LIPO FANS, this is for you

[mOOsE]

Just thought I would link these for you guys that run lithiums or want to run lithiums. These are cheap solutions that would greatly benefit some of you.

The first is a universal voltage cutoff so you can run lithiums on a standard ESC without ruining your cells...under 20 bucks.
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=KKMAVC1AIR


The second item is a voltage cutoff that you can use to charge lipo's with a standard charger....but ONLY if you can regulate the amperage. Lipos must only be charged up to 1 times there capacity so : 1900mah = charge 1.9 amps max
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=KKMLIPOSG2S

I have not tried the second device but post results if you do and always remember to watch your lipo's no matter what...things can get a little hairy if something bad happens

[pimpsmurf]

The first is a universal voltage cutoff so you can run lithiums on a standard ESC without ruining your cells...under 20 bucks.
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=KKMAVC1AIR


Hot dog. That is freaking sweet, but beware. That will only work with an external ESC setup. I think it's weird that they can properly measure voltage with only the positive terminal. I mean, you wouldn't need it with the mamba ESC, but any ESC that regulated the voltage to the reciever I would think would mess up the numbers. I mean, can it measure holes (positive) without equal EMF from the negative side? I guess so or they wouldn't sell it. lol.




The second item is a voltage cutoff that you can use to charge lipo's with a standard charger....but ONLY if you can regulate the amperage. Lipos must only be charged up to 1 times there capacity so : 1900mah = charge 1.9 amps max
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=KKMLIPOSG2S

I have not tried the second device but post results if you do and always remember to watch your lipo's no matter what...things can get a little hairy if something bad happens

Actually some batteries (specifically, many cell phone lipos) have 1.5c-2c charge rates. Lipo designs are a mixture of high current, high capacity, or slightly higher charger rates. Cell phones don't have a need for high current, so they aim twards charge time, and capacity. sweet.

Indeed things can get hairy if something goes wrong. b-p-p has charing containers that are cheap and sweet! They also have a cell balancer that works inline with the charger, or as a standalone unit. Very freaking sweet (and also cheap.)

-JNY

[mOOsE]

here is the link to the lipo container if anyone is interested in that as well. It is a fire-proof container designed for charging your batteries indoors. Great for those people who don't want to baby-sit their chargers...like me.
http://www.b-p-p.com/proddetail.php?prod=1_BB

[Hawk]

Actually some batteries (specifically, many cell phone lipos) have 1.5c-2c charge rates. Lipo designs are a mixture of high current, high capacity, or slightly higher charger rates. Cell phones don't have a need for high current, so they aim twards charge time, and capacity. sweet.

-JNY
I know my (Motorola) Cell Phone is Lion, not LiPo. They are different in how they act/react. I don't think they have the heat runaway issues that LiPo does.

[pimpsmurf]

Lithium ions most certainly do have the similar issues. Some consider them more dangerous because you can see a lipo overheating and ballooning, but if you see a lithium ion overheat, it is generally already too late to prevent an explosion (more of a pop from my experience... still, shrapnell sucks.)

Newer phones use lithium polymers instead of lithium ions. Not all new phones. Mine has a lipo and charges, from totally dead, in 30 minutes. 4 day talk time usually.

-JNY

[mOOsE]

both battery types are similar in how they react to overcharging...the reason you see them expand is not because of the battery type, but because they are a gell-type cell. Typical NiMh/NiCd batteries are housed in a metal container that will still hold in the gases until the point of bursting. Expansion is caused by the gases that are forming in your now, expensive firework, lithium battery that was overcharged/discharged. :)

[Hawk]

from what I have read in several places, rechargeable Lithium Ion battery packs, since the early 1990's have had built in safety systems. over-charge, over-discharge and short protection is required due to the liquid electrolyte of LiIon in a sealed metal can is a micro hand grenade with some pretty nasty stuff.

LiPo cells are not considered as high a risk because of the plastic bag construction that allows them to vent by rupturing the bag.

So, the chemistry is actually more dangerous but they are proctected because of that and the sealed can packaging.

Also, the LiPo is actually a hybrid that is LiIon/Po. Instead of liquid electrolyte, a gel sheet that is perforated is used with additonal electrolyte. So LiPo is really a LiIon too.

[scottb]

The second item is a voltage cutoff that you can use to charge lipo's with a standard charger....but ONLY if you can regulate the amperage. Lipos must only be charged up to 1 times there capacity so : 1900mah = charge 1.9 amps max
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=KKMLIPOSG2S

This item from Kokam is only for use with a Lipo charger (e.g. Triton, Ice, etc.). You can not use this with a standard Nicd/nimh charger - your pack will not peak or it will over-charge. This device is similar to the Polyquest charge guard (PCM).

Note on Lipo's - I've only run lipo's for 3 months. I took the time and went to some airplane forums to read up (rcgroups.com rcuniverse.com). If interested, I would suggest doing the same (maybe I'll find a good link). Lipo's do not always have charge guards (they are becoming less popular now). Lithium Ion batteries (used in cell phones, cameras, etc.) will not work - they can not handle the amps - and will cut out (they will work in mini-z's and smaller). Lipo's are worth it - but do all the reading you can before you invest.

[mOOsE]

Here is the description from FMA
"Kokam has developed the new Safety Guard to prevent overvoltage when charging LiPo packs with a current-regulated LiPo charger. When connected between charger and battery pack Safety Guard limits charge voltage to 4.2 volts per cell. Many LiPo chargers have selectable output voltages for charging LiPo packs in various configurations (2S,3S,4S, etc.). If you accidentally apply a too-high voltage to a pack, the pack will be damaged or destroyed. Safety Guard prevents overvoltage damage.

Safety Guard has other important features like making charging LiPo packs possible with sources not specifically designed for that purpose. (See the manual for Safety Guard under the SUPPORT section of the FMA website for more information)."

This was only a simple solution if you want to try this product. I still recommend a lipo charger but you CAN use this with a non-lipo charger according to FMA!

[pimpsmurf]

Hawk,
Indeed! Most PACKS do, but most hobbiests don't use over-draw protection like comes in the packs (batteryspace.com sells them.)

They are neat, but will cause problems when you are intentionally overdrawing them. It can cause your *brushed* car to "cogg". Most people with very hot motors on 1:24 scale can't use the protectors unless they have 2s2p lithium ions. Even then, sometimes (X2 Light Speed Pro Edition) you can have unintended issues. =)

m00se, No way. Don't risk that. Bad idea. Use it with a lipo charger if you have a really cheap one like the batteryspace 1-4 cell charger and have mental retardation issues. If you have an auto charger, (like the dynamite NiCD/NMHd/LiPo charger which owns all) it is a waste of money.

-JNY

[mOOsE]

I use a Duratrax ice, but thanks for reading :rolleyes:

[pimpsmurf]

I know you do brother! I see how you got that out of my post. I was in a rush because I am sort of working here.

I was just worried about people around here that might start a fire. I read you comment man. I'm just countering your post of Kokam's info. Screw that charger interface. Cheap 110v lipo wall-chargers are $25. Is it worth saving $15 to have a more serious fire risk? Take no chances with lithium power kids! :D

-JNY

[pimpsmurf]

Thats for the info on the lipo cutoff. I just scored a Mini LST which I want to keep w/ brushed motors for now, and it's going to be very useful!

You rock man,
-JNY