Fiido L3 controller upgrade

Mitsoskart

1 mW
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Jan 3, 2023
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Hi guys, sorry if this is the wrong category, I am new to the forums.
I need some help picking a new controller to upgrade my Fiido l3 since I am a beginner in the subject. I have been looking at various controllers on eBay rated at 48volts 20A or 22A to replace the 13A controller the bike has now.
However, the bike currently has a break light that is always on, a front light with a switch and a horn and I don't know if I can get a new controller without losing those functionalities.
Also I see that there are many different connections for the cables and I don't know if I can find a new controller with all the cables matching? I guess I would have to change the connectors for some of the cables myself?
The reason that I want to change the controller is that I would like some more power for going up hills and I don't like that the top speed gets capped lower as the battery decreases. The battery is pretty big at 1100Wh but I find that I want to recharge it every time it drops by one bar because the bike starts feeling too slow.
That's the controller I have now https://www.fiido.com/products/fiido-l3-controller
Any recommendations or advice would be very appreciated
 

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To get the connectors to match you will need to get the same controller. To upgrade going to need to change connectors/wire in new controller. There is no wire color standard, don't try to match colors.
 
Mitsoskart said:
I have been looking at various controllers on eBay rated at 48volts 20A or 22A to replace the 13A controller the bike has now.
However, the bike currently has a break light that is always on, a front light with a switch and a horn and I don't know if I can get a new controller without losing those functionalities.
Before you upgrade, you should confirm what the current capability is of the battery pack. It looks like they are generic Chinese cells, but per the spec sheet, and assuming the pack is 13S8P, it should be good for 40A. But you want to also know that the battery BMS can provide that as well.

On the lights, you'll probably have a challenge finding a controller that supports your lights as they are currently set up. I think it's best to keep the lights/accessories separate from the ebike components, so the better solution is to get a small 60v to 12V buck converter for running the lights. That way you have the most flexibility in choosing the controller. https://www.amazon.com/36V-48V-Converter-Transformer-Waterproof/dp/B09HTXNZDY/ref=sr_1_18?gclid=Cj0KCQiAzeSdBhC4ARIsACj36uEaC7_LAmK5ndZsb0A__vc5fvNSSrI589SvKddWfm7B4AXZuXomAboaAhlOEALw_wcB&hvadid=238250442840&hvdev=c&hvlocphy=1014187&hvnetw=g&hvqmt=e&hvrand=1225724878755269536&hvtargid=kwd-393014449606&hydadcr=18946_9701214&keywords=60v+to+12v+dc+dc+converter+circuit&qid=1673133837&sr=8-18

Mitsoskart said:
The reason that I want to change the controller is that I would like some more power for going up hills and I don't like that the top speed gets capped lower as the battery decreases. The battery is pretty big at 1100Wh but I find that I want to recharge it every time it drops by one bar because the bike starts feeling too slow.

It's normal behavior for the bike to run slower as the voltage drops. Motors are designed so their speed is relative to/proportional to the voltage provided. The controller could help on the hills, help with the sluggishness, but won't help with the speed, at least at the speeds that bike is capable of (above 20mph, more power is needed to overcome wind drag, so in that case, more power may provide additional speed).

Also, note that you'll also be replacing the control switches and display. Controllers and displays have to be matched and from the same manufacture. You should be able to reuse you pedal assist sensor, brake levers, and throttle.
 
This is what their support told me about the cells
"Dear Customer
The cells are all 18650-2900mAh of Dongmag, 48V23.2Ah is 13 series and 8 parallels, 48V14.5Ah is 13 series and 5 parallels, the battery pack has a continuous discharge current of 15A, and the maximum discharge current is 20A.
I hope my answer is helpful for you. Please feel free to let us know if you have any further questions.
Best Regards!"
I could not find anything about Dongmag cells, but on their website they say the battery is by DMEGC which I did find https://www.dmegcbattery.com/alkaline-batteries/li-ion-18650/
Also on the email they say "the battery pack has a continuous discharge current of 15A, and the maximum discharge current is 20A." but there are 2 different size packs and these numbers seem very low so I 'm not sure if they are correct, unless they are about the bms on the battery pack, what do you think?
 
Mitsoskart said:
This is what their support told me about the cells
"Dear Customer
The cells are all 18650-2900mAh of Dongmag, 48V23.2Ah is 13 series and 8 parallels, 48V14.5Ah is 13 series and 5 parallels, the battery pack has a continuous discharge current of 15A, and the maximum discharge current is 20A.
I hope my answer is helpful for you. Please feel free to let us know if you have any further questions.
Best Regards!"
I could not find anything about Dongmag cells, but on their website they say the battery is by DMEGC which I did find https://www.dmegcbattery.com/alkaline-batteries/li-ion-18650/
Also on the email they say "the battery pack has a continuous discharge current of 15A, and the maximum discharge current is 20A." but there are 2 different size packs and these numbers seem very low so I 'm not sure if they are correct, unless they are about the bms on the battery pack, what do you think?
Per the data sheet, the cells can provide max current at 2C, so for the 2900mAh cell, it can provide 5.8A max. 8 parallel groups would be 46.4A max for the pack, if you believe the specs which sound overly optimistic. It sounds like they are limiting the output current to 20A via the BMS, although the cells should be capable of more. A 20A controller should be fine.
 
Ok so if I were to get a 22A controller, or even 25A cause I don't see many options at 20A will that be just limited at 20A by the bms or is it going to fry a safety on the bms or something like that and stop working? I don't really know how a bms works, other than it balances the cells
 
Mitsoskart said:
Ok so if I were to get a 22A controller, or even 25A cause I don't see many options at 20A will that be just limited at 20A by the bms or is it going to fry a safety on the bms or something like that and stop working? I don't really know how a bms works, other than it balances the cells

Should be fine. Depending on the controller, you can limit the current through the setup parameters. KT (Kunteng) controllers allow you to do that and are fairly user friendly.
 
I wonder what is limiting the the output of your bike. Is it this one? Single speed. 14" wheels.

I think most of us agree that a typical 500W hubmotor on a 26" wheel will go about 24 mph at 48V. That means it's spinning at about 310 rpm. If we put that same motor in your bike, the same RPM on a 14" wheel gives 13 mph. Your motor probably spins faster than 310 rpm, but not much faster. I think you're going to be stuck somewhere between 16 -18 mph.



fiido_l3.jpg
 
docw009 said:
I wonder what is limiting the the output of your bike. Is it this one? Single speed. 14" wheels.

I think most of us agree that a typical 500W hubmotor on a 26" wheel will go about 24 mph at 48V. That means it's spinning at about 310 rpm. If we put that same motor in your bike, the same RPM on a 14" wheel gives 13 mph. Your motor probably spins faster than 310 rpm, but not much faster. I think you're going to be stuck somewhere between 16 -18 mph.



fiido_l3.jpg

Yes that's the bike, it goes up to 40 km/h at full battery if the wheel spins in the air but when it drops to 4/5 bars it spins up to 36km/h and even lower at 3/5 bars etc so this seems to me like a feature of the controller and not caused just by the voltage dropping but I could be wrong. It would be great if it could keep the 40km/h top speed constantly with a better cobtroller with more amps. But I agree with you that most likely the motor can't spin any faster than that
 
Mitsoskart said:
Ok so if I were to get a 22A controller, or even 25A cause I don't see many options at 20A will that be just limited at 20A by the bms or is it going to fry a safety on the bms or something like that and stop working? I don't really know how a bms works, other than it balances the cells
Assuming the BMS is correctly designed and working right, it will just turn off all output power once it's current limit is exceeded. So your bike will just shutdown (lose power, turn off) whenever you use the controller's full power.

If the BMS isn't designed or working right, then it won't shut off to protect the cells against overcurrent, and the overload will cause excessive voltage sag (and cell heating and aging), the sag will mean you probably won't actually see any greater power from the higher current above the cells' capabilities, since power (watts) is volts x amps.

As E-HP notes, if you use the KT controller, you can just program it for lower current to match the battery capability, to avoid the problems above altogether.


Note that as the battery ages, it will still sag in voltage more and more at the higher currents. This may cause shutdowns under higher loads as the battery is closer to empty than full once the battery is old enough.
 
Mitsoskart said:
Yes that's the bike, it goes up to 40 km/h at full battery if the wheel spins in the air but when it drops to 4/5 bars it spins up to 36km/h and even lower at 3/5 bars etc so this seems to me like a feature of the controller and not caused just by the voltage dropping but I could be wrong. It would be great if it could keep the 40km/h top speed constantly with a better cobtroller with more amps. But I agree with you that most likely the motor can't spin any faster than that

One solution to that is to replace the battery with a higher voltage one, and use a controller capable of handling that. It can then spin the motor faster from the higher voltage.

More or less, more volts gives more speed, while more amps gives more torque...approximately--as you get faster you need both to overcome wind resistance/etc. You can go to http://ebikes.ca/tools/simulator.html to see how the system interactions work.
 
Mitsoskart said:
Yes that's the bike, it goes up to 40 km/h at full battery if the wheel spins in the air but when it drops to 4/5 bars it spins up to 36km/h and even lower at 3/5 bars etc so this seems to me like a feature of the controller and not caused just by the voltage dropping but I could be wrong. It would be great if it could keep the 40km/h top speed constantly with a better cobtroller with more amps. But I agree with you that most likely the motor can't spin any faster than that

Using a quick estimate of the voltage that 3/5 represents, the speed at that voltage is between 33 to 34 mph, based on the voltage (around 46V). Given that bars are probably the worst way of estimating remaining charge, and usually tend to be on the high side, I'd say the speed decrease you are observing is all based on the voltage drop (46/54.6=0.84; 0.84 x 40 = 33.7mph).
 
I see, so for a higher top speed I can either change the battery, or get a different motor capable of a higher max rpm at 48 volts. Looks like if I only change the controller to more amps it will be a disappointing upgrade, since the battery will be discharging faster and I ‘ll be riding with a top speed lower than 40km/h most of the time.
 
Mitsoskart said:
I see, so for a higher top speed I can either change the battery, or get a different motor capable of a higher max rpm at 48 volts. Looks like if I only change the controller to more amps it will be a disappointing upgrade, since the battery will be discharging faster and I ‘ll be riding with a top speed lower than 40km/h most of the time.

But you will zoom up the hills easier and faster and accelerate quicker. If/since you're battery should be capable, it's nice to take advantage of that and have the power on tap.
 
What do you think of this controller https://www.aliexpress.com/item/1005002780952533.html?spm=a2g0o.productlist.main.27.597470fbyAjaqY&algo_pvid=3ac829a0-6839-4dc1-9177-9c2de62398cb&algo_exp_id=3ac829a0-6839-4dc1-9177-9c2de62398cb-13&pdp_ext_f=%7B%22sku_id%22%3A%2212000022154544805%22%7D&pdp_npi=2%40dis%21EUR%21114.64%2185.98%21%21%21%21%21%402102111816732862564794967d0688%2112000022154544805%21sea&curPageLogUid=E4YPne4YgfTm ? The 36V48V 500W LCD5 model at € 67,78
 
Mitsoskart said:
What do you think of this controller https://www.aliexpress.com/item/1005002780952533.html?spm=a2g0o.productlist.main.27.597470fbyAjaqY&algo_pvid=3ac829a0-6839-4dc1-9177-9c2de62398cb&algo_exp_id=3ac829a0-6839-4dc1-9177-9c2de62398cb-13&pdp_ext_f=%7B%22sku_id%22%3A%2212000022154544805%22%7D&pdp_npi=2%40dis%21EUR%21114.64%2185.98%21%21%21%21%21%402102111816732862564794967d0688%2112000022154544805%21sea&curPageLogUid=E4YPne4YgfTm ? The 36V48V 500W LCD5 model at € 67,78

The link didn't work for me, but if it's something like this one, it should be fine, but you'll need a separate solution for your lights:
https://www.amazon.com/Controller-KUNTENG-Brushless-Electric-Compatible/dp/B0B19H3SB9?th=1
 
Small update, I 've ordered this kit https://www.aliexpress.com/item/1005005098242961.html?spm=a2g0o.order_list.order_list_main.4.60551802i7h2k6
It looks like it has the same lights as my bike and the controller is 30a with an s900 display, so hopefully I will get a nice boost in acceleration and there should be an option on that display to limit the power if my battery bms has a 20a limit, should arrive in 1-2 months
 
I have changed controller and motor, my new top speed it 45km/h at full battery which is a bit disappointing because before I could get 37 km/h at full battery. However the motor spins up to 54 km/h without any load which is a big difference. The old motor would spin up to 40km/h with no load so only 3 km/h difference in real world use. Apart from that the bike can reach around 40km/h even going uphill whereas before I would not be able to go faster than 20-25 km/h at the same spots and the acceleration is very good. Total cost of the upgrade was around 500eur +780 for the original bike. It is very fun to ride now just a bit disappointed about the motor.
 
The display shows up to 2000w under load so there should be enough power to reach 50km/h+, I 'm guessing that either the motor is not very good and does not have much torque at that speed or there is a lot of voltage sag , which I don't know if I can do anything about. For example I read somewhere that the thickness of the cables play a role in voltage sag but I 'm not sure if that is correct. The batteries have a 50a limit so they should be good.
 
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