Connecting Voilamart 1000w kit to battery? (Updated with photos)

[Mohammed]

Hi,

This is my first post on here, I've owned a few ebikes over the years and have already browsed many threads, picking up tips and info along the way.

Apologies in advance if this is a silly question but this is my first time trying to build my own ebike...

I have a Voilamart 1000w rear wheel kit. The red and black wires coming from the controller have bullet connectors. The battery that I have bought (which had excellent reviews from people who have paired it with the same kit) has black and red wires coming out of it without any connectors. A label on the controller says that peak amps are 25+-¹.

After much searching, I couldn't find any bullet connectors rated to about 30amps but I have bought two yellow butt splice connectors that are rated to 30 amps.

Can I simply cut off the bullet connectors from the red and black controller wires and butt splice the red-red and black-black wires from the controller to my battery? Common sense says this should work but as I have no experience I don't know if there's something I have missed?

Thank you in advance for any help, I have no experience with this but have watched many YouTube videos and read anything relevant on here.

 

[Manbeer]

yes, normal yellow butt splice connectors will do just fine here, Just make sure to get a good connection

 

[E-HP]

Hi,

This is my first post on here, I've owned a few ebikes over the years and have already browsed many threads, picking up tips and info along the way.

Apologies in advance if this is a silly question but this is my first time trying to build my own ebike...

I have a Voilamart 1000w rear wheel kit. The red and black wires coming from the controller have bullet connectors. The battery that I have bought (which had excellent reviews from people who have paired it with the same kit) has black and red wires coming out of it without any connectors. A label on the controller says that peak amps are 25+-¹.

After much searching, I couldn't find any bullet connectors rated to about 30amps but I have bought two yellow butt splice connectors that are rated to 30 amps.

Can I simply cut off the bullet connectors from the red and black controller wires and butt splice the red-red and black-black wires from the controller to my battery? Common sense says this should work but as I have no experience I don't know if there's something I have missed?

Thank you in advance for any help, I have no experience with this but have watched many YouTube videos and read anything relevant on here.

I would go with XT-90 or Anderson connectors, since at some point you may need to unplug the connection to do maintenance, trouble shooting, or upgrades. If it's just for testing, just twist the bare wires together and put on a wire nut.

 

[Mohammed]

Thank you both for your replies. Much appreciated.

I read that the XT90 S connector is an anti spark connector which is an advantage but I have also read that the fewer splices in your wiring the better. I would need 4 splice connections instead of 2 if I use XT90's as I would need to attach male onto one existing set of red black and the female connector onto the other existing red black.

Would this matter at all?

 

[Mohammed]

Hi!

I have a Voilamart 1000w rear wheel hub kit and Lithium battery. I am going to join the controller and battery by connecting the red to red and black to black wires. As the existing wires are short, it would be useful to extend them.

I have found 27 amp wire (controller says that peak amps are 25) but it is only 12v wire and the kit is a 48v kit so does this mean this wire is unsuitable and will melt/blow up if I use it to extend the existing wires?

Many thanks for any help

Edit: After searching on eBay I am totally confused. I have found 30amp 12v cable but in the description it says rated up to 600v?

 

[amberwolf]

I have a Voilamart 1000w rear wheel hub kit and Lithium battery. I am going to join the controller and battery by connecting the red to red and black to black wires. As the existing wires are short, it would be useful to extend them.

I have found 27 amp wire (controller says that peak amps are 25) but it is only 12v wire and the kit is a 48v kit so does this mean this wire is unsuitable and will melt/blow up if I use it to extend the existing wires?

Edit: After searching on eBay I am totally confused. I have found 30amp 12v cable but in the description it says rated up to 600v?

I moved your new thread into your existing one, as it is directly related, so that those helping you already can continue to do so, and so that they will be able to see you still need help with this same project.


Regarding wire, for your application the voltage doesn't matter, unless it has very very very thin insulation (like less than paper thick, which would be super unusual).

What matters is the thickness of the wire inside. You need to get wire that is at least the same gauge (thickness) as the thinnest wire already being used in the connection you wish to extend.

If you are not actually using full power all the time (meaning your system isn't drawing more than a few amps, whcih is typical of ebikes) then most likely anything that is 12g would work perfectly fine. You can go to 10g if you'd like to minimize any voltage drop between the two and the wire run will be long.

If you want heavy duty you can go to 8g, but it's pretty thick wire. I use that on my SB Cruiser trike because it draws peaks of 80-100A for a few seconds, and 20-40A regularly when hauling cargo, and I have several feet of wire between the battery and the two controllers.

Thicker insulation, or a cable with multiple separately-insulated wires inside an outer jacket (like your hubmotor wires and some extension cords have) can help protect against damage or abrasion if the wires are in an exposed place, but arent' necesary if secured inside cable runs and whatnot.


Where on the bike is the battery being mounted, vs where the controller goes? And what is the wiring routing path? If you can post a picture of the actual bike, with a drawing of where you want to put everything including the wires, we can also suggest possible alternatives.

 

[Mohammed]

Wow thank you so much for all the info Amberwolf much appreciated.

Apologies for the poor quality of the first photo but here are the existing red and black wires? I am guessing that this is 2.5mm squared cable?

The second is a photo of my layout. Green is the battery, blue is the controller bag and white is a mini junction box where the join in wiring will be contained. (Red is wiring) The controller won't fit underneath the top tube as a lot of people go for as the battery is too tall.

I hope this helps to see what I am trying to do.

Thanks again

 

[Big_Truck]

Battery cables are 4mm csa, I think.

Anderson connectors are ok, make sure they are protected from water. If you want to joint the cables, bare back the insulation, twist the cables together londitudinaly, solder completely and cover in heatshrink. If you do it properly, there is no problem with extra joints.

HTH

 

[Mohammed]

Thank you Big Truck,

I have ordered the 4mm cable in the photo below, hopefully it's the correct type. It says rated up to 41amps which is well above the controller peak amp rating of 26amps.

 

[E-HP]

I read that the XT90 S connector is an anti spark connector which is an advantage but I have also read that the fewer splices in your wiring the better.

So most of the things your read suggested eliminating the connector?

 

[Big_Truck]

It isn't as flexible as the battery cable, but will be capable of carrying the current. Mechanically support any joints

If you are riding in the UK/rain, pay attention to waterproofing. Make sure rain and splashes cannot drip down or capillairy into the joints.

 

[99t4]

Suggesting maybe a better location for the controller is on the seat tube, either above or below the "junction box" (which you may not need if you can seal up the connections well with sealant inside of heatshrink tubing, wrapped with silicone repair tape)(talking soldered or crimped connections) or on the back side of the seat tube, or on the the downtube, underneath the battery.

Question about what you are calling your "junction box:" You mean like for house mains wiring? Might be more problem than it's worth. Difficult to really waterproof it to where no water can enter, then if it's almost waterproof means it's hard for any water to exit.

+1 on the comment regarding proper orientation of the components so any water ingress can drain out on its own.

Also, if you will be riding in the rain, FULL fenders. :thumb:

 

[amberwolf]

blue is the controller bag

If you mean putting the controller (that makes heat) inside a bag, I don't recommend that. If enough heat is generated (depends on your riding situation/etc) the controller can be immediately damaged under those conditions (not common, but it can happen), and even if it's not, it will age the parts in teh controller faster than if it is in the airflow where it is designed to be.

With very small 100-200w or thereabouts systems, there's not all that much heat, but a 1000w system has a significant amount of waste heat generated in both controller and motor under some conditions. As an example, a controller might be 80-90% effficient (maybe more, but not a lot). If the laod on the wheel is enough to pull 1000w from teh battery, then if it's 90% efficient, then there's still 100w lost as heat inside the controller...have you ever touched a 100w incandescent light bulb? It won't be under those kinds of loads and generating that kind of heat all the time, but when it is, it would.

The location you've chosen shoudl work ok, as it is least likely to be splashed by water from the wheels, and the rider and seat will tend to shield it some from direct rain, while riding. (wont' do anything if it's just parked outside, but neither would any other location on the bike). Most controllers have some grommets on the ends to minimize water intrusion, but they are not waterproof by any means, so wherever you mount it put the wire exit end pointing down, so any water that does get in will drain via those grommets. You can also make "drip loops" at the entrances / exits to any of the units (controller, box, battery, motor) to help water runing down a cable not go directly into the entrance/exit.

and white is a mini junction box where the join in wiring will be contained.

If this is a plastic / etc box with waterproof (or resistant, at least) "cable glands" in it, then that's probably a good way to contain all the connectors against water intrusion as well as making a neater-looking setup.


Regarding wire size, it's highly likely that the wire strippers you're (hopefully) going to use to remove insulation prior to soldering or crimping connections together have the wire size in iether mm or gauge marked next to each size hole. The hole is the size of the actual conductor, so you can fit that part of your wire in each hole with the strippers closed and tell which size your wire is.

 

[Mohammed]

Brilliant info here thank you so much :thumb:

I hadn't thought of the wire stripper idea to work out wire thickness but will definitely do that.

Although it looks like it should fit, the battery is much bigger in real life than in my rubbish diagram so unfortunately the controller doesn't fit inside the triangle of the bike frame.

Here is the "junction box" for reference. I am planning on attaching it upright with the black to black connection going through one hole and the red to red connection going through the other hole. (If that makes sense!)

 

[Mohammed]

Here is a progress update, I was going to use crimps but my neighbour (who is also planning on building an ebike) said that soldering and heatshrinking the wires would give a better quality connection. Thanks again to everyone for your advice, the wire was indeed 4mm. I am now in the process of attaching everything as neatly as possible to the bike frame.

 

[greektony]

How you getting on Mohammed?

 

[Mohammed]

Hi Greektony,

I am almost there, I have attached all the wiring and tried to keep the install as neat as possible. I have run out of money for the time being so not quite finished yet. I still need to:

- fit mudguards
- build a supporting 'base' for the controller bag so it won't flop over. I am planning on using acrylic to do that
- buy a decent kickstand. I made the mistake of going for a cheap one from eBay which was basically made from spaghetti but I did get a refund from the seller
- I have a very solid D lock which has a mounting bracket but haven't found a suitable mounting point yet. I am thinking of fitting a rear pannier?

Thanks

 

[99t4]

Looks like you didn't need the junction box?

What about a small strap to affix the top rear of the controller bag to the front of the seat rails in the bottom of the seat? Surely that could be easier than fabricating something out of acrylic?

 

[LewTwo]

- build a supporting 'base' for the controller bag so it won't flop over. I am planning on using acrylic to do that

From the picture, it appears that there is enough room to just let it hang underneath the top bar. Is the picture deceiving ?

 

[Mohammed]

- build a supporting 'base' for the controller bag so it won't flop over. I am planning on using acrylic to do that

From the picture, it appears that there is enough room to just let it hang underneath the top bar. Is the picture deceiving ?

Yes it certainly looks like it should fit there but the bag is just slightly too long to fit in that space. (Very annoying as this is where I originally wanted to locate the bag)

I have used sticky back velcro for the time being as a temporary fix.