DC-DC Step Down Power Supply Adjustable Push-button Module with LCD Display | eBay
I like these because you can Amps and Voltage
I like these because you can Amps and Voltage
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Roadster charging
- Thread starter Tommie66
- Start date
You mean what to use for the power source for the DC/DC converters
I assume you are using 9 of them, at a max 3 amps you need a 18 Amp, greater than 5v but less than 23v power supply. I have an old HAM radio power supply I found at a yard sale, they are usually pretty powerful.
I would just do a search on ebay for a 20-30-40 amp dc power supply, ideally regulated.
A quick search yields
33 Amp 12 Volt DC 13.8V Regulated Power Supply 30A Real MegaWatt® 683405633754 | eBay
I assume you are using 9 of them, at a max 3 amps you need a 18 Amp, greater than 5v but less than 23v power supply. I have an old HAM radio power supply I found at a yard sale, they are usually pretty powerful.
I would just do a search on ebay for a 20-30-40 amp dc power supply, ideally regulated.
A quick search yields
33 Amp 12 Volt DC 13.8V Regulated Power Supply 30A Real MegaWatt® 683405633754 | eBay
I will point out if your are not familiar with electronics this is not recommended, 60v will kill you, this is the reason many e-bikes are 48v. so playing with a 400v-200v,100v pack is potentially lethal. Before you start PULL THE DISCONNECT. Have the battery isolated. check with a multi-meter with insulation rated for 400V.
Check again and if any of the procedure seems complicated (as unfortunately you give that appearance that right now you are way out of your depth) I would defer to someone else. Most people conduct this type of experiment armed with plenty of knowledge and behind closed doors. Its not something recommended to anyone needing to ask as many questions as you have. Nearly everything stated so far could have been found with a cursory search.
This is not meant to dissuade you in any way, but even professionals have managed to burn down their workshops attempting this kind of thing, what ever you do next is going to not only be at your own risk no matter what advise you have been given. A lithium-ion fire will burn itself out, you can NOT stop it and it will ignite anything around it.
Just making sure you are thoroughly aware of what you are sticking your hand into. A fully charged pack has a lot more potential to do something bad than a dead one. A hot cell is a dangerous cell and you will be bypassing the cooling system to to whole pack. Make sure you fully understand that before progressing and don't try to put more than the bare minimum into any brick, if the voltage reads 2.0v, i would bring it up to 2.4 before going any further, not to 3.8v because a 3.8v cell will a) be far more dangerious, and b) be able to be controlled by the BMB and not need bypassing.
Check again and if any of the procedure seems complicated (as unfortunately you give that appearance that right now you are way out of your depth) I would defer to someone else. Most people conduct this type of experiment armed with plenty of knowledge and behind closed doors. Its not something recommended to anyone needing to ask as many questions as you have. Nearly everything stated so far could have been found with a cursory search.
This is not meant to dissuade you in any way, but even professionals have managed to burn down their workshops attempting this kind of thing, what ever you do next is going to not only be at your own risk no matter what advise you have been given. A lithium-ion fire will burn itself out, you can NOT stop it and it will ignite anything around it.
Just making sure you are thoroughly aware of what you are sticking your hand into. A fully charged pack has a lot more potential to do something bad than a dead one. A hot cell is a dangerous cell and you will be bypassing the cooling system to to whole pack. Make sure you fully understand that before progressing and don't try to put more than the bare minimum into any brick, if the voltage reads 2.0v, i would bring it up to 2.4 before going any further, not to 3.8v because a 3.8v cell will a) be far more dangerious, and b) be able to be controlled by the BMB and not need bypassing.
Thank you for the cautions! I do understand the risks! I want to make sure I’m going about in a way that has been successful for others.
Can you help me with this? I sent the Gerber file to a company to build the boards . I do not know how to read the files since I’m not an electronic wizard
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Bruce Wittels
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you can get one from Henry Sharp- he has a roadster and manufactures them contact him @ hcsharp.com
Please confirm the input on Nicks designed charging boards? Looks like the left input to be negative and the rest are all positive?
Please ask someone who can show you how to wire a 9s bms before you do anything. You should understand how a bms works before you start bypassing one. Or at least how to wire one up. There is a skill set you are missing here. Find a local kid who has built an e-bike battery. Endless Sphere would be a good place to start.
Odd question, and I haven’t searched... at all. But, could one use a model 3 charge port on their roadster, say... in the trunk or anywhere the oem model 3 wiring lends itself to?
That's possible, but given the convenience of using the CAN SR adapter to connect the Model 3's charge cable to the Roadster charge port, why bother?
My thought being, I don’t have a CAN SR, but I have access to a model 3 charge port and j1772 adapter. If all I have to do is disconnect roadster plug wires from the PEM and reconnect model 3 wires, why would I want to use something bulky with multiple adapters?
I have seen a Roadster with an experimental replacement of the charging with the Models S/X/3 socket. I think it may have been implemented with a 3-D printed part. I don't know how hard it might be to mount the OEM Model 3 socket in place of the Roadster socket. I believe the Roadster socket is held in place with adhesive rather than bolts, which would make the replacement more difficult. Some years ago @tomsax made a J1772 replacement for the Roadster socket, but that project was abandoned for various reasons. That used to be a sticky thread in this forum.
I have access to 3D scanners/printers, aluminum casting equipment, and various types of epoxy. I suppose it doesn’t have to be a model 3 socket, it could be any of the Tesla ones. Point being to get rid of the bulky roadster connector and open myself up to ease of use going forward, many HPWC /destination chargers and chademo chargers are around me.
No, not CHAdeMO. That will not work with the AC-only charge plumbing of the Roadster.
I really recommend leaving the port the way it is, and just get both of Henry's CAN adapters (JR and SR). They are robust, work very well, and the one you use most frequently can sit comfortably in the CAN holder (aka cup holder) next to the center console.
I understand the desire to simplify the charging requirements, a hpwc would then serve all the Tesla requirements and it’s unfortunate that the roadster was such an oddball. I’m not sure a model 3 port would be any good, or at least the wiring as the model 3 only supported 48a, an early model S May be a better idea. The roadster socket is a pretty robust item though, much more so than the later Tesla item. That was my primary concern when looking for a connector for my conversion car.
I understand not chademo(my roadster has chademo already added). I’ve been doing this EV thing for about a decade now.
I will never run into a roadster charging station, so, given this information, I will begin setting up my roadster to use a standard Tesla port/plug. Thank you for the replies to my questions.
I didn't want to be the one to post this response because I have a bias in that I sell these adapters, which might reduce my credibility. With that in mind, here are my thoughts.My thought being, I don’t have a CAN SR, but I have access to a model 3 charge port and j1772 adapter. If all I have to do is disconnect roadster plug wires from the PEM and reconnect model 3 wires, why would I want to use something bulky with multiple adapters?
I admire your DIY spirit and completely agree with the convenience of not having to use adapters on a daily basis. Having said that, it's pretty clear that you may not be fully aware of the scope of the project ahead of you. I know a couple of CAN SR users who 3D printed Model S inlets and mounted them in their Roadsters. They are not currently active on this forum. Both of them have since removed the DIY inlet and re-installed the original Roadster inlet. You might want to read the thread documenting the development of the CAN SR:
HPWC / UMC2 to Roadster adapter
It's a long read with nearly 500 posts. Quick summary: You can't simply "disconnect roadster plug wires from the PEM and reconnect model 3 wires" like you're hoping to do. Here are just a few things you probably haven't thought about:
- Older HPWCs for the Model S require some electronics in your inlet to be able to work with the Roadster. Most of them have been replaced but it might be an unpleasant surprise the first time you encounter one.
- Does your 3D printer make parts with high heat tolerance? If not you are taking a significant risk. I've witnessed charging fires first hand (fortunately never with one of my adapters) when contacts were dirty or crimps not tight enough or similar problems. I don't recommend just assuming it will never happen to you.
- The Model S/X/3 all have an electric solenoid that locks the connector into the charge port. It will be way more work to implement such a latch than probably the rest of the charge port. Without it you run a very high risk of having a live disconnect which ruins your charge port as well as the charging connector. Even if you don't mind the damage to your own car, it's not really fair to the next person who uses that TWC/HPWC.
- Tesla's modern chargers have no way to stop charging. Perhaps not a big deal to open your car and press Stop on the VDS, but a switch is much more convenient. Once again, implementation involves much more than just swapping a few parts and wires.
- How will you keep dust out of your new charge port? One more thing to implement. Dust accumulation on your contacts contributes to both safety and reliability problems.
Disclosure: I have reason to be biased so take it all with a grain of salt.
Henry, thank you for replying. I’m not against a CAN SR, but I don’t have a HPWC at home nor do I want to charge the roadster above the available 40-50a at the local destination chargers&home BMW i wall charger, so I figured a Tesla to J1772 plug would be ultra slim coming out of the door.
Jdemo would handle all of my long driving.
re: 3D printers, I was only going to use them to epoxy part of the oem Tesla charge connector to the oem roadster quarterpanel/opening. In no way do I wish to play with printing an entire chargeport. That’s terrifying and incredibly short sided, for the reasons you mentioned.
Re: dust - having owned quite a few different EVs over the years, from BMW to Nissan to Fiat to Ford(for a short period)... I can’t say that Chevrolet cares about the J1772 on the new bolt, Fiat had a hilarious piece of foam covering it that is attached to the charge port “flap”, If it became an issue with a no charge, I’d replace the port and learn my lesson and buy the engineered Fiat foam.
Re: handshake, I assumed some sort of protocol was there to handle that, something that could be done with an arduino and can shield -> IP65 rated push button to stop charging/deactivate the port
again, just spit balling here. At some point it either becomes worth it to buy a CAN and ‘tote the line’, buy a roadster 70a charger and risk degradation due to charge rate, or buy a whip from a roadster owner and an old juicebox adjusted down to 40-50a. With the clear understanding that I have access to chademo charging for all away from home trips (they’ve removed the last roadster charger that was in the wild, near me).
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