sunjack 14W system, which retails for $149 (with the power bank) is a good place to start. You could also consider their 20W kit with two lithium battery packs, for $169.

The Sunjack’s 10,000 mAh Advanced Powerbank ($29 without the solar kit) has three ports: the standard USB, the micro-USB and the new USB-C. What I really like is that it comes with Qualcomm’s “Quick Charge 3.0” technology. This means if you have a phone or other device that is “quick charge” compatible (such as my Samsung 7), this little unit will charge your device up to 80 percent faster. It really does work — my cellphone was charged in about 20 minutes. In an emergency situation, this could be crucial.

We also reviewed the Goal Zero Venture 30 solar recharging kit ($169.95) that combines their Nomad 7-watt solar panel with a 30-watt-hour, 7,800 mAh power bank. Together they weigh a little more than 1-1/2 pounds.

The battery component has features you don’t usually get in a power bank. Its “ruggedized” design is weatherproof (light rain but not submersion) and shockproof (moderate impact resistance) and can remember charging profiles of the devices you connect.

One outstanding feature is that it can be placed into a mode designed to avoid self-discharge during periods of storage. You never know when the next disaster will occur, so this could come in very handy. According to the manufacturer, the battery is designed to last for a hundred life-charging cycles, which should keep you in back-up power for a long time.

The Nomad panel we reviewed has a 7-watt capacity, which means it takes 16 hours to charge the battery. It’s designed for travel or backpacking. For home use, I think you’re better off with Goal Zero’s 13- or 20-watt solar panel, which will cut recharge time to as little as six hours. (A standard 2A USB plug-in source can charge the battery in as little as five hours).

Both the Sunjack and Goal Zero kits are high quality and handy to have if the grid goes down. I suggest a dry run with the devices you plan to use before the emergency occurs, so you understand the limits and capabilities of your recharger kits.

Mike Meyer is chief information officer for Honolulu Community College. Reach him at mmeyer@hawaii.edu.