What are people opinions on these. I was reading about some packs that can deliver high amps, 120 A pulsed 90 A cont. They were 6000 mAH, 18.5 v and only weighed about 600 g. The downside is that they were US$400.
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So even the rain that falls isn't actually going to fill our dams and our river systems

I've been sussing out Li-Poly batteries lately too....
What I've found is....
DON'T try to high volt/high amp charge them - they don't seem to mind blowing up if you try (so slow charge with a Li- Poly charger only)
if they get pierced, they may spark and burn ... but no battery likes getting pierced anyway.

Those are some huge Li-Poly packs you are looking at though.... the ones I'm looking at are 13.6V 1800 mAH that weigh much less than 600g and only cost about $70 AUS. Cheap enough to have several packs that can be interchanged between bouts...
The 11.1V packs (1800 mAH) at the local shop are only around $45 AUS, with charger to suit only $65 AUS approx.
I'll have to check the amps on the packs though.
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There is no such thing as excessive carnage.

90A continuous would be fantastic! From all the warnings I have read, LiPoly batteries are rather delicate & demanding; they would be better in a bot with a current-limiting ESC and fan cooling. Manufacturers also recommend shock-mounting and foam padding - how do you combine fan cooling with foam padding?

The US guys mostly use LiPoly in antweight bots where its more affordable. I looked at them and decided they were still too expensive, even if they solve some weight problems.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

from what I've seen they don't last too long (short cycle life) and they are very finicky about charging.

The charge voltage needs to be within 0.1v of specs, and the current must be controlled depending on the capacity of the cell.

Over current or over voltage will kill them very quickly, which also means that you can't fast charge them (actually you can't really even slow charge them - they have to be charged at a specific rate)
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The Engine Whisperer - fixer of things

I held a li pol today. It was surprising how light it was even though I had already read it's weight. The 11.1 v 2450 mAH 12C battery was half the size of the palm of my hand and about the weight of a receiver battery. All for only $150. It would only take four of these to make Marauder happy. Two in series two in parallel. Then another four while the first are on charge. I wont be buying them any time soon.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Does anyone know if the voltage increase with these batteries.
example is a 14.8 volt battery actually 14.8 volts.
Was wondering if you had a ten cell esc which in theory can handle 15 volts, would that be safe to use with a 14.8 lipol or would the lipol battery increase its voltage when fully charged. Otherwise you have to go to 11.1 volts.
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Bots that do not destroy you, only make you stronger.

I am just guessing here, but I notice that the PCMguard charger accessory sold on RMP limits the cell charge to 4.2V per cell. That adds up to 16.8v per 4S pack, which might toast your ESC Best to ask Steve at Hilltop Batteries or Jim at RMP.

Who's going to be first to run a featherweight bot entirely from LiPoly in Australia?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I think Carnage Nick will but you might beat him Magmotor Nick
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https://www.halfdonethings.com/

yeah, I'm getting some packs sussed out at the moment... master-instruments can build Li-Poly packs to meet individual needs - but the cells are 3.6V each (I think) and from what I read yesterday, they really don't like high amp draws...

but while I was checking out a hard copy catalogue (from M.I.), I found some thin SLA packs in 12V - at only 800 grams per battery..... tempting....
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There is no such thing as excessive carnage.

The LiPol cells I was looking at on the MI site were fairly good. All were 3.7v cells and they have from 250mah right through to 1000amp cells. 80% of the cells I looked at all had a 2C continous rating and a 10C peak rating.
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https://www.halfdonethings.com/

I don't think marauder would need 4 batteries. Your driving off the drill packs atm and the main problem i think your having with them is charging. I think one pack at 22.2v or would work fine. If it was one of the 1800mah ones nick can get it would prolly cost bout $100 and i think that would drive you round for a fair while. Or you could buy a triton and charge the drill packs properly and this would also let you charge the LiPols if you bought them.
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Check out the largest 6AH packs from Polyquest ont the RMP site - 90A continuous. Another problem with LiPoly that you only find in the fine print is that you can only charge them at 1C or risk damage or a fire, so a 6AH pack would take up to 6 hours to recharge and you would likely need one pack for every battle at an event.

I typically use about 2.8 to 3AH of my NiCad packs so I would need 3 hours charging time plus cool-down time between matches - at least 8 packs (two x 11.1V packsor $1600 US
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

quote:

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Another problem with LiPoly that you only find in the fine print is that you can only charge them at 1C or risk damage or a fire, so a 6AH pack would take up to 6 hours to recharge and you would likely need one pack for every battle at an event.

I typically use about 2.8 to 3AH of my NiCad packs so I would need 3 hours charging time plus cool-down time between matches - at least 8 packs (two x 11.1V packsor $1600 US

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dahhhh wtf does the "c" meen??
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as a shadow is seen and not heard i am here
-Waddy the phoenix

The C stands for Capacity well sorta. If you charge at 1C then that means you charge at the same Rating of the Battery eg 6000mah as above. 2C would be twice as much.
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Steven Martin
Twisted Constructions
http://www.botbitz.com