Brendon_m Moke

Post up a thread for your EV. Progress pics, description and assorted alliteration
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Yes, I've been watching your build closely it's all been very impressive.
Makes me feel bad because it's a polar opposite of my slap dash hack job.
francisco.shi
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Re: Brendon_m Moke

Post by francisco.shi »

I have seen a few conversions and I think the most difficult and messy part is the battery modules and the wiring. So I have been trying to design something that can help others to make conversions easier. Also unless you use a Tesla battery module the energy density and performance is quite low.
I am hoping to get a few people to use the battery modules I am making. It would make it cheaper if I could get a few modules done in one go. It is quite easy to change the configuration and size so I could easily make custom size modules without any extra design work.
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Do you have ball park figures on costs?
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Re: Brendon_m Moke

Post by francisco.shi »

I am hoping for about A$300/kwh for the complete pack without the BMS and about $200 for both ends.
The ends are the manifold for the water cooling which are also what you use to bolt the battery to the case. The cost of the ends is really a matter of how long you make the battery. I have made one module which is 1.6m long. So if you make one module instead of two shorter ones then you save the cost of the ends.
The BMS goes between the cells and it needs to be installed when the pack is made because you can not get to the inside cell tabs after the module is assembled. If you want to use a different BMS I will have to put the sense wires as I assemble the pack.
I still don't know how much the BMS will cost but I am expecting about $15 per cell for the active BMS (active meaning when it is in bypass mode it pushes the energy to the rest of the pack instead of dissipating the energy in a resistor) and there will be another board that manages all the cells and the battery as a whole with a contactor to disconnect the battery if it overheats or over currents. The benefit of the active BMS is that you can discharge all cells equally and use the energy instead of making heat so you get slightly more range. But I do not know how much more. The battery specs say the battery capacity is within 3% to 4%. So my guess is you could get as much as 3% more out of the pack.
At the moment I have 3 cells in parallel which give enough space for the BMS to fit in between the cells. This gives a 189Ah capacity. The cells are 63Ah each. If you need less than 3 parallel cells I will need to check if the BMS can still fit inside. For more than 3 parallel cells it should not be a problem.
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

After a bit of a delay sourcing a battery pack I arrived home today with 80 x 50ah ncm cells
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Now I have them I can plan how to shove them in the car.
The plan is to put them in the boxes that run down the sides. That is where the fuel tank amd 12v battery were located. Both of which are gone.
I can't fit the whole pack on one side and that would be lopsided with weight distribution so the plan is to split the pack into 2 48v modules at 150ah each, or I can cram as much into the passenger side and put the last few cells in the drivers side. That gives me some storage space but I don't think I need it because I had a jacket in one of the panels that I thought I lost 9 years ago which I found when I was pulling everything out from the car.

Having 2x 48v packs may allow me to have 2 'cheap' 48v chargers rather than 1 'expensive' 96v one.
I've also toyed with the idea of using the pack as home storage because the moke is going to sit for the majority of its life.
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Also I had trouble with one rear wheel turning most of a revolution then locking up, keep pushing and it would free up and then lock in another spot
I pulled the wheel off and think I found part of the trauma...
IMG_20190426_074349.jpg
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brunohill
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Re: Brendon_m Moke

Post by brunohill »

You won't need that anymore anyway. You will have regen braking now :lol:
What are the batteries from I3? Imiev ?
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Imiev
francisco.shi
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Re: Brendon_m Moke

Post by francisco.shi »

How much did the batteries cost you?
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

$2500 including freight (how expensive is it to drive a truck really, crikey) so even with buying the sirion for its pack and then not having the heart to strip it and letting it become my daily, im still under budget.
Your cells would have been nice but overkill for my build and I'd already ditched the better water-cooled version of my motor to avoid having coolant, hopefully that won't bite me in the arse...
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Re: Brendon_m Moke

Post by francisco.shi »

If you don't drive it hard I don't think you need the water cooling.
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Re: Brendon_m Moke

Post by whimpurinter »

Yes, the drums probably need machining to make the brake surfaces a proper circle again.
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Re: Brendon_m Moke

Post by wovenrovings »

I have a moke that I am going to convert too! Watching closely. :)
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

So I'm in trouble, I've hit a really major trauma. And I don't know what to do about it.
It all started at the beginning of the build when I weighed the moke. I ran an old set of mechanical bathroom scales under each corner of the moke to work out its weight. I was super proud of not having to take the car to a weighbridge. I ended up with some figures that were accurate enough for my purposes and were in line with official data I gleamed from manuals.
I've been looking at fitting the cells I've got in the pontoon type bits down each side of the car and thought I should re-weigh to work out the front/rear loadings without the engine, radiator etc
I went to use the scales again and found out they are wrong. Way to wrong to make a guess with an acceptable margin of error.
Now the whole car from factory is 660kgs, with the majority of the weight in the front. I measured about 230kg on each front wheel and 90kg on the rears. I thought that's good I can put the cells in the side and my weight distribution will be really good
I couldn't use the mechanical scales as everything I pressed on them they would read different and not go back down to the same point.
However I've removed over 150kg from the front of the car so I should be roughly 165kg on each front wheel.
So I snuck into the house and got the fancy new digital bathroom scales and flipped them overand had a look, rated up to 180kg, awesome!
So I ran outside to the sound of my wife saying "don't break my scales" and re-weighed the moke.
Now here's the thing, I weighed it and it was nowhere near what I thought it was going to be, 100kg at the rear right. 80kg on the rear left and 145kg at the front left wheel and 148kg at the front right.
Cool I thought, it's lighter and we all know less weight = more fasterer.
Now it might take you a second, looking at those figures to see what's wrong. I didn't actually realise until the next day how much I had stuffed up.
148kg on the heaviest corner... I was super careful in weighing it, turned the car around to make sure there wasn't a slope on the floor causing any inaccuracies. 8 had all the non measured wheels on blocks so the car was level, I gently lowered the car on the scales to avoid overloading them or warping the calibration by maxing out the load cells. Super careful and thought of everything (well I thought I did). I even weighed myself before and after to make sure it was still calibrated. But... I stuffed up. Majorly.
The problem was how I put the car on the scales. I wasn't exactly in the middle. So the scales weren't evenly loaded up. Now when you stand on one corner of the scales they glitch out and turn off, I think I cracked the circuit board under the glass.
I'm a dead man.
She told me not to break them...
francisco.shi
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Re: Brendon_m Moke

Post by francisco.shi »

Quickly go and buy a new scale that looks the same and hope she doesn't notice.
I had some similar problem before with some metal scales. The top surface is too weak and if you put the weight off the center it doesn't measure properly. So what o have done in the past is put a bit of wood on the top to spread the load.
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Re: Brendon_m Moke

Post by whimpurinter »

I went buying scales lots of years ago and noted that mechanical scale readings cruised up and down as I massaged the top of the scales with different positions. Bought a japanese digital set in the end. They're still working. You always have to stand in the middle from side to side since your toes and heels usual go close to the edge.
I worked on mokes in the late 60's, both the small wheels and the later bigger wheels. They are light construction.

There would have been no reason to have had a 20kg difference between the right rear and the left rear :)

I couldn't do what you're going to do, but I wonder if the general construction of the side body is up to the task considering the box section is probably well up to driving stresses but significant weights along there were never anticipated.
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Yeah she knows, she discovered that they were broken, I tested them after I finish and they were working, I stayed within the weight limit and they were still working afterwards. That's my defence. Apparently the argument "maybe you broke them" was not the correct answer. :?

In terms of the weight difference at the rear.
I have no idea, that's why I turned the cat around to check the slope of the ground. 20kg is so much. I put it down to some weird suspension bias because there is just nothing different between the sides. The panel that coves the fuel tank is missing but that's like half a square meter of sheet metal, hardly going to be 20kg

With the weight in the side boxes, it'll be 70kg a side. The fuel tank and battery sat in those boxes, 30ish kg each so I'm adding about 45kg a side and they will be in big frames that bolt at the ends and all along the sides to spread the load.
Not letting water in is another challenge. Keeping things dry in those boxes was not easy when the roads were wet.
Oh, and getting heat out, I was just planning on a little fan to shift the hot air out. Hopefully that will be enough
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

I've been saved. I tried changing the batteries, no change. Pulled them apart. Corrosion on the battery holder. Woooo hoo, it wasn't me. Cleaned up chipper. :D
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Re: Brendon_m Moke

Post by wovenrovings »

How much do your batteries weigh?
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

Each cell is 1.8kg and I'm going to be using 78 cells (26s3p) so 140kg. It'll be split into 2 packs of 70kg along each side of the car
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Re: Brendon_m Moke

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I've been progressing along with the battery packs. The frames are mostly done I just need to finish the mounting bits and reinforcing where the packs bolt to the body work.
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Also I've made the majority of the interconnects. The pack will be split in 2 packs of 13s 3p making 26s3p all up. I opted(stupidly) to make my own out of copper pipe.
1 piece of 3/4 pipe is good for the peak current I'm expecting but to be safe and minimise resistance I've decided to double up on the bars. Cue 52x 300mm long bits of pipe squashed flat in a vice with 6 holes drilled in them
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My arms hurt just thinking about it
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

I've managed to finish up one of my packs and squeezed it into place. I'm thinking I should call this build "project snug" because there isn't a lot of clearance... anywhere.
I had to lift the back end in half way, then the front and slide it forward and then the back the rest of the way. All while holding the pack on a 10 degree angle and once it's all the way up I can tuck it into the lip that runs down the length of the car.
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Please excuse the awesome colour scheme. I'm trying to decide on a colour to repaint
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Re: Brendon_m Moke

Post by jonescg »

All the colours!
AEVA National President, WA branch director.
T1 Terry
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Re: Brendon_m Moke

Post by T1 Terry »

jonescg wrote: Tue, 09 Jul 2019, 15:36 All the colours!
Known as "Bogan camouflage" :lol: Or a taxi respray ;)

T1 Terry
Green but want to learn
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brendon_m
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Re: Brendon_m Moke

Post by brendon_m »

I could paint it rattle can flat black for that stolen look
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