Batteries NCads or Lipo's

[Ritchie]

Hi Guys, technical advice please this time, how would you wire up two NCads for more battery power or how would you wire up two Lipo'sfor more power. Should i use deans connection or leave standard. Also with regard to using Lipo's what is the alarm for and how do you wire it in.

Regards

Ritchie

[Wooders28]

Don't really get Nicads (nickelcadmium) anymore,moved to Nimh (Nickelmetal hydride),which give a better usage.

A normal 6 cell (1.2v a cell,giving 7.2v) are soldered in series,so you 'could' join a neg (-) off one pack to a pos (+) of the other, giving you the other - and + to fit a connection of your choosing to,that would give you 14.4v.

Lipo (lithium polymer) cells are 3.7v each and are for all intents and purposes,unstable and dangerous if not treated with care and respect,(have a look on YouTube for lipo explosions).

You need an alarm/cut off as if the voltage drops too low (≈3v per cell) when in use ,it destroys them/they blow up,if you over charge them,it destroys them/they blow up (which is why you only charge them in fire proof explosion bags and never in the car and never unattended)

You can connect them in series as per Nimh,but any mistakes/short circuits,it'll blow up.

[beefmuffin]

LOLOL "they blow up"... yeah, other than the blowing up part, not bad. LOL

[Ritchie]

Thanks guys, guess its Nimh's then, are deans connections any better than the standard one?

regards

Ritchie

[sparkysx]

Use common sense with lipos and they are fine.

[Wooders28]

Stock tamiya connectors melt if you draw a high current.

I went to deans,(or T-plugs I've seen them been called) work well.

Lipos are a great power source,but as they hold a load of energy, they need to be handled with a bit more care than your normal battery,or they blow up! 😱

[beefmuffin]

I think we should start a new thread about all different things that are great... except for the whole 'blowing up' thing. LOL I love it.

McDonald's has a new sandwich that's fantastic, except sometimes it blows your head off. But other than that, delicious!

[waterbok]

XT60 is a good alternativ for connectors

[Wooders28]

I think we should start a new thread about all different things that are great... except for the whole 'blowing up' thing. LOL I love it.

McDonald's has a new sandwich that's fantastic, except sometimes it blows your head off. But other than that, delicious!

Glad to have cheered up someone's day.😀

WATCH OUT FOR THE........

[Mad Ax]

I've been using LiPos for years, but they've never blown up, not even once

I actually threw all my NiMH batteries away as I was sick of them dumping early, and tired of all the charging hassle.

Lots of people worry about LiPo but as said above, if you follow the instructions, use a proper balancing lipo charger and use a charging sack just in case they blow up, you'll be fine.

As Wooders said in post 2, a LiPo alarm usually plugs into the balance lead on the battery pack and will start making an horrific racket if the battery voltage gets close to the danger zone. If you don't listen to the alarm, or if you don't fit one and your battery voltage drops too low, the pack can be irreversibly damaged. And sometimes it can blow up.

Alternatively, instead of worrying about LiPo alarms, use an ESC that has a Low Voltage Cutoff facility - many modern ESCs (including budget ones like the Probe WP) have a built-in cutoff. Be wary of the Tamiya ESCs that their cutoff is set for LiFe batteries, which cut off at a lower voltage. I think Tamiya prefer LiFe because they don't blow up.

(I have accidentally over-discharged a LiPo pack once, my charger wouldn't recharge it, said cell voltage too low. So I put it on a low-current NiMH charge for a few minutes, then switched back to LiPo mode and it charged up fine - and I've been using it ever since. It didn't even blow up, not even once.)

Have fun whatever you buy, and try not to blow yourself up

[Wooders28]

Lots of people worry about LiPo but as said above, if you follow the instructions, use a proper balancing lipo charger and use a charging sack just in case they blow up, you'll be fine.

You shouldn't worry about lipos,but you definitely shouldn't be blasé either.

I didn't want to answer with,it's OK to join 2 lipos,which is all a saddle pack is, and then someone has a garage fire etc.

Reading between the lines, I'm guessing Ritchie is like me a few years back,new back to the hobby after a while (with a nicad reference, a long while! lol) and realising it's changed a bit.

If I was to advise a me few years back,I would say to buy and modern classic,ie an RE RE,fit it with a brushless set up and a 3S lipo (correct charger,charge sack etc!).More power and speed that you ever thought possible BITD,without any faffing about.

[Saito2]

Ford once made this wonderful little car called the Pinto. They were great and in Ford's words "a carefree little car" except...they blew up! Joking aside (and not meaning to hijack too badly), is there a possible Lipo replacement on the horizon?

[Backlash]

Ritchie,

Due to the varied capacity and the need not to over discharge LiPo Batteries, I would not recommend connecting 2 random LiPo batteries in series to get more voltage, especially if they are not identical, and one battery was old, and the other new..

Instead I would recommend buying a 3S or 4S LiPo battery to meet your voltage requirements..

If you have a chassis that requires you to use 2 individual batteries, then I would recommend using 2 identical LiPo's.. By identical, I mean brand, capacity, C rating, and *Age.. But even 2 new identical batteries may not be matched, so some extra care will be required, and I would also run a Low voltage alarm on the balance lead of each battery just to be safe..

*By "Age" I mean the same batch and amount of charge/discharge cycles..

[Gruntfuggly]

Agree with Backlash - get a 4S LiPo if you want double the voltage. You'll be able to balance charge it properly and there's no reason why it should be any more likely to blow up than any other battery.

Any battery can be a fire hazard - the only real difference is that when a LiPo catches fire, you can't easily put it out because it's not burning oxygen.

Don't overestimate the safety of nimh/nicd vs. lipo - just follow the rules:

- use the right charger

- charge it properly

- charge it in a bag

- keep an eye on it

- if it swells up, get rid of it (safely).

- if it starts to hiss or smoke comes out, get it out of your house or garage quickly

The above applies to all batteries.

[mr crispy]

Agreed with all the above regarding lipos. They don't blow up unless something pretty serious happens to them. These YouTube clips make me laugh where people are shocked at the results when you stab a fully charged lipo with a steel blade... yeah most things won't react too well including me with 6" of steel stuck in me. Is that really surprising? Be sensible and careful and it's fine. Don't forget you probably have a lipo battery in your phone and keep it a few inches from your groin without ever worrying... until now! 😏

[Nitomor]

I have one round case lipo that is permanently swollen. It doesn't swell with use it has just become swollen with time. It has never been abused, run low or improperly charged. It has never got hot nor ever been discharged anywhere near its discharge capacity rate. I've often wondered should I dispose of it, the other three I have are fine, but I've also read that sometimes they can swell and remain swollen yet still be fine. It's an HPI one so decent quality. I've read heli guys having similar issues and saying they are still fine to use. It charges and works as expected.

What's the consensus on that?

I keep the Nimh for the kids, but I'm rapidly getting tempted to equip their cars with lipo compatible ESC's so when we go out on bashes together we have the reliability and consistency of happily using lipo's (charged by me) rather than having nimh ruin the bash with their unpredictability which has happened many a time. Lipo just gets on with it and is a pleasure, so dependable with loads more oomph to boot and run time.

I wouldn't trust kids unsupervised with Lipo's purely from the potential to go wrong, if one accidentally short circuited for example. I keep all of mine in safe sacks now in the conservatory and won't charge them unattended, also kept in lipo sacks while charging.

[Percymon]

Also remember that when you go to higher voltages, you'll need a suitable ESC to handle the voltage, and possibly high voltage servo for the steering, not to mention a tidy motor too.

3S lipo packs can be quite small, and will fit loosely in the standard battery compartments of models designed for 7.2V stick pack (NiCd/NiMH). When you step up to 4S the packs become too large for 95% of Tamiyas models, so you're faced with finding some place and method to secure them in use.

[Percymon]

I have one round case lipo that is permanently swollen. It doesn't swell with use it has just become swollen with time. It has never been abused, run low or improperly charged. It has never got hot nor ever been discharged anywhere near its discharge capacity rate. I've often wondered should I dispose of it, the other three I have are fine, but I've also read that sometimes they can swell and remain swollen yet still be fine. It's an HPI one so decent quality. I've read heli guys having similar issues and saying they are still fine to use. It charges and works as expected.

What's the consensus on that?

I've had a few early 2200mAh 2S soft pack lipos swell a little with time - they had very little use but the voltage was always maintained at a healthy level. I just took the view that I could replace them for under a tenner each, so the best place for them was the council recycling point.

Even though I always charge in a suitable sack, on a non flammable surface the thought of having to handle/remove a defective battery on charge, or worse still in a model whilst in use just wasn't worth the risk. Maybe if they'd been £60 race spec batteries I'd have taken some advice, but the technology is getting cheaper by the day - even the cheapest lipos these days have 30C or higher discharge rates, just not worth any risk.

[Ritchie]

Hi all, Wooders28, you are right, I used to be into R/C many years and i have only recently came back to the hobby. The reason i asked about two Nicads/Nimh's is that i was given some duff gen about double the batteries, double the power/run time etc. Some people suggested Lipo's but i dont know much about Lipo's alarms, which ESC's to use etc hence my questions. I am grateful for the suggestions so far. In reality which is the best (reasonable cost) motor to use, battery, charger, ESC combo to use. If the suggestion are for Lipo's, can I ask what charger i need, alarm thingy, charge bag and anyhting else.

Thanks again all, much appreciated.

[Wooders28]

Hi all, Wooders28, you are right, I used to be into R/C many years and i have only recently came back to the hobby.

You'll find there's a lot of people been in the same boat,career,mortgage, marriage and kids,kind of put a stop to all the fun! lol

If you think of the games consoles around at the time BITD,mega drive etc and compare that to the PS4 now,the same improvements have happened with motors and batteries in the RC world.

The reason i asked about two Nicads/Nimh's is that i was given some duff gen about double the batteries, double the power/run time etc.

I wouldn't say it was duff,in theory it's correct, but I just wouldn't bother,I'd risk getting blown up and go lipo! 😁

Some people suggested Lipo's but i dont know much about Lipo's alarms, which ESC's to use

I'd say,the same it's always been,the best you can afford.

[Backlash]

Ritchie,

I buy a lot of my RC stuff from HobbyKing.. If you are looking at making the switch to LiPo batteries, then you should be able to get pretty much everything that you need in one order.. Have a look at the UK warehouse and see what they have in stock..

There are some of the things that I use.. The links are to the Hong Kong/global warehouse.. I cannot access the UK warehouse from Australia, so you will need to check the UK warehouse yourself..

LiPo charging sack (Large)

http://www.hobbyking.com/hobbyking/store/__4364__Lithium_Polymer_Charge_Pack_25x33cm_JUMBO_Sack.html

LiPo Charging Sack (small)

http://www.hobbyking.com/hobbyking/store/__4134__Lithium_Polymer_Charge_Pack_18x22cm_Sack.html]

I usually buy one or two charging sacks each time I buy a new LiPo battery, and then use them to store the batteries in when the batteries are not in use..

Low Voltage alarm. (For 2S and 3S batteries) These alarms just connect to the balance lead on the battery.

http://www.hobbyking.com/hobbyking/store/__22749__HobbyKing_8482_Lipoly_Low_Voltage_Alarm_2s_3s_.html

IMAX B6AC Charger.. I don't have one of these myself, but they do seem to be quite popular, and you can charge from a mains wall outlet at home, or off your car battery in the field... (Just be sure to get one suited to your countries mains supply voltage)

http://www.hobbyking.com/hobbyking/store/__58285__IMAX_B6AC_V2_Professional_Balance_Charger_Discharger.html

AND 2S 7.4Volt Hard Case Batteries... You will need to check the physical size / measurements of the LiPo batteries, and the battery holder on your car to ensure that the battery will fit.. (I recommend using only HARD CASE batteries in an RC car)

http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=411&LiPoConfig=2&sortlist=&CatSortOrder=desc

[Backlash]

Ritchie,

Before you go out and buy 3S LiPo batteries in the search for more speed, may I suggest that you try running one of your RC cars on a 2S LiPo battery first as a trial..

LiPo batteries often have a lower weight, and also a lower internal resistance than NiCd and NiMh batteries, and may find that your cars will go better/faster when using a LiPo battery..

LiPo batteries have a flatter discharge curve than NiCd/NiMh batteries, which gives a higher overall average discharge voltage, and makes it seem like they run for longer than a similar capacity NiCd/NiMh battery..

As for using your older ESC's with 2S 7.4 Volt LiPo batteries, you should not have any problems.. Just be aware that most older ESC's will NOT have an inbuilt Low Voltage cut off, so you will need to use an external Low Voltage Cut Off or Low Voltage Alarm when using a LiPo battery, with your older ESC..

[Ritchie]

Backlash, many thanks for the thread, i will look at Hobbyking as i have heard of them, To the rest of the guys, thanks again for the advice.

yours in R/C ing

Ritchie

[berman]

Just take into account the old adage "You get what you pay for."

While I appreciate hobbyking has gotten a lot of people into various the hobby for a low cost, there is a reason they are so cheap.

I only buy their LSD AA's now.

[Wooders28]

You'll need to have an idea of where you want to go power wise,

If you plan on wanting a mentally quick 6S (22.2v) monster,then you'll need an esc that will handle it.

I edged my bets and went for a castle mamba max pro,runs upto 6S and plugs into a laptop to alter power curves/delivery, braking power etc, So much so that my RB5 with 3S lipo could be slowed down enough for an 8yr old to drive.