li-po's and normal battery packs

[Danny11]

Hi !!!

Please can anyone tell me the difference between li-po battery packs and normal battery packs and why li-po's are so expensive?

cheers
Danny

[emtee]

Errrr.... OK... ...

lipo= lightweight, 3.7v per cell, low maintenance...

nimh= heavyweight, 1.2v per cell, high maintenance...

In a nutshell, that is it really... both types need dedicated chargers... I guess the lipo price reflects the cell chemistry/technology/manufacturing costs...

Anyone got owt else to add...?

[Bungleaio]

For the performance and usability they offer I think lipo's are a bargain!

[Col]

You only need 1 pack of lipo, and 1 pack of nimh per race so lipo are actually cheaper.

[brooksy]

With lipos you can basicly have one battery and run all day with it. You can put it on charge as soon as you've finished racing and then put it back in your car for the next round!.
Normal batterys after being run need to be discharged and re-charged from flat. If you don't do this you won't get the best out of the cells.
Also with normal cells they will get warm after a run and you have to give them time to cool down before re-charging them.
Usualy people who run nimh batterys will have 4 or 5 sets.

As I said above,if you really wanted too you could just buy one lipo pack and run all day with that!.

Go lipo, it's the future!!!!!!.

[JCJC]

Originally Posted by Danny11

Hi !!!

Please can anyone tell me the difference between li-po battery packs and normal battery packs and why li-po's are so expensive?

Hang on, I can remember paying £60 a half dozen for matched nimh cells, then having to solder them up and add connectors, discharge and whatever to keep in good condition............and these were cheap matched cells.

Our lipo's were much the same price and its easy peasy, and we run them all day, top up between rounds. Never used nimh cells more than twice in a day, had to have a few packs and some were better than others, no contest.

[kevinjh]

To run LIPO do you need to change Servos or receivers,
What is the basic requirements and what sort of price will it be, i.e battery, charger, battery charge case. what is the life span of the battery?
Thought about using them but know absolutely zilch about what is needed.

[blue_pinky]

No need to change anything else on the car...it's just a power source at the end of the day!

Take a browse around some of the online RC shops for the various options of what to get...there's a big and growing choice overall. Off the top of my head...

Battery's £60-£90 depending on the brand/capacity.

Charger's, balance chargers range from £60 to £150+ depending on quality/power/charge current rating.

Charge case...seems to be personal preference...some poeple like to use them, I personally charge my lipo's in the car or at least where I can see them.

Lifespan is hard to determine, it depends on how the cells are charged/discharged during their life. Suffice to say, it's longer than a set of NiMH's!...100+ cycles at peak performance...much longer in reality although the punch does slowly decrease over time. My packs are still perfectly usable after a years weekly club use.

[peetbee]

My lipos are about 2 years old now (bought secondhand) and they're still going fine. I doubt any nimhs would be able to do the same (run weekly at club, plus additional weekends).

[SlowOne]

Also remember that 'round' (NiCad/NiMh) cells were price-controlled for over 25 years, and that price was kept artificially low in this country. LiPo cells had no price controls to start with, so they found their 'real' price level in a competitive market. Once that was done, there is a price control planned.

One advantage we have is that there are now so many competitors in the LiPo market that there is genuine competition to drive some price competition. 'Round' cells were the province of one supplier (Sanyo) for 20 years, and many markets had one distributor - controlling prices was easy, and there was no competiton.

When IB took the market over, their product was better, and so they had no need to sell at low prices. By the time they had ruined the NiMh market, and made the path easy for LiPo, a lot of people were willing to pay any money to get the convenience of LiPo, and we had to pay for expensive development and tooling costs to get the hard case, etc.

So here we are. Personally, paying just £100 for two packs that last two years without any maintenance is a bargain, not an expensive option. HTH

[emtee]

One consideration is that if you are going to use lipo PLEASE make sure your ESC has a lipo cut-off... this will stop you discharging your lipo TOO far... this is the only real downside of lipo... if you discharge them below @ 3v per cell (I think...!) they may become damaged and unusable... check a well known auction site for lipo cells and chargers at good prices... decent (3800mah at least...) hard case pack £20-£30... B6 lipo compatible charger around the same price...

[Danny11]

sorry but what does the top scentence mean?

[JCJC]

Originally Posted by Danny11

sorry but what does the top scentence mean?

Lipo's in 10th off road are 7.2 volts, as they discharge the voltage drops down, when/if they get to 6 volts the battery can become damaged and a lipo charger may refuse to recharge it, some speed controls have a cut off at 6.5 volts (adjustable) or you can fit a cutoff that monitors battery volts, or you can use a voltmeter and test yourself or make sure you do not run the car for to long or when you feel performance is down.

[Big G]

he means 7.4 volts, but the rest is right. my speedo is set to 3v per cell cut off.

[JCJC]

Originally Posted by Big G

he means 7.4 volts, but the rest is right. my speedo is set to 3v per cell cut off.

sorry 7.4 volts, they come off the charger higher but drop down under load.

EDIT: just a thought, and its happened to me, do not leave batteries in the car connected between meetings, even with the switch in the off position a small discharge will flatten your battery over time.

[emtee]

Originally Posted by Danny11

sorry but what does the top scentence mean?

1 lipo cell is rated at 3.7v, 2 lipo cells in series(connected together..) make the 7.4v we lipo users like... If that voltage drops below 3v per cell the cell may become damaged and will not charge up again therefore that means a ruined (expensive..)pack... A lipo cut-off prevents this and are usually found in your Electronic Speed Controller... if not, a stand alone audible alarm can be used... this will beep when the pack voltage approaches 6v...

Is that better..?