Drysuit heating controller options

[Richard Dayan]

The main challenge is that many (most?) divers already have the batteries which run at around 14.4 or supposedly 12 volts (which is actually 11V).

Having a DC to DC converter could give a constant output with a variable input.

One other small feature: you must be able to replace the E/O connector cables during the life of the converter -- they are almost guaranteed to break if folded, etc.

It's possible to make an in-line dc to dc converter, to plug into the battery but I didn't need it in practice. Also lithium ion has these problems more than LFP batteries.

 

[Wibble]

Commercially you may want to think about that as it won’t add much to your build costs but it will get you a wider market.

Batteries are by far and away the most expensive part of a drysuit heating system. Extending the life of an older battery is a good saving. Also many of us own the not quite 12V Light-for-Me heater batteries. 18AH but around 11V or lower. A change of battery is $$$$, well over a grand. Stomping up, say, $300 for a controller that would make the thing work makes great economic sense.

BTW I’ve two of those heater batteries.

Another feature could be a switching function for, say, 2 inputs and two outputs means being able to use two batteries on long dives without wet-swapping the E/O cables and also run two heating circuits — e.g. suit and gloves

 

[Richard Dayan]

Commercially you may want to think about that as it won’t add much to your build costs but it will get you a wider market.

Batteries are by far and away the most expensive part of a drysuit heating system. Extending the life of an older battery is a good saving. Also many of us own the not quite 12V Light-for-Me heater batteries. 18AH but around 11V or lower. A change of battery is $$$$, well over a grand. Stomping up, say, $300 for a controller that would make the thing work makes great economic sense.

BTW I’ve two of those heater batteries.

Another feature could be a switching function for, say, 2 inputs and two outputs means being able to use two batteries on long dives without wet-swapping the E/O cables and also run two heating circuits — e.g. suit and gloves

I will be making batteries also, including a budget battery for $500.

 

[Wibble]

I will be making batteries also, including a budget battery for $500.

Then please look into doing something like using a power tool battery housing. Those are 18V/20V and cheap due to the volume they make. Back to that DC to DC converter again!

The point about power tool batteries is you can get them pretty much anywhere, even rent them. Flying ceases to be an issue if you can get them at the destination.

 

[grantmac]

A power tool battery canister would be pretty slick.

 

[Richard Dayan]

What we want is a system that can keep us warm and comfortable in any water temperature and is reliable and travel friendly. We want to buy just one system that can handle anything, last for at least 10 years, never breaks, is low maintenance and can come with us on trips. Thats is the goal.

 

[Bartek]

Miranda heating batteries solved this problem
are built from 4S packs and the controller constantly measures the voltage on the pack and changes the frequency so that the output is always the same as the one set by the diver, voltage in the range of 0V to 12V

 

[grantctobin]

Baterie grzewcze Miranda rozwiązały ten problem
zbudowane są z pakietów 4S, a kontroler stale mierzy napięcie na pakiecie i zmienia częstotliwość tak, aby wyjście było zawsze takie samo, jak ustawione przez nurka, napięcie w zakresie od 0V do 12V

~
“Miranda heating batteries solved this problem
they are built from 4S packs, and the controller constantly measures the voltage on the pack and changes the frequency so that the output is always the same as set by the diver, voltage in the range of 0V to 12V“

 

[Bartek]

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)

Miranda has a controller that has a continuous measurement of the voltage on the pack and makes the frequency correction itself, so as to maintain the diver's settings. If you set 12 V, you will have 12 V until the battery runs out, additional regulation is smooth from 0 to 12 V Heating battery 400 Wh equivalent to 36 Ah