BMS, which one is good for my aplication.

[menace]

Hi guys, my first post here. So hello to all those reading my post. Have done a fair bit of reading of the threads in here and its a great forum with some great minds.

Im am slowly piecing together the parts to build a portable boom box thingy for playing music. The batteries i will use are A123 26650's( I have these already) in a 4s2p configuration The idea is that it will never have to be plugged in to a power source and will charge from solar during the day when needed. So it will need to be able to charge and play music at the same time.

First, will this board be suitable for what i want to Do? (I will definatly not be drawing anything close to 7 amps)
http://www.batteryspace.com/pcbprotectioncircuitmodulefor4cells128vlifepo3batterypackat7aimit.aspx

Second, am i able to just wire the solar panel to the charge/discharge termionals on the board?

Also with regard to this board, I am also interested in looking after the cells so i can get a ten year plus life span from my "boombox". So are the max/minimum voltages of this board appriopriate to achieve this?

Kind regards, menace.

P.S. I realise that "portable boombox"s" are not the focus of this forum but this is the best place i have found so far where people are into the technologies I am using.

 

[menace]

Nobody?

 

[SamTexas]

I have no hand-on experience with that PCB. But according to the specs, it does not balance, only hvc/lvc and current limiting. In other words, you still have to check for proper balance and balance the cells manually if and when neccessary.

 

[Ykick]

There's a lot of ways to do what you describe. Those are decent density cells and can deliver more current than most small audio amps will require. I've got some here 5-6 years old still running power tools and portable devices.

Rarely dipping into LVC region will drastically reduce the need for balancing. You should decide if you will likely run it until dead or use shallow DOD's? If the later, you might be fine with a simple 12V solar charge controller and crude LVC/alarm, power meter, RC Charger, single cell wall wart, etc. Frequently running until dead you will want to spec a balancing or sometimes called "Equilibrium" BMS.

I've always felt battery powered sound & light stages may someday earn a place in music festival performance. Solar charge during the day and party into the night!

Would love to see what you have in mind for your boom box...

 

[menace]

There's a lot of ways to do what you describe. Those are decent density cells and can deliver more current than most small audio amps will require. I've got some here 5-6 years old still running power tools and portable devices.

Rarely dipping into LVC region will drastically reduce the need for balancing. You should decide if you will likely run it until dead or use shallow DOD's? If the later, you might be fine with a simple 12V solar charge controller and crude LVC/alarm, power meter, RC Charger, single cell wall wart, etc. Frequently running until dead you will want to spec a balancing or sometimes called "Equilibrium" BMS.

I've always felt battery powered sound & light stages may someday earn a place in music festival performance. Solar charge during the day and party into the night!

Would love to see what you have in mind for your boom box...

Thanks for the reply.

The amplifier i have will draw upto 360mA, so when the days are not quite so long and the party manages to last all night then there is definatly good chance of reaching LVC.
Shallows DOD's sounds good to me, as the A123's paper on there nanotechnology suggest potential of 7000 1c 1c cycle's and still mantaining 80 percent of original capacity(well thats whats on there graph anyway). This seems too good a posibility to waste in my opinion. Could it be possible to use an imax b6 charger? This would draw a little current itself i think or? In anycase could it be permantly connected? I want to build a perminant solution, something that is built and then not maintaned bar circuit breaking switch's for as long as possible.

Perhaps this board is more what im after, it appears pretty much designed to be used with a solar panel. Not sure if its balancing though.
The second link is to its manual and has more detail.
http://www.batteryspace.com/CMBfor12.8VLiFePO4BatteryPack-16Alimited.aspx
http://www.batteryspace.com/prod-specs/5352_3.pdf

Quite a few people have been building such "boombox" systems lately, Class D(switching) audio amplifier's are common, cheap and very efficiant these days AND great sound quality also..
I can link you to a couple of common projects if you would like to see.

Cheers, menace

 

[Ykick]

That should work (sans balance) to liason solar panels, battery pack and amp load together. Charge rate only 3A input - qualify your best case solar panel output?

As long as you match the cells reasonably well when assembling the pack (use the iMax?) and perhaps add JST pigtail for occasional balance maintenance - they should remain in decent equalibrium over the course of use with that form of BMS.

I hear you about amp tech. Only getting better and better plus high power batteries certainly reduce the need for isolation transformers, PS filtering, eh? Feel free to link me up!