Az 33 ev

[Dan Cooper]

It's been kinda warm in the garage, so I have been working indoors on the dash.33' Dash.jpg

[Dan Cooper]

Although I did mention it being kinda warm in the garage, that is an under statement. It is hot here in Phoenix area. Never the less I do try to get something done. Here I was just a little of what I was doing. Trying to figure out where to locate things based on wiring and plumbing for coolant lines.33 Mock up.jpg I have the Tesla 10k charger sitting on the battery box, the heat ex-changer is for the Model 3 motor in the rear. Next to that is the DC to DC converter that charges the 12 volt battery, on the firewall I have the remote brake reservoirs. Then The controller for the electric power steering. The power steering is bolted in place, it doen't appear to be in the way of the battery box.

[BradC]

That's good progress with the temperature being center-of-volcano-like! It's been like that here too the past week. Such fun...

That looks like a good layout. I put my heat exchanger in the front grill and the fan has still never kicked on. I've driven it for extended lengths in up to about 95F so far and it stays below the 50C trigger.

[Dan Cooper]

I'm actually planning to use the radiator that came with the kit to cool the batteries, also the condenser will mount to the radiator . It has the electric fan too. I will give it a try and see how it cools. I modified the radiator by cutting off the radiator hose fittings. I will weld a cap over these with a fitting on it the size I need for the battery coolant lines.

[BradC]

I would guess that you'll never see the batteries trigger the fan with the stock radiator (not a bad thing) - it'll always be the condenser. Granted mine aren't the Tesla packs and I'm driving in lower temps on average, but I've never seen my pack temps go more than a couple of degrees over ambient. That would change drastically though if you plan on getting DC fast charging working on it.

[Dan Cooper]

As hot as it is now it seems I can't have too much cooling. Besides I might learn something in the process. Kinda scary thought.

[BradC]

Yeah - it should work just fine. Are you planning for DC fast charging capability? That's a whole new topic to me that would be interesting to follow if you pull it off.

[Dan Cooper]

I was looking into it with one of the other battery options I looked at. I haven't given it a lot of thought since I started installing the Model 3 Batteries. If you consider the cooling and the battery packs I have, it might not hurt to investigate that again. Thanks for the thoughts.

[BradC]

There's a lot more to it. Charger and BMS has to support it and you would probably need more systems powered up during charging so the water pump and fan can run for battery cooling. Maybe the DC/DC converter too?

I only had a 30A circuit available in the garage so my charger was capped down to 5KW, but it still doesn't take too long to charge. I kind of felt like DC fast charging was too much of a risk for a DIY EV. Try to explain burning down the house to my wife and then the insurance company doesn't sound fun... haha.

[Dan Cooper]

I have a 60A circuit for my Tesla wall charger, with the Tesla 10K charger I am putting in the car it should charge reasonably well. But I had a thought if you want to see about looking into the DC fast charger. If it doesn't work well I have a spare bedroom. Just a thought, maybe not a good one.

[BradC]

Haha - I think I'll stick with not leveling my house but thanks!!

Your setup will charge 2X faster than mine and I'm good with the way it works now for the way I drive the car. That's easier on the batteries too than DC fast so there's that...

[Dan Cooper]

I just don't think I really would need fast charging. For what I intend to use the car for.

[Dan Cooper]

As usual I have changed plans somewhat. I am no longer using the radiator from FFR kit. Mostly due to fitment reasons. What I am doing is using 2 Derale Heat exchangers with electric fans. One Heat exchanger will be for the Battery packs, and the other will be for the Tesla M3 motor and the Tesla 10K charger. I have installed the condenser coil in the Grill with the electric fan that came with FFR radiator. It seems I have several 12 volt devices in my build so I decided to do some load testing of the devices to determine if the DC to DC converter I have will be adequate. After testing power steering, power windows, all cooling fans, two fluid pumps, and the A/C blower motor, headlights, tail lights, not including the electric compressor for the A/C system I have about maxed out the capacity of the 1K DC to DC converter I have. Just to explain the DC to DC converter briefly, it basically takes the place of an alternator on a gas powered car. With that said I have ordered a 1.5K DC to DC converter from Elcon. This will be more than adequate. We are test fitting the battery packs in the battery box and locating bulkhead fittings for electrical and cooling lines.Battery box3.jpg

[BradC]

Nice progress on the battery box!

[Dan Cooper]

Thanks Brad, we are finally getting a break in the weather. Its been a brutal summer

[BradC]

Yeah was a hot one here too although definitely not as bad as yours. I found my comfort limit with the car was upper 90's. Not too bad without an engine adding heat though when my friends with Cobras were not having any fun. Still haven't had my motor radiator fan come on once yet. I might drop the trigger temp down just to hear it cycle. Ha..

[Dan Cooper]

Brad, do you have motor temps on your display? I'm curious as to what temps you might be getting. I know you don't have liquid cooling for your batteries but what kind of temperatures are you seeing on those?

[BradC]

I do have motor temps reporting but haven't been paying much attention to the exact values relative to outside temp. I have it on a needle gauge for the main display but there's another page that shows the values. I'll look closer next time I take it out. Battery temps during charging are maybe 1-2 above ambient. I don't have battery temps reporting to the display - just a warning if any exceed the 50C limit - but it's never triggered. I can monitor them by a laptop though. Next time I get back from driving I'll hook it up and see what they are.

[Dan Cooper]

Don't go to any trouble, I am just curious. Things I have thought about along the way

[progmgr1]

Since you guys sometimes wander off into Engineer Land, here is some potentially useful arcana from days of old (when I worked for a living):

Hold down the ALT key and type the numbers 248 and you get the degree symbol: °

Hold down the ALT key and type the numbers 241 and you get the plus or minus symbol: ±

Hold down the ALT key and type the numbers 234 and you get the ohm (Omega) symbol: Ω

IIRC, these are part of an extended ASCII character set and there are a lot more symbols available. These are just the ones I used often enough to remember the key strokes.

Keith HR #894

[Dan Cooper]

Thanks Keith. I have used the degree symbol but either forgot or I didn't use the others. Very helpful information.

[JimLev]

Thanks for the Omega one, didn’t know that one.
Here are a bunch more.

IMG_3875.jpeg

[BradC]

I didn't know about those shortcuts. Thanks!

Dan - here are my motor temps after a longer drive today. These are after going through my neighborhood slower for maybe 5 minutes, and my phone app said it was 78° F outside (yes, I used the handy shortcut there!). I have my fan trigger set to 50°C and I believe that correlates to the inverter and/or heatsink temp in the motor controller. I didn't hook the laptop up for battery temps this time.

IMG_5888.jpg

[Dan Cooper]

Thanks Jim, I had no idea of all those. I will have to print that so I can remember where to find them.

[Dan Cooper]

Thanks for the info Brad, My Tesla doesn't give me that information so I was curious as to what temperatures it could be operating at.