Open Source Arduino Alternator Regulator

[Cowpoos]

Be able to use alternator ac wave form.for rpm, to configure alternator load for small engines at low rpm.

[Bellinghamster]

As for mounting a temperature sensor, whether it be thermistor, 1-wire TO-92 package, thermocouple or thermostat - high temperature epoxy to 'pot' it in the barrel of a ring lug has worked for me. Easy to bolt on anywhere. Glue-filled heatshrink over the barrel and wire lead helps insulate it from ambient and strain relieve (relief?) the wire. Downsides are not as fast response compared to a welded-on thermocouple, and the epoxy takes time to set so production in volume takes some fixturing and space.

1-wire sensors seem to top out at 125C, which is probably adequate. If you need to go higher, then something like a MAX31850 (thermocouple to 1-wire IC, can still be parasitic powered) on a PCB near the sense point with a short thermocouple wire that could be placed inside the alternator... but it's a $10 IC, plus PCB, plus enclosure, plus thermocouple and mounting.

Keep adding these $10-15 "features" and before long you're closing in on the cost of the commercially available regulators. I for one want a low-cost, 12V nominal-only external regulator set up for LiFePo4 charging with rudimentary status interface (local display, wifi or NMEA2000) and an input to shut off charging gracefully. Trying to make one-size-fits-all adds unecessary cost and complexity. Sure, maybe include hardware stuff options for 24V and maybe even 48V in the design (PCB real estate is not too costly) and have different models , but I think the largest potential user base is 12V systems and those 99.5% of those folks are unlikely to convert to higher voltage somewhere down the road.

A $100-ish 12V regulator would be a a no-brainer upgrade path for me - cheap enough to carry a spare or even a couple of them to be able to upgrade other boaters one meets along the way. Over $200 and I'd have to think about it.

[Jon Hacking]

I'm pretty much with Bellinghamster. 12v primarily, maybe 24v/48v if it's easy, but I don't think there are many DIYers out there going high, & cost is a primary concern. Having said that, as an EE, I like knowing what my equipment is doing, so the display is well worthwhile IMO (& a major issue with my VSRs).

I wrap 3 long tie-wraps (cable-ties) around my alternator, with my temp-sensor underneath. Not ideal, as the nylon needs to be replaced now & then, but I've never had one fail on me. They have enough stretch to actually hold the sensor securely, but I have to mount it on the iron core, as I can't get to the diodes, which are probably more important.

[nfbr]

Motor temp standards
https://www.nema.org/docs/default-so...rsn=947aee6f_2

Stator laminations are often hotter than case due to induced eddy currents.

[scottburch]

I would be very interested in this. Starting a design myself, so this could be a helpful shortcut.

My requirement is very basic. I have a bad belt setup, so all I really need is to manually adjust the current to the field wire. Was going to use a basic transistor setup for this. But, would be interesting to add an arduino to add more charging features.

Please point to the design when you are ready.

[nfbr]

Originally Posted by scottburch

I would be very interested in this. Starting a design myself, so this could be a helpful shortcut.

My requirement is very basic. I have a bad belt setup, so all I really need is to manually adjust the current to the field wire. Was going to use a basic transistor setup for this. But, would be interesting to add an arduino to add more charging features.

Please point to the design when you are ready.

$5 adjustable 10A DC to DC Buck works well for that. I used one for testing.

[openear]

Before you do too much reinventing the wheel, be sure to see the excellent open source regulator already created by by William A. Thomason. VSR Alternator Regulator

Originally Posted by markxengineerin

I am mostly done developing an alternator regulator with the following features

• Fully open source, based on Arduino Uno microcontroller, programmable with any PC/laptop
• Probably <half the cost of any other product in this category
• Display showing voltage, current, temperature, field command and any error data
• 12, 24, 48V system support (automatically, same hardware + software)
• Max 12 amp field current
• Remote voltage sensing
• Thermistor for alternator temp sensing
• Hall effect type alternator output current sensor (clamp style for easy installation)
• Infinitely programmable charge profile for any battery chemistry
• Infinitely expandable to communicate with any other device (CAN, NMEA, etc) or add other inputs/outputs
• Protected + stable power supply (Buck/Boost power regulator operates from 2V to 100V, Reverse Polarity Protected to –40V)
• 120dB warning buzzer programmable for any fault condition
  

Are there any other features that people want? Now is the easiest time to add things before finalizing the first PCB order.

[markxengineerin]

Ok, design review time

Here are the claimed features

Here is the schematic and a description of components

The next task will be the PCB layout.

I'm also interested in feedback on the website, which is intended to help anyone interested in getting started with Arduino for boat applications.

Thanks for the help so far

[Jon Hacking]

"Laser cut wood enclosure"? Really? Wouldn't plastic be better on a boat? Oh, I see, you're tired of plastic. We've had lots of issues with wood (although your photo looks cool, if a bit elaborate).

"I’m not planning to conformally coat or pot the board..." Your choice, I suppose. Our battery compartment (where this would be mounted) is under our helm, about in the middle of the boat. It's nominally dry-ish, but I had a LiFePO4 BMS corrode away to oblivion in there once. We all live in a moist, salt, marine environment. I view coatings as good, but I don't know how much they cost.

Your "Alternator Wiring" diagram shows your regulator connected to the alternator output, not to the battery. The alternator wire is carrying significant current, so you're reading the alternator voltage, not the battery voltage. Is this on purpose? I'd MUCH rather my regulator was looking at battery voltage, on a wire carrying no significant current. I don't really care what voltage my alternator is outputting. With LiFePO4, even hundredths of a volt are relevant.

[s/v Jedi]

You write “open source” but then you also write that you intend to make and sell these?

Of course I will only participate in diy non-commercial efforts.

[markxengineerin]

You write “open source” but then you also write that you intend to make and sell these?

Yes the two can exist together, at least how I think of it. Other businesses with similar models https://en.wikipedia.org/wiki/List_o...s_and_services

Of course I will only participate in diy non-commercial efforts.

I hear you, but let me try to change your mind, because I would like your participation:

• The hardware and software are both open source, nothing hidden, anyone can do what they want with it, including build it themselves if they prefer
• But you also have the option to buy pre-made hardware, to support what I'm doing and make your life easier. Price undecided, but it's going to be much cheaper than anything else on the market for what it is
• Making money will compensate me for my efforts, and pay for future product development. It will mostly be the latter, I'm keeping my day job and this is more of a hobby/experiment at least for the foreseeable future
• Participation is not required, and in many cases will be as simple as someone here saying "why don't you consider an ESP32?" This thought probably took someone a split second to type, but it totally changed the project direction for the better.
• The above level of participation is not that different in principle than posting a review or opinion about any commercial product.
• Heck, you already have participated, I think one of your posts was my intro to the INA219. That was valuable and if you'd like a free prototype, PM me and I'll ask for your shipping address when something is ready. I'm guessing a couple months from now if all goes well.

@JonHacking, thanks for the feedback, noted. I will learn more about conformal coatings when the PCB is finalized, maybe I'm just imagining spray causing continuity issues with connections, unless masking is used, and I don't know how complex that ends up looking, how quality is controlled, etc. I also don't know much about the costs, none of the vendors I've found offer that (although I haven't looked very deeply). Open for ideas in this area. I would like to offer something that's corrosion resistant, haven't found a clear path to do it yet.

I'd MUCH rather my regulator was looking at battery voltage, on a wire carrying no significant current. I don't really care what voltage my alternator is outputting. With LiFePO4, even hundredths of a volt are relevant.

I'll update the diagram, it's not a good one. The sensor shown was current only, no voltage measurement location is shown. You're free to locate either measurement at any location you choose. In my breadboard prototype, I'm measuring current from the alternator, but voltage at the battery. Opinions on this will vary, but the system can handle any option, or all at once if someone wants.

[markxengineerin]

About connectors- the screw terminals selected are the highest we found, and only good to 15 amps. The PWM chip is good to 40, so, better connectors would allow higher currents. Anyone know of anything friendly for a DIY wiring harness, but higher current rating than a screw terminal?

[jcapo]

Originally Posted by markxengineerin

Anyone know of anything friendly for a DIY wiring harness, but higher current rating than a screw terminal?

Bulky but good old fashion barrier terminal strips.

I like open source projects that are also available as a finished project for those that don't want to have a PCB made and source all of the parts.

[s/v Jedi]

Anderson PowerPole connectors. Also available for PCB mount.

[markxengineerin]

What about the P type vs. N type setup- does anyone need N type?

15 amps at 12V max field current, and P type only is the most convenient way to move ahead, but I don't know if there are special cases out there requiring >15 amps, higher than a 12V field, or N type. I asked some of these questions in another thread, but might as well check again here, because now is the time to decide.