Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

total noob, need advice on battery

Status
Not open for further replies.

eanhl2004

New Member
Here is the problem, I have a Supertooth Disco portable speaker for work, it does not play at high volume for 10 hours... the included battery is two 4.8 volt, 4 cell battery packs at 2200maH's for a total of 9.6 volts and 4400maH's. The device is charged by a wall plug and the battery packs permanently installed in the case, it takes about 3 hours to charge as it is and once it's done a Green Light let's you know it's fully charged... (it's red when first plugged in)...

I am looking to create two new battery packs with 10,000maH or greater.. but I am not sure if they will fully charge being installed permanently inside of the unit and plugged into a wall.. how does the charger know when the batteries are full?

you can find a video on youtube showing some of the supertooth disco internals...

supertooth disco battery replacement

I am worried that I will spend my time upgrading the battery only to have the charge not be completed and still only have the same playing time as I currently do!!!

Thanks for any help!
 
Now that you mention it I have the same question. How does the battery charge indicator know how much juice is left? I think it's not a voltage meter, as some batteries present a flat voltage curve until they are almost dead!

I hope your question may also solve mine
 
Last edited:
...the included battery is two 4.8 volt, 4 cell battery packs at 2200mAh's for a total of 9.6 volts and 4400mAh's.

Your math is misapplied. Depending on how the battery packs are connected, you can double the voltage or you can double the capacity, but not both which would represent a quadrupling of total power.

(2.2Ah X 2) X 4.8V = 21.12Wh or (4.8V X 2) X 2.2Ah = 21.12Wh
 
Charge controllers vary in sophistication and by battery chemistry but generally measure three factors to terminate charge: voltage, temperature and time. Without knowing the battery chemistry, cell configuration and charger design specifications, a redesign would be guess work.

It may be possible to replace the AA packs with C or D packs of the same type and configuration and simply take much longer to charge, or some less favorable outcome could result.
 
the internal resistance of the battery changes under discharge. measure that and u can track soc.
 
The battery is an old Ni-Cad or a newer Ni-MH type.
Some simple chargers for them are simple timers.

You cannot use the existing timer to fully charge a battery with a higher capacity because the charging current must be increased.
 
Your math is misapplied. Depending on how the battery packs are connected, you can double the voltage or you can double the capacity, but not both which would represent a quadrupling of total power.

(2.2Ah X 2) X 4.8V = 21.12Wh or (4.8V X 2) X 2.2Ah = 21.12Wh


Thanks for the information, not really the question I was trying to ask.... the point is going from 4400mah total to 10,000mah or more so that I can at least double the length of time I can listen to the unit at a higher volume! I do not plan to change the wiring scheme of the unit, just replace batteries with more maH which should double the length of use before recharge assuming the charger fills the batteries AND I wire it the exact same way keeping the volts the same, correct?
 
The battery is an old Ni-Cad or a newer Ni-MH type.
Some simple chargers for them are simple timers.

You cannot use the existing timer to fully charge a battery with a higher capacity because the charging current must be increased.

So in order to know which way my charger works I need to take a picture of the PCB and show somebody who would know how to read it? How complicated is a timer to make, expense? Is it a better idea to replace the battery packs with a cell holder and then recharged the batteries with a wall charger (If even possible)
 
going from 4400mah total to 10,000mah or more so that I can at least double the length of time I can listen to the unit at a higher volume!
No.
The volume will be the same. The mAh of a battery determines its length of playing time before it is discharged. If you want more volume then you need a more powerful sound system (higher battery voltage, better amplifier and better speakers).

I do not plan to change the wiring scheme of the unit, just replace batteries with more maH which should double the length of use before recharge assuming the charger fills the batteries AND I wire it the exact same way keeping the volts the same, correct?
Maybe. The existing charger might not fully charge a larger battery.
How will you connect to a larger battery without changing the wiring?

So in order to know which way my charger works I need to take a picture of the PCB and show somebody who would know how to read it?
Usually we see how a circuit works from its schematic, not from a photo.
But its parts might be Chinese that we do not know anything about.
 
going from 4400 mAh

Let me rephrase without the math. You don't have 9.6V at 4400mAh. You have 9.6V at 2200mAh (likely) or you have 4.8V at 4400mAh (unlikely).

I know you don't care about this. You just want to know if you can hack in some D cells where you have AA's and get 5 times the play time. The answer is maybe.
 
You can try the larger batteries with the built-in charger and see if it works to fully charge the batteries. If not then the easiest would likely be to just charge them with an external charger designed for that purpose. The best chasrgers are those that actually monitor the voltage delta and perhaps temperature to determine when the battery is charged, rather than the cheap chargers than just charge for a fixed time period.
 
Well I normally use the supertooth disco for 8 hours at low-medium volume and it dies some time after that.. then I think it takes 3 hours to charge once the red low battery indicator comes on... yesterday I didn't use it the whole day and we got out early.. it charged up to GREEN in two hours or less.. so it's not 'timer based'

At $120 shipped and considering it's brand new & not easily torn apart (hot glued rather than screwed) I am thinking that it just isn't worth tearing apart and trying longer life batteries on a hunch.. I think I would be better served to just buy a second unit! I'm a noob and just building a battery pack is a challenge to me (mostly the soldering part)

Building my own speaker system from the ground up sounds like a better idea because I would KNOW what was what!!!! Thanks for the help guys!!! (In Over My Head)
 
Another possibility that you might consider is plugging in an external 12V battery. The unit has a coaxial DC power jack that it uses for charging so if it will run while charging, that would work and the internal batteries would be charged from the 12V battery if needed. The internal batteries may not charge completely when the 12V battery is run down a bit.

Something like this would give you at least 4 times the run time.

http://www.frys.com/product/6607874?site=sr:SEARCH:MAIN_RSLT_PG

Of course you would need a conector and a small charger for it. A battery specialty store like Batteries Plus could set it up for you or you could do it yourself.
 
Last edited:
Another possibility that you might consider is plugging in an external 12V battery. The unit has a coaxial DC power jack that it uses for charging so if it will run while charging, that would work and the internal batteries would be charged from the 12V battery if needed. The internal batteries may not charge completely when the 12V battery is run down a bit.

Something like this would give you at least 4 times the run time.

http://www.frys.com/product/6607874?site=sr:SEARCH:MAIN_RSLT_PG

Of course you would need a conector and a small charger for it. A battery specialty store like Batteries Plus could set it up for you or you could do it yourself.

I was thinking about that possibility but it brings more trouble than it's worth.. too much to carry and too much to attach to my work environment (fork truck/tugger) etc
 
I'd be looking to plug into the virtually unlimited onboard supply which would only require connectors and cable but that might require some voltage conversion.
 
I'd be looking to plug into the virtually unlimited onboard supply which would only require connectors and cable but that might require some voltage conversion.

That mod could lead to my termination.. I can utilize the USB power ports though as it's not a permanent modification!
 
I'd be surprised if a machine that has 5V USB power available doesn't also have 12V auxilliary connectors.

If you worked for me I'd fire you for playing music through anything other than ear buds since you're subjecting your coworkers to your music, invading their minds and interferring with the safe and efficient performance of their work. :p
 
Last edited:
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top