Can I change the cutoff voltage of a KT48ZWSRLT-LCD for 16S Lipo usage?

Ed Waldrep

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Apr 4, 2018
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I've been running a 1000watt E-Bay hub motor on a 48 volt controller, the KT48ZWSRLT-LCD, for a while now with HobbyKing Lipo batteries on a 100. I started with 12s on the first run, laughing the whole time at how the batteries normally propelling an RC EDF jet were now pushing me around. I didn't get much range, about 3 miles, before the 40 volt low voltage cutoff killed the power. I know through research that I started late last summer that 13S is one of the normal ranges of cell counts with ebikes and the li-ion batteries. I had a box full of 4S 5000 mah packs my friend gave me when he moved, so I was sort of set to use RC Lipos, vs buying new batteries. I have a plethora of chargers also, some will charge 6s max and some 9s max. I tried 13S using a 4 x 4 x 5 one day and that was better. I decided to give 16S a try, fearing I might fry the controller, but it worked fine, only one time I've had the LCD give some error message, but upon rebooting it worked fine and the motor ran. The low capacity of the packs and their age means I'm pushing the limits every time I ride more than a few miles. I've used voltage monitors with audible alarms that go off at 3 volts per cell early on but didn't have enough for every pack. I marked the packs, and what cells were low on capacity but it's no fullproof, no alarm on some packs means I've puffed a few cells, and the other day an entire pack!

I'd really like a controller that would let me set the low voltage cutoff to my desired level, vs being stuck at 40 volts, which at 16S is well below 3 volts per cell. I'd like to mod my present controller, the KT48ZWSRLT-LCD, but have found very little info on it, a few mentions of it here and there but no detailed info about possible jumper mods or anything like that (I can do soldering and repair my packs, change connectors but electronics are a bit beyond me...I knew I should have told the air force recruiter "avionics"...oh well).

I thinking a new controller would be my only or best option, I saw one that's bluetooth, though I have a windows 10 phone so probably no app for the controller. I could just run 12S with the new 16000mah Multistar packs I have on order, that'd keep my cutoff at 3.33 volts per cell so I'd be very unlikely to damage them, but that limits the capacity I can get out of them.

Any recomendations? I've read a lot in the past, I get on a kick and have 20 browser tabs opening and reading but seem to come up short on info on this controller. If it was an RC controller I'd probably have a programming cable to hook to the PC to change things but they don't have hall sensors in them.
 
I have been running 12S LiPoly for years, but I use geared motors that allow me to pick a motor speed that will reach a decent top speed on a low Volt system. DD motor are known to like a lot of Volts and I think you realize you won't be happy w/ 12S.
Your options, the way I see it are;
1)Switch the a square wave Infineon and if you went w/ a Lyen, he could set the LVC to anything you want.
2)Get a Voltmeter up somewhere on your bike where it's "in your face" and combined w/ a low-Voltage alarm, you should be able to "catch it" in time. As you are finding out, Low-Voltage alarms are hard to set to where they they don't start beeping early while still telling you when to syop. Especially since you are running your LiPoly to too low a cell Voltage. Below 3.6 V, the cells start to stray and there really not much energy below 3.6 V anyhow. The other thing that can be done is to, use the advantage of the Multistar's smaller form factor and lighter weight, to carry lot's of capacity, then you don't have to go so low on your pack.
I really like these flat Voltmeters from Luna Cycle;
https://lunacycle.com/luna-voltage-meter/
They fit in the clear top pocket of a sm. frame bag and since the screen is LED, they can be left hooked up all the time w/out draining the battery. Here's two of them on my 2WD;
100_0037.JPG
Also, if you go w/ LiPoly bricks, you should be bulk charging, so you don't have to "break the string". I use the great Mean Well HLG series potted power supplies and Battery Medics. The HLG-320-54A can be adjusted high enough to charge 15S LiPoly. Search my posts w/ search-words like LiPoly, bulk charging and mean well HLG for more details.
 
Ed Waldrep said:
I'd like to mod my present controller, the KT48ZWSRLT-LCD, but have found very little info on it,

If it helps, the KT controllers are Kun Teng or Kunteng brand, so there is a fair bit of general info on them around the forum. HOwever, much of the time they are simply called KT, and the forum search wont find two letter acronyms properly, so youd need to do a google site search for KT controller* to find many references.
 
You should look our OpenSource firmware for KT controllers, where you can choose the voltages and current, etc.
 
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