Li-on system help

kasar · Post by **kasar** » Thu Jul 03, 2008 12:14 pm

well, after read some of batteries, I finally decided pay a little more for get a fine li-on system,but before buy, I need be sure this will work, and will not ruin/burn my project

will this work?

here is the stuff IÂ´m planning buy:

battery
protection circuit board
battery charge monitoring

I know the circuit board prot, is for 3 cells, but I didnt saw one for 1, So I was wondering if trouble can come if I use this one

another trouble is Idk if will be nice use the original gamecube charger for charge the battery (trought the pcb)

and also for charge/play at same time I was wondering if would be a nice idea.

IÂ´m a noob about Li-on batteries.

help!

Gordon1 · Post by **Gordon1** » Thu Jul 03, 2008 12:24 pm

I don't think that is right, I think you need to hook each cells negative onto the pcb but I am not sure. You still need a charger. click you cannot rely on the protection circuit alone for your battery charging safety.

What you should do is just buy 3 of these cells that have 1250mah more storage capacity for $52.50 (which is the same price as your other batteries cells). Then put them onto the protection circuit. Your battery is designed for an rc or robot application so, you are paying an extra $750 for two wires and a connector.

kasar · Post by **kasar** » Thu Jul 03, 2008 12:34 pm

ok, So there is no way to play and charge at same time?

Well,Just another question, if I charge the battery from the Li-on charger
(for example this one) should I charge the battery directly? or throught the protection circuit?

Gordon1 · Post by **Gordon1** » Thu Jul 03, 2008 12:40 pm

sorry, I screwed up and posted my comment before I was done with it. I'm sure you can play and charge, but I do not know what battery contacts co where onto that protection circuit. but you can for sure use that charger.

kasar · Post by **kasar** » Thu Jul 03, 2008 12:55 pm

thx.
about the connections B+ means battery +,B- means battery -,P+ means power +,P- means Power -, but it also have B1,B2 and B3, So IDK if I should connect the + of the battery also to the B1

EDIT:oh,I just saw your pic, but I only have 1 battery cell (not 3 at serial) thats why I was wondering if this PCB will work at me. So is there anyway to connect it to the PCB alone? wich will be the conection?

mmm,I am a little confusing now, I think the original gamecube powerplug, (wich give 12V 3A) 3A is enough for feed a 2.25A system and charge the battery slowly.

the PCB prevent the battery from overcharge and extremlyundercharge (this is most danger at li-on batteries I think), So I supose it "Cut" the power automatly when the battery is fully charged, then I think no risks.

but what exactly a "oficial" li-on charger do exactly? it cut the power when battery is fully charged? I think The PCB do this already. So IÂ´m very confused ^^

Also I preffer still using the original gamecube power suply to charge/play at same time,Cause think it is a nice charger, and Do it with simple I think It will make things easier. But Anyway I will consider any other options

so there is anyway to make this posible? (charge/play at sametime using the gc power suply)

Gordon1 · Post by **Gordon1** » Thu Jul 03, 2008 1:20 pm

kasar wrote:thx.
about the connections B+ means battery +,B- means battery -,P+ means power +,P- means Power -, but it also have B1,B2 and B3, So IDK if I should connect the + of the battery also to the B1

EDIT:oh,I just saw your pic, but I only have 1 battery cell (not 3 at serial) thats why I was wondering if this PCB will work at me. So is there anyway to connect it to the PCB alone? wich will be the conection?

mmm,I am a little confusing now, I think the original gamecube powerplug, (wich give 12V 3A) 3A is enough for feed a 2.25Ah system and charge the battery slowly.

the PCB prevent the battery from overcharge and extremlyundercharge (this is most danger at li-on batteries I think), So I supose it "Cut" the power automatly when the battery is fully charged, then I think no risks.

but what exactly a "oficial" li-on charger do exactly? it cut the power when battery is fully charged? I think The PCB do this already. So IÂ´m very confused ^^

Also I preffer still using the original gamecube power suply to charge/play at same time,Cause think it is a nice charger, and Do it with simple I think It will make things easier. But Anyway I will consider any other options

so there is anyway to make this posible? (charge/play at sametime using the gc power suply)

That battery pack has three cells wired in series wrapped up in plastic. A protection circuit is only designed to protect the battery, not charge it. If you want to be cheap then don't go with li-ions, use some ni-cad or ni-mh batteries. As for the game cube adapter, you can't use it, unless it magically has a li-ion charger built into it you are running the risk of explosions and death. as for the charge and play, the li-ion specific charger will allow you to do this. As for the b1, b2, b3..... stuff just follow the diagram I provided. The pic in the top right corner is the data sheet provided on the site.

and 2.25ah is a measure of capacity not amperage. 2.25A is correct terminology.

kasar · Post by **kasar** » Thu Jul 03, 2008 2:13 pm

Gordon1 wrote:
That battery pack has three cells wired in series wrapped up in plastic. A protection circuit is only designed to protect the battery, not charge it. If you want to be cheap then don't go with li-ions, use some ni-cad or ni-mh batteries. As for the game cube adapter, you can't use it, unless it magically has a li-ion charger built into it you are running the risk of explosions and death. as for the charge and play, the li-ion specific charger will allow you to do this. As for the b1, b2, b3..... stuff just follow the diagram I provided. The pic in the top right corner is the data sheet provided on the site.

and 2.25ah is a measure of capacity not amperage. 2.25A is correct terminology.

ah ok

hehe srry,seems I missed some important things.

Ok,well, seems there is much trouble with li-on for me, IÂ´m also cheap for somethings,my money isnÂ´t famous for the quantity, So I will consider look for some ni-mh packs.

I found some interesting one
http://www.batteryspace.com/index.asp?P ... rodID=1943
Idk if ni-mh explodes or get into flames like li-ons but I think It will be a bit easier, Dont know also what happen if overcharge

timmeh87 · Post by **timmeh87** » Thu Jul 03, 2008 3:23 pm

Woah woah woah slow down guys. Lets start from the beginning.

In the first picture, the battery pictured is a pack. That means it /already/ has a protection circuit inside. You do not need to connect it to another one.

You have to use the right number of cells for the protection circuit, as I am fairly certain that if the circuit does not see every battery, it will assume the missing ones are currently on fire or something and shut down.

A protection circuit is the last measure of saving yourself from an industrial accident, it is not a battery charger. In a lot of cases, once tripped, the protection circuit needs to be reset in some way, maybe pulling a pin low or writing to it over an i2c bus. Its not supposed to happen.

If you want to be cheap, you can just constant-voltage charge your cells, hooking the pack up to a voltage supply of ~4.15v per cell. This works fine, but it takes a lot longer (a day or two) and theres always a chance that you set the power supply wrong and burn your house down.

Otherwise, a smart charger will 'power-charge' the batteries to 70 or 80% at several amps, and then CV charge it as described above (low current). This can take as short as an hour or two. (This effect can be seen if you watch your laptop charge)

Anyways I designed a flashlight myself with bare cells and a home-built protection PCB, and I still have both my hands. The protection circuit even caught something once. It seems simple enough to be safe about it. Now one day I will apply this technology to a portable too.

Chapel · Post by **Chapel** » Thu Jul 03, 2008 4:04 pm

timmeh87 wrote:In the first picture, the battery pictured is a pack. That means it /already/ has a protection circuit inside. You do not need to connect it to another one.

I want to thank you for that statement as it put my mind very much at ease. I started reading this and was thinking, "Crap, did I forget to buy something for my first portable experiment? Am I risking blowing off my hands by messing around with this mess of wires and circuit boards on my desk?"

kasar · Post by **kasar** » Thu Jul 03, 2008 8:03 pm

thanks for the info timmeh87.

anyway seems the li-on batteris are a bit hard, dangerous, and expensive to handle. So i think I will try another easier kind of bateries.

(ok well, I admit,I still a noob here,I just finished one portable, well... cant call it portable to the first ugly plastic box I posted the forum when I registered,It also had a heavy battery like this

I connected it directly to the 12v suply of the gamecube and worked fine meanwhile using it. but at my cuarent project i want do at least a little advance respect from my first project.)

IÂ´m searching now a small 12v battery with enough power to feed my system at least 1:30 hours,I want also let it "built in" inside the system (this mean that will no be required extract the battery for charging) , also will be a nice idea use the same "power plug" for charge/use the system at same time, and finally will be nice be a not really expensive/dangerous pack of items wich be relative easy to set and install.

Well,I admit IÂ´m dreaming so much, but that should be the perfect pack for me, IÂ´m not fully sure if any ni-cd or ni-mh will got this couple of things working.
So if someone recomend me a fine pack wich got those features,I will be very thankfull