You may have seen these bayonet/car tyre adapters on eBay in recent months (left). The bayonet end clamps into your IK’s raft valve (won’t work on Boston valves). The other end is a regular Schrader valve like on your car/bike wheel. Attach that to your 12-volt Halfords tyre compressor and you can inflate your IK from your car battery. No more of that effortful, back-breaking pumping!
Me, I’ve never seen the value of electric pumps for IKs. You can only use them near a power source and how hard is inflating an IK with a good barrel pump anyway? It seems some think it is
The difference between tyres and IKs:
• a car tyre is a low volume running high pressure (~30 litres @ ~30psi)
• an IK has high volume but runs low pressure (3 chambers of 50–160 litres @ ~3psi). Drop-stitch has less volume but runs much more.
That’s up to five times more volume in an IK but at a tenth of the pressure. I would guess the swept volume of my better-than-average car pump (left) is 3–5cc. My Bravo RED 4 barrel pump is 2 x 2000cc (it pumps on the up and the down stroke).
Even if my 12-volt compressor whizzes along at 1001rpm, it will still take a long, long time to fill a 160-litre IK floor. But for a fiver, I thought I’d prove myself right.
The easiest way was to pump my Seawave’s floor to the point the PRV purged at about 3psi. The actual psi is immaterial but it’s consistant.
No surprise: it took less than a minute to pump up the 160-litre floor with the barrel. With my car tyre pump it took over 7 minutes.
And if you want say 4psi in the sides, or a 10psi drop-stitch boat, the duration of the tyre pump (or effort with the barrel pump) rises exponentially. It will take forever with the car pump adapter and I think the tyre pump would auto shut-off or burn-out before it reached anywhere near 10psi.
I read about portable USB rechargable electric pumps like the Pumteck or Sunta (left) on amazon from just £15. These are great for pool toys, air beds and other low-pressure items which just need a shape, not rigidity.
The Pumteck claims an obscure pressure rating of 4.5 kPa which sounds impressive but translates to just 0.65 psi or 0.045 bar. That is slackraft presure; there is no worthwhile IK that runs such a low psi, so all it will do is save you the easy initial pumping. For a typical 3-psi IK you’ll still need some sort of manual pump to top off and on a D-S IK, forget it. If your back can’t handle a barrel pump, get a Bravo foot pump.