LM1875 P2P "solar powered"

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Hi,
Summer is coming, I would like to listen to music for free in the garden !
So this new amp will be connect with two Li Ion batteries (near 15 volts) and recharged with solar charger.

One LM is missing at home, and for P2P I choose LM1875, and cause I have.

Schematic :

An externally hosted image should be here but it was not working when we last tested it.


Rz and Cz on output posts, distance about 5 cm between LM.
I will use two heatsinks, maybe cause pin 3 are connected to socket of LM.
I will try to have very short wirings.
Phil.
 
Hi Andrew,
Sorry for my poor english, but psu amp is two batteries (wiring in serial), solar charger is just for recharge the battery, like this :
12v solar panels; home solar panels; off grid solar power | Sunstore
i'ts just for example.
Phil.

Hi
can you discuss the charger for your batteries, perhaps post your solutions in the 'Power Supply' section of this forum. This would be the most challenge in this interesting project.
I suppose you are using two identical panels > charger> batteries to support listening whilst charging?
thanks
BTW I agree with the other posters, many class D amps in the same power range have a single supply together with higher efficiencies equals smaller set-up over all.
 
You are right about T or D amp, but I have the LM's and all componants for building..
Single rail vs Dual rail ?
Hum, I have two class T (Trends and chinese TDA2020) with single rail (12vdc), I found none that sounds good (mid and high), but it's my taste.
With dual rail, it's possible to have no componants in the signal path.
I try LM3886 with two batteries, I love it !
Power ? I don't need much, it's not for outdoor party, just listen music in front of a cup of tea.

At this time, I have two bat, charger, and solar panel.. Missing a converter 12 volts/230 volts.
Infinia, you are right, maybe a thread at "power suply" can help to find a better way.
Phil.
 

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probably a pair 12V SLA directly connecting a couple of 10-20W PV panels are more universal than using the newer battery chemistries. otherwise no sense in using solar for portability eg MSW inverters and cheap AC chargers, usually a unwise mix by itself. IMO don't give upon finding a better D amp.
 
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How about using an LME49600? It can operate at ±15 V and will provide up to 250 mA out if provided enough cooling. That's enough for 250 mW RMS, which is enough for about 80 dB SPL at 1 m with even an inefficient bookshelf speaker. That's a good 20 dB above normal background music levels.

If your question is about how to build the charging circuit, I suggest looking into peak power trackers. You want to adjust the charging current into the battery such that you get the peak power out of the solar panels.

Tom
 
Power ? I don't need much, it's not for outdoor party, just listen music in front of a cup of tea.

With a couple of good speakers, this set up will be sure to please..

PAM8403 Mini Digital Power Amplifier Board Class D USB DC 3W 5V Supply Audio | eBay

Mini 360 DC DC Buck Converter Step Down Module 4 75V 23V to 1v 17V | eBay

5600mAh Portable External Battery USB Charger Power Bank for Mobile Phone iPhone | eBay

US Bluetooth Wireless Speaker Receiver Cordless Music Transmitter USB Power | eBay

12v 5w Monocrystalline Solar Panels; off grid energy; off grid solar

Connect the regulator board to the solar panel and adjust the output to 5 volts. (Charge controller is already in the battery) Cut one of the ends from the little male/male jumper on the Bluetooth receiver and solder directly to the amp board. (Speaker out/power wires too) Get creative and whack up a couple USB cables for charging the battery and powering the amp/Bluetooth. Use the type A USB connection at the battery for switching the system on/off..

You can either connect with Bluetooth or extend a source cable down to where you need it. It will operate from the battery for for a couple of days without the Bluetooth receiver. (Amp Only-No Charge)

I use this system myself. I have it on my screen porch. I use Bluetooth for my connection. While using, I disconnect the mini USB and run on straight battery. I pull the larger USB from the battery to shut down and plug the mini back in to charge while I'm at work during the day..

Just an idea.. ;)
 
^

good stuff cant believe those prices > DIY is being a system engineer now


PV> buck converter/I wonder how big of a panel this will handle ? I reckon it's the max bulk charge current or Pd of SOIC so 5W PV gives about ~ 800mA into Li ion type cell. assuming total losses of about 1W. sounds about right wouldn't be prudent to go higher.
see here for adjusting converter voltage at end of charge http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
 
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That's the magic of the bank battery. Just supply it with a regulated 5 volts and it controls the charge by itself. If charging from a computer, the input voltage remains constant..

do you know how it works?, probably a PWM pass element Rds on control


that's an idea I had to use a custom* buck converter feeding a cheap PWM controller on a bigger scale 30-40A for a DIY real MPPT rig.

*details deleted
 
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Hi guys,
Thank's for interest :)
Sure that 5 volts is a good idea !

This project is a little for fun, to build a P2P amp, and using that I have at home..
I found a idea for "solar powered", I already have a solar panel (on the roof), a 12v 45Ah bat, Li Ion charger and two bat 14,4 v..
Just 12vdc/230vac is missing, I could find it for about 30 euros (150watt), it's not a pur sinus, but I hope is good enough.

An externally hosted image should be here but it was not working when we last tested it.


Phil.
 
I don't understand the +/- config of the battery in your first post. For what I see, the LM1875 only needs a single supply..

Go to this site and see how much sun you have to work with at your location in December. Design for the worst and it will work year round.. ;)

Sunrise, sunset, dawn and dusk times around the World - Gaisma

Look at the bottom of your battery charger and see how much power it requires. (Watts, Amperage, Voltage) Then we can figure the charging load from the inverter to the battery..

What is the Ahr rating of the batteries you plan to operate the amp from? This figure will tell us approx. how long it takes the charger to recharge the battery..

This information will help decide how much wattage in panel and the size of storage battery you need..
 
Hi,
This setup is for summer, for winter maybe I use a savonius wind turbine :)

Batteries are connected in serial (+ and - connected for 0 volt), so that give +15 volt, -15 volt and 0 volt at center..

Below, you can see LM3886 amp powered with two 1500 mA (14 volt nicd) batteries, it can works during about 7 hours at low level.
You can see also the wiring power.
Phil.
 

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7hrs from a 1500mAhr (1.5Ahr) seems pretty good.
Will a solar recharge that over a day of sunlight?

Sorry Andrew, I dont understand well your question.
For recharge one Li Ion, it take 30 minutes with charger 230 v and 80 watts uptake..
How with a converter 12/230 volt ? I don't know.
With a sunny day, it need almost one day to recharge completly the 12 volt battery.
Phil.
 
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