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Know of a cheap 24v li-ion to run a boom box?

Hello,

I've been building boom boxes of various sizes using 24v amplifiers. I can never find medium sized 12v class d amplifiers, so I am forced to used 24v. My favorite amplifier is the tk2050. The inexpensive li-ion cctv batteries I use for my 12v amplifiers can't be used in series because the internal circuitry seems to cut out. 

Can anyone help?

Extra points for simple, cheap, light.

Something around 7 Amp/hrs would be great. Maybe under $30.

Oh, and how would you charge it?

Thanks!!!

Tor



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torclausen (author) 3 years ago

I would like to add a follow up to this discussion.I have made dozens of boomboxes since this post, some large, some small. There seems to be a diminishing return on size. You can have a larger suitcase, higher voltage, more speakers... and it only minimally increases volume.

  1. LiPo Batteries: The rolls royce of batteries. They are perfect for boomboxes, if money is no object.

2. Ni MH batteries are excellent as well. Much cheaper, but less power for the size.

3. Li-ion Batteries, or cctv batteries. These are the blue plastic batteries from hong kong sold on ebay. They are good batteries, but two things you should know. a) the ratings are half what they say they are. b) the voltage is 11.5 at the highest.

4. SLA batteries. Those brick shaped black batteries with two tab terminals on the top. Cheap, deep cycle, easily charged, big and heavy.

5. Household alkaline batteries. A very popular amplifier, the

http://www.parts-express.com/dayton-audio-dta-1-cl...

runs on these. Its a great way to go.

I learned that I always wanted the highest volume these little 12v amplifiers could muster, so this eliminated the cheap blue Lithium batteries, because they ran at 11.5 volts, and all the other batteries run at over 14 volts. Thats a very noticeable volume difference.

Charging is a whole nother topic. At least know that the charger needs to operate at a higher voltage than your battery, and if you want to run your amplifier at the same time, it needs to accept that high charging voltage and still operate. This little fact removes some very good amplifier options.

Hope this helps for anyone interested in choosing batteries for their next boombox.




Could you post a link to a cctv battery you have used for your 12v amps? I am trying to find a good battery to run my lepai amp powered boombox.

thanks!

Those batteries from HK are in fact lipo's. Highest voltage is 12.6, nominal is 11.1. Lipo or li-ion or both good if used and manufactured correctly. The 'Rolls Royce' of batteries is LiFePO4, not lipo. AA batteries are not a great way to go. They aren't cheap considering they only last you 1 (pretty short) time. They are by far the most expensive option when taking cycle life of other battery types in consideration. Charging and playing is not a great option since chargers are not made for a variable load like an amplifier, nor do they supply enough current (in most cases). NiMH shouldn't even be considered unless it's free.

Your asking for way too much. Especially at that price range. You can find good Li-ion batteries that offer 24V @ 9Ah but you'll have to pay ten times what your wanting to pay for it. Not to mention they are about 7"x4"x3". If you want a compact size and lower cost than you need to do some more engineering on your power needs. Find a better amp that will run on less power but still give you the sound you want.
torclausen (author)  mpilchfamily4 years ago
What about buying a "c" battery holder with enough bays for 24v, and a 24v scooter 2 amp charger? How much are those lithium cells?

I can get a wonderful cctv lithium battery, 12v, 10 amp/hr... $25. Seems I should be able to find something out there in the ball park.

Does anyone know souped up scooter batteries?

T
I've seen the $25 ones as well but am suspicious about them. When most good quality Lithium batteries of that size run in the range of $100 and $300. A battery that cheap has something wrong with it. Either its not going to provide the voltage you expect, won't last as long as it claims, doesn't hold a charge very well, has cheap/bad charge protection, or may just plain catch fire on you. There are a lot of cheap knockoff products that come out of China that can cause some major problems for you since they are imitations and slide past any quality assurance processes that may be required for those products. So buyer beware on these kinds of things. This may be why those cheap 12V ones won't work in series. It shouldn't matter to the battery if there are more than 1 of them connected in series or parallel. It will only matter when it comes to charging them. You will have to disconnect them and recharge them as separate batteries.