DIY: Range extender for Levo (and Kenevo)

chagolucho

Member
Apr 7, 2021
9
0
Chile
I will test if there is current going out from the load port. Thanks.
Oh, another thing, I plan on using a 30A ideal diode on the original battery pack as I can using it by itself without risking the system, and a smaller 15A on the external battery.
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
I will test if there is current going out from the load port. Thanks.
Oh, another thing, I plan on using a 30A ideal diode on the original battery pack as I can using it by itself without risking the system, and a smaller 15A on the external battery.
If both are going to work in parallel and with a similar voltage, I don't think it is a problem, I have preferred to size it so that it can work with either of them, for whatever it may be.
If for whatever reason you must use only the extender (not in parallel or with the original one with little load) remember not to exceed 75% load.
 

eagerly

Active member
Oct 6, 2018
131
172
Pordenone
One question. I see here very interesting projects, but I notice the absence of a switch to power on the extender after the main battery. Why? You think not ncessary?
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
One question. I see here very interesting projects, but I notice the absence of a switch to power on the extender after the main battery. Why? You think not ncessary?
Yes, of course it is interesting, the issue is that a switch that holds a possible 20A is difficult to find (I was going to put 2 of 10A in parallel) but in my case, when I get home, I open the zipper and disconnect the battery with the XT60 connector and it is already solved, I do not reconnect it until I am not going to leave again, I also have to open the zipper to load it because inside the bag is the independent charging connector.
It doesn't bother me much and I avoid having "things" inside the bag that could damage the battery in the event of a hit.
 

eagerly

Active member
Oct 6, 2018
131
172
Pordenone
Yes, of course it is interesting, the issue is that a switch that holds a possible 20A is difficult to find (I was going to put 2 of 10A in parallel) but in my case, when I get home, I open the zipper and disconnect the battery with the XT60 connector and it is already solved, I do not reconnect it until I am not going to leave again, I also have to open the zipper to load it because inside the bag is the independent charging connector.
It doesn't bother me much and I avoid having "things" inside the bag that could damage the battery in the event of a hit.

The point is that the main battery has the TCU (in the Levo case) to power on the battery and the BMS for all the check and level up the cells.
Now the extender: if it comes with no switch whatsoever, then it is directly connected to the motor already before the bike is powered on, a better practice may be to wait a sort of consensus from the main one (a relè closing the positive or a manual switch connected to the BMS) before it is connected to the motor. I suppose a 10A switch would be sufficient because during the ride, the extender is not working -never- alone, and during the startup there is almost no load (if you are not riding).
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
The point is that the main battery has the TCU (in the Levo case) to power on the battery and the BMS for all the check and level up the cells.
Now the extender: if it comes with no switch whatsoever, then it is directly connected to the motor already before the bike is powered on, a better practice may be to wait a sort of consensus from the main one (a relè closing the positive or a manual switch connected to the BMS) before it is connected to the motor. I suppose a 10A switch would be sufficient because during the ride, the extender is not working -never- alone, and during the startup there is almost no load (if you are not riding).
I first turn on the bike through the main battery and then I plug in the extender, and at the end I always disconnect the extender, otherwise the motor continues to consume even though the main battery is off.


There is an option, as those of Levorex mount it, that mounts it with 2 solid state relays that already incorporate the diodes. These relays are activated by receiving power from the main battery, so I consider them the best option.

The problem is not when connecting it to disconnect it, but when the voltage goes down, the intensity increases to satisfy the motor and I prefer to contemplate a possible case in which the main battery is at 20% and I put another battery in the 100% extend. so the extender would have to withstand higher loads and the 10A switch or it could go wrong.
 

eagerly

Active member
Oct 6, 2018
131
172
Pordenone
There is an option, as those of Levorex mount it, that mounts it with 2 solid state relays that already incorporate the diodes. These relays are activated by receiving power from the main battery, so I consider them the best option.
Actually the Levorex uses only one relays 10A/250V although the pics show 2. I know it because I had one and dismounted it
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
Actually the Levorex uses only one relays 10A/250V although the pics show 2. I know it because I had one and dismounted it
It does not seem very correct to me, it assumes that it will always work with the extender and therefore the load will be shared, but 10A is very little and also that these relays get quite hot.
Besides that the ratio of 10A and 250VAC is not very comparable to the volts in DC that we use.
I imagine that he assumes that the extender will turn off its own button and that the BMS itself prevents voltage input to the extender's battery, I prefer to do it with fewer "assumptions."
 
Last edited:

eagerly

Active member
Oct 6, 2018
131
172
Pordenone
It does not seem very correct to me, it assumes that it will always work with the extender and therefore the load will be shared, but 10A is very little and also that these relays get quite hot.
Besides that the ratio of 10A and 250VAC is not very comparable to the volts in DC that we use.
I imagine that he assumes that the extender will turn off its own button and that the BMS itself prevents voltage input to the extender's battery, I prefer to do it with fewer "assumptions."
Maybe you should look to the specifications but i don't know if i can post them here. Anyway the relay is a 24V and therefore a resistance is needed to trig . The maximum current is 15A I don't see why you say very little. Peak power of the motor is around 600w roughly, it gives 14 amps...therefore when used coupled with the main battery there shouldn't be any problem
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
Maybe you should look to the specifications but i don't know if i can post them here. Anyway the relay is a 24V and therefore a resistance is needed to trig . The maximum current is 15A I don't see why you say very little. Peak power of the motor is around 600w roughly, it gives 14 amps...therefore when used coupled with the main battery there shouldn't be any problem

This is a test of my Drive T
1617984484726.png


And a Drive S...
1617986195018.png


As you can see, the Drive S (1.3) go up to 780w (the image show 785w, I know)

And in absolutely all the solid state relays that I have seen, they indicate that they must take their radiator to cool because they get very hot ... especially when they go over X% of their maximum capacity that I do not remember exactly the percentage now, but it was not a lot, and if above, its maximum power is 15A, it will surely pass. The point is that when you go only with the original battery, you can reach peaks of 19 and 20A and that will surely heat it up ...

The 600w sounds to me that they are mechanical power, effective force, not consumption.

If you send me the information of the specific relay by message I can look up its data sheet.
 
Last edited:

chagolucho

Member
Apr 7, 2021
9
0
Chile
Just wanted to say that I was able to use a ES-2 scooter external battery on my kenevo, had to cut some of the battery's ´ñastic but now I have around 190Wh more. Awesome!
 

Eddy Current

E*POWAH Master
Oct 20, 2019
578
315
NORTH Spain

sorry all, let me comunicate with him in spanish if you dont mind, thanks!

Hola Jose! Oye puedes ir con el extender solo quitando la bateria principal para salidas cortas ir ligerito? Sin diodo, enchufado a pelo al cargador me refiero. El extender oficial de Rocky funciona asi, y he visto una página en italia que venden extenders que van al puerto de carga ...

Un saludo!
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
sorry all, let me comunicate with him in spanish if you dont mind, thanks!

Hola Jose! Oye puedes ir con el extender solo quitando la bateria principal para salidas cortas ir ligerito? Sin diodo, enchufado a pelo al cargador me refiero. El extender oficial de Rocky funciona asi, y he visto una página en italia que venden extenders que van al puerto de carga ...

Un saludo!
Sure he can, the diode does not affect this.

In the case of Turbo Levo, it is not possible to connect to the charging port as it is the junction between the motor and the battery and we have to disconnect the motor to access the charging port.

----------------------------------

Claro que él puede, el diodo no afecta a esto.

En el caso de las Turbo Levo no es posible conectar al puerto de carga pues es la unión entre el motor y la batería y tenemos que desconectar el motor para acceder al puerto de carga.
 

eagerly

Active member
Oct 6, 2018
131
172
Pordenone
Dear all, I have a question for you. I use a range extender with a separate diode, to decouple the main battery. So in total there are 2 diodes one connected to the + of the main battery, and one connected to the + of the range extender. Now, when i connect the power supply to the extender to recharge it, the TCU powers on without touching it, this happens even if the connector of the main battery is open, the TCU auto-switches on but of course a red light is displayed because there is no main battery connected. This strange behaviour does not show without the second diode, and therefore it has something to do with the diode. Maybe when it switches on a voltage disurbance is interpreted as a TCU press? I am really in the dark...
 

tapda01

Member
Jun 12, 2021
2
6
Melbourne
Hi, I have a 2019 Kenevo with the standard 460 watt Battery. I have been watching this thread for over a year now as I tend to run out of power on any ride over 50ks. After much hesitation I eventually bit the bullet and built the following range extender using a short length of storm pipe to house 10 Samsung 50E 21700 5,000mAh batteries and BMS to give an extra 180 watts of power. Tried it out for first time yesterday and very pleased with the results... I also think it looks quite elegant for a storm pipe!! What do you think?
installed extender.JPG
extender close up 2.JPG
extender close up.JPG
 

Yoniboi

New Member
Jul 15, 2021
8
5
Madrid
Brilliant thread this! Thanks for all the info. I know it's a little old now but it'd be good to know how your homemade range extenders have got on over the last couple of years!!!
I'm going down that route myself and find the biggest hurdle the connector. My best bet would be one of these:
My question to all of those more knowledgeable than me is, can one of these take the current, or will it short and/or melt?
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
Brilliant thread this! Thanks for all the info. I know it's a little old now but it'd be good to know how your homemade range extenders have got on over the last couple of years!!!
I'm going down that route myself and find the biggest hurdle the connector. My best bet would be one of these:
My question to all of those more knowledgeable than me is, can one of these take the current, or will it short and/or melt?
Both me and my bike are happy with the extender, not a single problem, just cheers.

That connector is going to fry, it is 22AWG and the minimum that would be 14AWG, ideally 12AWG.
 

Yoniboi

New Member
Jul 15, 2021
8
5
Madrid
Thanks for your speedy replies.
Villho, glad to hear everything's still running smooth.
joliver, thanks for your input.
The gauge of the wire was an interesting point but I'm finding that when looking for the best connector almost none of the manufacturers specify wire gauge, whereas most do specify voltage and amps.
Should I be looking at 20A or is 10A enough?
Thanks
 

joliver

Member
Oct 19, 2020
37
11
Barcelone (Spain)
Thanks for your speedy replies.
Villho, glad to hear everything's still running smooth.
joliver, thanks for your input.
The gauge of the wire was an interesting point but I'm finding that when looking for the best connector almost none of the manufacturers specify wire gauge, whereas most do specify voltage and amps.
Should I be looking at 20A or is 10A enough?
Thanks
I used this table as a reference, taking into account that the peak of our motors can reach 20A, I sized everything to support those amps.
1626408472961.png

It is also true that if it is going to work in parallel and both batteries have similar capacities, the maximum of each one would be 10A, but I preferred that it be left over and avoid possible problems.

I always carry the extender, now instead of charging it at each outlet, I charge it every 3 outlets, and that's why I didn't put an external connector on it.
 

Yoniboi

New Member
Jul 15, 2021
8
5
Madrid
Thanks. The 20A peak figure sounded familiar but I couldn't find it anywhere in the Shimano tech sheet as they only talk about nominal or average values.
 

EMTB Forums

Since 2018

The World's largest electric mountain bike community.

523K
Messages
25,796
Members
Join Our Community

Latest articles


Top