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simalarion

My Experience with Nimh & Lipo

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First off all i just recently learned about using both Lipo & Nimh and charging them correctly. And for others that are new to this hobby again (returning to the Hobby after many years ) here is what i wanted to know:

In short when driving Tamiya kits only i found out. 2wd kit will do just fine on Nimh, in my TGH wit Torque Tuned motor (with propper bearings ofc) i feel like its already to fast for its own good so its no point even with a 2s lipo in this one. I also think even a 2S here will burn out that motor pretty fast actually, its real angry as it is :)

4wd will be OK on nimh but to get s stable punch and a good stable  top speed you will need 2s Lipo. I drive Top-Force

Monster Truck Txt-1 & 2 (probably other trucks with dual motor), now Nimh will not do the jobb, the diff will not get strong enough momentum to work effective in deep snow to take one axample and it will also be a bit to slow. In my Agrios i have 3s and the setting on ESC is 75% max fwd, 50% max bkw, High cutoff lvc, the motors do not get very hotter than before (but noe its also cold outside) and the Monster truck itself was like a hole new kit, diff worked so much better and it now drive throug the snow like it was not there, further the mentioned ESC setting is fast enough for ge Stock motors, also fast enough for a monster truck.

Drawback with Lipo is as most off you here know that Lipo should be handeled and used with respect. So i bought s good charger, a Discharger (as the charger only DC at 0,6 A), boxes to store them in & a temp reader for a even safer charging.

So where i see no point in Lipo is when using 2wd RC Cars or in kits  Kids (5-9)  are driving. Other than that if you have time, money Lipo is the way.

One last point is that i also think you should stick to Nimh as long as you are not sure if you are going to use much time on your hobby.

As for myself i found out that going out (with or without kids) anf just drive around make me ekstreemly relaxed and for dome reason i just love to watch how the Rc Cars behave in different scenarios, especially my Top-Force with new Hop-up dampers, oh boy how smooth it ride with those!. Edit: forgot the point for writing this, so point was im pretty sure i will stick to this Hobby at this point, hopefully i get atleast one of my daugthers with me on this :).

This info regarding batteries is what i would like to know when i picked this hobby up again, it is also my experience, ofc.

 

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I’m sure the people that have Lipo’s and know how to maintain them it’s no big deal. But for me, I’m still an outsider getting in.  these last two months is the first time I touched RC in 30 years I’m steering clear Lipo. Seems like having a Lipo is like having a diesel car, it’s a lot more work I’ll stick with petrol 1:1 cars and NiMH in my RC. You know those people who win Lottery and blow all their money within a year? Yeah that would be me. So I’d probably burn my house down w/ Lipo.  As the season go by, I need to move from this hobby back into Bmx and then back into Modern and vintage Honda dirt bikes/duals sport and I can’t be worried about how I left off with RC, so I have time and I have money but I clumsy and sometimes careless,  I got to stick with simple-stupid  

 

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I had to get into LiPo for my drone - at the time I could get 2 x decent LiPo for £30 

So not much more than nimh

the charger was the biggest change Although again they aren’t lots 

tbh in my cars I just use and abuse them

j have a LiPo alarm 

I charge them and keep them charged in a £10 ex military ammo box

your phone battery is just as dangerous tbh 

the power density and deliver from the LiPo is loads better than nimh though 

beetle in 3s LiPo brushless 


 

and with brushless - you can get a goolRC motor and ESC combo for £30 so that’s not a big cost either 

but nothing is ever suitable for everyone :)

JJ

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2 minutes ago, Exit13 said:

I’m sure the people that have Lipo’s and know how to maintain them it’s no big deal. But for me, I’m still an outsider getting in.  these last two months is the first time I touched RC in 30 years I’m steering clear Lipo. Seems like having a Lipo is like having a diesel car, it’s a lot more work I’ll stick with petrol 1:1 cars and NiMH in my RC. You know those people who win Lottery and blow all their money within a year? Yeah that would be me. So I’d probably burn my house down w/ Lipo.  As the season go by, I need to move from this hobby back into Bmx and then back into Modern and vintage Honda dirt bikes/duals sport and I can’t be worried about how I left off with RC, so I have time and I have money but I clumsy and sometimes careless,  I got to stick with simple-stupid  

 

My exerpeince is much like yours. 
I had been away from the hobby for decades. When I got back in I got an RtR 2wd Traxxas from my local hobby ahop 

The performance on 7 cell Nihm blew me away compared to what I was used to back in the late 80s with NiCd. I even used the standard car cigarette lighter charger that came with the truck. 
I was satisfied with Nihm 

Eventually I picked up a used charger which could do multi chemistry, preparing myself for eventually upgrading to Lipo.

I did a lot of homework reading up on safe handling and charging before I ever made that leap.

 

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1 hour ago, Exit13 said:

Seems like having a Lipo is like having a diesel car, it’s a lot more work

Urm, what? I love diesels , buckets of torque (360nm) at an RPM you can use (1600-2200rpm), fuel up and drive, no spark plugs, ignition to worry about, and 40mpg at 'motorway speeds 🙄

Lipos come into their own under high current demand, so if you're running a silver can /torque tuned etc, you might not notice a big difference (except maybe the extra speed from the extra volt), it's when you start getting into the lower turn motors, the difference is staggering.

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I've used NiCd (80s & 90s), NiMh (2004-2007) and now Lipo since 2014. To me and many, many others, Lipo is the way. You get to skip the many other process of maintaining a NiMh before charging. Discharging, conditioning, charging for an hour and using it only for 5-10mins. Too much hassle. Also, Lipo batteries and chargers are dirt cheap now so I wouldn't waste time on NiMh anymore. 15 years ago, a 6-cell 3800mah NiMh would cost about $60. A decent 2S 4.0 Lipo only cost around $25-30. A single charge on a Lipo will run up to an hour. You can spilt that into four 15-minutes run. When I went to on-road races before, I had to have at least 5-6 battery sets and two chargers, discharger, conditioner. Now I only have to bring two batteries and a charger. Lipo/LiFe battery on TX has has longer life than any AA/AAA batteries. 

I also have 3 FF chassis kits which are basically 2wd and I would never go back to using NiMh. Lipo is the way to go. Just make sure you store them on storage charge and in LiPo bags when not in use.

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26 minutes ago, Nicadraus said:

Just make sure you store them on storage charge and in LiPo bags when not in use.

Good advice. I’m relatively new to LiPo as well. I was curious if you need to “repeat” the storage charge if you don’t use the battery for several months? I assume it drains a little bit even when not in use?

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27 minutes ago, Nicadraus said:

LiPo bags when not in use

With the "Bat safe" which removes alot of smoke ,if the unthinkable happens, charging inside doesn't even seem daunting!

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25 minutes ago, Room335 said:

Good advice. I’m relatively new to LiPo as well. I was curious if you need to “repeat” the storage charge if you don’t use the battery for several months? I assume it drains a little bit even when not in use?

Storrage mode is actually close to 50% charged batteries, so if the batteries are in ok condition they should last longet than a month, though it would not hurth to check the storage mode once pr second month i believe. Also should always balance charge to keep each cell as simillar as possible:

standard volt for each cell is 3,7v wich make a standard v for 3s 11,1v. Max volt for each cell is 4,2, which make a max volt for 3s 12,6 volt.

Storage charge is ca 3,85 v each cell, that is 11,55v for 3s battery

Edit: For 2s battery ofc do the same math but * 2 

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1 hour ago, Room335 said:

Good advice. I’m relatively new to LiPo as well. I was curious if you need to “repeat” the storage charge if you don’t use the battery for several months? I assume it drains a little bit even when not in use?

It doesn't. I have two 3s Lipo batteries for my 450 size heli. I've not flown it for over three years and last December, I brought it out to just hover in front of my house for a few minutes. I didn't charge the battery as they were storage charged only. When I checked before flight, They still have the same amount of voltage on each cell when I left them.

1 hour ago, Wooders28 said:

With the "Bat safe" which removes alot of smoke ,if the unthinkable happens, charging inside doesn't even seem daunting!

That's why I charge my batteries on the ceramic tile floor in the house or at the garage concrete floor. That is just to make sure. I also did this with my NiMh batteries before. This is "if" something goes wrong.

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4 hours ago, Exit13 said:

I’m sure the people that have Lipo’s and know how to maintain them it’s no big deal. But for me, I’m still an outsider getting in.  these last two months is the first time I touched RC in 30 years I’m steering clear Lipo. Seems like having a Lipo is like having a diesel car, it’s a lot more work I’ll stick with petrol 1:1 cars and NiMH in my RC. You know those people who win Lottery and blow all their money within a year? 

 

LiPos are easier to maintain and less work in maintaining them unlike NiMh/NiCd. They also last a long time. But like any battery, they are short lived if not used/maintained properly or overused. Batteries constantly used for regular racing may not even reach a year. But for occasional racing and bashing, Lipos will last longer than NiMh. Plus the fact that they will run longer (4-6 times) than NiMh. You'll love using Lipos. You may or will probably forget about using NiMh once you've tried Lipo.

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This is really useful, thank you to those who have posted above.

I've been fine with NiMH up till now but I'm working on a crawler which would benefit from a small but decent 2S or 3S LiPo, an Agrios and converting my FTX Outlaw to brushless.

LiPo is starting to feel inevitable...

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Its a funny coincidence you made this thread, I have some battery related questions. I got 2 5000mah NIMH batteries and a 3600 mah NIMH on the 2wd slash. Only one 5000 mah battery has been charged, the slash is as is from the box and has yet to be charged. I have been considering getting a Lipo bag when I charge the NIMH out of extra caution. Currently I put the battery in a glass food serving bowl (i havent a real use for it food just yet, mostly its taking up space) when it's on charge, it's easier to unplug and handle should something go wrong. I'm not petrified of charging NIMH but some precautions are being considered. I top up the battery on my TTO2 every 2-3 weeks, it's mostly been a shelf queen as I don't really want to run it on snow much and prefer dry conditions. Is my time interval to top up the battery ok?

I feel like I am babying the TTO2 way too much but I don't have any convenient area To run it outside without using a 1:1 car to go to a proper area free of traffic.

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@nel33 - Nimh have the advantage of bieng safer to Charge/Discharge, that is the reason for all the safe boxes/bags are called Lipo-Safe/Guard. Nimh batteries do not like heat though and should never be hot to tuch when charging (over 55-60 C is standard stop point for a dmart charger but i think that is a bit to hot, mine is set to 45c). And ofc a good charger with a controll panel is also prefered for Nimh, they also last much longer than Lipo. 

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I like the weight of nihm batteries, when running on a damp track. Also I found that I have to completely change my set up when using lipo, adding a bit more weight to the hubs. I still use both and it's about what works for you.

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1 hour ago, markbt73 said:

One point on your original post: using a lipo battery won't "burn out" any motor. The current is pulled from the battery by the motor, not pushed by the battery.

Voltage matters, but 540 motors are industrial motors rated for 12 volts, so a 2s (7.4 volt) or 3s (11.1 volt) lipo will work just fine with them. In fact, my favorite power combo for many years now has been a basic 540 silver can with a 4000 mah 2s lipo. Punchy, quick, but not crazy-fast, and the run times are incredible. You just have to make sure to use an ESC with a cutoff, or a separate cutoff/alarm, to keep it from over-discharging.

While it's true that a lipo won't "push" current into a motor, it's also true that some nimh/nicad setups were current limited by the battery, specially during burst situations, and inserting a lipo into the mix removes that current limit and can in some situations give the motor enough rope to hang itself. Usually 2s is fine but there have been exceptions where a system that was running on the edge thermally is suddenly given a power source that allows the motor to draw more current and get hotter compared to nimh/nicad

It also depends on gearing terrain etc too. A Clod Buster with it's very low gearing will run well on a silver can and 3s (plus two motors sharing the work). The same cannot necessarily be said for all scenarios.
 

 

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9 hours ago, simalarion said:

@nel33 - Nimh have the advantage of bieng safer to Charge/Discharge, that is the reason for all the safe boxes/bags are called Lipo-Safe/Guard. Nimh batteries do not like heat though and should never be hot to tuch when charging (over 55-60 C is standard stop point for a dmart charger but i think that is a bit to hot, mine is set to 45c). And ofc a good charger with a controll panel is also prefered for Nimh, they also last much longer than Lipo. 

Thank you for the reply, I will keep the current glass dish setup. The glass will prevent contact with anything that might get a bit warm or be flammable.  Now I got to go charge my Traxxas battery as I've made all out of box upgrades on the RTR 2wd slash ie aluminum caster and wheel hex plus RPM  front bearing carriers. The body shell is now beefed up so i wont worry so much.

I guess the Traxxas ID plug battery packs don't come cheap, I have the 3000mah and I will soon see how long that could last on a run tomorrow. I'm thinking of getting 4200mah one using that I'd system as a spare.  

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54 minutes ago, markbt73 said:

Well of course it threw a wind, running it flat-out with no load after getting it hot. That's like putting your car in neutral and standing on the gas pedal. Eventually something will break. That's abuse, not use.

And when you "volt up," you always "gear down." That's Motor Setup 101.

I think "after getting it hot" is a slight understatement considering it gave out smoke signals after being used. The ceramic coatings on the windings were burnt out.

Also, electric motors are not internal combustion engines. Temperature depends on current draw which depends on load. 

The motor was smoking after normal use. Running it no load would have been much less stressful but the damage was already done by then anyway.

They just aren't practical for running on 3s unless you're doing a few high speed passes on road.

3s lipos and silver can motors do not make a good match unless you have a vehicle like a crawler or Clod which is geared way lower than you could practically gear an on-road or buggy and even if you could, the resulting speed decrease would cancel out the benefit of having greater RPM.

 

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Majority of 1/10 kits, in particular Tamiya are geared for 2S / 7.4 - 8.4 volts. 

So a 540 silver can on 3S / 12.4 v will surely burn up, period.  The only chance the motor has is if you can gear it way up to an FDR above 12. 

A 540 silver can motor on 2S will burn up only if you gear it too high.. eg final drive ratio below 4.0

My 7 year old son recently got into racing. I set up his TT02 for VTA racing, which uses a 25.5 brushless. Since motor did not arrive, I asked race director if I could run the torque tuned. He said go ahead.  I geared the motor around 4. After each heat I removed the motor and it was under 100° F, yet I could smell a hint of something cooking. By the 3rd heat, the motor slowed way down, eventually quitting. After removing it from car, I saw one of the brushes lodged into abs plastic of chassis lol. (Btw motor had a high rpm Whats that all about then? fan blowing on it)
 

So moral is even checking temps won’t tell you what’s going on inside a silver can.. one must use their nose! 

 

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Depends on the load a lot too. A motor rated for 12v or even 18v is still going to burn out on 3s or even 2s if it's put under too much strain and RC cars put a fair amount of strain on motors and generally have them on the go continually for relatively long periods too.

The usage scenario counts for a lot. I tried to upgrade a toy grade once from the stock 85 turn 370 motor to a 25 turn. In the spec sheets it was rated for up to 9.6v but died within minutes on 2s. When I read up about it more it was intended to be used in short controlled bursts such as ATM machines and transport mechanisms inside VHS players etc. Putting it in an RC cooked it alive. 

 

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Strain? Not quite sure what you put in Strain. But im quite sure the less the motor has to work with the faster it will turn and then  you can burn those brushes faster to, not the other way around. That means that the fastest way to burn brushes is to torture the 540 like in the video over with no resistance at all and set full throtle over time.

Thats also why i think TGH would not last 1 run with 3s.. not even worth to try

Most 540 motors have 7.2 normal v and 12 Max i have seen after googling it. And as i wrote in earlier post:

standard volt for each cell is 3,7v wich make a standard v for 3s 11,1v. Max volt for each cell is 4,2, which make a max volt for 3s 12,6 volt

So a fully charged 3s would be a problem if no resistance and full throttle, for sure no question asked. But with resistance Fans and as i did on TXT-2 set the ESC to max forward 75% it seem to be just fine, i have been running it s lot now with no problem, will they last as long as with Nimh, ofc not the motors are working much more and longer to..,

Whats strangly enoug is not mentioned here (as far as i can see) regarding Nimh is that 7.2 v is not a fully charged Nimh, a fully peak charge nimh can be over 9v (but will often dropp a bit after charging, mine stop charging at 9.2v but can not hold that very long and dropp fast). Nimh have 6 cells max for each its a bit over 1.4 if the battery is good (tiny bit lower than standard Alkaline wich have 1.5V stable). So its not that far from 3s as many makes it sound. If you drive a Nimh on 7,2v i will probably be cutoff time :)

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Strain is how much load is put on the motor. The motor draws more current when it has a higher load put upon it. More current means more arcing between the bushes and communtator. Arcing creates heat and accelerates brush wear and commutator damage. Higher voltage also increases arcing.

Running a motor with no load but at it's specified voltage is about the most gentle thing you can do to it. Arcing from over loading or over volting the motor will cause much more serious wear and damage.

The motor in that video was already damaged beyond repair by the time it was free run.

I guarantee if you put a healthy motor in a vice and run it at 7.2v it will last a great deal longer than 10 seconds before spitting out red hot brushes and smoke.

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