Does your car's 12V system float? Mine doesn't. In fact, it is buck charged from the 384V chain. All these issues have been discussed before, but not "everyone, everywhere, all at once.".
Too dangerous.
Fair enough, but you have not yet told us how the 12V battery is charged.
By "it" do you mean the 12V cell, when not part of the 384V chain, is charged from the remainder of the 384V chain?
And if yes to the above, then why switch the 12V cell in and out at all? When charging the 12V cell from the 384V chain, you take out X energy from the other 384V cells, and put Y energy (Y < X due to charge losses) into the 12V cell. When you switch the 12V cell back in, you will deliver Z energy into the chain discharging the 12V cell (but Z will be < Y due to extraction losses). So in the end, you only lose energy needlessly with this scheme.
Charging the 12V cell from the same battery string that it becomes part of for discharge sounds an awful lot like an attempt at a perpetual motion machine.
It is best to assume that no one, other than yourself, has read and remembered everything you have ever posted across all time. We can't read your mind over USENET to know the facts that you've left unstated.
If so, then how does your four pole variant not interrupt the 384V chain without also simultaneously shorting the 12V battery?
If you short across the 12V battery first, to not interrupt the 384V chain, you have just briefly shorted the 12V battery (for at least as long as it takes for the second pole to disengage the 12V battery).
If you disengage the 12V battery from the chain first, before shorting across the gap left by the 12V battery's removal to restore the 384V chain, you have also briefly interrupted the 384V chain.
Yes, charging from a buck converter from the 384V chain.
The goal is to boost the 384V chain to 396V or 408V to deeper cycle it.
Not at all. A 396V or 408V chain can discharge cells down to 2.5V when a 384V chain can only discharge to 3.5V.
No shorting as long as the "Switch Switching Time: is long enough.
Opening/Interrupting one of the 384V chain is fine. Shorting is NOT.
You are talking to Ed Lee. You will be lucky to ever get a useful description of what he's looking for until every possibility is exhausted.
That literally makes no sense. At some point the entire battery needs to be charged. Charging one bit from the other is pointless.
Now that you put it that way, this may be exactly what Ed Lee would want to do.
It's hard to understand that people don't get how pointless this type of conversation is with Ed Lee. He has something in his mind, that he is not able to share with others. Since you can't get that info, you will be forever hopping around on one foot trying to figure it out.
Good luck.
You, of all people, should know exactly what i am upto, but not Everyone, Everywhere, All at once.
The vehicle 12V system is charged from buck converter from the 384V chain, no energy loss while the 384V chain is also charged from external source.
To be precise, the 12V/24V system is charged via buck converter in parallel with the 384V system from external source, then run in series after a few miles. It is running in parallel for a while, in order not to over-voltage the system.
Why is this so difficult to understand?
Because what you say, often makes little sense. How do you charge a 384V battery and a 12V battery in parallel? I have no idea what you are trying to describe when you say this.
Are you trying to say the main battery, at 384V (nominal) is charged by an external power source. At the same time, the 12V battery is charged by a DC/DC converter from the 384V power source?
If this is what you are talking about, then you have conveyed your message. But where is the problem? At one point you talk about interrupting the 384V battery current path as being a problem. Elsewhere you say it's not a problem.
What is the bit you are having trouble with?
Yes, we charge the 384V with a J1772 plug or DCFC plug. The system 12V battery is always charged by the build-in buck converter. It's not obvious where the 12V and 384V are tied together. It could be the +192V or -192V or center. It makes sense to ground the center, since there is a cut-off switch there.
I thought that's obvious for all EVs.
Someone else said it's a problem. I said it's not a problem to open/interrupt my expansion battery.
I can't say. I've never taken my Tesla apart. My understanding is, they simply use the full voltage of the main battery to charge the 12V battery through a regulator. I'm sure they never put the 12V battery in series with the high voltage battery. I expect the high current would make the 12V battery explode.
Sorry, I have no idea what an expansion battery is. This is why I hate discussing these things with you. Every answer you give, requires more questions. Every single time!
Are you saying this is a battery in parallel with the main battery? Something external to the car that you lay in the trunk? Are you building your own control electronics? When do you expect the flames to burst out?
I will ask this one more time. What is the problem you are having with this design? What is your actual question?
I guess you missed the work "check". And I guess you missed the question I asked him: "Ok, so is this what you want?: "
It is obvious from the thread that we (readers of the thread) do not have a complete understanding of what he wants. I sure don't. That's why I asked. And the schematic can be used to show what he wants, or what posters such as yourself mean.
I have not posted a solution, only a request for clarification, so your criticism is of no use.
Rd
The negative side of 12V system is grounded. One side of the buck converter is virtually grounded, but no idea where it is grounded to. The input of the buck converter is in parallel to the high voltage battery, not in series.
Yes. Yes. Yes. Not yet.
What is the Switching Time of the heavy duty toggle switch? Can I expect shorting condition (if any) of less than second/4. My system can handle shorting s/4, but probably not much more.
I don't understand why you are asking us about the switching time of some switch/relay that we don't have. It's not like they are all the same.
I do know that DT switches and relays can be bought as "make-before-break" or "break before make". I assume these are self explanatory. If not, ask. I expect you need the break before make switch/relay.
BTW, I'm pretty sure shorting any of these voltages will have catastrophic impact on the switch/relay if nothing else. Even a quarter second of very high current will be very, very bad.
Speaking of high current. Will your switches/relays handle the current of the motor? You are talking about putting the switch in the high voltage/high current line, right?
I got no response from manufacturer. Just wondering if anyone got experiences, or just good guesses.
Not doing it intensionally, but sparking/bouncing/ringing will be unavoidable, which should be within the switching time.
The switch can handle 10A. The expansion chain should draw around 5A, but not a good idea to short it more than s/4. The switches are wired between chains, with 10A circuit breakers and some resistors to lower the current.
"sparking/bouncing/ringing" is not shorting. You need to get that straight. Bouncing is nearly unavoidable. Sparking is a result of inductive loads. I've not seen ringing in such a circuit. I you mean switch bounce, then say that. It's not shorting at all.
That's only 2 kW. That's not much power, even in a little car like a Leaf.
I will repeat, it's a *bad* idea for your switches to short the power source for *any* amount of time. That is how contacts are welded together. Then you have a real problem.
Remember Ed's rule 13. I can fit around 20 of them (26x20=520 pounds) to catch up with Tesla's weight.
That's your goal, to be as heavy as a Tesla? Strange.
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