75 Rupp Centaur

[harrisonpatm]

Why do I need a series of 14v to reach a 72v? Why can't I just buy a 72v50-80ah battery with Samsung cells with 300-400 bms current, with a peak of 420 to 560amps?
Id think that would be perfect as it's a battery that supports up to almost 40k watts. Volts x amps
Then with the controller 500a with peak of 1000a so it should carry that little 3 wheeler quite well in takeoff an performance for what I want. The controller I'm looking at is recommended for lightweight electric vehicles. This thing is NOT heavy lol For some reason some of you guys think I'm trying to power a car. Lol

You could go that route, if you want. Nobody is stopping you. It's just that you're getting multiple accounts suggesting that a 72v50ah battery isn't going to get you the range that you're hoping for. You asked for advice, and the advice is to go bigger. You don't have to follow said advice.

We suggest automotive modules because their often a much better quality, higher performance, and lower cost, while often being constructed in heavy-duty and easy to assemble units. They are also usually cheaper per kwh than premade packs like Amorge, and they'll likely last longer.

 

[xXSaneXx]

Ok but a prem

You could go that route, if you want. Nobody is stopping you. It's just that you're getting multiple accounts suggesting that a 72v50ah battery isn't going to get you the range that you're hoping for. You asked for advice, and the advice is to go bigger. You don't have to follow said advice.

We suggest automotive modules because their often a much better quality, higher performance, and lower cost, while often being constructed in heavy-duty and easy to assemble units. They are also usually cheaper per kwh than premade packs like Amorge, and they'll likely last longer.

Adequate pack would suit me best because idk how to put packs together like most keep suggesting. The 72v50-80ah is used on motorcycles as well so why exactly would it not work? I'm not looking to go 100mph or 100 miles in range. It's a short trip cruiser toy. I'm not interested in long rides. If it goes 30 miles in range for start an does over 45mph that's fine. I'm not making a race bike like most the guys with razors an surrons do lol

 

[xXSaneXx]

Ok but a prem

Adequate pack would suit me best because idk how to put packs together like most keep suggesting. The 72v50-80ah is used on motorcycles as well so why exactly would it not work? I'm not looking to go 100mph or 100 miles in range. It's a short trip cruiser toy. I'm not interested in long rides. If it goes 30 miles in range for start an does over 45mph that's fine. I'm not making a race bike like most the guys with razors an surrons do lol

A premade*

 

[bananu7]

I mean, if you can afford a pre-made 72v80ah pack, then sure, that's the best thing one can get now, especially on 21700 cells, and that's what powers the best motorbikes out there right now. I think the reason why people are recommending larger batteries is that since you do have the extra space, you can make the build slightly differently.

When building a small battery, you have to choose between large capacity cells, high power cells or very expensive cells. Thing is, the more battery you add, max power becomes less of a problem, since you can spread the current over many more P cells. At a sufficient size, you can get largest capacity cells available with small power rating, without paying the premium for high discharge, while the entire pack can still supply the amperage needed.

 

[jkrienert]

How much does the trike weigh, 500-700lb.? Is that with or without rider(s)?

 

[xXSaneXx]

How much does the trike weigh, 500-700lb.? Is that with or without rider(s)?

700lbs without rider. It's a 2 seater but I'm deleting the second seat, I weigh 190.

 

[hugok]

As I said if you chose Amorge it will be like 3+ times the price for 1/3 of the battery capacity.

If you don't care about cost, just go for Amorge. I don't know exactly how the tariffs works but as I understand you will have to pay 54% extra on those batteries now. I personally would just buy from battery hookup but you do as you please.

Regarding the larger motor and controller, just because your controller can deliver a lot of power doesn't mean you have to use it. A larger controller will be running cooler and you have that extra power if you like. You just set it up as you like, if you want to limit the power to let's say 10kw, you just do that.

 

[xXSaneXx]

As I said if you chose Amorge it will be like 3+ times the price for 1/3 of the battery capacity.

If you don't care about cost, just go for Amorge. I don't know exactly how the tariffs works but as I understand you will have to pay 54% extra on those batteries now. I personally would just buy from battery hookup but you do as you please.

Regarding the larger motor and controller, just because your controller can deliver a lot of power doesn't mean you have to use it. A larger controller will be running cooler and you have that extra power if you like. You just set it up as you like, if you want to limit the power to let's say 10kw, you just do that.

It's not the cost part, it's more like idk what's involved in putting multiple battery packs ect. Someone said to use a battery from a electric car. The batteries qre to big. I was thinking amorge because it's already put together and I dint have to worry bout me screwing up on putting multiple battery packs together ect. Lol

 

[StultusEst]

It's not the cost part, it's more like idk what's involved in putting multiple battery packs ect. Someone said to use a battery from a electric car. The batteries qre to big. I was thinking amorge because it's already put together and I dint have to worry bout me screwing up on putting multiple battery packs together ect. Lol

I was in the same boat where I didn't know a lot of stuff involved in doing an EV conversion, but I was able to learn a whole lot from this forum. If you decide to go down the path of combining battery packs you can easily get help from the super knowledgeable people here. I'd read as many build threads and ask as many questions as you can.

I personally went with getting a premade pack from Amorge and it worked pretty well for me. I also didn't want to have to worry about me screwing up and causing a battery fire between my legs while riding. The Amorge battery I got came with a bluetooth BMS (battery management system) which is a really useful feature. It also came with QS8 connectors which have a precharge resistor built in which is pretty cool.

The cool thing about doing your own conversion is that you learn a bunch of stuff doing it, and if cost isn't an issue you can always upgrade it later on. That being said, I'd definitely lean towards more battery to begin with. You might kick yourself for not having enough battery, but you won't regret having more power than you need.

 

[xXSaneXx]

I was looking at other electric motor options. Would the geared qs138 be a better option?Does that mean there is a gear to shift to or does that mean it has like 3 modes? Would a direct drive qs138 be better for this? I'm thinking I'll use 1 motor, chain driven to start an then eventually and another gear to the axle adding another motor so I'll have a motor for both rear wheels. I'm dropping to a atv style wheel, lighter, an with a meatier tire. I was thinking the lines of a 12 or 13inch tire, less to spin. I currently have a 15x7 with 195/55/15 tires. The shorter tires in rear (matching close to the original 13inch wheels that were in rear) giving it much better acceleration and with a controller I can set to speedometer with the correct mileage it's actually going. The front wheel is a 16inch, unknown of the tire size but I'm going to go with a sport bike style tire. With the rear wheel an tire setup the rear will sit lower.
As far as a battery I been exploring options.i have room for a golf cart type battery, think they would work?

 

[bananu7]

I was looking at other electric motor options. Would the geared qs138 be a better option?Does that mean there is a gear to shift to or does that mean it has like 3 modes? Would a direct drive qs138 be better for this?

QS138v3 has a 2.35:1 reduction gearbox permanently mounted to the motor. It makes it a better fit for motorcycle wheels, as then you can use regular drivetrains (or closer to regular than would otherwise be necessary).

If you plan on using very small wheels, you'll need to spin them quite fast, and then the non-reduction motor might be a better choice. It's quite easy to calculate - take the desired wheel circumference, multiply by the max (or optimal) motor RPM for your powertrain, multiply by all gearing in the process, and you'll get the speed. You'll want to target around 75% of the non-flux-weakened max RPM you can get for your target cruise speed. Knowing all that, it should be easier to choose.

 

[xXSaneXx]

QS138v3 has a 2.35:1 reduction gearbox permanently mounted to the motor. It makes it a better fit for motorcycle wheels, as then you can use regular drivetrains (or closer to regular than would otherwise be necessary).

If you plan on using very small wheels, you'll need to spin them quite fast, and then the non-reduction motor might be a better choice. It's quite easy to calculate - take the desired wheel circumference, multiply by the max (or optimal) motor RPM for your powertrain, multiply by all gearing in the process, and you'll get the speed. You'll want to target around 75% of the non-flux-weakened max RPM you can get for your target cruise speed. Knowing all that, it should be easier to choose.

I think after some more research I'll use a qs138 90h without the gearing. I'm looking at controllers. I was recommended a em550 and to go with a 96v battery. I know alot of you are saying buy battery packs an put them together an run them in sync to work together. He's one do that when they have never put one together? I read you need to buy a bms pack too? Am I misunderstanding this? I'd probably be better off buying the stuff an have a experienced person put them together. If starg vark weren't so expensive I'd get a battery like there's. I wouldn't know what to get to make something close to or similar.