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Old 06-16-2008, 06:13 AM   #1
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Default Lipos For Dummies

Am thinking about making the move to Lipos.
So people who currently race and have good knowledge about the subject enlighten the beginner like me what to do and the do nots.

What do I need to get started into racing with using lipos.

We must have a charger to do lipos.(I have that)
Do all Lipos "ROAR" approved packs fit all current model cars with out issues
Do I need a balancer-what sort of balancer do I buy
How many packs do I need - where the race format consists of 2 heats and 3 finals with roughly an hour between rounds.
Do I have to wait for the pack to cool before charging
Do I stick to the recommended charge rate or is there advantage of charging faster
Do I need ro repeak
How often do I need to balance Lipo packs
Do I need to charge the packs on race day peak just before my race or can I charge them the night before.
Are the cheaper pack just as safe to use as a more expensive one and would they last roughly the same a more expensive pack as in runtime and the number of charges it could take before they die.
Do the expensive packs have more punch
How do you measure the internal resistance- can my charger do this?
How do you measure the condition of your pack.- Peak Voltage gets lower and lower???
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Old 06-16-2008, 10:35 AM   #2
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Quote:
Originally Posted by yeahyeah View Post
Am thinking about making the move to Lipos.
So people who currently race and have good knowledge about the subject enlighten the beginner like me what to do and the do nots.

What do I need to get started into racing with using lipos.

We must have a charger to do lipos.(I have that)
Do all Lipos "ROAR" approved packs fit all current model cars with out issues
Do I need a balancer-what sort of balancer do I buy
How many packs do I need - where the race format consists of 2 heats and 3 finals with roughly an hour between rounds.
Do I have to wait for the pack to cool before charging
Do I stick to the recommended charge rate or is there advantage of charging faster
Do I need ro repeak
How often do I need to balance Lipo packs
Do I need to charge the packs on race day peak just before my race or can I charge them the night before.
Are the cheaper pack just as safe to use as a more expensive one and would they last roughly the same a more expensive pack as in runtime and the number of charges it could take before they die.
Do the expensive packs have more punch
How do you measure the internal resistance- can my charger do this?
How do you measure the condition of your pack.- Peak Voltage gets lower and lower???
1. No
2. Recommended, but not necessary. Only needed for 1st charge of the day.
3. For me, 1 batt per car works.
4. No
5. There isn't any advantage. Although for top competitive batteries like to be heated and they seem to give off a bit more voltage. I race off-road mostly so this isn't needed for me.
6. You can just charge them the night before. No advantage to repeaking.
7. Get a quality pack. These batteries will last a while between replacements so it's worth the extra investment.
8. Depends on their rating. Some packs have 18C rating, some have 20 and above. Higher the # more punch it can offer.
9. Not sure.
10. Amount of charge it can take. As the pack ages, it loses capacity which leads to decreased runtime and voltage. Although quality packs only lose about 10% over 1000 charges.

Good luck. Me personally. I love it and I won't go back. Other item you'll need is a lipo sack or some sort of fireproof container to charge your packs in. Never charge your battery in your car. Never leave it in your car after the race day is complete. I recommend storing each battery in its own sack, that way if one goes up, it won't take any more out along with it.

I personally run Orion 3200s for now. For racing, since the discharge rate is so flat, the battery doesn't have to be peaked to get you through a race. Just make sure you have a lipo cutof sorts. either the novak or one built into your ESC.

Paul
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Old 06-16-2008, 10:38 AM   #3
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This is on the ROAR website as a general information sheet that might answer a few of your questions.

http://www.roarracing.com/downloads/...ipo_Reader.pdf
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Old 06-16-2008, 04:47 PM   #4
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Default Lipo

Thanks guys for the helpful information .
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Old 06-17-2008, 09:59 AM   #5
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Copy and paste from what i posted on another forum:

Balancer is always a good idea for lipos, irregardless of how big or small they are.

In the case of airplanes, the lipos experience a relatively consistent amp draw, this is good in a way that they don't 'shock' the cells.
For cars, we have very different demands in comparison, our amp draw tend to have huge flactuations, going from low draw to massive surges in amps when we're exiting corners with full throttle, against the car's inertia and road resistance. This tends to put the lipos thru a much harsher 'lifestyle' which do tend to magnify the underlying micro differences in every single cell, which could promote an overall imbalance.

Another area to note, imbalance is almost gauranteed to happen when we subject the pack to over discharging. With the newer developments on voltage cutoff controls, chances are reduced, which is a good thing.

Chargers nowadays have came a pretty long way in their precision of voltage control and evaluation, which is critical for CC-CV charging, in other words, lipo. Certain chargers come with balancers built in as well, some chargers have circuitries which charge every cell individually, some requires an external balancer, some takes a feedback loop from their external balancer, etc.

Take your pick

2 packs will be a good number for a day's racing without overstressing the lipos.

Wait for the pack to cool off a bit, as long as it's not hot or spiking warm, you're ok to charge. For better longevity protection, it will be good for it cool to close to ambient temperature before charging.

You can charge your packs the day before your race, no need to repeak.

There are good cheap packs, there are lousy cheap packs, there are even lousy expensive packs, don't be surprised here. Pick something of 20C and onwards. It's better to settle for a real 20C claim than a 25C overclaim.
5 years of experience with lipos small and big, mine as well as my customers' taught me a lot about these batteries. i will share with you whatever u want to know, as long as i know it
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Old 06-17-2008, 10:34 AM   #6
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Perhaps we need a "RcTech for Dummies" thread with instructions on how to use the search button!

Just kidding with (kinda). Good luck with the lipos.
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Old 08-04-2008, 08:27 PM   #7
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After a 5 or 6 minute race

How long do you wait for the battery to cool down before we can recharge?
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