LiPo, the big guide thread *updated March '10* *

[Bobbit]

Where are the best places to buy Lipos online? I’ve looked but only found modelsport, rcgeeks and hobbyking.

[everclear1984]

25 minutes ago, Bobbit said:

Where are the best places to buy Lipos online? I’ve looked but only found modelsport, rcgeeks and hobbyking.

 

Any of the above. Hobbyking will likely be cheapest. 

[TheFunkeyGibbon]

I know this has probably been answered before but can you charge a LiPo that hasn't been exhausted. I took my RC out for a quick buzz but by no means a long run and so the battery still has charge. Should I do something with this? Can it be charge to top it up?

It has been disconnected and stored in a LiPo bag in a metal tin until I need it.

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[Stormbringer]

you should put it on storage charge and charge it fully when needed 

[TheFunkeyGibbon]

I'm going to be honest, with the included charger I can't see any options. I imagine it doesn't have them and I'll need to buy a better charger.

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[Simon Hester]

Hi

 

Looking for Lipo battery advice. Looking to switch from Nimh to Lipo my car has an esc that is rated  at 45amps. I've checked and the esc has the required low voltage cut off although not sure why the max rating of the motor is? The motor is brushless 3421Kv  BS701-007R by bsd racing.

 

I saw at the start of the post the calculation between Mah and the c rating but not sure what the max amps is for the motor. So what sort of C rating should I be aiming for? 

 

Thanks

 

Simon

 

[fnknan]

Your esc is only 45 amps so if you had a 5000 mah pack youd need a pack with 9c.

 

Id go with 20c packs of I were you

[Simon Hester]

Quite novice at all this I do wonder if i should just stick with Nimh batteries. 

 

I assume the ESC rating would be rating of the motor? 

The spares list for the car does show a LiPo of 32 mah 20 C which put it at a rating 64. I assume a bigger value than 45 is safe to run? BUt getting anything really big is just not worth it?

 

Also what sort of run time would I expect to get doing a bit of bashing on a car park and grass field? Is the run time affected by the C rating?

 

Thanks

 

 

 

 

[fnknan]

Yeah anything higher than 45 should be good. 

 

C rating doesn't affect run time. Only mah rating

[Simon Hester]

I was reading through my ESC manual and it mentions the burst current 190a for the model I have does this need to factored into the batteries C rating?

 

The EZrun ESC manual is here oddly it only lists a 35amp or 60 amp unit mine appears to be 45amp account to the spare parts list on centryuk.com

https://www.hobbywing.com/products/enpdf/EzRun60A.pdf 

Thanks

[suicideneil]

19 hours ago, Simon Hester said:

stuff and things

 

I wouldn't be too concerned about burst ratings on the esc/motor as any burst will only last for a split second under heavy acceleration. Provided your batteries are rated for at least the continuous current ( with a little overhead ) you'll be fine ( mAh x C rating ).

 

I wouldn't worry about the specs vs manual either- most Chinese brands will use the same manual for all of their escs as they have identical programming features- saves time & money on having different manuals for no real reason other than to change the voltage or current rating in the specs list...

[Simon Hester]

Thanks for the replies 

Looking to get the following 2 x Turnigy nano-tech 3300mAh 2S 35~70C Lipo Pack w/XT-60 https://hobbyking.com/en_us/turnigy-nano-tech-3300mah-2s-35-70c-lipo-pack-xt-60.html

 

and IMAX B6AC V2 Professional Balance Charger/Discharger (UK Plug) https://hobbyking.com/en_us/imax-b6ac-v2-professional-balance-charger-discharger-uk-plug.html?___store=en_us

[Simon Hester]

Thought I had my choices made then realised the batteries were not hard case type LiPo. When i checked with HobbyKing they suggest hardcase is a must for RC cars is that correct?

Also what mah rating should i go for. It seem the higher mah ratings the higher the C numbers go and i just don't need bigger C numbers but would like a good run time maybe 15 - 25 mins. 

Currently thinking of this battery https://hobbyking.com/en_us/zippy-4000mah-2s1p-25c-car-lipoly-roar-approved-de-warehouse.html?queryID=2e8878adf4b46090128183678f6a305f&objectID=24562&indexName=hbk_live_magento_en_us_products 

Or would it be better go for one of the 5200mah or 5000mah found here https://hobbyking.com/en_us/batteries-chargers/batteries/lipo.html#q=&idx=hbk_live_magento_en_us_products&dFR[battery_pack_type][0]=Hardcase&dFR[brand][0]=Zippy&dFR[config][0]=2&dFR[warehouses][0]=UK&dFR[warehouses][1]=Global&dFR[warehouses][2]=EU&dFR[warehouses_stock_data][0]=UK|1&dFR[warehouses_stock_data][1]=UK|2&dFR[warehouses_stock_data][2]=UK|3&dFR[warehouses_stock_data][3]=Global|1&dFR[warehouses_stock_data][4]=Global|2&dFR[warehouses_stock_data][5]=Global|3&dFR[warehouses_stock_data][6]=EU|1&dFR[warehouses_stock_data][7]=EU|2&dFR[warehouses_stock_data][8]=EU|3&hFR[categories.level0][0]=Vehicles %2F%2F%2F Cars&is_v=1

Thanks in advance

 

[suicideneil]

Hard case lipos aren't a must at all- not unless you're racing at some kind of event or track that requires them for safety reasons, or your model's chassis leaves the batteries quite exposed- not sure what model you have so you'll have to decide that for yourself.

 

If you can afford it, get the highest capacity you can that will fit your model- more mAh ( capacity ) will mean the battery is physically larger so keep that in mind- measure the battery trays and check the battery dimensions, buy the largest capacity/ highest c rating your wallet allows without going crazy. 

 

What I will say however is that look into buying lipos from reputable UK retailers if you can ( assuming you're Uk based )- hobbyking is great because they have lots of cheap options but if there is a problem then you're pretty much out of luck- most of us have played that game before. Don't overthink it though- there are literally millions of options for lipos that would be suitable, check sizes, check wallet, stick with good/known brands- there is plenty of info and reviews to read into if you want 2nd opinions, research is fun...

[Simon Hester]

Thanks for the comments Suicideneil. I guess my battery is quite exposed on the side of the chassis just under the plastic cover. 

 

I was going to go with Hobbyking whats a good alternative I'm UK based?  figured they were a US company and I guess from what your saying returns are difficult. I would have gone to my local shop but it shut down a few years back but were always really friendly and helpful. 

My current plan was the following given my budget is about £100.

2 x Turnigy 5200mAh 2S 30C Hardcase Pack (ROAR APPROVED)

IMAX B6AC V2 Professional Balance Charger/Discharger (UK Plug)

I then needed a lead adaptor for charging and some HXT 4mm connectors to replace my current Tamiya connector on my ESC It all came to just under £100. 

Thanks

 

Simon

[Stormbringer]

model sport is good source 

https://www.modelsport.co.uk/batteries/rc-car-categories/9920/992025&MSAttributeID[32]=840&MSAttributeID[30]=598

but they are getting a bit low on stock tho

have a look through that mate 🍻

[suicideneil]

Hobbyking are based in China, but they have global warehouses- not much in the UK one usually though so.... yeah.

 

As for retailers- behold: http://www.robotwars.00server.com/usefullinks.html scroll down towards the bottom. I would also suggest modelsport as a good place to find lipos and a charger- won't end up waiting 2-4 weeks or more for delivery and dealing with import charges either. 

[BlackpoolAndy]

Hi peeps, I’m a tad lost and hoping you guys can help. My other brushless models have come new to us so i purchased the lipo batteries as part of combo.

 

I picked up a used Dhk Zombie the other day, came home stripped and rebuilt and thread locked every screw. Quite impressed with the Truck build. A lot more onboard tuning options that the Outcast. The truck is 3s (esc says 2-4s) and came with a new 2s lipo. The previous owner kept the butchered 3s battery.

 

So I bought a 4000mah 50c Volts 3s 11.1v and myself and my son went for a blast. 
we didn’t stay long as there was interference where we went. As per normal took shell off but couldn’t disconnect the Deans. I took it home and had to prise it part with a knife so obviously got very hot. When I put the 2s in it did not turn on, so I had a look at the Deans plug male side and some black on the metal. I cleaned that off and it worked fine.
 

I think I bought the wrong battery? The motor is DHK kv2260 and the esc is 80Amp.

 

On wheelspin the truck was sold as a combo with a 3600mah 40c 3s. Is this the max mah/C battery I can safely use? 
 

Sorry for long windedness, still trying to get my head around it

[Logie]

With LIPO batterys, do they work full power untill you reach the cutoff voltage and the car stops? Been really impressed since going from nitro to electric. I have never run a battery low enough for the cut off. But a few of us are wondering do these lipos work then stop, not like NIMH where car gets slower and slow

[suicideneil]

On 12/07/2020 at 22:10, BlackpoolAndy said:

Hi peeps, I’m a tad lost...

 

You didn't buy the wrong battery- if the esc is rated for 2 to 4s then 3s is right in the middle, no issue there.

More likely the issue is either incorrect gearing, or possibly some binding in the drive train ( pinion and spur set too tight perhaps ). I would say look up a manual for the model if possible and see if there is a gearing chart; typically you need to gear down ( smaller pinion and/or larger spur gear ) when using higher voltages.

On a side note Deans connectors are the work of the devil- might be worth looking into upgrading to XT60s for a better connection.

[suicideneil]

8 hours ago, Logie said:

With LIPO batterys, do they work full power untill you reach the cutoff voltage and the car stops? Been really impressed since going from nitro to electric. I have never run a battery low enough for the cut off. But a few of us are wondering do these lipos work then stop, not like NIMH where car gets slower and slow

 

The LVC ( Low Voltage Cutoff ) built into the esc is what stops the model from running when the battery voltage drops too low in order to avoid damage- the battery itself won't have any built-in protection as such and can very easily be damaged if you keep running after the cut-off voltage is reached- say, if the lvc is not set correctly or there isn't one at all on the esc. Below about 3v per cell is potentially enough to risk puffing the lipo, or the charger will throw up a warning that the cell voltage is too low and will refuse to charge it. 

~3.2-3.3v per cell is a fairly typical LVC setting for reference, depends what settings you have available to tweak.

[Logie]

Yea i understand the cutoff with the ESC but im wondering do Lipo give max performance untill you hit the cutoff?

[BlackpoolAndy]

12 hours ago, suicideneil said:

 

You didn't buy the wrong battery- if the esc is rated for 2 to 4s then 3s is right in the middle, no issue there.

More likely the issue is either incorrect gearing, or possibly some binding in the drive train ( pinion and spur set too tight perhaps ). I would say look up a manual for the model if possible and see if there is a gearing chart; typically you need to gear down ( smaller pinion and/or larger spur gear ) when using higher voltages.

On a side note Deans connectors are the work of the devil- might be worth looking into upgrading to XT60s for a better connection.

Cheers for reply. The battery is dud. Connected to charger and got connection break. Wheelspin is sorting it as it was not even used for 5/10 mins and each cell is still circa 4.18v per cell. Done some research and backwards and forwards to Wheelspin.

 

i will upgrade the connector, outcast has decent ones so I will switch to them.

 

again thanks for reply 👍🏻

[suicideneil]

13 hours ago, Logie said:

Yea i understand the cutoff with the ESC but im wondering do Lipo give max performance untill you hit the cutoff?

 

Yes, pretty much- the discharge curve is pretty flat right until you reach the cutoff point, just after that it drops off a cliff.

[Tels]

On 13/07/2020 at 23:00, suicideneil said:

 

The LVC ( Low Voltage Cutoff ) built into the esc is what stops the model from running when the battery voltage drops too low in order to avoid damage- the battery itself won't have any built-in protection as such and can very easily be damaged if you keep running after the cut-off voltage is reached- say, if the lvc is not set correctly or there isn't one at all on the esc. Below about 3v per cell is potentially enough to risk puffing the lipo, or the charger will throw up a warning that the cell voltage is too low and will refuse to charge it. 

~3.2-3.3v per cell is a fairly typical LVC setting for reference, depends what settings you have available to tweak.

Hi. How do you charge the battery if the charger refuses to charge the battery cause its too low? 

My problem!