Newbie getting a Lehner 1950/4 LK.

[nosybody]

Hi, I'm new to RC boating and just placed an order for a Lehner 1950/4 LK for my Hydro Stealth Outrigger by MHZ. The hydro is designed for 12-16 cells Sub C and Ultra 920-8 or Viper 700, or brushless (or glow plug up to 3.5 cc).

What is the maximum voltages I can safely push to the limit without risk of damaging my motor? I don't see any specs from Lehner site about voltage range for the 1950/4 motor. The winding was based on 14,4volt, 120A, at 45000rpm = 1950/4 LK. The LK is for the new added air-cooling fan inside the motor.

I've emailed Lehner information about this hydro and they recommeded the 1950/4 for use with 4 LiPo. I like to see if I have any room to push higher voltages but not too much and risk damaging my $450 USD or 315.261 EUR (aircooling-version) & WK S 19 (watercooling series 19) new motor which is being built for me at their plant in Germany right now.

I was planing to use 2 packs of A123 Systems 4600mAh 6.6V 2S2P Lithium-ion LiFePo4 Battery together or just stick with the LiPo 5200mAh 4-Cell/4S 14.8V at 50C. Not sure about the pros and cons between the Thunder Power's 50C Lipo vs A123's 30C LiFePo4.


A123 Systems 4600mAh 6.6V 2S2P Lithium-ion LiFePo4 Battery
2S2P 4600mAh
Voltage : 6.6V x 2 packs = 13.2V
Max C-rate cont. : 30C
Max C-rate pulse : 60C
Max Current cont. : 69A
Max Current pulse : 138A


Thunder Power G4 Pro Race 50C Series Lipo Batteries
TP5200-4SPR50
5200mAh 4-Cell/4S
Voltage : 14.8V
Max Charge : 6C
Max Cont. Discharge : 50C
Max Burst Discharge : 100C
Max Chg. Current : 31.2A
Max Cont. Current : 260A
Max Burst Current : 520A

[tth]

It would be better if you post this in the Fast Electric Q&A Topic ( very first discussion thread ). I used to have a Lehner 1950/7. It used to rock on 4s but on 6s was uncontrollable. Lehner is a very strong 2 pole motor. For what you paid you should have gotten a Neu right here from Steven (OSE)

[nosybody]

Thanks, since I just jointed I'm still not familiar with this forum but will do better next time. I have not receive my motor yet but already regret forking out that kind of dough. LMT (Lehner) was pretty good with their customer service and with answering all my email questions everynight (and I had lots of questions since I'm new to rc boat). Their replies to me are usually short sentences, probably since english is not their main language. On my future projects I will get a Neu instead (not to put down Lehner), it just that the motor cost more then double the price of the hull.

[Fluid]

The Lehner 1450/4 has a Kv of 3135, meaning that it shouldn't use more than 3S in direct drive applications. I don't know why Lehner would recommend 4S, that is too high for any normal running and is for experienced FE boaters, not a new guy. If you want to run two SAW passes and bring the boat in then fine, but extended running will cause damage to the cells, ESC and/or motor. A better motor for the relatively small Stealth rigger would have been the LMT 1940/7. Smaller and lighter, it would still spin an appropriate prop well over 30,000 rpm on the water.

You should not use more than 4S in any case IMO, that will cause you nothing but problems. With the right prop your motor will have plenty of speed with 3S packs and be more appropriate for the small MHZ rigger.




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[nosybody]

Thanks, bad news like this makes me want to smack myself on the head :doh: for throwing $ before asking the right questions and getting all the facts. It may be too late to ask Lehner to stop (if they haven't already finished) and change my motor configuration. I've place the order and made the payment on 12/18 and it's Christmas already today in Germany. They suggested this motor specs after asking me if I'm going to do SAW and I told them yes. I've ask them if I can run more then 4S without damaging the motor and they said approve for 5S ok (I figure they mean only the motor can handle the power and heat and got nothing to do with the hydro or the ESC since the motor is their product). I guess if I'm going to do oval course or just playing around most of the time then I just have to run with 3S. I'll keep the 4S standing by just in case I'm surrounded by faster boats and I don't want to look like an amature....not that they couldn't tell eventually by my skills, or lack off.

[vvviivvv]

you might be lucky, ive ordered some speed controllers from Germany and they stopped production from early December till January 4th... email and ask you might get lucky