Goal Zero Venture 35 review: a waterproof power bank that refills from a small solar panel when the grid is down

This is a research-based review, based on manufacturer specs and published data. We do not test products. Specs and FAQ answers come from Goal Zero's Venture 35 product page, checked November 1, 2026. Planning guidance comes from Ready.gov.

Ready.gov's outage advice includes planning batteries and alternative power sources, such as a portable charger or power bank. Most power banks are made for desks and backpacks. Outages, especially hurricane and flood outages, happen in rain, in cars and in shelters, where water and grit are part of the deal. The Venture 35 is built for that: Goal Zero rates it IP67, dust tight and able to survive submersion to 1 meter for at least 30 minutes with the port door shut.

The capacity is modest. At 35.52 Wh, Goal Zero rates about three smartphone recharges. What makes it useful in a long outage is that it can be refilled from a small solar panel in a day, so it keeps cycling as long as the sun comes out.

Who should buy it

• People in hurricane, flood and wildfire areas who may be charging devices outdoors, in a car or in a shelter.
• Anyone building a go-bag who wants phone power that survives a soaking.
• Households that own, or plan to buy, a small foldable solar panel.
• Owners of USB-C lights and radios such as the Midland ER310PRO.

Who should skip it

• Households that want one bank for everyone. The Anker 737 holds 24,000 mAh and outputs up to 140 W.
• Laptop users. 18 W USB-C is too slow for most laptops.
• Anyone who will not recharge it between outages. Goal Zero's own shelf-life guidance is to charge it every 3 to 6 months.
• People who need AC power. That is a job for a power station such as the EcoFlow RIVER 3 Plus.

Strengths

• IP67. Protected against dust, sand and debris and rated for submersion to 1 m for at least 30 minutes, per Goal Zero.
• Solar-ready. Goal Zero lists charge times from its own panels: 6 to 12 hours with a Nomad 10, 4 to 8 hours with a Nomad 20.
• Two-way USB-C. One port charges the bank and charges your devices, up to 18 W.
• Clear expectations. Goal Zero publishes device estimates: about 3 smartphone recharges, 7 headlamp recharges, 1 tablet recharge.
• Built-in flashlight. A 50-lumen LED, enough for a hallway or tent.
• Light. 10.12 oz.

Drawbacks

• Small for a household. 35.52 Wh is a one-person, few-day bank.
• Needs regular top-ups in storage. Goal Zero says to charge it every 3 to 6 months.
• Narrow operating range. Goal Zero lists 32 to 113°F. A winter outage in an unheated house or car is outside that range.
• Solar panel sold separately. The Nomad charge times assume you own one.
• 18 W limit. Fine for phones, slow for tablets and too slow for most laptops.

How it compares

The Venture 35 against a larger power bank, a small power station and a lantern that doubles as a USB hub. Figures are from each manufacturer's page, checked November 1, 2026.

Using it in a long outage

Budget the 35 Wh

Goal Zero rates about three smartphone recharges per full charge. In a multi-day outage, that is one phone for three days if you top up once a day, or two phones for a day and a half. Put phones in low-power mode, and charge headlamps and radios from it rather than from the phone. Goal Zero rates about seven headlamp recharges, a far better use of the energy than a tablet.

Solar routine

1. 01Charge it fully over USB-C before the storm. Goal Zero lists about 3 hours with an 18 W source.
2. 02During the outage, set a USB solar panel in full sun and plug the bank into it in the morning.
3. 03Charge devices from the bank in the evening, not straight from the panel, so passing clouds do not interrupt them.
4. 04Keep the port door closed whenever it is outdoors or in a wet go-bag. The IP67 rating depends on it.

Goal Zero's figure for its Nomad 10 panel is 6 to 12 hours to refill, so one sunny day roughly refills it. In winter or under cloud, expect the long end or worse.

Storage and temperature

Goal Zero lists a 32 to 113°F operating range and a shelf-life note to charge it every 3 to 6 months. Keep it inside the heated part of the house in winter, not in a car or garage, and add a reminder to charge it when you change smoke alarm batteries or check your blackout checklist. For a USB-powered battery charger that runs off a bank like this, see the Panasonic BQ-CC87.