Reddit reviews F900 Mini Bluetooth Power Amplifier Wireless Audio Receiver with Power Supply 12V 5A, Stereo Hi-Fi Digital Amp 2 Channel 50W 2 with AUX/USB/Bluetooth Input

Yea, a lot of (especially cheap) car stereos aren't terribly efficient because well, they're built for a car, which has an engine, and (for all intents and purposes to the stereo designer) an unlimited power supply. :P Most of their inefficiencies comes from heat they give off due to cheap electronics. (That said, if the heat benefits you... hey... no harm there and it's essentially no longer inefficient. XD)

I know the shitty stereo in my truck draws close to freaking 200 Watts if I'm just listening to the radio at a moderate volume. :P Not the peak of what I'd call efficient. :(

A higher end car stereo, or at least a higher build quality one could work, but just verify how much power it's going to use ahead of time. Keep in mind also, that the louder you have the volume, the more power it uses, because well, it takes power to make sound. :P

I take it you'll probably just be using bluetooth or such from your phone to play music a lot of the time, so if you eliminate the CD player and such, you can probably save some cash... All you really need is an amplifier that runs off 12 volts and some speakers. :) Definitely something that can be cobbled together and sound pretty good without shelling out big $$$.

You could use something like this: https://www.amazon.com/Channel-Bluetooth-Amplifier-Wireless-Speakers/dp/B072Q157FY/

It comes with an AC - DC adapter, but if you look at the casing it specifies you can input 9 - 24 volts. So, that means you could run it direct off your battery with no issues I'd venture to say. :)

Whatever you do, try and keep it DC though. Remember, you LOSE power going through the inverter from DC to AC. :( So if you want to run a 10 Watt appliance that uses 10 Watts AC, you'll probably be using about 11 or 12 Watts from the battery. Then you also have the inverter's standby draw (self consumption) of about ~12 - 30 Watts, depending on the inverter.


Let's look at a power budget:

Let's assume you've got a speaker solution that uses ~60 Watts (this is a lot, but probably somewhere in line with what a well built car stereo, or that little thing on Amazon I linked, will use at 'full blast').

Let's say you've got ~25 Watts of LED's as well.

And let's say your inverter has a standby draw (cause we're still going with that you wanna be able to charge your laptop, etc.) of 12 Watts.

If we add all that up, we get 97 Watts consistent draw. If you're out there for 4 hours in a day, that's 97 x 4 = 388 Watt-hours.

We'll say each laptop charge uses (accounting for inverter efficiency losses) about 100 Watt-hours.

So, we'll call it 500 Watt-hours per day (Watt-hours or Wh is a measure of energy. An actual 'amount'. Watts, is a RATE of usage. Thus why 100 Watts for an hour is 100 Watt-hours. :) )


How many panels?

To generate 500 Watt-hours, in the approximate ~3 hours of peak sun of the day (when solar panels work well), you'll need to have at least ~170 Watts of solar panels, not counting that they don't put out their peak in the real world.

When we factor in the ~60% rated output for the panels, we get ~280 Watts of solar panels needed. :) It's not that much. :) But don't go with much less, you'll be disappointed if I had to guess.


How much in battery storage?

Well, 500 Watt-hours isn't a whole lot, but we want to add in a little extra probably because we want to account for less than perfect conditions, and maybe another person charging a laptop or something. We'll smack that up to ~750 Watt-hours of storage, usable.

Since you'll probably use Lead Acid (cheapest) like AGM or such, you'll want to have twice that in RATED capacity, to avoid over-discharging your batteries. (Max 50% Depth of Discharge is recommended.)

So, that's 1500 Wh, or 1.5 KWh of storage needed.

If you divide that by 12 volts, you get 125 Amp-hours. So two 100 Ah batteries would be plenty. :) Just, don't use marine batteries. Get some proper deep cycle AGM ones for ease of use and safety, and longevity in your usage conditions. :)

I'm with /u/polypeptide147 on this. The more features, the more possibilities for noise, etc.

The cheap amps I own are all much more heavily affected by power noise, crappy audio cables, etc. The Lepai 2020ti handles it better than most. It also benefits from a good power supply.

For example, this line of amps are decent for an outdoor / garage audio setup, but I would never use one on a computer (speaker hiss, very noisy when idle). You're going to be much more sensitive to speaker hiss and distortion, along with many of the "featureful" amps having auto-shutoffs with a slight delay coming back on (causing the start of notification sounds to get cut off).

Edit: if you want featureful, I would go with something like the SMSL AD18 (no personal experience with them) or the Klipsch Powergate (What I'm currently using. See my comment here for some issues I have with it.)

Also see the right sidebar at old.reddit.com/r/BudgetAudiophile

Powered/Active: Edifier R980T, Edifier R1280T, Edifier R1280DB

Separates: Budget $55 Bundle 6-1/2" 2-Way Bookshelf Speaker Pair and Hi-Fi Mini Amplifier Bundle

Mini Amp: F900 Mini Bluetooth Amp AUX/USB/Bluetooth $33, Kinter K2020A $33, Nobsound Mini 50W x 2 Bluetooth Amplifier $31, SMSL SA36 $52

Speakers: Dayton Audio B652-AIR with AMT Tweeter $50 or Polk Audio T15 $50

Speaker wire and wire stripper.

I 2nd the AIR recommendation. Not much reason to be $10 or whatever stingy when the AMT tweeters are a big step up from the normal B652s.

I'll plug the Nobsound Mini BT amp again. Better connectivity than the SMSL and it's quite cheap. I've had 3 of varying names brand and they have all worked well for smaller setups.

https://www.amazon.com/Channel-Bluetooth-Amplifier-Wireless-Speakers/dp/B072Q157FY/ref=sr_1_1?ie=UTF8&qid=1541738012&sr=8-1&keywords=ns-01g

If you look up ALS Techreview there's a bunch of videos on the Nobsound.

My Spit came with speakers in the parcel shelves. They are hidden from sight but unfortunately they are too large so they push the parcel shelves out of position. I will reposition them and also install one of these:

https://www.amazon.com/gp/product/B072Q157FY/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

Thanks! Going to try this now but im pretty sure the issue presents when I turn on the amp. It's this cheap one: https://www.amazon.com/gp/product/B072Q157FY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Technical Pro MB5000 monitors

Pockville 68C "6.5" classic passive Bookshelf speakers pair

Facmogu F900 mini bluetooth amp

maybe this one

Something like this?

https://www.amazon.com/Channel-Bluetooth-Amplifier-Wireless-Speakers/dp/B072Q157FY/ref=sr_1_3?ie=UTF8&qid=1524527663&sr=8-3&keywords=bluetooth+amplifier

You could try one of those mini amps: https://www.amazon.com/Bluetooth-Amplifier-Wireless-Receiver-Adapter/dp/B072Q157FY/