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EV2Go
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Post by EV2Go » Fri, 23 Oct 2009, 21:20

Ok this is not EV related but it is motor related...

Looking at adding an electric supercharger to my bike to give it a bit more punch, problem is I don’t know if the battery has enough grunt to handle the current draw.

Watched some you tube videos and it showed the power draw was 68 amps @ 12v how many AH battery do I need? And do you think a bike battery could pull that safely?

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Post by lithbattboss » Fri, 23 Oct 2009, 21:23

EV2Go wrote: Ok this is not EV related but it is motor related...

Looking at adding an electric supercharger to my bike to give it a bit more punch, problem is I don’t know if the battery has enough grunt to handle the current draw.

Watched some you tube videos and it showed the power draw was 68 amps @ 12v how many AH battery do I need? And do you think a bike battery could pull that safely?


Come and say hello to me at the Sydney EV field day and I will show you a LiFePO4 battery which will do that easily!!
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Post by EV2Go » Fri, 23 Oct 2009, 21:44

was wondering if I would need to go lithium or if the factory gel battery would do it. Need to comnfirm but I think the factory battery is 11Ah

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Post by Electrocycle » Fri, 23 Oct 2009, 22:06

the factory one will do it, but probably won't last long with the extra strain.
A lithium pack will certainly do it quite well and last a lot longer.

An electric supercharger is not likely to add much power to the engine though at those current levels. (~600w motor output into a ~60% efficient blower)
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Post by EV2Go » Fri, 23 Oct 2009, 22:07

Just remembered the A123's can do some serious output in a small form factor

ANR26650M1A: The ANR26650M1A is A123Systems’ pioneering product, originally designed for a new class of power tools. Applicable to a wide variety of system designs and currently in mass production, the 26650 cell offers excellent price-performance.
•     Power: Over 3000 W/kg and 5800 W/L
•     Safety: Excellent abuse tolerance and environmentally friendly
•     Life: Excellent calendar life, 10X cycle life vs. conventional lithium ion

Our batteries use a new type of cell construction based on a dual plate tubular design optimized to deliver very high power with high efficiency. This new design does not use crimp seals and instead opts for a more advanced “all laser welded” construction optimized for very low humidity penetration over the life of the battery as well as stronger, thicker dual plate headers.
•     Download Specs
For high volume orders, customized energy solutions, or OEM pricing only, please contact us at 617-778-5575 or email:
producteval@a123systems.com
•     Nominal voltage: 3.3V
•     Nominal capacity: 2.3Ah
•     Core cell weight: 70 grams
•     Internal impedance: (1kHz AC) 8 mΩ typical
•     Typical fast charge current: 10A to 3.6V CCCV
•     70A continuous discharge
•     120A, 10 sec pulse discharge
•     Cycle life at 10C discharge, 100% DOD: over 1,000 cycles

120Ah should cover system voltage requirements and electric supercharger, only need 10 second bursts, and I have gotten to the end of the quarter

Thoughts?

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Post by EV2Go » Fri, 23 Oct 2009, 22:13

Electrocycle wrote: the factory one will do it, but probably won't last long with the extra strain.
A lithium pack will certainly do it quite well and last a lot longer.

An electric supercharger is not likely to add much power to the engine though at those current levels. (~600w motor output into a ~60% efficient blower)


Can’t run massive boost anyway it has 12.7:1 static, so a pound or two boost would suffice. Mostly need it for off the line and mid track.

Just ordered a Power Commander V, wide band auto tune kit for PCV, 1 tooth smaller front sprocket and a speedo healer. Hoping the auto tuner will take care of any additional fuel needs.

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Post by Electrocycle » Fri, 23 Oct 2009, 22:22

I'd be very surprised if the supercharger could make a psi or two.

I've done some testing with various electric powered fans before, and a single stage centrifugal fan with enough flow for an engine will not usually make more than .5psi static pressure (and that's with a 1500w+ motor!
The best I've seen pressure wise was a dual stage pump with a 2000w motor.
It made 4psi static, but nowhere near enough flow to keep up with an engine.
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Post by EV2Go » Fri, 23 Oct 2009, 22:45

How did you calculate watts? V * A?

In the video it peaked at 68 amps, so that would be 12 x 68 (816 watts)?

What size motor were trying to fit it to, remember the bike is only a 1000cc

Even if I picked up 5hp most aftermarket mufflers costing $1000+ and only get that and sacrifice the bottom end.

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Post by Electrocycle » Fri, 23 Oct 2009, 22:54

I never fit one to an engine - there was nowhere near enough flow.
Remember that 1000cc engine does double the revs of a typical 2L engine.

I calculated the watts as V*A minus a bit for efficiency losses.

I reckon the only way to do a decent electric supercharger would be to use a very large R/C brushless inrunner motor (which can do 5kw+), a compressor side from a turbo, and a ~36v pack of LiPo batteries (maybe A123s)
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Post by EV2Go » Sat, 24 Oct 2009, 01:49

Yeah good point... but it would produce twice the boost at lower revs.
Can’t really use scroll type compression because of the way the intake is set up.

They designed the bike to use a ram air effect, so the only electric supercharger I can use is one that doesn’t stop the ram air effect when it is turned off.

Getting back to the batteries how big of a battery pack would I need if I use something like A123’s or similar?

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Post by Electrocycle » Sat, 24 Oct 2009, 04:21

well you need around 100A, and as much voltage as you can fit in.
You're talking a few kg at least.

Do you have a link to the superchargers you've been looking at?
If they're an axial design they're probably a radio control plane ducted fan setup - which flows a lot of air, but not at very high pressure.
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Post by EV2Go » Sat, 24 Oct 2009, 04:23


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Post by EV2Go » Sat, 24 Oct 2009, 04:25

can't go more than 12v as I still need to power the bike
Last edited by EV2Go on Fri, 23 Oct 2009, 17:25, edited 1 time in total.

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Post by Electrocycle » Sat, 24 Oct 2009, 04:58

you could add a battery just for the supercharger.

Either way, if you want to try out that force flow setup, don't spend $550 when you can buy the bits for 1/10th of the price :)

http://www.hobbycity.com/hobbycity/stor ... oduct=5484

http://www.hobbycity.com/hobbycity/stor ... 0-100A_ESC


Those will work on a 4 cell pack (or the bike's battery) and have about the same power rating at the force flow gear.



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Post by EV2Go » Tue, 27 Oct 2009, 14:49

Thanks Andrew, also would be nice if I didn’t have to pull it apart to use it, since I doubt it is going to fit in to the intake tract in the round chrome cylinder.

Went through the bike manual last night and it mentions all sorts of sensors like air temp, atmospheric sensors etc. Because the bike was designed with ram air in mind they appear to have already factored in a bit of positive pressure.

Ordered a Power Commander V and auto tune kit last week so that should take care of any minor fuel changes it needs.

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Post by EV2Go » Tue, 27 Oct 2009, 20:18

Any way to convert thrust to boost pressure?

http://www.hobbycity.com/hobbycity/stor ... de_3.5inch

but figuring more thrust the better...

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Post by Electrocycle » Tue, 27 Oct 2009, 22:00

that one doesn't come with a motor :)

thrust is based on mass flow and velocity, and it's definitely the more the better - but none of these are designed to make much pressure, so you can't really predict how well they work in that application.

A single stage axial fan can never make much pressure though.
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Post by EV2Go » Tue, 27 Oct 2009, 23:15

Yeah I realise that a single stage axial flow will always be massively restricted by its very design, but really with 12.9:1 static compression I can’t afford to add any massive boost anyway. It’s more for sh*ts and giggles then any serious HP increase.

But at the other end of the spectrum if I am going to attempt it, I want to try achieve the maximum results possible, if that means creating a custom package to do it that really doesn’t overly concern me it is as much the learning curve as it is the result.

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Post by Electrocycle » Tue, 27 Oct 2009, 23:53

it's not so much that it's restrictive, it's just that an axial fan can't make much pressure.
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Post by EV2Go » Wed, 28 Oct 2009, 04:26

nah I didn't mean restrictive by flow I meant restrictive by design in that it's not a positive displacement design, therefore it will only ever make extremely average boost figures.

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Post by Electrocycle » Wed, 28 Oct 2009, 04:35

you can get decent boost from a non positive displacement blower - if it's centrifugal or multi stage :)
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Post by EV2Go » Wed, 28 Oct 2009, 04:43

yeah but centrifugal is still a semi compression design because it stacks the air against itself in the compressor housing, any axial flow will only achieve boost once it can deliver far more air than the engine can consume.

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Post by Electrocycle » Wed, 28 Oct 2009, 04:56

they stall at a very low pressure ratio though.

That's why jet engines use lots of stages in axial compressors, but can get away with a single stage centrifugal.
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Post by EV2Go » Wed, 28 Oct 2009, 17:37

yeah a single stage is a fairly poor compromise but I guess I'm not expecting miracles here. we're not talking 100%+ power increases we are only talking maybe 5-8 hp on something that is already making 190hp so percentage wise it is very limited gain.

Thanks again for pointing me to that website, with careful selection of bits I can probably find something better for a lot less then $550.

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Post by Bluefang » Fri, 30 Oct 2009, 18:03

Have you looked on you tube, there is a video of someone doing a dyno tune on his car, a mate comes up to the car shoves a leaf blower into the intake, blasts it, and the engine does like another 10% on that power run compared to the first with out the blower in the intake :) so yes they do work

Its not so much the extra pressure your after more the removal of all the inefficiency in the intake system, like having you engine pulled apart, honed, ported, flow matched, and blueprinted all in one. The Axel ducted fans for a hobby jet plane are more then adequate for your bike if they are over 60amps at 12V. Yes a centrifugal design would be better but chances of getting one to that size and spec off the shelf is never going to happen. :)

http://www.youtube.com/watch?v=UQ7YWT6rX0o Couldnt find the better video where they used a hand held blower and showed all the charts before and after of the power runs

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