Keeping warm while diving in the winter months could now be a lot easier, thanks to some innovative heated undergarments built in the EU by Santi Diving. It sent me its electrically heated glove system to try out.

Power Source
A lithium-ion (li-ion) rechargeable battery powers the system. It's housed in a tough sealed case made from polyacetal and Delrin with a hexagonal profile.
The battery-pack measures 115mm x 74mm and incorporates a single-press piezoelectric on-off switch, a 55cm cable with a built-in blue LED “on” indicator and rubberised two-pin connector.
A single slot has been cut into the case for mounting the battery-pack onto 5cm webbing, such as the waist-belt on a BC.
The battery delivers 12.6V dc at 1.8A with a power output of 30W and is mains-rechargeable. It’s depth-rated to 100m, weighs in at just over 300g, and is also rated as “flight safe”.

The Thermovalve
To get the wiring inside your drysuit, Santi has built a connector incorporated into a drysuit inflation-valve. It calls this a “Thermovalve”, and it replaces your existing valve.
The Thermovalve is precision-built using Delrin and can be supplied with either CENJ or Seatec (international) couplings. It has a 45° swivel for the low-pressure hose-mount, with the inflation-valve set centrally.
A 15cm cable with a rubberised two-pin connector plugs into the battery-cable externally with a rubber-to-rubber push-seal; blank caps are provided if you decide to dive without the system connected.

An internal cable with a locking connection joins long twin wires, which thread down the inside of the drysuit arms and through the wrist-seals to connect the gloves. A twin internal connector is available to power both gloves and Santi’s heated under-suit or vest.

The Heated Gloves
The gloves are made from a breathable fabric with a Thinsulate lining. Silicon-coated heating wires are evenly distributed on the fingers and the outer side of the palm, leaving the inner palms free of wiring to aid unrestricted movement. Waterproof rubberised two-pin sockets connect the gloves to the power system.
The gloves are hand- or machine-washable on a cold cycle and can be tumble-dried at low temperatures. Importantly, in use the heated gloves need to be kept dry, which calls for a dry-glove system to be used.
Santi makes these with either latex wrist or ring-fitted seals, although any dry-glove system can be used.

In the Water
I took the heating system to Wraysbury to get under water with nice warm hands. Unfortunately the water temperature was around 16°C, and while I would normally be very pleased with this, on that particular day I wanted it to be colder to give me a good idea of how these gloves can perform.
Unseasonal weather meant that my hands were more than warm enough without switching on the power, but I carried on with the tests. I mounted the battery-pack on my BC waistband with the internal wires connected and threaded through the arms of my drysuit, and put on the heated gloves.
Santi had sent me a pair of latex dry gloves with conical wrist-seals, and these added bulk to my hands, making intricate operations a little more difficult, though they were no more cumbersome than any other dry-glove system I’ve used in the past.
Under water they compressed with depth, giving me back some dexterity. After switching on the power it took around 30 seconds for the gloves to reach full temperature.
Santi tells me that the gloves can peak at 40°C, and in the temperate waters of the inland site they certainly felt very warm, bringing new meaning to the word “toasty”.
The power was easy to turn on and off with a simple press of the piezoelectric disc placed on top of the battery-pack, even with the dry gloves fitted.
I can’t comment on the burntimes, as I wasn’t able to conduct a definitive test, but the maker claims that the gloves will heat for 160-180 minutes used on their own and 35-45 minutes when used in tandem with their heated vest. The battery is said to take 4-5 hours to fully charge.

Conclusion
Santi is associated with high-end dive-gear, and its heated glove system echoes this. The build quality and attention to detail was excellent.
I’ve seen electrically heated vests and undersuits before, some with the power-packs on the inside of the drysuit, leaving me terrified that a leak could cause chemical burns to the wearer. The Santi system’s external battery left me feeling safe in this respect.
Heated gloves are new to me. I’m not sure if they’re unique but they worked flawlessly. I have problems with cold hands under water, and in the past have sat out dives simply because my digits were feeling as if they were broken.
With this heating system I’m ready to visit the Silfra rift in Iceland or photograph leopard seals in the Antarctic, safe in the knowledge that my handie-pandies will be warm and dry. Now all I need is a pair of heated socks. I wonder if Santi’s designers have any on their drawing boards?

PRICE Gloves Combo+ (gloves, Thermovalve, battery, charger and leads) £545
POWER 12V, 6Ah rechargeable li-ion battery
DEPTH RATING 100m
BURNTIMES 160-180min gloves only
CHARGING TIME 5hr max, mains 110-240V supply
SIZES XS, S, M, L, XL, XXL
CE CERTIFICATED Yes
CONTACT www.santidiving.com
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