2x 4000mah lipo batteries for $30 on ebay

Gordon1 · Post by **Gordon1** » Tue Jan 13, 2009 11:24 pm

bgnome wrote:
hailrazer wrote:Yes guys they will work. You just need the charging circuit linked to on page 1 of this thread and then a charger also linked on the first page.
please correct me if i am wrong, but i do not think you need to buy a separate protection circuit. the charger itself has the protection circuit built in to it. you are supposed to hook up the balancing connector to it and it is supposed to take care of maintaining each cell and bringing them up to the correct voltage.

Yes, these batteries need a protection circuit. I bought some and took them apart. If they get drained to much there is a chance they might catch fire. The protection circuit stops power coming from the batteries if the voltage gets too low. So, if you don't wanna burn get a protection circuit.

hailrazer · Post by **hailrazer** » Wed Jan 14, 2009 1:18 am

As mentioned.... THE ONLY PROPER AND SAFE WAY TO USE/CHARGE THESE BATTERIES IS WITH THE PROTECTION CIRCUIT !!!!

Do not attempt to charge these without one. It will not be nice.

cowsgoquack101 · Post by **cowsgoquack101** » Wed Jan 14, 2009 3:55 pm

Wait, just a question since I know little to nothing about batteries, is that charger linked on one of the pages (1st or 2nd) able to charge them without a protection circuit or will that still be necessary? Because the charger has the same connector for the batteries.

collinE · Post by **collinE** » Wed Jan 14, 2009 4:38 pm

cowsgoquack101 wrote:Wait, just a question since I know little to nothing about batteries, is that charger linked on one of the pages (1st or 2nd) able to charge them without a protection circuit or will that still be necessary? Because the charger has the same connector for the batteries.

the charger will only keep it from overcharging, but the safety PCB will keep it from overcharging, being drained too far (will cut off power once it gets to a certain voltage), and some will keep each cell balanced and equally charged.

jjhammerstein · Post by **jjhammerstein** » Wed Jan 14, 2009 4:44 pm

I think that the charger is made with the protection built in.
It HAS to be, otherwise they couldn't sell them together without a third piece.

hailrazer · Post by **hailrazer** » Wed Jan 14, 2009 5:30 pm

Dear Lord you guys are stubborn.

YOU HAVE TO HAVE THE PROTECTION CIRCUIT AND THE CHARGER !!!!!

End of discussion.

Gordon1 · Post by **Gordon1** » Wed Jan 14, 2009 5:31 pm

jjhammerstein wrote:I think that the charger is made with the protection built in.
It HAS to be, otherwise they couldn't sell them together without a third piece.

so, when your batteries are not being charged what is protecting them? Just buy the protection circuit. If you are too poor to afford one then you should not be porablizing.

hailrazer · Post by **hailrazer** » Wed Jan 14, 2009 5:33 pm

jjhammerstein wrote:I think that the charger is made with the protection built in.
It HAS to be, otherwise they couldn't sell them together without a third piece.

They sell them separate for a reason. They have different Current Limits, Overcharge Ratings, extra gauges and such.

One protection circuit won't work for all Li-Poly batteries. You need the correct one for the batteries you have.

bgnome · Post by **bgnome** » Wed Jan 14, 2009 5:57 pm

hailrazer wrote:Dear Lord you guys are stubborn.

YOU HAVE TO HAVE THE PROTECTION CIRCUIT AND THE CHARGER !!!!!

End of discussion.

i am with hammer on this one. like i have said, i have been doing quite a bit of research on this, and i think you might be confused as to the particular application these batteries are meant for. they are not being sold as single cells all willy-nilly-like, they are designed for RC application. NONE of the RC lipos come with an integrated protection circuit as they are designed for somewhat high discharge rates, which i would think would limit the amp output.

Here's a course paper by an electrical engineer that describes the options you have, (PCM integrated or not), and the advantages/disadvantages depending on the application. It is not a definitive source, but all I am saying is that no PCM is required if you use the correct type of charger. The overcharge protection and so on is built in to the charger, as described in the paper as one of the options, which is how they do it in the RC world.

If you use a balancing charger, you connect it to the balancing connection, which is wired to each individual cell. If you are not using a balancing charger, you will have to make sure that each cell is not overcharged, etc., which is where a PCM is important. Since the "smart charger" from allbattery is not meant to be a balancing charger, a PCM is required.

hailrazer · Post by **hailrazer** » Wed Jan 14, 2009 11:39 pm

But we're not using them for RC's. So you need a protection board. Simple as that.

jjhammerstein · Post by **jjhammerstein** » Thu Jan 15, 2009 12:36 pm

The protection board is for charging.
If this charger is made specifically for these batteries, unmodified, then it is VERY HIGHLY likeley that the charger has SOME sort of technology to prevent catastrophic failure.

bgnome · Post by **bgnome** » Thu Jan 15, 2009 5:03 pm

jjhammerstein wrote:The protection board is for charging.
If this charger is made specifically for these batteries, unmodified, then it is VERY HIGHLY likeley that the charger has SOME sort of technology to prevent catastrophic failure.

yes, the have a protection circuit IN them. not all chargers do, just these balancing ones.

hailrazer · Post by **hailrazer** » Thu Jan 15, 2009 5:58 pm

The protection circuit is also so that you don't overdischarge the batteries.

Website · Post by **Life of Brian** » Thu Jan 15, 2009 6:22 pm

hailrazer wrote:The protection circuit is also so that you don't overdischarge the batteries.

I was just going to mention that. Regardless of whether the charger has a protection circuit, you'll need something in the portable to prevent discharging the batteries too much. Besides, a protection circuit costs like, what, $3.50? Please. Put one in.

jjhammerstein · Post by **jjhammerstein** » Thu Jan 15, 2009 9:48 pm

I'm convinced.