Range extender / acceleration mod for electric moped

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badnewswade
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Range extender / acceleration mod for electric moped

Postby badnewswade » Fri Sep 28, 2007 10:46 pm

8) Maplins are selling an 80w lithium battery for £50! 8)

Here is the spec sheet:

Battery capacity: 4700mAh
Dimensions: 19 x 210 x 290mm approx A4 size
Energy: 80Wh
High power port: 19-21V (6A)
Medium power port: 12V
USB power port: 5V
Weight: 1kg approx

Here's how it fits into my plan to upgrade my pedelec's range / acceleration:

* Put it into "high power mode"
* Plumb it into the bike with a dash switch to turn it on and off, or maybe a button for power assist when accelerating and a blocking diode so it doesn't snarf power from the main battery
* Recharge nightly

Of course the problem is, that the system voltage is 36V. Will I blow up the bike if I don't use a DC-DC converter, or switch to plan B (which is:)

* Buy three of them
* Put them into 12v mode
* Plumb them in serially
* And so on

What do you think I should do? I am also thinking of maybe gettin banks of lower power 12 volt lithiums or SLAs and using them - is this a better idea? (certianly seems cheaper). How much tolerance do you think the Sakura's system will have for this kind of "overclocking"?

Answers on a postcard 8)

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ChrisB
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Postby ChrisB » Sat Sep 29, 2007 9:42 am

:shock: errrr dont think this is really going to work I'm afraid, nice idea but the spec says the "high power out put is 6A " well I suspect the moped will pull 4 times that maybe more.

Nope that batts just not going to work I'm afraid :cry:

You need to be looking at either bigger li-ions but then you'll be paying much higher prices or going down the route of say F size 7ah Nicads or sealed LA's

I see you've asked about my Yuasa's and these would be your best and easist route , PM sent BTW , not that I'm trying to flog you them but I think you wold find it being the best way.

ChrisB
I reject reality and substitute my own !!!!!!

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badnewswade
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Postby badnewswade » Sat Sep 29, 2007 1:12 pm

Ahhhh..... I see... (comprehension dawns on untrained mind)

so what you're saying is that a 200w motor will try to yank those amps out of a battery whether they're there or not, at worst causing permanent damage or maybe even (gulp) thermal runaway! :shock:

What about using a second controller or a capacitor or diodes as a buffer?


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