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Discussion Starter · #1 ·
Hi

I am increasingly getting stressed over certifying my car in the UK the costs appear to be around £5k and as there has been very little experience of this precess for kit cars rather than conversions so good chance of failing and not sure what cost would be for this. Sooo i had the idea of changing to a 48v system as this then does not require any certification at all, i am currently using 144v HPEVS 35x2 motor with 96 calb 72 batteries and could swap to a 34x2 48v from hpevs this would mean the current chain drive i have would work and everyhting would fit fine although my power and acceleration would obviously suffer although there would be a big weight and space gain reducing from 96 to 26 batteries and i could double up motors to double the torque.

Any advice greatly received is AC still sensible for 48v are there more powerful motors out there at 48v etc.
 

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Ever drive a fully loaded forklift @ 3 ton in an amazon warehouse? 48v series DC can give you all the performance you would want, up to perhaps 30 mph where performance starts to fall off because of back emf. Less weight and higher ratio gearing might get you to 60 mph but cooling and battery capacity becomes an issue here. I've never operated a new multi phase forklift so I can't comment on one of those, and they might be higher voltage. The other comment: I have seen golf carts go suprisingly fast. I also don't know your regulatory system so it may be possible to use the battery system with a voltage doubler scheme on your existing motor/ controller. Back in the day, 48 volt FLA systems were all you had. Didnt stop people from making Los Angeles freeway capable cars. Whashisname Ed who lived next door to Bill Nye had a RABBIT like this
 

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Discussion Starter · #3 ·
I have been doing some research on this and it seems the lower voltage limits the RPM and the current determins the torque, so my existing setup with 144v and 1000 amps max i get about 240 Nm torque from 0-5000 rpm but with a 48v motor with 1400 amps i get more torque 280 Nm but it drops off around 18000 rpm however i save hugely on batteries droping from 96 to 26 saving a lot of space. I could put a second 48v motor in keeping the voltage at 48 but doubling the torque from 287 to an amazing 550 Nm and 52 batteries so still lighter
 

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Hi

I am increasingly getting stressed over certifying my car in the UK the costs appear to be around £5k and as there has been very little experience of this precess for kit cars rather than conversions so good chance of failing and not sure what cost would be for this.
If it's anything like the US over there, it's all about finding the right person to perform the inspection. In the States, independent mechanics are able to do safety inspections (they presumably go through some sort of an application process with the state department of motor vehicles). Here, you just need to find one that can bend the rules for you a bit.

It's all a little corrupt.
 
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