Posted November 21, 201014 yr hello all its possible to power up your pf engins bij using a lipo 11,1v i bought a lippo batt for 10 euro the lego 8858 i believe is much expensiver and lower voltage the size is a bit longer but lower and tighter i use the 11,1v in the 8043 watch the improvment! thnx to jurgen k and buffalo
November 21, 201014 yr Of course it works, but it is dangerous for your PF components so don't do this! read the philohome site about stressing the motors. b.t.w. lipo is potentially very dangerous!
November 21, 201014 yr Author Of course it works, but it is dangerous for your PF components so don't do this! read the philohome site about stressing the motors. b.t.w. lipo is potentially very dangerous! PF XL Torque Rotation speed Current Mechanical power Electrical power Efficiency 4.5 V 14.5 N.cm 43 rpm 0.52 A 0.65 W 2.34 W 28 % 7 V 14.5 N.cm 100 rpm 0.54 A 1.51 W 3.78 W 40 % 9 V 14.5 N.cm 146 rpm 0.55 A 2.21 W 4.95 W 45 % 12 V 14.5 N.cm 214 rpm 0.56 A 3.24 W 6.72 W 48 % they can handle 12v i stayed down from that to be safe lipo is indeet dangerer atatch them good pos on the pos and neg on neg ore els ther can be fire!!!! u use the 8043 many time to kill time and no probs so far befor i forgeti use castrol 2 stroke oil to greas it up more power so more maintaince! on the gears next to the engines befor i was using the oil some gears broke in in 2 now i use oil it never happend agian! also in the engines are 6 gears inside they want oil also after a good use of the xl motor the grease is no use anymore on the gears inside so to regrease the gears inside i just drop some castrol inside the engine sounds stupid but i have a shit load of pf stuf so i experiment a lot:D results are: the are smooter running less noise and deffentlie stronger and if you aske me i think its less stress for the engine i also do this wiht the LA's i tested the oil wiht lego and no cemical reaction just a verry smooth working 8043 Edited November 21, 201014 yr by rien
November 21, 201014 yr Well but he also clearly says: "Caution ! Though I tested motors with a 12V supply, I can't guarantee that they bear the extra load for extended time period. Use that at your own risks !" It is not wise to use higher voltage than 9V on your LEGO PF!!! The XL motors are already drawing quite some current in certain situations. Since U = I x R (Ohm's Law), it is for sure that 3 volt difference with the same resistance of the motor can already cause a current that is well beyond specifications. B.t.w. Rien, I think people would appreciate you to at least try so spell correctly or use a spell checker (you might be a dyslect, but even then).
November 21, 201014 yr Author Well but he also clearly says: "Caution ! Though I tested motors with a 12V supply, I can't guarantee that they bear the extra load for extended time period. Use that at your own risks !" It is not wise to use higher voltage than 9V on your LEGO PF!!! The XL motors are already drawing quite some current in certain situations. Since U = I x R (Ohm's Law), it is for sure that 3 volt difference with the same resistance of the motor can already cause a current that is well beyond specifications. B.t.w. Rien, I think people would appreciate you to at least try so spell correctly or use a spell checker (you might be a dyslect, but even then). youre right about that but(with the same resistance ) i also use oil to create less resistance the grease they put in on the factory is working onley a short time think of a gearbox in a car there is oil all the time if they would use grease the car would drive not for long so i do something on the one side but also on the other side i try to balans that i wil make some pict when oiling a engine my englis is crappy i know sorry for that
November 21, 201014 yr Rien, ok, that last post is readable, but I really struggled to read your second one! What oil (or grease) do you use for lubricating your gears and inside of your motors? I wouldn't recommended running PF motors on a 12V for a prolonged period of time.
November 21, 201014 yr Author Rien, ok, that last post is readable, but I really struggled to read your second one! What oil (or grease) do you use for lubricating your gears and inside of your motors? I wouldn't recommended running PF motors on a 12V for a prolonged period of time. hello sorry for the bad english i agree no prolonged but when using the 8043 it are short times 1 engine boom up then another engine takes over and the other has a rest period for some seconds and im lower than 12 im on 11,1 :P u use castrol 2-stroke oil or afterun oil from tornado
November 21, 201014 yr @JopieK There may be some initial ohmic resistance, but this can practically be ignored unless the motor is nearly stalled. @rien Adding oil will decrease load, and therefore decrease current, not resistance. It is perfectly safe to connect PF motors to 11.1v, just don't stall them. When stalled, the heating could rise to (11.1/9)^2 = 1.5x the heating caused by a 9v supply. The difference in heating is less considerable when the motors are not under heavy loads.
November 21, 201014 yr There was a recent (Aug 2010) post about the "Max Voltage for Power Functions": http://www.eurobricks.com/forum/index.php?showtopic=45289 . The bottom line is that, if rien's Power Functions equipment has not burned up and he has a lot of PF motors to experiment with, then his findings are useful in possibly IMPROVING THE PERFORMANCE of not only the 8043 Motorized Excavator, but also other motorized Technic models as well. Here is rien's http://www.youtube.com/watch?v=vXid6Nrdnqo"'>YouTube video showing how it functions: Edited November 21, 201014 yr by DLuders
November 21, 201014 yr @JopieK There may be some initial ohmic resistance, but this can practically be ignored unless the motor is nearly stalled. @rien Adding oil will decrease load, and therefore decrease current, not resistance. It is perfectly safe to connect PF motors to 11.1v, just don't stall them. When stalled, the heating could rise to (11.1/9)^2 = 1.5x the heating caused by a 9v supply. The difference in heating is less considerable when the motors are not under heavy loads. So and how about the H-bridge that is in the PF receiver: LB1836M. The datasheet says: 10.5V is the absolute max rating for the supply voltage to the motors...
November 21, 201014 yr Author So and how about the H-bridge that is in the PF receiver: LB1836M. The datasheet says: 10.5V is the absolute max rating for the supply voltage to the motors... i heard that too but stil i tridet it hoped that there would be no probs and it seems to do fine plus datasheet dont tel the exact limit it is keepen people away of trying if they read 10.5 and the lego pf wont break down they are not gonna tell you that if you put 11,1 v on them they work fine also but it may break easyer
November 21, 201014 yr So and how about the H-bridge that is in the PF receiver: LB1836M. The datasheet says: 10.5V is the absolute max rating for the supply voltage to the motors... I did not know that, but this might be the maximum voltage when there is a few 100 mA of current, but in this case the supply voltage might drop from 11.1v to something below 10.5v. When there is no current, 11.1v might not cause any damage (just guessing). Having said that, it also mentions 'Allowable operating ranges', where it says 9v is the maximum . I agree that connecting PF receivers to 11.1v is not a great idea. The motors should be able to handle 11.1v as long as they are not under very heavy loads.
November 21, 201014 yr i heard that too but stil i tridet it hoped that there would be no probs and it seems to do fine plus datasheet dont tel the exact limit it is keepen people away of trying if they read 10.5 and the lego pf wont break down they are not gonna tell you that if you put 11,1 v on them they work fine also but it may break easyer Well the manufacturer just gives the spec's in order that you can decide on what you should do and shouldn't do that is all. If it works, it works, but nevertheless should be also state legit concerns here since the whole world can read along and some people might get hurt if you don't follow the manufacturer rules.
November 21, 201014 yr Author Well the manufacturer just gives the spec's in order that you can decide on what you should do and shouldn't do that is all. If it works, it works, but nevertheless should be also state legit concerns here since the whole world can read along and some people might get hurt if you don't follow the manufacturer rules. thats what i ment ;)but the in plain languages
November 21, 201014 yr thats what i ment ;)but the in plain languages Well that might not say anything, but I have been a teacher in English you know ;) I don't know what school you attend, but I might help out there (I guess, reading your English, you are a Dutch highschool student).
November 21, 201014 yr Author Well that might not say anything, but I have been a teacher in English you know ;) I don't know what school you attend, but I might help out there (I guess, reading your English, you are a Dutch highschool student). no im a 31 year dutch self employd Ship mechanic didnt like school verry much coudent keep mine mind to it now they call it ADHD :S i can talk it but writing it is hard also strugeling in dutch some times :S im better of with a diesel engine or lego ill ask my wife to type for me :P greetz
November 21, 201014 yr Well at least he's got it working at a less sleep inducing speed I would also say your English is far better than my Dutch Besides, in the real world electricity is not an exact science, there are sometimes surprisingly large tolerances. If the PF components really are high quality products then their tolerances SHOULD be big enough to cope with 11.1V. Edited November 21, 201014 yr by allanp
November 21, 201014 yr This is an interesting topic, as I am experimenting with PF myself at the moment, so thanks for sharing Rien! Bad English isn't a problem, but lazy typing is. Could you at least try to use a capitol at the beginning of a sentence and have proper punctuation, i.e. a dot at the end of a sentence? I am a high school drop out, as I didn't care much for school either, but I really do my best to post decently on the forum.
November 21, 201014 yr Sorry about my insult than rien ;) I'm also 31 :) although I'm a computer science teacher I was always quite fluent in languages. But anyway. It seems that TLG has used a motor-driver that is already a bit outdated at the moment but SFE has some alternatives: http://www.sparkfun.com/products/9457 They are more voltage tolerant. Well my college's wouldn't say that electrical engineering is an exact science I guess, but I agree that the real world is sometimes more forgiving than the math.
November 21, 201014 yr Has anyone actually used Lego motors above 9V on a longer term basis? Many small, off-the-shelf DC motors are designed for 12V operation, and I wouldn't be surprised if the actual motor cores TLG uses are like this. TLG may have kept the voltage of the whole system down in order to meet toy safety regulations. I recall that the 12V train system was not available in the US for this reason. The receivers are of course a different matter and should be kept down to 9V.
November 22, 201014 yr There was a recent (Aug 2010) post about the "Max Voltage for Power Functions": http://www.eurobricks.com/forum/index.php?showtopic=45289 . The bottom line is that, if rien's Power Functions equipment has not burned up and he has a lot of PF motors to experiment with, then his findings are useful in possibly IMPROVING THE PERFORMANCE of not only the 8043 Motorized Excavator, but also other motorized Technic models as well. Hmmm ... I would have said the bottom line from that (excellent) thread was that it is not a good idea to go above 10.5V for the PF Receiver (outside of the motor controller manufacturer's stated limits). Mortymore did an awesome job of reverse engineering the PF Receiver for us. So it may well work, at least for a while, but I certainly wouldn't want to recommend anyone try it! 10.5V is the stated absolute maximum rating, i.e. that means the chip-maker is saying there is a reasonable chance that the motor controller will start to deteriorate if you exceed those limits. Even if it does, you probably won't see it straight away. Personally, I would keep well clear of the 10.5V limit -- I say stick with at maximum 6 alkalines (9.6V) for the PF receiver. The motors are a different story - I'd be willing to experiment with higher voltages on those, so long as you're very careful not to let them stall.
November 23, 201014 yr Author :D played for some hours now still no probs on recivers or motors just smooth running if prob comes i will post it here 11,1 is onley 0,6v more than 10,5 not a big isseu for lego :D Edited November 23, 201014 yr by rien
November 23, 201014 yr Has anyone actually used Lego motors above 9V on a longer term basis? I made a Robotwars-MOC back in 2005 where I had four Light Gray Electric, Motor 9V (pre PF) on 18 V (two battery-boxes hooked in series). It was not long term, max about an hour in total with pretty short sessions. Worked fine and the motors did not feel that hot (I never stalled the motors). I would however never run higher voltage through a micro controller such as the PF-receiver.
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