12v 9800mah battery from ebay.

[dino_squirrel]

so as an electronics guy, my friend told me about this battery he heard about in here, that guys were using -> http://www.ebay.com/itm/New-DC-12V-P...item27c429bc98

I know A LOT about batteries, and when I saw this, red flags went up EVERYWEHRE! So I bought it... Bad news kids. If you want to seriously endanger your life, your equipment, and home, then go ahead and use this battery.

Here's why.

1) The battery is NOT Lithium Ion, It's lithium Polymer. LiIon cells are metal cased and much safer.
2) the cells are not even REMOTELY close to the advertised capacity.
3) You MUST have a special charger for ANY Lithium cell - MUST. You need a balancer, or have a PCB that balances the cells or you WILL eventually start a fire - Lithium fires are absoluterly no jokes. Check out any RC forum and look for pictures of guys who walked away from their charging batteries when their cheap charger failed. Check out youtube for the same.

Here's the dirty

Inside this battery pack there are 6 cells. All Lithium cells are 3.7 volts, so in a series they add up to 11.1volts at a nominal charge. So when these batteries are fully charged they are 12.6, and dead are 10.5. Because there are 6 cells, they are run in series to raise the voltage, and parallel to raise the capacity. So two cells act as one, and are then run in series. That's all fine, except the capacity of these cells is VERY low. The batteries say ON THEM - 3.7v 8.6wh (watt hour). The conversion per cell, is 3.7v at 2.3ah/2300mah (just drop the zeros and you have AH, aka AmpHour, so lets deal in that for now on). So in parallel it's only 4.6ah! Last time I checked, that's a full 5.2ah that's missing! RC li-pos that are 11.1v 5.2ah are more than DOUBLE the size of these batteries. Why they're dangerous is because the charger that is used is NOT a balancer, it does NOT stop outputing voltage, it does NOT indicate voltage charge, and will continue to try and charge the pack once ONE battery is up to capacity. A liPo's charge is 4.2 full and 3.5 dead, therefore, if a battery reaches it's charge first, it will then continue to charge - when lipos overcharge, they explode, VERY VERY VIOLENTLY! THIS IS NOT A JOKE - Generally when LiPos go, they burn down EVERYTHING around them. Unless you have a LiPO BOX (generally steel, or concrete) you're chances of much surviving are low.

The reason you can't charge LiPos in series is because each cell, reaches it's voltage at different times. So like I said, if one cell is at 4.2 and another 3.9, then by the time the lower one gets to 4.2, the other is most likely at 4.5 or higher and that's considered lethal at that point. This battery pack has no balancing PCB inside, BUT does have fuses that cut off output current, but that doesn't help the charging.

Another reason these batteries are garbage - LiPos are Light, HIGH capacity, and GREAT for discharging at high current, but not these. haha, I tried to pull 2 amps and didn't even come close. LiPos usually discharge at 15x and higher their capacity, but this battery won't even do more than 2 amps. Here's a link to the exact cells inside -> http://sz-haosheng.en.alibaba.com/pr...ufacturer.html
You can tell by the tiny wires coming off this battery that are for low current applications, and running a camera, monitor, and ANYTHING else is not low current.

Bottom line - RUN don't walk, RUN away from these things. Are a real danger with their given setup. Stop buying them, advise others to do so. If you don't believe me, or believe I've stated something wrong then I urge you to speak up. I may have, even I make mistakes. ;)

Oh, I almost forgot. If you discharge the battery below 10.5, then just throw it away. Once the battery goes below a certain voltage it's ruined and there is NO WAY to revive them. If you heard otherwise, I know what you're going to try, DON'T - You WILL set the battery on fire.

Here's what happens when you catch an overcharge (IF you can see the batteries) http://www.youtube.com/watch?v=0ZiG62Tawcc
Here's what happens when you don't catch and overcharge http://www.youtube.com/watch?v=EseOh...eature=related

[richg101]

is there not a protection circuit within the shrinkwrap? I'd be surprised if there wasnt. a cut off/over charge/discharge is standard in any multi cell pack. At this price one should expect the rated capacity to be a little untrue. Also remember this is designed for temporary cctv cams and the like. 2 amps is still useful for a battery of this weight and price. I dont know many dslr's, or camcorders which pull more than 1.5a at 12v. this battery will provide 24watts continuous (at 2a, 12v). thats a lot of light if using led's. 24x 1w luxeons will blow your head off. pulling more than 1a continuous from a cyclic 12v sla will render the operating times significantly less than the rated capacity (rated at 1a) as well. Horses for courses if you ask me. if you need 15c discharge, go with lipos designed for rc models. our profession doesnt see us running brushless dc motors at 1000w for 3 minute races very often

[dino_squirrel]

There is a small pcb that two cells are soldered to, but it contains no IC and is just straight series to match .with most people looking to run a monitor, camera, and maybe a lav, I don't see the battery doing much. I knew someone would have lipo knowledge on here. The cells do have what I presume to be some sort of current regulating component, but if it shuts off while charging, that means that the rest of the cells starve and don't get fully charged. I even told myself that even if the battery has 3/4 the capacity it would be worth it, but considering the draw current being so low,I don't think it comes even close

[Green Hornet]

I purchased another brand that was sealed in a plastic case. Said it was 9800 MHA, and 12 volts. It looks much nicer and has a power switch and led.
I used it 3 weeks ago to power an on camera monitor and it lasted 4 hours of shooting time, 1 hour of standby.
Not sure how to see how long it will last until dead. The shoot was over, so not sure how much more was left in it.
I think I paid like $36 to my door, from a guy named sinedya on ebay. Great product.

[djosbun]

That's why I never buy no-name eBay stuff, since there's a high percentage that it will be junk. Used to work with a guy that bought memory cards on eBay and almost 50% of them were DOA.

Dave

[Blue Bomber]

Saw someone using this on YouTube:
http://www.youtube.com/watch?v=yzMja...81365044EC4344

Should be safe enough, right? They also make a cheaper version.

[Paul Jonathan]

Sorry to dig up this old thread, but any else successfully using these? I am looking to power a SmallHD DP6 with them, but there seems to be a plenty of different options on Ebay. If anyone has any experience with using the 12v DC Ebay batteries like these or has any other suggestions on how to power the monitor cheaply let me know!

Thanks

[Paul F]

I have them. I haven't used them much. I wouldn't recommend them. It's a nice package, but the insides are garbage. I had one arrive non-working. I wanted a replacement and the vendor said to take it to an electronics store and have them fix it and they would cover the cost. The reason they did this is that they knew exactly what was wrong (broken wires)

I took it apart and found a piece of junk inside. As said, they are not Li-Ion batteries. They have several flat-pack cells glued together in a box that is too big for the cells (probably to prevent overheating). The problem is that they don't have a good way to keep the cells in the center of the box (glue). If it is dropped, the glue comes loose and the cells now are rattling around inside the box.

Secondly, the wires are nearly hair-thin, like tiny transformer wire. I don't know how much power those wires can support, but it can't be much.

I use a lot of cheap stuff to save money, but this isn't one I recommend. Stay away from these. Get a legitimate battery system. The problem is, I don't have anything to recommend. I don't know of anything that has this packaging that would work well for a monitor.That's why these are so attractive. I switched to a Lilliput monitor that has the battery plate built in for various batteries and I use that now. But if you want to go wireless, than you need a different battery pack that will power the wireless 5v receiver and the 12v monitor. There are solutions for that; one recently posted. I'll look for it and post it if I find it.

I suspect many people have had a decent experience with these, but it's not a good investment over the long run.

[Paul Jonathan]

Thank you so much for your advice Paul, I guess I will stay away from these then. It's just that I will be mostly powering the monitor via D-tap when on larger camera systems, but I would like to have a portable solution when using it with my t2i for smaller stuff. The battery plates only work for the 5D batteries, which I don't own, so buying the Canon plate and new batteries, which I can't use for anything else, would set me back almost $150.

How is everyone else powering their monitor here if not with camera batteries?