12v voltage regulator inside canister

[Open Ocean Diver]

I'm not sure if I understand your question but this is the backside:

View attachment 642658

View attachment 642659
More pictures in the url above.

That little square patch is that the back side of the regulator? Is so is it conductive?

 

[Leto]

I think it is a small area to make a note on with a pen.

 

[lucca brassi]

I would go with more Ah on battery pack and slightly higher voltage over standard 12 -13,8 V. LiFePO4 can made much more cycles than LiPo an more stable output

Like Headway Battery LiFePO4

What I see on UWLD controller it have one piezo switch that mean it could cycle around prepared stages like 0% - 20%-40%-60%-80%-100%-0%

With proper PWM controller you can drive low inner resistance FET direct on gate and that is all you need IMO or just modify some degradable jacket controller

https://www.amazon.com/Temperature-Controller-Portable-Thermostat-Reduction/dp/B082W81LMV

 

[Open Ocean Diver]

I think it is a small area to make a note on with a pen.

Normally this is a heat sink pad, I was thinking of a way to use the pad to dissipate heat outside of the canister.

 

[Leto]

I would go with more Ah on battery pack and slightly higher voltage over standard 12 -13,8 V. LiFePO4 can made much more cycles than LiPo an more stable output

Like Headway Battery LiFePO4

What I see on UWLD controller it have one piezo switch that mean it could cycle around prepared stages like 0% - 20%-40%-60%-80%-100%-0%

With proper PWM controller you can drive low inner resistance FET direct on gate and that is all you need IMO or just modify some degradable jacket controller

https://www.amazon.com/Temperature-Controller-Portable-Thermostat-Reduction/dp/B082W81LMV

The 3.2 flat discharge curve is very good for a high stable heat output (4x3,2=12,8V). Unfortunately, I can only get 8 (3,2V,10A) Headway cells in the canister which translates to only 20AH. I tried fitting 18650 LiFePO4 but that also only gets me to about 240WH/20AH. Did I say I love the discharge curve, for example:

 

[lucca brassi]

What is size canister inside ? I just made two packs with LiFePO4 32700 6Ah (4S3P)

 

[broncobowsher]

I can't see a good reason to step a pack down to 12V first, then go to a second stage step down to adjust final output.
I've seen plenty of generic regulators (mostly buck convertors) that you can specify a desired output voltage and it will give it regardless of what pack voltage is driving it. So long as the pack voltage stays above desired output. That is where UWLD packs shine, there is enough over-voltage in the pack that even at minimal charge levels there is still enough voltage on the table for full output.

 

[Leto]

What is size canister inside ? I just made two packs with LiFePO4 32700 6Ah (4S3P)

Inner dimensions about 29.5 x 11.5 CM and the 4S BMS 80x60x15 mm. I'm using a modular system called Nese: AMtech – AMtech I've used it to build a 7S14P Li-ION batterypack for my Suex 7, it rocks (when you have access to a fast&reliable 3d printer). 4P 18650 Nese module is 86x75x21 mm

This is what a 4S12P looks inside the canister with the BMS on top.

Pasteboard - Uploaded Image

 

[Leto]

I can't see a good reason to step a pack down to 12V first, then go to a second stage step down to adjust final output.
I

I agree, to do this in a single step using a single PWM conversion (100% -> 12V / 80% -> 9.6V) be would ideal. However, I don't have the skills to build/design so a thing. What I can do is put a 12V regulator inside the canister and then add a pitkin or scaleo controller for stepping down the heating when required. What I want to avoid is the pack voltage running down and less and less heat being available later, when you need it the most, in the dive.

Just for fun let's take a heated vest rated at 48W at 12V with 3 Ohm resistance (watts = volts² / ohms) and run the standard 3S Li-ION batterypack down.

12.6V = 53W / 4.2A
12V = 48W / 4A
10V = 33W / 3,3A
9V = 27W / 3A

What I'm not sure about is how this works in relation to current limiting inside the heated stuff. Maybe @tbone1004 can shed some light on this. I'm not a pro at this electrical stuff, I just like to understand and learn about it. So if there are errors in my calculations or reasoning please let me know.

btw, using LifePO4 makes the 12v regulator pretty much obsolete as the discharge curve is extremely flat at 3,2 (4s = 12,8). Energy density is about half of the normal Li-ION but I got some space inside the canister

I can't see a good reason to step a pack down to 12V first, then go to a second stage step down to adjust final output.
've seen plenty of generic regulators (mostly buck convertors) that you can specify a desired output voltage and it will give it regardless of what pack voltage is driving it. So long as the pack voltage stays above desired output. That is where UWLD packs shine, there is enough over-voltage in the pack that even at minimal charge levels there is still enough voltage on the table for full output.
I

Well the efficiency of a voltage regulator when V-in and V-out are wide apart goes down. When pulling 8 amps that adds up. Dropout voltage when outputting 8A is usually 2-3V. That means that a minimum pack voltage of about 14/15V is needed for a regulator to enable it to convert to 12V. That's is why UWLD uses a 5S pack, it ideal for converting to 12V (v-in and v-out close together and min pack voltage of about 5x2.8=14V)

 

[lucca brassi]

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