12v voltage regulator inside canister

[Open Ocean Diver]

Hi guys,

I want/prefer a stable 12V for powering a heated vest & gloves (about 100W ). I've got a Halcyon Pro 14 canister with plenty room for a batterypack, bms and a dc dc converter.

I'm thinking about using a synchronous switching step-down voltage regulator like the Pololu 12V, 15A Step-Down Voltage Regulator D24V150F12 (~50$)

View attachment 642583

Pololu 12V, 15A Step-Down Voltage Regulator D24V150F12

Using a 5S or 6S batterypack should give quite good efficiency aound 93% at ~8-9A (according the spec sheet).

View attachment 642584

Has anyone experience in using a switched converter in a (large) canister. I'm worried about the heat generated by the regulator inside a closed canister. I'm not sure how good Delrin is conducting heat away to the (cold) water outside the canister.

Mount a heatsink on the outside of the canister with a seal screw, then glue the MOSFET case with heatsink glue inside the canister. Problem solved.

 

[Leto]

Thanks for all suggestions and tips guys. I did some measurements and I'm able to fit a LiFePO4 4S14P = 56 cells pack inside my Pro14 together with a BMS. This translates into a 300WH pack. With a nominal voltage of 12.8V this is ~24A and good enough to power a vest and gloves for about 3 hours which was my goal. This pretty much eliminates the need for a voltage regulator.

The 12.8V is very close to the 12.6V of a fully charged standard Li-ion pack so this should not be a problem even with the Santi vest which states '12V only' in the manual.

I think i'll go with either a Pitkin or Scaleo controller to take the heat down a bit when needed.

 

[tbone1004]

please remember with the voltage thing, they are saying 12v only so people don't put them on 4s lipo packs which are 14.8v nominal with a full charge just shy of 17v. These things are however designed to be used in motorcycle applications where the alternators are putting out 13.6-14v, so that is their actual designed voltage for the panels.

 

[Leto]

I just did the math on 12V vs 16,8V with a 55W / 12V santi vest. With 12V and resistance of 2,6 Ohm it will output 55W drawing 4,6A. Plugging in 16,8 it goes to 108W drawing 6.46A. That will hurt!

The heating wire will probably do some self current limiting I guess but still way to warm.

 

[lucca brassi]

nominal voltage for LiFePO4 4S= 4*3,3V= 13,2V and max 4*3,6V= 14,4V but this would be managed by BMS (end of charge )

Santi vest is limited to 55W means 4,1A and the same time with max temp of 45°C !

attery running time:
SANTI 6Ah: 1h15min ~ 1h30min of heating,
SANTI 24Ah: 5 ~ 6h of heating

Total power of connected devices cannot exceed 200W. Those devices must be designed to be powered with 10.8-12V input.
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if you look THEIR l : battery spec

• capacity: 24 Ah,
• operating voltage: 11,1 V,
• cells type: Li-Ion

you can switch on 3S and more P .

PS : you have these SANTI connectors or china replicas ?

 

[Pkishino]

I recently built another cannister for a friend using the same mini pwm dimmer I built for my own.
Using LG 21700 batteries, a nice 35Ah, max 400W, dual output.
The pww dimmer uses a ATTiny85, combined with some resistors and a n-mosfet. Simple program that adjusts between user selectable 100%/75/50/25 flicking on/off power
The santi connectors are made by chogori, used to find on aliexpress but no luck recently..