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Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: Walker on April 20, 2020, 12:20:41 AM

Title: Range extender - external battery pack
Post by: Walker on April 20, 2020, 12:20:41 AM
Hi all. I am building an external battery pack as  a "range exteder" for my Zero SR2018 and need help with connecting it to the bike.

My thoughts:
- I am not gonna use it everyday, just for long distance traveling
- the pack will be charged and balanced with an external charger and then fully charged connected to the bike (at the same voltage of course)
- pack consists of 2170 5000mAh cells, 2,4kWh in total (28S4P)

- I think the easiest way would be via external SBS charging connector. There is a fuse - I think 100Amps -  so I can´t use all the power of the bike, It would burn it, but that´s OK, my cruising consumption is about 50Wh/km only.

What dou you think?
Title: Re: Range extender - external battery pack
Post by: Auriga on April 20, 2020, 06:03:21 AM
This is extremely risky, complicated, and dangerous. Different chemistry batteries have massively different impedance curves under load and at different temperatures This thing might start off at roughly the same voltage, but there's no way it'll stay that way.

Say this add-on pack sags 1V below the monolith and the wire resistance of the wire between the two battery packs is 5 milliohms. You just dumped 200A into your range extender, and either blown the fuse, the connector, or damaged your add on pack. And this could happen as soon as you try to draw a load.

Connecting it to the same bus without careful consideration of impedance will cause very bad things very fast

Only one person(outside Zero) has added batteries to expand range, but he used additional Zero batteries with the same chemistry. Zero's batteries have mechanical contractors and battery management boards designed to disconnect them under any unsafe condition.

The fact that you're asking this on this forums suggests that you do not have the knowledge necessary to do this safely.



Title: Re: Range extender - external battery pack
Post by: DonTom on April 20, 2020, 01:47:55 PM
Hi all. I am building an external battery pack as  a "range exteder" for my Zero SR2018 and need help with connecting it to the bike.

My thoughts:
- I am not gonna use it everyday, just for long distance traveling
- the pack will be charged and balanced with an external charger and then fully charged connected to the bike (at the same voltage of course)
- pack consists of 2170 5000mAh cells, 2,4kWh in total (28S4P)

- I think the easiest way would be via external SBS charging connector. There is a fuse - I think 100Amps -  so I can´t use all the power of the bike, It would burn it, but that´s OK, my cruising consumption is about 50Wh/km only.

What dou you think?
I think you should do it the correct way and buy the power tank for your 2018 SR.

-Don-  Auburn, CA
Title: Re: Range extender - external battery pack
Post by: Walker on April 23, 2020, 12:20:36 PM
I have to test technology of building such a battery pack for my next project and why not to connect it to my bike and test it there....but just for your information, price of original "Power tank" in our country is about 3800USD, this 2,4kWh DYI pack is about 280USD including charger.
Title: Re: Range extender - external battery pack
Post by: TEV on April 23, 2020, 11:24:12 PM
The Zero BMS is quite smart, you can't just connect the extra pack to the bike and have it running.
If you do succeed to learn how to have the motorcycle running with the extra pack connected,  then you may burn some fuses or boards and your $280 project will cost a lot more.
Title: Re: Range extender - external battery pack
Post by: DonTom on April 24, 2020, 11:03:36 AM
The Zero BMS is quite smart, you can't just connect the extra pack to the bike and have it running.
If you do succeed to learn how to have the motorcycle running with the extra pack connected,  then you may burn some fuses or boards and your $280 project will cost a lot more.
Or even worse when the thing blows up.

-Don-  Reno, NV