MPPT Controller for Thermoelectric Power Generation???

[JeepDaddy]

The sun goes down, the campfire is roaring - time to roast marshmallows and Peltier modules.

Most Peltier modules are rated at max power with a load of somewhere around 3 or 4 ohms. For discussion's sake, let's say OC voltage is 0-10V and max power is at 5 volts.

Having several Peltier modules in series to get the voltage high enough, would it be a possible, or a good idea, to use an MPPT charge controller to optimize the power output of the thermoelectric modules?

 

[snoobler]

Welcome to the forum.

No idea, but it sounds like you have an experiment on your hands!

Search results for query: Peltier

diysolarforum.com

 

[Hedges]

TEC's have a particular range they can tolerate, depending on solder used in construction and the like.
I played with one (meant for an ice chest) and managed to deliver a lot of heat to the hot side while not getting as much cold as I wanted (trying to chill a flow of dry gas for IC testing.) Electric generation is similarly inefficient, needs a lot of heat put in and taken out, in proportion to electricity generated.

Here's a thread with a commercial unit that delivers usable amounts of power:

Renogy DCC50S powered by Thermoelectric generator

I just picked up the DCC50S and have been losing sleep wondering if the Thermoelectric generator on my diesel air heater would be able to work as the alternator and I'm happy to say that it does! Now I can charge the batteries at night while using the heater.

diysolarforum.com

 

[JeepDaddy]

TEC's have a particular range they can tolerate, depending on solder used in construction and the like.
I played with one (meant for an ice chest) and managed to deliver a lot of heat to the hot side while not getting as much cold as I wanted (trying to chill a flow of dry gas for IC testing.) Electric generation is similarly inefficient, needs a lot of heat put in and taken out, in proportion to electricity generated.

Here's a thread with a commercial unit that delivers usable amounts of power:

Renogy DCC50S powered by Thermoelectric generator

I just picked up the DCC50S and have been losing sleep wondering if the Thermoelectric generator on my diesel air heater would be able to work as the alternator and I'm happy to say that it does! Now I can charge the batteries at night while using the heater.

diysolarforum.com

I agree they are inefficient. Considering I will have a campfire going anyway, the heat is available to use. I'll probably have more design challenges on the cooling side.

I know that there are different types of Peltier modules that are designed differently. TEC (ThermoElectric Cooler) modules are designed to transfer heat when powered and TEG (ThermoElectric Generator) modules are designed to generate power from a temperature difference. I believe the TEG modules have a higher temperature rating. The ones I'm looking at are rated for up to 300C.

 

[FilterGuy]

Keep us posted...... It sounds impractical but fun!!

 

[JeepDaddy]

Keep us posted...... It sounds impractical but fun!!

Excellent description for this project - IBF

 

[JeepDaddy]

Welcome to the forum.

No idea, but it sounds like you have an experiment on your hands!

Search results for query: Peltier

diysolarforum.com

Thanks for the welcome. I have used this forum to research my 280AH LiFePo4 battery builds and found it quite useful.

I thought it would be good to join and ask this MPPT/TEG question before I potentially destroy my Victron SCC.

 

[Hedges]

I would expect an MPPT to be appropriate for TEG.
Is the TEG going to deliver voltage sufficiently above battery? Or will it need a boost regulator?
You've mentioned 5V to 10V. Easiest is probably to connect several in series and use an MPPT SCC.
Not sure there are many/any boost SCC around. You'd have to get a suitable boost converter probably able to operate CV/CC and have that charge battery. Doubt there's much benefit to having boost regulator feed SCC.

 

[FilterGuy]

I thought it would be good to join and ask this MPPT/TEG question before I potentially destroy my Victron SCC.

If there is a Victron rep reading this he/she probably wants to post that it will void the warranty.....
However, as long as you keep the input voltage below the spec for the device, I don't see how it would damage anything.

You could start by just putting a large wattage resistor accross the outputs and not hook up the SCC. You can calculate the resister value and wattage using the expected voltage and amperage. From that you will know what the Peltiers are actually doing and decide if you want to go to the next stage of hooking up the SCC.

 

[JeepDaddy]

I would expect an MPPT to be appropriate for TEG.
Is the TEG going to deliver voltage sufficiently above battery? Or will it need a boost regulator?
You've mentioned 5V to 10V. Easiest is probably to connect several in series and use an MPPT SCC.
Not sure there are many/any boost SCC around. You'd have to get a suitable boost converter probably able to operate CV/CC and have that charge battery. Doubt there's much benefit to having boost regulator feed SCC.

I'm thinking 4 or 5 modules in series right now so maybe 20-25V at full load. A boost controller would be needed with 1 or 2, but I want to have enough power to do something more than charge a phone at the end of the day anyway. I have a 75/15 MPPT which should be more than sufficient as long as it works. The TE (ThermoElectric) folks refer to a MVPT controller which uses a different charging algorithm. I already have a MPPT to use if it works in TE applications.

 

[FilterGuy]

I'm thinking 4 or 5 modules in series right now so maybe 20-25V at full load.

That is enough voltage for a 12V nominal system but not enough for a 24V system.

 

[snoobler]

I would expect an MPPT to be appropriate for TEG.
Is the TEG going to deliver voltage sufficiently above battery? Or will it need a boost regulator?
You've mentioned 5V to 10V. Easiest is probably to connect several in series and use an MPPT SCC.
Not sure there are many/any boost SCC around. You'd have to get a suitable boost converter probably able to operate CV/CC and have that charge battery. Doubt there's much benefit to having boost regulator feed SCC.

I've seen one boosting MPPT:

 

[JeepDaddy]

That is enough voltage for a 12V nominal system but not enough for a 24V system.

Yes, indeed. Mine will be a for a 12V system. I need to actually source and test the modules before knowing what voltages I actually am dealing with.

 

[Daken]

Yes, indeed. Mine will be a for a 12V system. I need to actually source and test the modules before knowing what voltages I actually am dealing with.

Hi new guy here. Any update regarding your set up for the TEG? Thx

 

[JamesB]

Interested in this as well. Have a 15k sol-ark I'd like use. I figure use a group combined in series and parallel depending on modules used. I have plenty of solar for the sunny days, but seriously lacking when the sun goes down. Already have batteries for short-term, but long term isn't viable. Additionally, looking to generate some power off of spent fuel in the furnace.

 

[HarryN]

It is unclear to me why you would use an mppt solar charge controller.

Why not just hook some thermal modules up in series until the voltage hits ~ 16 volts.

Add diode to prevent reverse current flows.

Use a flex charge controller (for AGMs) or just a voltage limiting diode to prevent going over 14.5 volts.

Alternatively, you might try to just use the light coming off of the fire to see if it will trigger a PV module and a simple bogart pwm controller.