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[GNU]

Hi,
Has anyone successfully modified an existing  Zero battery or found a way to extend range by hooking up a custom battery to their bike?

I've got a bunch of 5.8Ah 35C cells around from an electric ultralight aircraft (paramotor) project I worked on 2 years ago. I used some of them to build an electric bicycle and I'm now considering building a custom back that I can hook up to the bike for longer trips.

What kind of interfaces are available on the 2013-2014 bikes?

Worst case I guess one could hook up an inverter and let it charge as I drive (and loose about 25% efficiency or more). Assuming the bike accepts a charge while driving.

//Arvid

 

[eyeinsky]

You could just use a DC to DC step up converter, ultimately if you are runing the bike over charging would never be a issue.

http://www.ebay.com/itm/261293791102?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Jerry

[emotofreak]

The bike will not enable with a Zero charger attached. This is for safety so you can't drive off with a charger still plugged in.

[eyeinsky]

But we can re-gen brake! its just how you choose to wire it. Ultimately if you dump power on the main power bus and it is higher than bus voltage the battery will charge.

[Tudor]

But can you regen and draw power simultaneously? Guess you would need to control it to add to regen when regen or coasting.

[Justin Andrews]

But can you regen and draw power simultaneously?

Yes, Bikes with regen already do this, otherwise all their systems which draw power (dash etc) would black out during regenerative braking otherwise...

[NoiseBoy]

There has to be a point where adding batteries becomes self defeating.  Ok so you could travel an extra 30 miles, but then it is going to take you 13 hours or something silly to recharge.  If i was going to be adding weight to the bike, id rather it was in the form of chargers. At least until Fast DC charging is commonplace.

[Tudor]

But can you regen and draw power simultaneously?

Yes, Bikes with regen already do this, otherwise all their systems which draw power (dash etc) would black out during regenerative braking otherwise...

Ah, good point!

[Justin Andrews]

In reality its more to do with power balancing, technically you cannot draw power out of a battery while its being charged...

However if you assume that a motor during regeneration provides 100 units of power.
Then the onboard systems stop using battery power, and use 1 unit of motor generated power;
And the battery recieves 99 units of the rest of the motor generated power.

Once regen ends, the systems go back to drawing power from the battery.

[eyeinsky]

All this is correct but the tread was related to custom battery a battery pack that could be added to supplement main battery. I see a use for this, even if you would use this for range extender or reserve pack. I have seen some fairly cheap pack on eBay and would consider having a pack that I could use with a DC to DC converter simply connected to the main bus as required. Any power put on to this bus would simply be consumed by the bike or would be returned to the main battery till the supplemental was discharged with the end result adding range to the bike. For example if you had a 10ah 48v pack with DC to DC converter 600w converting to 72v on my 2012 xu it would power load of 500w 72v to main bus. While the bike was powered most of the 500w power would be consumed by the bike. if you stop the 500w would be recharging the main pack. 

Thanks Jerry   

[GNU]

Thanks for the great replies!
I don't think you even need a DC-DC converter. Just add 28 of (well balanced) cells in series and ta-daa, you got a 111V battery.
The 2013 Zero batteries seem to be 102-116V so I'm assuming they're 25-30 cells in series. (Source: http://www.zeromotorcycles.com/powertrains/powertrains-sales-sheets.pdf)


Is there a good spot where one can hook something like this up to the suply voltage bus?

[grindz145]

Look into Doc bass' stuff.

[eyeinsky]

Thanks for the great replies!
I don't think you even need a DC-DC converter. Just add 28 of (well balanced) cells in series and ta-daa, you got a 111V battery.
The 2013 Zero batteries seem to be 102-116V so I'm assuming they're 25-30 cells in series. (Source: http://www.zeromotorcycles.com/powertrains/powertrains-sales-sheets.pdf)


Is there a good spot where one can hook something like this up to the suply voltage bus?

The problem is the cheap cells have  a different voltage per cell and internal resistance. Therefore the DC to DC converter would be a good option to supplement the main batt also you could setup low voltage cut so the pack could fully utilized.

BTW the 2012 has 72 V pack much easier to fine DC to DC converter for this application.

You could take AC inverter 115V then rectify back to 115 DC to give you the DC to DC voltage for the new packs.


Jerry

[GNU]

You could take AC inverter 115V then rectify back to 115 DC to give you the DC to DC

Very clever!

[frodus]

Rectifying 120vac gives you about 170vdc with some ripple if you use a capacitor.