Swonder Seawolf S20Li Battery Electric SUP Pump Review | 2024

Swonder Seawolf S20Li Battery Electric Pump: Overview

The Swonder Seawolf electric SUP pump is available in two different options, a 12 Volt direct power pump and the internal lithium-ion battery powered pump. We reviewed the internal battery powered model and, to put it simply, the Seawolf is Swonderful (I couldn’t help myself). The Seawolf is easy to use, self-contained, gets the job done very quickly, and the battery has enough power to inflate many paddle boards completely.

— Swonder Seawolf S20Li Electric Pump Summary Ratings and Review —

Specifications

Features, Usability, and Portability

The Swonder Seawolf S20Li is very user friendly and doesn’t require an external power source to inflate your paddleboards quickly.

Built into the Seawolf pump is a massive 10,000mAh lithium-ion battery pack. This is 66% more energy capacity than any electric pump battery we’ve tested to date. That’s actually a larger capacity battery than what is in my e-bike! We’ll get more into the performance of this battery and pump in a bit.

The extra large battery capacity does add some weight to the package, though. At 5.2 lbs, the Seawolf is the heaviest paddle board pump we’ve tested so far. It also happens to be on the larger side of things, but it’s not so big that you wouldn’t be able to fit in many iSUP bags along with your board and paddle. Swonder cites the Seawolf Class submarine as the inspiration for both the name and shape of the pump. It certainly looks like it’s ready for action! It’s also available in three different color options. There is teal/orange we are using for this review, black/red, and green/yellow. Personally I think the teal and orange combo looks fantastic and the lighter colors will help keep the pump cooler when using it in the sun.

There is no storage bag included with the Seawolf, and no other way to keep the hose and pump attached together when not in use. It would be nice to see either some kind of clamp system to hold the hose or a storage bag to help keep it all together. The Seawolf does come with a standard set of hose adapters in addition to the standard Halkey-Roberts valve adapter for your paddle board. The adapters come on a plastic ring attached to the end of the hose. I’m not a huge fan of this as they tend to get in the way, so I cut the plastic string and tied a knot in the end to keep them all together (but off the hose).

The Seawolf has both inflation and deflation ports on the front of the pump. To use the deflate feature after releasing the pressure from your iSUP, simply move the hose to the deflate port and then activate the pump with the power button on the top of the pump. The Seawolf will stay in the high-volume Stage 1 mode to quickly remove the air from your board.

On the top of the pump there’s a 2.5” easy-to read screen that tells you all of the information you need to know at the same time. On the screen you’ll see the battery voltage and 5-bar battery meter, target PSI, real-time PSI, and indicators to let you know when the internal fan is running, and what stage the pump is in.

There are four buttons on top of the pump to let you adjust the units (PSI or BAR), increase and decrease the pressure setting, and to activate/deactivate the pump. The Seawolf will automatically change between the 350L/minute high-volume Stage 1 and the 100L/minute high pressure Stage 2 modes as needed.

The power button on the top of the pump only activates the pump to begin working. On the bottom of the Seawolf is a power switch which turns the entire unit on and off.

To charge the pump, simply plug the included USB-C cable into the side of the pump. There are four LED lights that will flash and then turn solid in sequence to let you know the charging status of the pump. It does take several hours to completely charge the Seawolf from empty, so if you are using it a lot it’s best to let it charge overnight.

Inflation Speed and Sound

With the high capacity battery and dual-piston design, the Swonder Seawolf is incredibly fast at inflating iSUPs. In our inflation speed test we use the same 11’ x 32” x 6” thick iSUP for every pump and time how long it takes the pump to inflate the board to 15 PSI. The Seawolf crushed the inflation speed test. The first inflation took only 8 minutes 23 seconds! Typically battery-powered pumps take longer than those powered directly by a 12v energy source. Our previous top-speed pump (running on 12v power) took 10 minutes 10 seconds to inflate the same board.

But as batteries are depleted they have less voltage and tend to run pumps at a slower rate. We did see that happen with the Seawolf, but it continued to work faster than our previous record holder for 6 inflations in a row! The total average time for the Seawolf to inflate our test board was 9 minutes, 21 seconds – and that was for 7 complete inflations.

Like most electric pumps, the Swonder Seawolf is pretty loud with sounds measuring in the mid 80-decibel level from roughly 5 feet above the pump (head-height). Our testing has shown us there is little variability in the actual volume of electric SUP pumps across the board, but all have been below the 90dB threshold for hearing damage. Still if you will be in close proximity to any electric pump while it’s operating, and especially if you use it indoors for any reason, it’s best to use hearing protection, or to walk away from the pump.

Battery

The lithium-ion battery built into the Swonder Seawolf pump is massive. 10,000mAh is 66% larger than the biggest external or internal batteries for SUP pumps we’ve tested. It’s even larger than many e-bike batteries (and uses the same style of 21700 battery cells). It does add some weight and size to the pump, but in my opinion – it’s totally worth it.

Swonder claims that the Seawolf S20Li has enough capacity to inflate 8 paddle boards. We were able to fully inflate 7 boards to 15 PSI and get an 8th board to the halfway mark before the pump stopped and gave a low-voltage warning. I really like that the pump gives you the low-voltage warning rather than running the battery all the way to zero (which can harm the overall lifespan of the battery).

Even though we didn’t quite hit the benchmark that Swonder set, inflating 7 boards is quite impressive, especially when 5 of those 7 took under 10 minutes.

Warranty and Customer Support

Swonder warranties the Seawolf S20Li for one year from the date of purchase. So far we’ve yet to see any electric pump manufacturer offer a warranty longer than 1 year. They do, however, have a 45 day return policy which is longer than the standard 30 day policies on most electric SUP pumps and other accessories. If you have any questions or concerns you can reach out to the team at Swonder via email, web form, or through social media.

Overall Impressions/Review Summary

The Seawolf S20Li electric SUP pump is fantastic. It’s got a high capacity battery that powers an extremely quick pump. It’s easy to use and looks great. It would be nice to see a storage bag for the pump, hose, and adapters for easier transportation and an option to power the pump directly. When you consider its price, capacity, and speed I think I’ve found a new go-to electric pump recommendation.

Swonder Seawolf S20Li Electric SUP Pump FAQ