Electric Go Kart with Solar Roof 2Pannels

HKZBob

New Member
Joined
Nov 7, 2020
Messages
52
Dear Forum,

I want to convert a gasoline Race Kart to an Solar Green Kart.
I have two panels a 100W. 20V on hand.
One panel will be used as a rear spoiler and the 2nd one shading the driver.

Here my question.
I want to power the Kart with scooter battery packs. 48V.
I like to run the electric motor on 96V.

What options do I have to use my solar grid 20V 200W or 40V 100W to charge my scooter cells.

Can I use a DC DC step up in front of each pack to charge then.

As an 12V storage for the Kart I have an 80Ah Lifepo4 available.

Solarpower to 12V Lifepo4 to DC DC step up to 48V Lion packs.

Who can provide feedback?

Merry Christmas
Bob



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HRTKD

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Apr 24, 2020
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Somewhere South of Denver
That controller says it can handle up to 15 amps. If your scooter motors require more than 15 amps you'll need to find a different controller.
 

HKZBob

New Member
Joined
Nov 7, 2020
Messages
52
My controller can take 32Amps and I am trying to go as much as possible to the upper voltage Level

The good this is that the alternator motor is very durable using automotive grade copper with quality coating.
Is has lots of inductance much copper thick winding.


So but how do I charge my high voltage cells with only two panels???

Step up transformer which presented above.

I like to use what I have

Here my battery for 12V storage. This should be my storage before it get transformed up to charge the high voltage cells!

What does the forum thinks

Merry Christmas.


IMG20201222142657.jpg
 

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Hedges

I See Electromagnetic Fields!
Joined
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Messages
9,096
Rewire battery packs parallel to charge, serial to discharge. Doubt you'll be driving kart much, so park in the sun to charge.

One thought I've had is to make a wire harness that brings all cell terminals out individually (64 in case of 96V pack, bunch of Molex connectors?)
Mating harness connects them in series to run motor. Different harness connects all cells in parallel to charge/balance.

A DC/DC converter with CV/CC could be used to convert PV input to single cell charging, although without MPPT. I would have just charged with a bench supply.

During discharge, low single cell cutout would be needed. Maybe resistor dividers to FET mux to comparitor, or to ADC inputs of a uP.
Unless you already have suitable BMS.
 

HKZBob

New Member
Joined
Nov 7, 2020
Messages
52
Thanks for the hints. I am getting free 48V scooter Lion batteries. So if I have 4 of them I would charge them on 48V level with a 12V/ 48V DC DC step up transformer. Each pack will get their own step up. When I go in drive mode would like to use two cells in serial connection.
96V. This is the plan.

Has somebody did this before.
Is my idea strange or executive.

For charging later would use my Server Supply as seen in the video!

Thanks.

But connecting all cells is not possible for me since the battery comes already in a pack, or I have to tear the scooter battery packs down and use a 36V pack to 72V
This is what my current controller can support.

Thanks for the help.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
9,096
In that case the packs should have some sort of BMS.
However, they may or may not implement disconnect internally. For all we know they communicate with external charger or scooter controller to terminate charge/discharge instead.
Better make sure the necessary protection is active.

If they have internal FET disconnect, wonder what happens with two in series and one disconnects? The FET circuit may not have been designed to handle that (reverse bias applied.)
 

HKZBob

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Nov 7, 2020
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I will secure each pack with strong diodes.

So in case of disconnect it will only 0.5V remain on the batterie pack.

I use rectifier diodes out of alternator. They take easy 50A.
 

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Hedges

I See Electromagnetic Fields!
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That takes care of letting current bypass them if they have FET for internal disconnect.

Still need to be sure how internal BMS protects against over/under voltage of individual cells - does pack have a disconnect, or does it just communicate with external charger/load?
 

HKZBob

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That I don't know yet. I don't have the batterie on hand

How about a 12V System and using step up transformer to bump it up to the desired voltage.
That is an alternative to big batterie packs. I can run several in paraelle to increase the current.

The transformed 72V is supplieing the BLDC Controller.
This would have the charm to stay on 12V .
Merry Christmas.
 

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HRTKD

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I'm with george65. You simply cannot install enough panels on a gokart to make enough difference.

The way I drive a gokart (total amateur, but not many beat me at the track), those panels wouldn't last long on the gokart, and it would just piss me off with the extra weight and different balance.
 
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