It's good to see you making steady progress Ali. I'm surprised the VW battery doesn't have thermal management, which seems a backwards step to me. I'm glad you're thinking about thermal management though, which seems a sensible option to me. Are you planning any kind of active cooling, maybe a temperature controlled fan for instance?
LOL, steady but Slooooow!
I must admit I've had a few surprises with this pack but for now I'm just keeping it as simple as possible so in short the answer is no, however I have a few thermocouples I plan to place in each battery box and will use them to keep an eye on temperatures. If it proves to be a problem I'll sort it on Ver 1.01. :p
My priority for now is to get it working but also have the boxes fully water tight.
 
I must admit I've had a few surprises with this pack but for now I'm just keeping it as simple as possible so in short the answer is no
Not nasty surprises I hope.
however I have a few thermocouples I plan to place in each battery box and will use them to keep an eye on temperatures. If it proves to be a problem I'll sort it on Ver 1.01.
That's sensible. No point in addressing a problem, unless you know there is problem to address.;)
My priority for now is to get it working but also have the boxes fully water tight.

Will you be putting some form of vent, just in case something goes horribly wrong with the battery pack?:eek:
 
So after several goes at making the fuel tank box this seems to be the best option. It may not be perfect and maybe I could fit more in but I'm being cautious as this is my first attempt at this.

View attachment 238546 View attachment 238547

However until I figure out exactly how to bolt the modules together fit them in the box I can't be certain this will work.
So I've started making the brackets to hold the four large modules together.

View attachment 238549
View attachment 238550
View attachment 238551

The idea is to have the 4 large modules bolted together with threaded bar then bolted to the box. I plan to have studs on the floor of the box but as I haven't sorted that yet I haven't drilled the brackets.
To help with cooling I'm spacing the modules with 3mm washers and have made the middle part of the bracket from 3mm steel.
Nice to see this progressing :)

Seeing as you're going to be presenting this for inspection by a government employee, who could be a right stickler, I'm going to give you a tip to make those welds pretty... Zirconium flapdiscs.

A flap disk is comprised of lots of little overlapping flaps of sandpaper like this:
Fan-shape-Convex.png


As such they have a little bit of spring in them, so they generally don't dig in, instead they only tend to catch the high pits, and are less aggressive to the base surface:

The flaps sweep across the surface with minimal pressure / friction / abrasion, like a wire brush attachment on your grinder, yet the lock up and become like a solid grinding stone when they encounter a high bit:
upload_2021-5-18_12-21-35.png

which means they dig in and take a chunk out of the weld without gouging the base metal. They give a really nice smooth finish, and in the case of those battery brackets, they would make the welds invisible on the underside, looking very factory from the point of view of the inspector. Don't get the cheap brown aluminium oxide ones, get the ever so slightly more expensive, but vastly superior blue zirconium oxide ones, they last about ten times longer and are much nicer to work with.
 
Nice to see this progressing :)

Seeing as you're going to be presenting this for inspection by a government employee, who could be a right stickler, I'm going to give you a tip to make those welds pretty... Zirconium flapdiscs.

A flap disk is comprised of lots of little overlapping flaps of sandpaper like this:
Fan-shape-Convex.png


As such they have a little bit of spring in them, so they generally don't dig in, instead they only tend to catch the high pits, and are less aggressive to the base surface:

The flaps sweep across the surface with minimal pressure / friction / abrasion, like a wire brush attachment on your grinder, yet the lock up and become like a solid grinding stone when they encounter a high bit:
View attachment 238571
which means they dig in and take a chunk out of the weld without gouging the base metal. They give a really nice smooth finish, and in the case of those battery brackets, they would make the welds invisible on the underside, looking very factory from the point of view of the inspector. Don't get the cheap brown aluminium oxide ones, get the ever so slightly more expensive, but vastly superior blue zirconium oxide ones, they last about ten times longer and are much nicer to work with.
Thanks mate, I already use them but if you're wondering why the welds are so full of holes I had issues with my gas bottle. Also I hadn't properly cleaned the steel before welding. I'm doing a little better on the subsequent brackets.
These brackets will be pretty hidden under the modules so unlikely an inspector will ever see them. The boxes on the otherhand.............
Not nasty surprises I hope.
Not nasty but I was surprised there is no physical disconnect. The Leaf has a big plug you remove from inside the car to disable the battery connection from the outside world whereas the eGolf disconnect is automatic.
Will you be putting some form of vent, just in case something goes horribly wrong with the battery pack?
Probably not unless I can find a way to do it and keep the boxes water proof, they will be under the car and at the mercy of all the rain Ireland can throw at them. (And that's a lot!)
 
Not nasty but I was surprised there is no physical disconnect. The Leaf has a big plug you remove from inside the car to disable the battery connection from the outside world whereas the eGolf disconnect is automatic.
That is strange. I'd have thought they would have had a manually operated isolator.
Probably not unless I can find a way to do it and keep the boxes water proof, they will be under the car and at the mercy of all the rain Ireland can throw at them. (And that's a lot!)
It might be worth putting an inverted U shaped breather, which will reduce issues with expansion and contraction of the air inside the boxes, although I suspect you'll not make them totally sealed.
 
That is strange. I'd have thought they would have had a manually operated isolator.

It might be worth putting an inverted U shaped breather, which will reduce issues with expansion and contraction of the air inside the boxes, although I suspect you'll not make them totally sealed.
I might put in a breather like the rear diff and the IRD have.
 
Thanks mate, I already use them but if you're wondering why the welds are so full of holes I had issues with my gas bottle. Also I hadn't properly cleaned the steel before welding. I'm doing a little better on the subsequent brackets.
These brackets will be pretty hidden under the modules so unlikely an inspector will ever see them. The boxes on the otherhand.............
OK - I thought the slotted plate was going underneath the batteries... as in:
Floorpan
Battery modules
Brackets


Road surface

So you're saying they are more like
Floorpan
Brackets
Battery modules


road surface.

My main computer's water pump is broken (not a wind up that is genuinely what's wrong with it) so there'sno snazzy diagrams tonight.

But yeah, what I seen on those welds is nothing that can't be made pretty with time and flap disks, And if they are going to be out of sight anyways, save the time / effort / abrasives for more deserving uses.
 
OK - I thought the slotted plate was going underneath the batteries... as in:


So you're saying they are more like


My main computer's water pump is broken (not a wind up that is genuinely what's wrong with it) so there'sno snazzy diagrams tonight.

But yeah, what I seen on those welds is nothing that can't be made pretty with time and flap disks, And if they are going to be out of sight anyways, save the time / effort / abrasives for more deserving uses.
LOL, I built my main computer from components bought last year. It was the first time in about 20 years I've actually paid for a motherboard, memory and processor as normally I make do with ancient salvaged PC's from customers after they had tech refresh. I was too mean to pay for a graphics card so bought an AMD processor with built in graphics.

The plan for the battery modules is to build a sealed box to put them in, it needs to be sealed as there is a lot of electronics under the plastic covers of these modules. I will weld mounting studs on the floor of the box so when I drop the modules in I can bolt them down. The modules on their sides will be bolted together with the brackets and threaded bar as I want them to be as secure as possible but also spaced a little for cooling, they can then be dropped into the box and bolted down too.
I haven't decided yet whether I should have all four of the large modules bolted together or just two but will probably go for two plus two as they are so heavy.
 
That is strange. I'd have thought they would have had a manually operated isolator.
Forgive me for being a clanky,but I'd prefer a manual Isolator than some piece of automatic electronic witchcraft... Could Ali reuse the leaf connector/isolator? Or should we look for an alternative? What kind of current are the motor and invertors likely to be pulling? If it's around 400V working voltage, you're probably looking for like a 250 amp contactor, could be done...

Probably not unless I can find a way to do it and keep the boxes water proof, they will be under the car and at the mercy of all the rain Ireland can throw at them. (And that's a lot!)
That's something I can help with, turns out oilrigs are wet and windy places too, hooda thunk ? :p

And for some reason they don't like the sparky-wirey bits going anywhere near the air with the potential gas / hydrocarbons in there. In the marine world we use "cable transits" which are basically holes cut in the bulkheads (walls) with rubber inserts to form a tight seal around them.

On hatches etc we use adhesive closed cell foam and bolted down flanges to form a seal. Actual proper electrical boxes are IP47 --> IP69k rated, depending on how stingy or generous the person writing the cheques is.

You can get cable glands in most sizes, so it's going to be pretty easy to make your battery boxes 99% water tight, if not necessarily International Space Station type of hermetically sealed. I'm happy to donate my consultation services to this endeavor :p

It might be worth putting an inverted U shaped breather, which will reduce issues with expansion and contraction of the air inside the boxes, although I suspect you'll not make them totally sealed.
That's actually a good shout, can I suggest a slight improvement on it, can we route all the battery box breathers to a manifold that goes through a dessicant breather filter to keep the moisture / humidity out of the boxes?
 
Forgive me for being a clanky,but I'd prefer a manual Isolator than some piece of automatic electronic witchcraft... Could Ali reuse the leaf connector/isolator? Or should we look for an alternative? What kind of current are the motor and invertors likely to be pulling? If it's around 400V working voltage, you're probably looking for like a 250 amp contactor, could be done...
I don't have the Leaf isolator so will have to purchase a manual switch for the job, it's normal practice in DIY EV's.
It will initially be 88S or 88 cells in series so approx 270V to 360V. In theory the Leaf inverter is 80Kw but I will have a lower voltage as the Leaf is 96S so expect a current draw of around 200A to 240A

That's something I can help with, turns out oilrigs are wet and windy places too, hooda thunk ? :p

And for some reason they don't like the sparky-wirey bits going anywhere near the air with the potential gas / hydrocarbons in there. In the marine world we use "cable transits" which are basically holes cut in the bulkheads (walls) with rubber inserts to form a tight seal around them.

On hatches etc we use adhesive closed cell foam and bolted down flanges to form a seal. Actual proper electrical boxes are IP47 --> IP69k rated, depending on how stingy or generous the person writing the cheques is.

You can get cable glands in most sizes, so it's going to be pretty easy to make your battery boxes 99% water tight, if not necessarily International Space Station type of hermetically sealed. I'm happy to donate my consultation services to this endeavor :p
That's very kind of you and so when I reach the stage of sealing this thing I'll be giving you a shout.

You've probably realised by now I don't get too excited about future issues as I'm having a hard enough time sorting out the current issues. I'll worry about that stuff when I get there. :p
 
I don't have the Leaf isolator so will have to purchase a manual switch for the job, it's normal practice in DIY EV's.
It will initially be 88S or 88 cells in series so approx 270V to 360V. In theory the Leaf inverter is 80Kw but I will have a lower voltage as the Leaf is 96S so expect a current draw of around 200A to 240A


That's very kind of you and so when I reach the stage of sealing this thing I'll be giving you a shout.

You've probably realised by now I don't get too excited about future issues as I'm having a hard enough time sorting out the current issues. I'll worry about that stuff when I get there. :p
Aye, you've taken on a giant project and are doing a grand job of it, I just hope you realise my observations and suggestions are meant constructively rather than snidely? I'm well aware that I seem to spend a fair bit of time critiquing your welding with you, but there's aye a suggestion on how to improve it. I've fired you some stuff in a post above this one just to let you put pictures in your mind to go the words I've used, but when you are at that stage we'll roll up our sleeves and I'll wade through the catalogues with you :)

Gid'night pal.
 
That's actually a good shout, can I suggest a slight improvement on it, can we route all the battery box breathers to a manifold that goes through a dessicant breather filter to keep the moisture / humidity out of the boxes?

I was already thinking about a desiccant breather, connected to all battery boxes by pipes.
This would allow for expansion and contraction of air inside the battery boxes, but only allow dry air to enter, which is sensible.
A way of keeping the inside dry would be a good idea too, as HV DC and corrosion wouldn't go well together.
 
I was already thinking about a desiccant breather, connected to all battery boxes by pipes.
This would allow for expansion and contraction of air inside the battery boxes, but only allow dry air to enter, which is sensible.
A way of keeping the inside dry would be a good idea too, as HV DC and corrosion wouldn't go well together.
You hadnae mentioned the desiccant in the breather, which is why I brought it up.

The batteries working should generate heat that will prevent condensation forming, and the desiccant elements should pull any moisture out of the air. For some of the electrical boxes in hazardous areas on the oil rigs, ie areas where there is a possibility of hydrocarbons being released, if the electrical equipment isn't or cannot be 100% hermetically sealed in an EX rated box, which is typically IP47 or higher seals we use a positive pressure purge system on it, where a trickle of pressurised air is released into the box to keep it a few milibars or half a pun above ambient air pressure...

Perhaps there might be some advantage in doing something like this for Ali's batteries, as in we could put a small little airpump like those used for aquariums, pulling in fresh air through a dessicant, slightly over pressuring the box, causing dried air to cascade into the other boxes, and or leaks contained therein. This could have a very small cooling effect, as well as keeping the batteries very dry.

OR: there is a much more elegant solution.... Lets do something clever with Ali's electric servo booster vacuum pump. It could be piped up to either pull air from, or pump air into the battery boxes breather system.
 
I didn't mention it, as my thoughts didn't make it into text.:oops:

I'm liking the positive dried air pressure, or even negative dried air through the boxes. Nice thinking. ;)
Cheers! You were probably heading on that track if you were already contemplating the of a desiccant.

What I'm currently thinking of is trying to find a way of dumping battery heat into the chassis, to use the car's body as a heatsink...

But I keep getting stymied by the fact that the metals that conduct heat the best are typically copper or aluminium, and I don't like the idea of putting dissimilar metals onto each other as they would form a corrosion hotspot. The best I've come up with would be sticking peltiers between the battery and the floorpan to pump some heat from the batteries into the floorpan, but I'm open to suggestions...
 
Mmmm, take the output of the Audi vac pump and feed it into one end of the first box, then feed from box to box with the final output fed into of a bowl desiccated coconut.
I like that idea. :p

Cheers! You were probably heading on that track if you were already contemplating the of a desiccant.

What I'm currently thinking of is trying to find a way of dumping battery heat into the chassis, to use the car's body as a heatsink...

But I keep getting stymied by the fact that the metals that conduct heat the best are typically copper or aluminium, and I don't like the idea of putting dissimilar metals onto each other as they would form a corrosion hotspot. The best I've come up with would be sticking peltiers between the battery and the floorpan to pump some heat from the batteries into the floorpan, but I'm open to suggestions...
Bare in mind this will be drawing a lot less current than it did in the eGolf. The Leaf was 80kW and the eGolf was around 100kW so I think the battery modules will be well within their comfort zone so I don't think over heating will be an issue.
 
This is the four brackets made and they are a very tight fit. I'm waiting for some threaded stud connectors to screw onto the ends of the threaded bar as I've no access to tighten nuts. Originally I planned to weld the inner brackets together but I think it will be easier to manage two modules at a time rather than 4.

IMG_20210519_211905265.jpg


Still a bit of trimming to do and need to drill the mounting holes but I'm happy they will do the job.
 
Mmmm, take the output of the Audi vac pump and feed it into one end of the first box, then feed from box to box with the final output fed into of a bowl desiccated coconut.
I like that idea.

You mean the input to the vac pump Ali. ;)
I recommend using the air dryer from a Discovery 3 suspension as the source of dried air for the battery boxes. The dryer could be placed in the engine bay for easy maintenance, the a pipe linking the boxes together in series, before finally joining to the vacuum pump input. This way only dried air will pass through the battery boxes, keeping them moisture free, and preventing issues due to pressure changes.

I'm assuming that you'll be leaving 1 panel of the boxes removable, maybe sealing it with a closed cell neoprene gasket.

Bare in mind this will be drawing a lot less current than it did in the eGolf. The Leaf was 80kW and the eGolf was around 100kW so I think the battery modules will be well within their comfort zone so I don't think over heating will be an issue.

That seems a logical theory, which will reduce the battery pack temperature substantially.

Does the E Golf have any battery heating?
 
You mean the input to the vac pump Ali. ;)
I figured the input was where the air got sucked in and the output was where it was blown out. :confused:
I guess it depends on whether I try to suck air through the boxes or push it through. If I use a single air pump for both the battery boxes and the brakes I need to bare in mind that the vacuum for the brakes is the no.1 most important thing so
I was thinking of using the exit to blow air through the boxes.

I recommend using the air dryer from a Discovery 3 suspension as the source of dried air for the battery boxes. The dryer could be placed in the engine bay for easy maintenance, the a pipe linking the boxes together in series, before finally joining to the vacuum pump input. This way only dried air will pass through the battery boxes, keeping them moisture free, and preventing issues due to pressure changes.

I'm assuming that you'll be leaving 1 panel of the boxes removable, maybe sealing it with a closed cell neoprene gasket.

Does the E Golf have any battery heating?
I plan to have the sides of the box high and put a lid on it with the sides of the lid coming maybe half way down the sides of the box. That way water would need to go up the gap between lid and box then force it's way through a seal to get into the box.
Hopefully this should prevent spray and splashes getting in and as I don't plan to be wading through floods I should only need to be concerned about damp.

As far as I can see there is no heating or cooling for the eGolf. Not from external sources anyway, VW may have been using the BMS to heat it but I can't see how they would have achieved much that way.
 

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