Bunky the eBug: A 30 Day EV Conversion

Tell us about the project you do with the open inverter
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by jrbe »

MattsAwesomeStuff wrote: Mon Mar 30, 2026 3:45 am Generally, compressing quickly is desirable, so that when you hit a bump, the tires can bounce upwards without much stopping them, while the cab stays at the same height. In that way, you won't feel the bump. It eventually needs to reset, but you want it resetting slower than it compressed, spread out over time, so you don't feel the impact. If it bounced back just as hard, it wouldn't feel like you had any suspension.
The goal of the shock is to keep the tire in contact with the ground, aka in control. Too stiff and the tire skips, too soft and the tire or chassis bounces. The steadier the downward force on the tire the more consistent the grip is mid corner.
Spring frequency (spring strength) drives the recovery timing. Wheelbase, spring frequency front vs. rear (each driven by spring strength), and vehicle speed drive the timing the rear recovers vs the front. This is why some vehicles feel great at certain speeds.
Shocks control the springs.
There are all sorts of damping techniques used in shocks. Sometimes they are used to mask other issues.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Ev8 »

Tell us more about the high voltage charger? Would like to up my voltage to gain some power
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

Ev8 wrote: Mon Mar 30, 2026 6:54 pm Tell us more about the high voltage charger? Would like to up my voltage to gain some power

Group Buy: Dilong 6.6kW OBC / 1.5kW DC-DC Converter, 300-550V Output
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by MattsAwesomeStuff »

MoonUnit wrote: Mon Mar 30, 2026 3:28 pmJust be aware that having lots of weight upfront makes the steering really heavy. I've tested it with 75Kg, and that made a very big difference. It was just about acceptable, but testing with with 96kg (8 x VDA355 modules) was really not.
*gulp*

Mine had 250 kg in the front.

I truly wonder how it drove, and will never know, I'm not putting 500kg of lead acid back in it.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

5th weekend of the build was spent on mounting the battery pack, eight BMW 530e hybrid modules

here is the general idea (four sticks across, and eight modules up and down, sardines style)
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so we make the mounting brackets to take advantage of the fuel tank mounting points
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sometimes you have to spend time doing nonsense like this
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

this C channel was notched so that the mounting tabs would sit in it flush
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drill baby drill
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I plan to weld these types of nuts under the C channel
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and fingers crossed maybe we'll finally get to use the stock OEM fancy BMW hardware, but at 85mm they seem a tad short
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »





tomorrow I hope to handle the top row, notice how it has a slightly different pitch
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Ghia66 »

Gregski wrote: Sun Apr 05, 2026 3:44 am 5th weekend of the build was spent on mounting the battery pack, eight BMW 530e hybrid modules

here is the general idea (four sticks across, and eight modules up and down, sardines style)

Snapshot_14.JPG


so we make the mounting brackets to take advantage of the fuel tank mounting points

IMG_7376.JPG


IMG_7378.JPG


IMG_7380.JPG


IMG_7382.JPG


IMG_7388.JPG


IMG_7392.JPG


IMG_7394.JPG


sometimes you have to spend time doing nonsense like this

IMG_7397.JPG

Tapping out those old threads really pays dividends! 🙂


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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

so here is the bottom shelf with all four modules bolted down using the 85mm stock BMW M6 bolts, when I feel underneath with my finger the bolts are just about even with the nuts, I wish they protruded out about 5 M&Ms
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

progress not perfection, here I was working on the mounts for the upper bracket for the bottom shelf (huh ?)

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and the lower bracket for the top shelf
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pretty happy that these two siamese twins won't need to be welded together after all and can be removed individually
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

so the bottom shelf is done and I started on the top one

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looks like the modules will clear the bracket mounting bolts, so happy
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

here I am welding on the studs for the top battery shelf bracket

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and welding on the backing nuts for the battery bolts
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also welded the backing nuts to the bottom bracket of the top shelf
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

and the battery pack is in, I even started farting around with the high voltage connections a bit

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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

here I am planning the sBox aka contactor box install

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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Ghia66 »

So tidy! Looks like it was meant to be from factory! 🙂
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by tom91 »

I would suggest you review the specs of all the components in the Sbox before utilizing them with 8 modules instead of 6.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Alibro »

Gregski wrote: Fri Apr 10, 2026 4:04 am here I am welding on the studs for the top battery shelf bracket


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IMG_7561 - Copy.JPG


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and welding on the backing nuts for the battery bolts

IMG_7573 - Copy.JPG


IMG_7575 - Copy.JPG


IMG_7577 - Copy.JPG


also welded the backing nuts to the bottom bracket of the top shelf

IMG_7569 - Copy.JPG
What was you reason for not using rivnuts? I used them in my battery box and they were very quick and easy.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

Alibro wrote: Fri Apr 10, 2026 9:09 am What was you reason for not using rivnuts? I used them in my battery box and they were very quick and easy.
all my drill bits are standard not metric, and for the M6 rivnuts you need a 9mm drill bit, so when I ordered all the stuff, the rivnuts showed up but the drill bit did not till I was almost done, but mostly it's because I had horrible luck installing them, so I think it's mostly me
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

tom91 wrote: Fri Apr 10, 2026 7:38 am I would suggest you review the specs of all the components in the Sbox before utilizing them with 8 modules instead of 6.
well Donkey Kong I thought the contactors were rated for 600 volts, but looks like only 500, in my defense the plan was to start off with six modules and if decent top speed was not achieved then expand to the additional ones, so I may be able to go to seven modules but not eight, unless I upgrade them orange cubes, good looking out Tom, you passed the test (wink, wink)

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Could someone please help me with this BGR30TQY resistor voltage specs and translate this table for me to fork lift terms?
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bgr resistor voltage rating.jpg
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by tom91 »

Resistor will be fine. Have a look at precharge relay.

I would in all fairness be most worried about the OEM BMW electronics, they likely will have an overvoltage limit in them. Probally around that of the contactor voltage.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

tom91 wrote: Fri Apr 10, 2026 1:01 pm Resistor will be fine. Have a look at precharge relay.

I would in all fairness be most worried about the OEM BMW electronics, they likely will have an overvoltage limit in them. Probally around that of the contactor voltage.
Ah yup the AECN 11012 precharge relay in the 2nd Gen aka 12 kWh BMW battery pack sBox can only handle 400 volts

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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Alibro »

I'm scared enough being around 400V but the thought of 600V is just NO!
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Ghia66 »

tom91 wrote: Fri Apr 10, 2026 1:01 pm Resistor will be fine. Have a look at precharge relay.

I would in all fairness be most worried about the OEM BMW electronics, they likely will have an overvoltage limit in them. Probally around that of the contactor voltage.
How about using the BMW SP44 HV Battery (G05) Sbox?
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by tom91 »

Ghia66 wrote: Fri Apr 10, 2026 3:32 pm How about using the BMW SP44 HV Battery (G05) Sbox?
Same architecture so same issue.
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Re: Bunky the eBug: A 30 Day EV Conversion

Post by Gregski »

the Greg almost rushes to finish installing the battery pack so he doesn't almost loose the shop


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