charging a lipo

Old 12-24-2014, 11:09 AM
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Originally Posted by Dave H View Post
I've tried it both ways. What I experienced was a higher internal resistance and quicker capacity loss with charging packs ahead of time compared to just in time. Same as most others who test have discovered.

Doesn't mean it can't be done, I just think it's worth knowing the tradeoffs. Batteries are disposable anyway and can be had fairly inexpensively, convenience is probably worth the reduction in performance for many, that's fine.

One item to be especially careful of is temperature changes while charged. Charge state changes with temperature, don't leave a charged pack in a parked car sitting in the sun for example.
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Old 12-24-2014, 11:32 PM
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Originally Posted by Mr RCTech View Post
Orca lipos
So typing it in a bigger font makes you feel justified spending $100 for a 2S lipo?

And the fact that I paid 1/3rd of the price for a 5800mah 2S hard case from China (and yea, it has a ROAR Approved sticker) must mean that I have a "crap" battery?

Time to remove the blinders, man.
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Old 12-24-2014, 11:46 PM
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Originally Posted by Dave H View Post
I've tried it both ways. What I experienced was a higher internal resistance and quicker capacity loss with charging packs ahead of time compared to just in time. Same as most others who test have discovered.

Doesn't mean it can't be done, I just think it's worth knowing the tradeoffs. Batteries are disposable anyway and can be had fairly inexpensively, convenience is probably worth the reduction in performance for many, that's fine.

One item to be especially careful of is temperature changes while charged. Charge state changes with temperature, don't leave a charged pack in a parked car sitting in the sun for example.
I've seen it at my LHS numerous times....2 things that kill cells and puff lipo's is newbs leaving them fully charged for days, even weeks without discharging and not charging them after running them....some even leave em still connected when they bring in the RC which we know drains them even further.

I hear the customer saying (here even) they don't have the time to put a lipo in proper storage mode......well then, so be it.

The alternative is to spend more $$$ on replacement lipo's...its that simple.
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Old 12-27-2014, 10:48 AM
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Originally Posted by Yosh70 View Post
So typing it in a bigger font makes you feel justified spending $100 for a 2S lipo?

And the fact that I paid 1/3rd of the price for a 5800mah 2S hard case from China (and yea, it has a ROAR Approved sticker) must mean that I have a "crap" battery?

Time to remove the blinders, man.
If your bashing I would say yes!

Well, racing there is a HUGE difference with running cheap lipos.
Never seen a cheap lipo battery in the A-main.
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Old 12-27-2014, 11:30 AM
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Originally Posted by Mr RCTech View Post
If your bashing I would say yes!

Well, racing there is a HUGE difference with running cheap lipos.
Never seen a cheap lipo battery in the A-main.
Whatever makes you feel good......
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Old 12-28-2014, 04:25 PM
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Let's dispell some of the myths here:
Originally Posted by Yosh70 View Post
I've seen it at my LHS numerous times....2 things that kill cells and puff lipo's is newbs leaving them fully charged for days, even weeks without discharging and not charging them after running them....some even leave em still connected when they bring in the RC which we know drains them even further....
Unless there was something already wrong with the LiPo, such as having been left in a warm display case at the store for many months or it is just a cheap 5-10C battery labelled as 50C (this happens even with some of the big name expensive batteries), leaving it fully charged for a few days or even a few weeks will not cause the LiPo to puff excessively, it will, however, reduce the internal resistance of the battery and over time the battery will lose its punch and degrade faster than it would if it had been stored correctly.

That said, leaving them plugged into the ESC even for a few hours can dramatically reduce their charge and will definitely lead to bad things. The same could be said for running batteries and not topping them up, but most cars have LiPo cutoffs now that can be set to cutoff at a safe storage level.

Also battery manufacture is not 100% fault free, every now and then a dud gets through and regardless of what the customer has done it will puff. This is more common with really cheap no-name batteries but it can happen with any battery, there are a lot of variables in the supply chain that can affect a LiPo.

All retailers of RC batteries should check the cells they sell before they go on the shelf and when the customer purchases them. Both the retailer and the customer are covered then.

Originally Posted by Yosh70 View Post
And the fact that I paid 1/3rd of the price for a 5800mah 2S hard case from China (and yea, it has a ROAR Approved sticker) must mean that I have a "crap" battery?
ALL RC LiPo batteries come from China, it is virtually impossible to get one from somewhere else. There are only a few factories in China who make reasonable race packs and they make them for all the big name brands. So if you are paying $19 for a ROAR pack or $100, chances are that they came from the same factory, off the same production line using exactly the same materials.

There IS a big difference however between a 25C battery and 50-60C battery and you will pay more for the extra C rating, because they cost more to manufacture. There is also a big cost difference to carbon nano-tube chemistry which means the cells will last even longer and have a lower IR. There are also a couple of other chemistries that have advantages and cost more but they aren't ROAR approved.

There are 3 or 4 highly reputable brands of battery out there and they tend not to be the ones sponsoring RC drivers, mainly because the market is way bigger in planes and multis, which is where they spend most of their marketing dollars.

Originally Posted by Mr RCTech View Post
If your bashing I would say yes!

Well, racing there is a HUGE difference with running cheap lipos.
Never seen a cheap lipo battery in the A-main.
The reason you have never seen a "cheap" battery in an A-main has nothing to do with the quality of the battery but is a consequence of marketing dollars. Every aspect of RC racing is sponsored now and if all the top racers are sponsored by Brand X then Brand X will always be in the A-main, it goes the same for chassis', ESCs, motors, servos and even paint; you could give most of the sponsored guys an RC10 and a 20 year old brushed motor and they would still be on the podium in 2WD mod. Don't be fooled into thinking it's their batteries, they get the sponsors because they are good, not the other way around.

Top level drivers are being paid in the hundreds of thousands of dollars and club level guys are getting free tyres and batteries, that money has to come from somewhere and that somewhere is the consumer who buys those brands.

Last edited by nckmat; 12-28-2014 at 04:39 PM.
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Old 12-28-2014, 05:44 PM
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I have always charged the day before as I never know when I get to the track. I used to charge on Thurs. for the Sat. race. I guess I could charge the two first packs the day of the race, and start charging the other two when I get there. It is not like I am at a loss for power when I race. I guess all you top level drivers need to do this, not me. Right now the weather is cooler, so less chance of over heating. I guess this would be very important for outdoor racers on 3s or higher.
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Old 12-30-2014, 11:50 PM
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Originally Posted by Mr RCTech View Post
Orca lipos
The question wasn't for you but yes Orca lipos are good.
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Old 12-31-2014, 12:00 AM
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Originally Posted by nckmat View Post
Let's dispell some of the myths here:


Unless there was something already wrong with the LiPo, such as having been left in a warm display case at the store for many months or it is just a cheap 5-10C battery labelled as 50C (this happens even with some of the big name expensive batteries), leaving it fully charged for a few days or even a few weeks will not cause the LiPo to puff excessively, it will, however, reduce the internal resistance of the battery and over time the battery will lose its punch and degrade faster than it would if it had been stored correctly.
If you store lipo incorrectly the IR will increase more than it otherwise would (not decrease), also the capacity will also decrease faster than it otherwise would.

So you end up with a battery with less punch and less voltage at the end of the run.

I have nearly 480 cycles on one of my lipos, I will have to run it through my 30A linear discharger to double check the capacity but IR is less than 2mOhm per cell and the last time I checked the capacity (about 20 cycles ago) it was 89% of the original.

Leaving your lipos stored full charged from the tests I have done will increase the packs IR and reduce capacity. They can still be used but performance on track will be reduced.

Leaving your lipos stored full charge may also result in damage which I have seen when the ambient temperature was high.

So why take the risk?

Why not get the best on track performance by charging the packs just before your next run whilst maintaining the packs in the best possible condition for longer life.
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Old 12-31-2014, 06:37 AM
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Originally Posted by nckmat View Post
Let's dispell some of the myths here:
.......

So if you are paying $19 for a ROAR pack or $100, chances are that they came from the same factory, off the same production line using exactly the same materials.

There IS a big difference however between a 25C battery and 50-60C battery and you will pay more for the extra C rating, because they cost more to manufacture. There is also a big cost difference to carbon nano-tube chemistry which means the cells will last even longer and have a lower IR.

......
How can they be made with exactly the same materials, yet be different chemistries?
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Old 12-31-2014, 10:38 AM
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Originally Posted by Dave H View Post
How can they be made with exactly the same materials, yet be different chemistries?
There are different grades of lipos, that use higher quality of materials.

This is from EA:
The IR and Voltage are better than the last batch. Still no where near as good as stuff we had last winter. But Im told they had to change some things inside (chemicals) due to new regulations and its whats causing the differences. They are still trying to get everything back to normal with these new regulations.
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