WTB stand-alone pitkin controller
Hi, looking for a stand-alone pitkin with EO connectors, unfortunately light monkey no longer makes them and I can?t find any other vendors that do. If you have one to sell please let me know.
Sent from my iPhone using Tapatalk
UWLD makes one that's quite a bit better than LM. Give Bobby a call and talk to him about it.
Main difference being the UWLD can give constant output and work with different input voltages as well as having more settings. The Pitkin was smaller/cheaper, but was restricted on output and because it had less settings you'd have heat output dropping as a function of battery capacity and can cause you to cycle the controller on and off to stay comfortable. I have one that I'm going to put on a DPV, but the controller from LD is a lot nicer for normal use
Originally Posted by tbone1004
Can you elaborate on this? I don't think battery capacity plays a role in the problem you were having, sound more like the board was getting bumped or reset.
Only works on UWLD canister however.
The LM pitkin doesn't try to maintain constant voltage so as the battery voltage sags under load the actual heat output at (eg) 60% starts to drop. After X minutes and a modest voltage drop you will need to bump up the setting to 80% to maintain the same approximate heat output.
I have a light monkey can now so I?m gonna try and stick with theirs if I can find one unless Bobby?s works with the LM cans.
Off topic but did you end up getting an ATS unilung? I?m still loving mine on the fathom, even though it?s a little big for my lung capacity
Sent from my iPhone using Tapatalk
didn't end up getting the unilung. Bought a SMCCR instead
It is always worth calling Bobby to ask him if he's willing to do something. You tend to get surprised.
rjack hit the nail on the head with the output. Basically the LM canisters are 3s packs, so nominal 11.1v which means that you never actually get the "full" output from the vests. They are designed for use with 12v applications which is actually like 13.6v so the vests on "high" are only about 80% of their original rated output. Not a problem in cave diving, and arguably better for most diving since they're less likely to burn you. That said, because the voltage being put out by the pitkin controller is say "80% of input", as the input voltage drops, the output voltage drops. It's cheaper/easier as it's an off-the-shelf part, rather than making a fully custom board with constant output.
With UWLD, they use 5s packs that are 18.5v so are always bucking the output voltage for the lights and the controllers which makes constant output a bit easier. They also have fully custom boards for everything which allows them to have the control that they do over their products.
Different design paradigms, with pros and cons to each.
Tboner is wrong again! LM doesn't use off the shelf components for their heater controller. Everything from programing the microprocessors and populating the boards is done in house. You can walk in and see Joel assembling them.
When I was talking to them a few years ago about it they said it was a standard board and they were reprogramming it, similar to the ESC's used by most of the dpv manufacturers. Admittedly this was really early on and it was one of the girls who told me, not Joel. If he's populating the boards himself then they must have changed something on there or tried to make it even smaller.
What's curious though is if you're saying he's making them himself, but the OP said they stopped making them, there must be a reason for it. That's usually a supplier issue
I have a LM standalone pitkin and the voltage definitely drops over time. I use 14.8V packs (nominal) though, so 100% at ~16.7V input is actually quite hot at the start. I usually run it at 60% and only on the longer decos does the voltage sag enough to require me to bump up the output. The best part of the stand alone (compared to UWLD's) is that I can bring multiple batteries and canisters on a trip and mix & match.
I'm curious if you're using Lithium batteries or not. I suspect that the "drop" has as much to do with thermodynamics and perception as it does with voltage. While it's strictly true that the voltage on a lithium battery drops, it's fairly flat and I'd be suprised if you could tell the difference over time.
I don't 100% know what LM is using in their controllers, but I'm fairly confident that they're using a small micro driving a transistor to PWM the voltage much like you would with a motor. There's a huge supply of hobby boards out there with all the correct components, connectors and could easily dropped into their product. Laying out your own board and sourcing your own components is so easy though that they'd be silly not to control their own supply chain. Just the board and electronics would cost them ~$5 at volume(not including EO connectors, obviously). My guess is that LM wasn't making enough money to justify production runs.
Posting Permissions
Reply With Quote
Bookmarks