going LIPO - is it worth my time?

[gkatz 49]

Hi all;

for someone who is the occasional driver, is it worth moving to LIPO?

it seems like its a hassle charging and discharging, low voltage cutoffs (i am suprt confused).

I am used to NiMH where I dont really care about this stuff. are this disclaimers for real? i mean, I dont want to work for the battery i want the battery to work for me

it would be nice to bump us the run time of the car though...

thanks in advance

[alvinlwh 5894]

If you feel it is not for you, then stay with what you are comfortable with. Don't let others talk you into something you don't want/need.

[Twinfan 1251]

LiPo doesn't bump up the run time of the car unless you're increasing the capacity.  The largest NiMH is 5000mAh, so you'd need a larger LiPo than that to increase run time.  LiPo has a higher initial voltage (7.4v versus 7.2v), and a less steep voltage decline, so you should get more performance for longer.

For me, it's much less hassle to run faster motors and multiple NiMH packs in my cars if I want more performance or longer run times, or both.  I only see the benefit of the LiPo inconvenience for racers, but as alvinlwh says it's a personal choice!

[Kowalski86 3030]

Its both the time and the risks that you should consider, sometime ago Gil Losi Sr himself (someone who knows a thing or two about RCs) had a garage fire due to a LiPO battery. They're both dangerous and nowhere near as fool-proof as NiMH.

If I raced I'd have a few, but for just casual driving about I don't think its worth the risk. Then theres always the stress that the extra voltage puts on the electronics.

Gearing, bearings, and heat dissapation play a big role in run time.

[MadInventor 3884]

Just to put the other side of the coin (And again, go with what you feel comfortable with), as well as having a less steep voltage decline, LiPos are considerably lighter than their NiMh equivalents, which is going to improve acceleration and handling. 

It's not just about the small amount of extra voltage, LiPos can provide a lot more current than equivalent NiMh cells, which equates to faster acceleration. I'm a casual user of cars, i.e. I don't go racing, and the difference in performance between Nimh and LiPo is quite striking. With regards to charging, I use a multi chemistry charger that has different charging profiles for different chemistries, even if you are just nimh, you should have a good quality charger like that to get the most out of the cells, not just a basic trickle charger. To get around the worries of garage fires, I bought an old ammo box, drilled a small hole in it to pass the charging cables through, and put the LiPos in that to charge them. Then, even if it explodes, the flammable mess should be contained to the box. I also never charge them at greater than 0.5C, so for a 4000mah battery, I never charge it at more than 2 amps, so the cells never get warm.

 

[alvinlwh 5894]

Oh yes, the fire risks. Are you the worrying type? Do you comfortable to store what are effectively bombs? Yes, many will say they never had problems with their lipo and/or they use fireproof containers to charge and store their lipo. 

Now, I use lipo, I am not the worrying type. They just get stored in the shed or in the house in a pile. And that is with me having personal experience with a lipo explosion; a vape device with a 800mah 3.7v battery. It was quite a mess, and it will be far worse with an RC lipo.

Recently a friend gave me some old lipo, the hard case ones look a little puffed, I am not 100% sure so I just binned them to be safe as they are coming on a plane to come home with me. A power bank recently went up on a plane in Asia, luckily it was still in the ground when it happened.

What I am trying to say is there are risks, and make sure that you are aware of them. Some will say they never had problems with lipo, they will not explode if you take care of them, not damage them, abuse them, etc... They may very well be correct, but how do you know if you did not have a bad lipo ? Do weigh up the pros and cons yourself as only you can assess the risks and decide for yourself what is acceptable.

[gkatz 49]

thanks everyone for your answer!!! you have been very helpful

to me, I think I now understand the i need to go with Nimh....

thanks again

[sosidge 624]

11 hours ago, gkatz said:

thanks everyone for your answer!!! you have been very helpful

to me, I think I now understand the i need to go with Nimh....

thanks again

There is no way I would spend money on a NiMH battery in 2023. LiPo is so much better. Better performance, and better lifespan. Just make sure you buy the right kind of charger (a NiMH-only charger will not charge a LiPo), and follow the instructions.

[gkatz 49]

i hardly remember what I ate today - its very likely I would take ****ty, border line neglegent care or a LiPO...

so I guess to each their own

[sosidge 624]

If you take sh*tty care of a NiMH it will quite happily blow up in your face. Seen plenty of NiMH cells turn into roasting hot projectiles when people don't treat them with care.

Everything has the potential to be dangerous if you aren't careful.

[BuggyDad 4450]

I think the risks have been covered here so I'll just comment on the process stuff from the perspective of a non serious rc irregular player with toy cars. 

It's not hard. It became second nature in no time. And I'm a fairly forgetful sort of person. After running, you pop the cells on the charger and press the "storage charge" button. It'll either charge or discharge them to a safe to store condition. Before running, you balance charge them, then they're charged (and balanced). That's it. Once in a blue moon if you haven't used them you pop them on storage charge again just to make sure. 

[Fish Slice 35]

3 hours ago, gkatz said:

so I guess to each their own

Exactly that. 

I use NiMh because I can, it makes the cars move fine, and a 5Ah battery lasts about three times longer than any battery I remember.

Plus I don't have to particularly worry about balance, storage charges, or kids charging it for what little gains I would get for something pootling around the garden or park.

I'm sure I'll get some LiPo action at some point, but probably if I ever get something that particularly warrants it.

Use whatever works for you, bothers you least and allows you to get on with enjoying the cars you have.

[Sogogi 3217]

No matter the battery chemistry, I would always go with reputable manufacturers. 

[Wooders28 4722]

Depends how you run your cars, and imo.

If you're wanting longer 'full power' running, or alot more speed and 'punch' , then going lipo (or the modern liHv) would be like going to HD telly from CRT, night and day better.

Both a 6s nimh and a 2s lipo are 8.4v fully charged, but the nimh voltage drops like a stone, when asked to do any work, 

This gives you the extra speed, the 'punch' comes from the extra amps that a lipo/liHv can discharge. Nimh struggles to deliver the amps like a lipo can, if the motor asks for 50amps, and the battery can only deliver 25, then it'll still go, but only half as spritely (?) as of it had the full 50.

I'd also add, if you're worried (?) , then you'll probably be a responsible lipo owner, and not wonder why bad things happen, if you're charging at 15c high charge rate, with it under your pillow.....

Firstly, I advise getting a decent lcd screened multi chemistry charger, from a decent RC outlet (not Amazon or Ebay etc, a known model shop). A decent charger will usually charge the nimh better than a cheaper charger (cycle charge etc).

 

On 1/15/2023 at 5:06 PM, gkatz said:

for someone who is the occasional driver, is it worth moving to LIPO?

The 'hassle' with lipo, is having to storage charge after use, I get that.

I've reduced this slightly, but setting some escs cut off voltage, to cut off at around storage charge voltage. This depends on the motor you're running (lower turn motors, pull the voltage down more ,voltage sag, so might be set at 3.4v per cell, and measure 3.7v when the battery is out and on the charger).

I've got lipos, that I've not used for over 2 years, but have put them on a storage charge once a year, and they've maybe lost 0.5v over that time, so not overly worrying.

New storage tech, like the 'Batsafe' offer some storage / charging safety, 

 

If there is a lipo fire, it's big news, and all over social media etc, like a plane crash, this is because they're rare, especially now with liHv, which are capable of being charged to 4.34v per cell, so if you charge them to the lipo setting of 4.2v, they're less stressed than a regular lipo.

There's thousands getting charged every week , there's over 100 racers just at our club at a bigger event, and 6 races, so that's 600+ charge cycles at just one meeting.

[Twinfan 1251]

7 minutes ago, Wooders28 said:

Both a 6s nimh and a 2s lipo are 8.4v fully charged, but the nimh voltage drops like a stone, when asked to do any work, 

I think that graph might be a bit misleading.  Shouldn't the area under the curve be the same if both batteries had the same capacity?  If so, the LiPo would deplete first if it's putting out more power for longer?  If all else were equal, according to that graph LiPo batteries would substantially outlast NiMh which I don't think is the case?

I don't dispute the voltage drop that NiMh has, but it seems very over-exaggerated in that mock up graph.

[MadInventor 3884]

23 minutes ago, Twinfan said:

I think that graph might be a bit misleading.  Shouldn't the area under the curve be the same if both batteries had the same capacity?  If so, the LiPo would deplete first if it's putting out more power for longer?  If all else were equal, according to that graph LiPo batteries would substantially outlast NiMh which I don't think is the case?

I don't dispute the voltage drop that NiMh has, but it seems very over-exaggerated in that mock up graph.

True, but also don't forget, if you take into account weight, where you have a  Nimh and LiPo that weigh the same amount, the LiPo will have a much larger capacity, and therefore last significantly longer.........

[Twinfan 1251]

Sure, I get the weight makes a difference.  Some Googling says a 5000mAh NiMH is ~400g vs a 5000mAh LiPo at ~250g.  So a 150g saving.

Using the Thundershot as an example, that weighs 1216g without a battery according to this thread:  https://www.tamiyaclub.com/forum/index.php?/topic/92398-the-tamiya-weigh-in/

So roughly 1600g vs 1450g once a battery is fitted.  The LiPo saves 10% of the overall weight, so let's say you might gain 10% more run time.  22mins rather than 20mins, depending on the motor used.  But the LiPo is discharging faster, giving you a performance boost, so you might not get a longer run time after all - just more performance due to the lack of voltage drop.

That's how I see it any way.  LiPos are for people who need increased or sustained performance over NiMH.  For me, a casual basher in the park, I'm perfectly happy with low maintainance NiMH packs.

[MadInventor 3884]

1 hour ago, Twinfan said:

Sure, I get the weight makes a difference.  Some Googling says a 5000mAh NiMH is ~400g vs a 5000mAh LiPo at ~250g.  So a 150g saving.

Using the Thundershot as an example, that weighs 1216g without a battery according to this thread:  https://www.tamiyaclub.com/forum/index.php?/topic/92398-the-tamiya-weigh-in/

So roughly 1600g vs 1450g once a battery is fitted.  The LiPo saves 10% of the overall weight, so let's say you might gain 10% more run time.  22mins rather than 20mins, depending on the motor used.  But the LiPo is discharging faster, giving you a performance boost, so you might not get a longer run time after all - just more performance due to the lack of voltage drop.

That's how I see it any way.  LiPos are for people who need increased or sustained performance over NiMH.  For me, a casual basher in the park, I'm perfectly happy with low maintainance NiMH packs.

Well put. However, duration has never been an issue for me as I usually break what I'm running due to the extra performance, before the battery gets anywhere near flat.............

 

[Twinfan 1251]

Ha ha, I can imagine!  I have enough trouble trying not to break my 13.5T brushless Fire Dragon on NiMH....

[alvinlwh 5894]

1 hour ago, Twinfan said:

But the LiPo is discharging faster, giving you a performance boost, so you might not get a longer run time after all

Actually lipo can discharge at a higher/more useful voltage for longer instead of dipping when under load gives it more useful runtime. For example NiMH cuts out to limp mode because voltage dips too low when giving it full throttle forwards and yet can reverse (assuming a 50% reverse ESC) at full speed. While the NiMH still have some of the mAh left, it can no longer supply it at a useful level.

IIRC, a flat 4000mah NiMH that can no longer move a car only takes 3000mah odd of juice to charge up, even accounting for wear of the pack, that is about 1/4 of the pack capacity being useless.

[El Gecko 1343]

I look at it like fuel for a 1:1 car:

NiCd = leaded gasoline, old tech, only used in the most ancient vehicles or high performance short runtime situations

NiMH = standard unleaded gasoline, of various octanes (the car runs better on 91 premium, but cheapo 87 will work just as well for most cases)

Lipo = methanol, true race gas, dangerous and only really necessary for the highest performance vehicles

I still have some old NiCds that will hold useful charges, but the runtime is very short (low mpg, high power). The NiMHs don't peak out at quite as high of a voltage, but the runtime is way longer (high mpg, slightly lower power). Based on my experience with my cousin's Lipo, you get high mpg and high power, but the danger factor is much higher, and my house is more important than having fast toys. If I had a full on racing program and was actually trying to be competitive, possibly possibly maybe I would think about looking at Lipo. But for a daily driver that races on the weekends (Racing by Post style), standard unleaded gas is perfectly usable and fun. If I need a boost, I just add more NiMH cells.

[Wooders28 4722]

12 hours ago, Twinfan said:

I think that graph might be a bit misleading.  Shouldn't the area under the curve be the same if both batteries had the same capacity? 

Mmmm 🤔,  never given it too much inspection tbh, as it seemed to correlate with my experience, the driving enjoyment running nimh, was fairly short lived, but the lipo run for ages, and you only notice the battery going flat, as it stops lifting the front end on command.

Must be a fairly decent current draw, to only last 9 mins though. 

I'm sure my charger ,let's you know actually how much juice its put in (mah) so should let me know, how much is used, between fully charged and low volt cut off, its something that's never crossed my mind.

5 hours ago, El Gecko said:

NiCd = leaded gasoline, old tech, only used in the most ancient vehicles or high performance short runtime situations

NiMH = standard unleaded gasoline, of various octanes (the car runs better on 91 premium, but cheapo 87 will work just as well for most cases)

Lipo = methanol, true race gas, dangerous and only really necessary for the highest performance vehicles

Close,

Nicad - 2 star petrol,

Nimh old style unleaded 

Lipo, modern fuel, with methanol (ethanol) mix . E10 is the norm now, although i believe you can still get E0 from Shell (?) but not for long. (lowest RON we get in the UK ,is 95 but 10% methanol, think the E0 is 98? ). Heard the street eliminator guys have found a supply of pump E85, so are turning up the boost.

 

Pretty much all modern tech runs on lipo or lithium ion batteries, from the watches on my kids wrist, and the drill in my garage, and safety has come on since the early days.

 

 

 

[alvinlwh 5894]

3 hours ago, Wooders28 said:

Lipo, modern fuel, with methanol (ethanol) mix . E10 is the norm now

If you believe some reports, E10 is the devil's brew. IDK as I am a diesel guy and there is only one grade. 😁

[Twinfan 1251]

E10 is indeed the devil's brew.  Shell V-Power and Tesco Momentum are E5, which is what we use in our cars.  Esso Supreme+ is E0 if you can get it near you.

All those Super Unleadeds are 99 RON.

[Wooders28 4722]

11 hours ago, alvinlwh said:

If you believe some reports, E10 is the devil's brew. IDK as I am a diesel guy and there is only one grade. 😁

Aye, lovely premature filter clogging, freezes quicker, 7% biodiesel....

My dailys have been diesels for 20yrs, peak torque at 2200rpm is brilliant.

My project car is petrol (pics in the 'not rc related' thead) , but been through the fuel system ,so it's ready for E10 (actually set up for E85, so...) , more out of necessity tbh, I'd run the engine to check the ECU worked, and came back to it a 'while' later and the fuel pump , level , fuel lines where all rotted....

4 hours ago, Twinfan said:

Esso Supreme+ is E0

Handy to know 👍