Drysuit heating controller options

[Wibble]

What heating controller options are available? Most of the controllers seem to be of the Pitkin variety which work by turning the current on and off to reduce the overall power to the heater element, e.g. 50% would be on for a while, then off for the same duration.

Does anyone know of any DC to DC converters? One of the main challenges with batteries is providing the exact 12 Volts required for the heated suit. As all batteries reduce their voltage as they are consumed, the heating available on the undersuit/gloves/socks is reduced. Also, lithium ion batteries don't add up to exactly 12V, so they tend to output less than 12V, especially if they're directly connected to the E/O cable.

I thought I saw an inline voltage controller (think it was German) which had an internal DC to DC converter that could handle any input voltage up to 15V and down to 10V, outputting 12V exactly. Double points for anyone who can find this controller!


(The reason I'm posting this is I've a couple of 18Ah heater batteries which have unregulated voltage output and would very much like a device to lift the voltage to keep me warm, not let me get cold as the battery discharges)

 

[Wibble]

Light Monkey Stand-Alone Heat Controller v2.0

The Heat Controller v2.0 was designed to go inline between a battery canister and heated drysuit systems. By toggling the switch, you reduce the power that is going to the heated undergarments and extend your burn time. Power levels available are 100%, 80%, 60%, and 30%. To reset back to 100%, simply switch the canister off for 10 seconds.

LED indicator light flashes for every drop down in power:
100% - Indicator remains on
80% - 3 flashes
60% - 2 flashes
30% - 1 flash

No mention of voltage control on this controller. Assume this is Pitkin only.

 

[Wibble]

Underwater Light Dude heat controller

One of the biggest issues with current heated systems is the diminishing heat output as battery life dwindles. The UW Light Dude heat controller’s innovative design offers functionality for a wide range of diving that requires heated undergarments and addresses the need for warmth when you need it most – longer duration dives.

There are 5 power settings and each setting gives the same heat output regardless of the battery voltage. Research has shown that cooling on the ascent/decompression portion of the dive has a negative affect on decompression.

Seems that this does the voltage correction, but is only available with an UWLD "Stack Cap" for fitting to one of their batteries. Obviously this won't work on other manufacturers batteries, so instantly adds $$$$ to the price.

 

[Wibble]

Smart-Tex wireless dive heating controller

Seems to be a lot of constraints, not least 8A max (~= 90W)

 

[ahereng]

These are "inbetween" SCALEO heat Heizungssteuerung | SCALEO
But to keep a constant 12,6v you have to use a batterypack with 4s(14,4v) and a controller that keeps a constant output at desired voltage.

 

[ChrisMBC]

Scaleo-heat is the controller I think you're referring to. It looks like it's out of stock and being replaced with a new version, which is internal to the suit.

 

[Whitrzac]

The carbon elements dont really care what voltage they get supplied with. A constant output controller adds a lot of cost, complexity, and failure points to the system. Even then, as the battery drains, current will go up to keep the same power output draining it even faster.

The simplest solution is to run a higher voltage at a lower PWM. Run a 4-5s pack at 60% rather than a 3s at 100%. It gives headroom for when the battery starts to drain down to turn it up.
After the first ~10% of discharge, the curve is pretty flat until it dies.

 

[broncobowsher]

The carbon elements dont really care what voltage they get supplied with. A constant output controller adds a lot of cost, complexity, and failure points to the system. Even then, as the battery drains, current will go up to keep the same power output draining it even faster.

The simplest solution is to run a higher voltage at a lower PWM. Run a 4-5s pack at 60% rather than a 3s at 100%. It gives headroom for when the battery starts to drain down to turn it up.
After the first ~10% of discharge, the curve is pretty flat until it dies.

That is what UWLD does. His battery packs are higher voltage, but throttled back to hold a steady wattage as the battery pack voltage drops.

The turn on and turn off is done in the Hertz range, not a minute on high and a minute on low.

 

[bananafeller]

That is what UWLD does. His battery packs are higher voltage, but throttled back to hold a steady wattage as the battery pack voltage drops.

The turn on and turn off is done in the Hertz range, not a minute on high and a minute on low.

So, he is using PWM?

 

[grantctobin]

So, he is using PWM?

He is using PWM, as are the Fathom and the LM controllers.