This week we round up some various and largely unrelated items for your viewing pleasure. We actually had a number of interesting things planned, and NONE of them really panned out. It was one disaster after another. The result was there really wasn’t much to show. Busted….
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Thanks to Count Domagni, we did get the new website up and running. It is now hosted entirely on Amazon.com. I’m assured it is graphically more pleasing than my large photograph efforts. But it has not been without problems. And we continue to struggle to work with all browsers and all movie formats. HTML5 was not the panacea expected, and so it is two steps forward and three steps back. We will stay with it. Many thanks for the various problem reports and suggestions.
Recall we had installed a brake transducer in the Mini Cooper. I’m quite enamored of this device and will post the first page of the data sheet here. They are available on DigiKey and they have them in a variety of pressure ranges and a variety of port sizes.
What I like about this device is that it puts out a 0-5v variable output based on brake pedal pressure. Actually, it reacts to changes in brake LINE pressure and of course that is a result of brake pedal pressure of course. It allows you to provide an input to your controller for regenerative braking that is truly representative of your pedal effort, giving a fantastic sense of control of regenerative braking.
The Mini Cooper Clubman has a power assisted braking system. We did NOT want to use a vacuum pump to enable that, and of course we DID want to take advantage of regenerative braking available in our AC induction drive system.
Recall we had replaced our TIMS600 controller, which I blew up, with a Rinehart Motion Systems controller at some additional expense. I have to tell you that I very much LIKE this controller, and cannot at this point recommend its use for any purpose. This thing just isn’t done. We’re kind of on the beta team.
Their manual had described a 5k potentiometer brake input for regenerative braking. But when we received the controller, we were told that that had not actually been implemented yet. But they planned to.
We have had a number of problems with the Rinehart, most notably a distinct and upsetting “shudder” when you first start in motion. They allude to “driveline resonance” as being the problem. As we had no such “driveline resonance” with the TIMS600 with the same motor, and have not encountered this in two other cars with AC induction drives, I guess I’m a little unconvinced that “its the car’s fault.” They put an anti-shudder algorithm in which helps, but then IT causes the car to jerk a bit when you are NOT moving.
In any event, they finally implemented the 3 wire input for regen and put in some new variables to set min, max, and change the brake mode.
We had previously helped them develop a braking ramp function based on time. This would cause the brake to initially match the regen level of the accelerator when you’re foot was off the throttle, and ramp up to a maximum regen variable you could set. You can also assign a time value to the process. We use about 3 seconds. And so when you step on the brake, the regen linearly increases over the course of 3 seconds. If you start to develop too much braking, simply lift your foot and stab it again to reset the ramp. This brake “pumping” exercise is slightly annoying, but actually works pretty well. It was a huge improvement on what they had, which had been MAXIMUM braking when you first stepped on the pedal and then linearly DECREASING as RPM came down. This made no sense at all and felt terrible.
We wired up the transducer to the new inputs. The results were mixed.
First, the brake transducer regen works and works very well. Much improved brake feel and we can of course tune it further by changing the maximum brake torque and the mapping of the brake pedal input. But it introduced NEW problems. Most notably, at some random point between 3500 and 5000 rpm, the controller shuts down completely. This happens both on acceleration and braking and we could find no pattern other than it occurs somewhere in that rpm range, and so more often in first gear than second.
The more alarming and thoroughly inexplicable problem is that if you put it in electric “reverse” and give it just a touch of throttle, the car BUCKS violently.
Unfortinately, the Rinehart guys were out this week working with a motorcycle racing team and didn’t have time to fool with us. This is a bit perplexing as it appears we are fooling around with THEM and spending a lot of time troubleshooting obvious problems that should have already been taken care of. Note that all of these items are NOT precisely configuration that we have not done correctly. Mostly they have involved new software releases to fix the problem. So we’re kind of on the beta time with Rinehart.
As I like the physical package, we don’t really mind. But it sure busted my program this week when they winked out on me. It takes some time to get set up for these tests and when you are reporting the results and have everything set up to make changes quickly and report back, it is a little disconcerting to get dumped for a better offer. Oh well, we have three guys and they have about that and it is just the nature of this cottage level industry.
We understand they are also working with a guy who has done an implementation of the Remy motor with a case that makes it something you COULD use and solves the cooling issues with this motor. More on that later.
So we think the Rinehart is a comer, but it’s not quite ready for prime time yet.
We decided to install the PowerOne Aurora solar inverter in the garage at the house. This is a 6kw unit we showed on an earlier show that has a wide DC input range of 120-530vdc and puts out standard 240vac split phase 60Hz just like your house.
Our garage is separate from the house, but on the same side of the meter. I actually have an AC disconnect switch and natural gas 10kw generator already installed. If we lose grid, the switch disconnects us from the grid, connects us to the generator, and starts the generator. In this way, if they are out working on the grid, we don’t light them up.
This is how this has been done for twenty years and it works extremely well. The problem is the switch is $400.
The Aurora is a grid tie inverter, and will match phase with your existing grid input. Any power you make with solar or wind for example, will be used locally and in fact, if it makes more power than you are using, it will run your meter backwards – if you have a meter that the utility hasn’t modified to NOT run backwards, meaning you pretty much have to be in a net metering state at this point.
We hooked up the Aurora in kind of a strange configuration. I was going to connect it with a conduit to an existing box in the garage. Matt noted that we could just put a heavy cord on it, and plug it IN to the receptacle, giving us the option of UNPLUGGING it quite easily. I bit on it.
We plugged a cord we were using on a heavy heater into the jack and carefully measured the distance to the connectors in the Aurora. Matt then cut the cable with a large set of thankfully insulated cable cutters.
Unfortunately, we still had the cable plugged IN to the wall. We lose more interns this way. We included a little bit of video illustrating this event in today’s show. Don’t try this at home.
We did hook up the Mini Cooper to the inverter, and in fact it DID make power. Quite well actually. It was a tad over 6kw and in comparing the voltage and current IN to what it was reporting as output, this is a VERY efficient inverter, and totally silent. Good equipment.
Unfortunately, it won’t work by itself as a backup power unit. Apparently, along the way, the power companies have caused some UL codes to be implemented that REQUIRES grid power for this device to operate at all. If you lose grid power, it shuts down as well. This “anti-islanding feature is ostensibly to prevent putting power out on the grid endangering the utility workers that might be working on the system.
What it really does is prevent you from using your solar or wind to backup your grid connection. I guess it eliminates the need for the $400 switch, but I smell an untold story of conspiracy and greed.
I went through every single inverter manufacturer I could find, and found a curious thing. They ALL had implemented this, and are apparently required to.
What about OFF grid inverters. Curiously, there aren’t many of them anymore. But there are a few. Outback still makes some. But curiously THEY are ALL limited to single phase 120vac. There are no 240vac off grid inverters I could find. Curiouser and curiouser.
So to generate a split phase 240vac 60hz waveform, we have to go to battery backup. Predictably enough, any small inexpensive versions of that are ALSO limited to 120vac single phase. You can’t simply use two of them. There is of course a phase relationship between the two phases to achieve the 240vac.
So I went back on eBay and had to find a refurbished and probably obsolete UPS battery backup system. We’ll have to use THAT to generate the 240vac 60hz so the Aurora will have something to synch to. All this so I can use one of the cars as a battery backup. Since I have a generator, I don’t even need this. I just wanted to demonstrate how to use an electric car to backup your house easily, if not inexpensively. The 6kw Aurora is already about $4000.
If any of you know of a small inexpensive circuit to convert DC to 240vac split phase, I’d like to hear about it. It doesn’t need to make any power at all – just present the waveforms at milliamperes of current really.
The device actually DOES accomplish what I actually DO need. We often have to discharge a car to a low battery level to set fuel gages etc. It’s a shame to just dump off that energy with the heater and waste it. Now I can plug a car in, and use the discharge energy for something useful, like running my house, while I discharge. But using it as an emergency backup just won’t work, without buying a battery backup UPS system, which is what we are wanting to create. Kind of a circular chase, and all entirely unnecessary. This “safety” system is useless, and I would encourage anyone doing any kind of alternate energy power system, be it generator, solar, battery, wind, or whatever, to STILL get an automatic AC disconnect switch in any event.
Basically, this switch is just a huge transfer relay. It uses grid power to close a relay connecting the grid to your house. If you lose grid power, the relay deenergizes, connecting you to your alternate system, and in the case of a generator, also starting the generator.
If you get grid power back, it closes the relay, connecting you back to the grid, and disconnecting your house from the alternate source. This always did work most excellently. The “anti-islanding” built into the individual components looks very suspicious to me.
Again, if you know of a little inverter, even to work off a 12v battery to make 240v split phase waveform, we would like to hear about it. Note that there ARE 240v inverters, but these are single phase for European applications – it is NOT a two phase inverter.