Lipos care???

[dave mac]

is their somewhear I can read about, how to care for my lipo. when it was brand new it was amazing, after only a few weeks, it has dropped of, it still better then my 3300, wondering if im doing something wrong, I know of another guy who says the same thing

[tcolesen]

It has probably gone out of balance. This is where the cells in a pack no longer have a similar voltage to each other. A pack will continue to worsen when out of balance, as one cell will be overcharged, and the other will be overdischarged. If your pack has taps on it, then it can be balanced. Otherwise, you could try to add taps yourself, or just buy a new one with taps.

BTW, an unbalanced pack is one cause of Lipo mishaps such as puffing or fire. Keeping a pack balanced not only makes the pack last longer (higher performance for more time), but it also keeps the pack as safe as possible.

[Craps]

Dave and all of us are using my TP cell balancer on the taps. We all just got a batch of brand new gen2 TP8000-2S4Ps that have lost that little bit of punch at first. Maybe we are doing something wrong by storing them fully charged and should back down to storing them half charged????

We are using the balancer just long enough to hook up and all the lights go off and not during the entire charging phase. Is this correct????

They are still strong, but not as strong as the very first 2 or 3 runs.

Suggestions????

[tcolesen]

Lipos should be stored at 50%. TP recommends 3.85v as the resting voltage for storage. That could definately degrade them a little bit.

I am unsure of how the TP balancer works, but if the instructions say that the pack is in balance when it does what you are saying, then it should be fine.

Often it is recommended to do a few "conditioning" cycles to a Lipo when you first buy it. This means charge at about .5C and discharge at about 5C. There isn't a singular way to go about the first few cycles, but that should do it.

[glassdoctor]

Have you checked the temps of the cells? How warm do they get?

First things that come to mind that degrade lipos...
1. Heat. Anything over about 160* is not good. Capacity and voltage will suffer.
2. Over-discharging obviously is bad... and charging to more than 4.2v per cell.

Craps's 8000mah should have no heat issues... so I don't know what's up with that.

Do the 8000 packs even get warm Craps?

[Craps]

Mildly warm probably not over 120 degrees even after 25 minutes of run time. I heard the competition airplane flyers even pre-heat they're li-po packs to 110 degrees for them to preform better in the plane??

[tcolesen]

They might do that, but that's only so that the initial voltage drop is lowered (resistance of Lipos decreases as heat goes up).

[glassdoctor]

Yeah, lipos don't perform well when it's cold. Is it possible that's why you are geting poor results... running in colder conditions?

If the pack is cold it will run like crap. It will run better if it's "prewarmed" like craps mentioned.

If you are runnign them outside in the winter it really is an issue... the plane guys have to keep the packs warm and wrap them to keep them warm while flying.

Newer lipos are getting better at this, but some of the older cells are really bad. They only work well @ like 80* and above.

[dave mac]

tanks

[Craps]

Watched a very interesting show on the Discovery Channel Science Channel called "How it's made". They showed making a li-po battery with thin lithium ribbons .060" thick wound 26 times coated with a polymer to keep it from sticking together made into a plate, each plate was stacked with foam between each and they even installed heat plates every so often to warm the cells up stating the operational range of the li-po was between 104 to 176 degrees. This was a big car size battery that was around 2' wide by 2' thick by around 5' long, but I would say the principals are the same. Interesting show!

[ffactory666]

Ok then.
How would you balance this pack http://www.maxamps.com/index.html?lmd=38701.874433 it's the 8000mah 7.4v pack and as you can see has no connection for balancing it .

[scoob]

Ok then.
How would you balance this pack http://www.maxamps.com/index.html?lmd=38701.874433 it's the 8000mah 7.4v pack and as you can see has no connection for balancing it .

I'm not sure, but I wouldn't buy that one. You can get the Thunder Power Tp8000 from www.battlepack.com for $157. Cheaper and Thunder Power has a great reputation. I have two of them and they're great. They have the balance connector.

[ffactory666]

I'm not sure, but I wouldn't buy that one. You can get the Thunder Power Tp8000 from www.battlepack.com for $157. Cheaper and Thunder Power has a great reputation. I have two of them and they're great. They have the balance connector.


Too late , already have the Maxamps pack and been running it in my Rustler.
Performance has been great with no loss yet , but just wanted to know what options i have for balancing that pack when preformance does start to suffer.


cheers

[aqualato1]

Ok then.
How would you balance this pack http://www.maxamps.com/index.html?lmd=38701.874433 it's the 8000mah 7.4v pack and as you can see has no connection for balancing it .

When did you buy this pack? Right now they have an upgrade option for 3 or 4 bucks where they will add a balancer connection to the battery. Maxamps also carries a new 12,000 mah :eek: yah 12,000 7.4v Li-Po battery.

[tcolesen]

Maxamps also carries a new 12,000 mah :eek: yah 12,000 7.4v Li-Po battery.

It's not a 12,000mah cell, but 3 4000mah cells in parallel.

Contact Maxamps and ask them if they could put a balance connector onto your battery. My thoughts are that they say they can (Maxamps has awesome customer support), but you will have to pay a few dollars.

[scoob]

ffactory- I don't know what to tell you then, except to try and get a balance connector put on. On the up side, from my experience so far I have run my packs quite a bit and they have never needed to be balanced. They've been checked several times (thanks to Craps) and have not needed balancing. So, hopefully you will get plenty of usage from them without balancing if they won't put it on.

[glassdoctor]

You can check the voltage of each cell individually to check for balance. I don't know how they have the pack wrapped up, but it shouldn't be too hard to get to the tabs.

Craps... I saw that same show. Those batts were pretty cool huh?

[Craps]

You can check the voltage of each cell individually to check for balance. I don't know how they have the pack wrapped up, but it shouldn't be too hard to get to the tabs.

Craps... I saw that same show. Those batts were pretty cool huh?

Not ever cutting open a li-po cell, I always thought there was a liquid chemical in it, but I quess the liquid would be the polymer coating on the lithium melting from excess heat over 176 degrees??? I assume the soft feel of the cells is the foam to protect the plates?

[glassdoctor]

I believe the soft feel is because the inside is mostly a clay like material. I haven't cut open one myself but I think I saw a pic of one once. The "plates" are the soft-yet-firm stuff.

Either that or I have brainwashed myself. :)

The large thin cells on the TV show did look more "rigid" plate-like....

[ffactory666]

Thanks all for your advice on my Maxamps pack.
Austin from Maxamps can make me an adapter to run from the balancer to the pack so all is cool.

[chilledoutuk]

i have seen science videos demonstrating the reactivity of lithium when placed in watter.
They cut the lithium with a nife thats how soft it was.
I think when put in water it it frantically fizzed as it reacted with the water.

again i cant be certain as i did see this video at school over 10 years ago.

[tcolesen]

That was elemental lithium you saw. Lipos don't use anything near pure lithium, since it is bonded with other elements.

[GordonFreeman]

Elemental Sodium is fun in water too. In thier elemental states, both Sodium and Chlorine (Sodium Cloride is table salt) are posions, yet together, they are safe and keep us alive. Ironic. Although once they separate in your body, they exist as ions. Fun with chemistry.

Anyway....back to our regularly scheduled program.

I've found that cell imbalance at full charge to be the biggest killer of LiPos. High discharge rates will reduce the life/capacity, but it 'aint gonna explode under "normal" discharge loads.

The next biggest killer is overdischarging one of the cells, this leads to pack imbalance, which leads to overcharging one of the cells during charging.

Cell balance at full charge is key.

[papapackard]

This discussion has convinced me even further of the value in the FMA Scorpion car packs. They feature built in cell balancing and low voltage cutoff.

[ElectricThunder]

This discussion has convinced me even further of the value in the FMA Scorpion car packs. They feature built in cell balancing and low voltage cutoff.
I'd say FMA is ahead of the Lipo game with those features, and make the batteries that much more versatile. And the fact they can be "quick charged" is really really cool/useful. If other manufacturers made Lipos like FMA, it'd make things a whole lot easier when it comes to cell balancing, LVC, etc. IMO.:D

[tcolesen]

And the fact they can be "quick charged" is really really cool/useful. If other manufacturers made Lipos like FMA, it'd make things a whole lot easier when it comes to cell balancing, LVC, etc. IMO.:D

Thunder Power now has it so that their balancers can actually communicate with their new TP-1010C charger. This will allow the Thunder Power Prolites to be charged at up to 3C, as the balancer can tell the charger to slow down the charge. You can even see the individual cell voltages on the charger's LCD display! This setup is more expensive than the FMA Scorpion charger setup, but the Scorpion charger pretty much ONLY works with the Scorpion packs. The TP setup will work with ANY batteries that have taps (adapters can be made to fit the TP taps).
The one thing that TP doesn't have is the built-in LVC, but IMO, that is best. Having an external LVC that can be used with one battery or the next is better (IMO) than having one that is exclusive to a single battery. Over time it will be more cost efficient.

[Craps]

Thunder Power now has it so that their balancers can actually communicate with their new TP-1010C charger. This will allow the Thunder Power Prolites to be charged at up to 3C, as the balancer can tell the charger to slow down the charge. You can even see the individual cell voltages on the charger's LCD display! This setup is more expensive than the FMA Scorpion charger setup, but the Scorpion charger pretty much ONLY works with the Scorpion packs. The TP setup will work with ANY batteries that have taps (adapters can be made to fit the TP taps).
The one thing that TP doesn't have is the built-in LVC, but IMO, that is best. Having an external LVC that can be used with one battery or the next is better (IMO) than having one that is exclusive to a single battery. Over time it will be more cost efficient.

What is the max amp charge rate of that charger? 8000 mahs = 8 amps x 3C = 24 amps??? Wow!!!

[tcolesen]

It is 10amps for up to a certain number of cells (not sure how many). It can also do up to 10s Lipo. So, it can charge up to 3300mah at 3C. TP doesn't really make anything with a capacity close to that.

[Craps]

I wish TP did make a 24 amp charger that would charge my TP8000-2S4Ps at the 3C rate hooked to the balancer. That would charging back up as fast as I could use it. In other words, with 2 batteries I could run non-stop as long as the radio and parts don't break.

[tcolesen]

Good luck getting them to do that... As the amps go up, the price could go up exponentially.

[aqualato1]

In the near future they might! ;)

[SpEEdyBL]

I wish TP did make a 24 amp charger that would charge my TP8000-2S4Ps at the 3C rate hooked to the balancer. That would charging back up as fast as I could use it. In other words, with 2 batteries I could run non-stop as long as the radio and parts don't break.

How about using 2 chargers to charge two separate TP4000-2s2p packs each at 10 amps.