Blog - Rebbl
- By ivovandenbrink
Municipalities in the South West of Friesland stimulate local organizations to work on a more sustainable level. A great succes. Rebbl was asked to deliver Fair Trade Certificates in an appropriate manner: with the electric VW T2.
Do you have a special promotion that needs a special car? We’ve got electric old-timers for rent 🙂 Contact us.
- By ivovandenbrink
Recently we reported our successful implementation of the Chademo fast charging standard for our DIY EV Conversions. The combination of our Orion BMS, the Chademo inlet and some extra hardware proved to be the right one. The last few weeks we experienced the great comfort of this, especially when the bus was rented for campaigning throughout the Netherlands. Fastned’s next station will be build along the A7, near Tijnje. We did encounter some problems with chargers from the Portugese company Efacec, exploited by the New Motion and Allego. This charger did not communicate with our car so we were not able to charge here. Together with Allego we have planned to do a test in August at their testlab. We will keep you posted.
- By ivovandenbrink
To good to be true? No, this is reality and it’s a great setup for high end DIY EV Conversions! The Emrax 228 permanent magnet AC motor, from Enstroj, weighs only 12,3kg, and can deliver 35 to 55 kW continuous output, depending on the RPM and cooling. The peak torque can be 240 Nm for a short period and 100kW peak power. The motor works fine in combination with a Bamocar D3 controller (8,5kg) from Unitek.
In our test you see the Emrax 228, liquid cooled, medium voltage version (upto 450V). We see great potential for electric drive trains where high performance, weight or fastcharging (because of the high voltage) are important. An Emrax 228 liquid cooled motor + resolver cable + I/O cable + Bamocar D3 controller + power cable connectors, will cost around € 7000,- excl. VAT.
- By ivovandenbrink
We did it! We solved the puzzle. In the past few months we’ve had intensive contact with professionals from Orion, to implement the communication protocol for DC fast charging for DIY EV Conversions! Today we succeeded, and charged the electric oldtimer VW T2 at the Leeuwarden Station from Fastned with roughly 30kW/h.
- By ivovandenbrink
Would you like to drive a high quality electric car, but don’t want to spend a fortune? Here’s your solution: buy yourself an original electric Peugeot or Citroen from the beginning of this millennium, and give it a Rebbl upgrade with a brand-new Lithium Batterypack. This is what Jos van der Veen did, to get himself a green car for daily commuting, shopping and functioning as a taxi for his kids, on a budget.
In this video Jos explains:
- how he got the car
- how he did the upgrade
- what materials he used
- the specs of the upgrade kit
- and the performance of the car after the upgrade
Enjoy, and feel free to share this post with friends!
- By ivovandenbrink
ACDC: these guys still rock!
But for DIY EV converters they can be a real pain in the butt. That’s because AC or DC is one of the toughest questions to answer. It is tempting to simply follow automotive, because they all have AC motors. But it’s not that simple. It is important to realize that you don’t play in the same league as automotive.
EV Conversions have their own league, and their own rules. And this is why:
At the moment there is not a lot of choice in electric vehicles from automotive, and the Tesla S seems to be the superior one. Automotive also tends to standardize in their drivetrains, because they want to make as much margin possible out of their volume. But, if you’re considering an individual car for an EV conversion there are a lot of options.
The Awards at the Wave Trophy 2014, a famous E-rally with almost 100 teams in Central-Europe, put this into perspective. The WAVE trophy gave awards to the attendants in different categories: for range, efficiency, comfort, exclusivity, for sexiness, practicality, charging flexibility etc. The Tesla S won non of these awards. All these single awards went to converted cars! And the general competition award was won by the Tesla roadster.
So take in mind: it is possible to beat automotive, with whatever you want to focus on, within our own DIY league.
And for boats? The most common electric boats are mostly friendly, pretty dull, low speed vessels around 4-5 meters in length. But how about regenerative drive systems for bigger sailing boats, hybrid drive trains for big transport vessels, power trains for speed boats and passenger catamarans? This is something you will have to and be able to do yourself.
So, let’s help you with one of the major questions, AC or DC:
AC or (brushed) DC that’s the question. To make up our mind, we will have to consider the motors incl. the recommended controllers. What we see most in DIY conversions are the following motor controller/combinations:
- Brushed DC in combination with the Soliton controllers or Alltrax, Netgain , Zilla in combination with Kostov or Netgain motors;
- AC induction, for example the Siemens/DMOC combination or a Curtis controller combined with a motor from HPEV;
- AC permanent magnet, f.e. Bamocar/Emrax combination, or YASA motors.
Sometimes we hear of brushless DC, like the Scott Drive controller. It is pretty close to AC induction.
Let’s start with DC. Although it is generally considered as less advanced, or a lower standard than AC, for DIY conversions there are a lot of serious arguments in favor of DC.
Arguments for DC:
- nothing can beat the brushed DC/Soliton’s regarding the price/performance ratio in the power league;
- large flexibility of peak power (kW) possible, from 10kW all the way up to 300kW;
- large flexibility on different voltages from battery packs, 10V – 340V maximum. Ideal for a grow scenario if you want to increase your battery pack gradually;
- huge torque at low rpm, especially with the 11” Warp motors;
- DC motors can easily handle overloads for 10-30 seconds;
- To set the parameters, you’ll need only a laptop with internetbrowser. No additional costs in dongles, handhelds and software. Some basic settings are all you have to consider, whereas AC controllers require a thorough study of the manual;
- Forced air-cooling will give the motor 20-30% extra continuous power, and for a relatively low amount this is a luxury for electric motors;
- Maintenance of brushed DC motors is still close to zero. In most occasions, only after 100.000km or 2000 hours of intense use you’ll have to replace the brushes;
- A simple but well engineered RPM sensor is all you need to prevent your motor from over-revving;
For a twin motor setup, only 1 controller can do both motors.
Disadvantages of DC:
- regenerative braking is not supported for brushed DC;
- DC motors are more sensitive to over-revving, because of the construction with the brushes. It is vital for the drivetrain to have a working RPM sensor installed (not-integrated);
- relatively poor temperature monitoring: the thermal switches or thermistors do not work properly with sudden overloads, pushing the motor beyond it’s temperature limits in a short period. They do work when the motor gradually reaches it’s limits;
- a direct drive option requires a set up with a power switch relay, to make it possible to drive backwards. To make this set up safe (no switch activation while driving) requires additional electronics and/or skills;
- the specifications of most DC motors are optimistic, and only valid to a max. load of 1 hour, and with the right RPM, and reasonable to good airflow in the motor compartment.
Summary on DC:
- much driving fun for your money, but beware how to handle: additional temperature monitoring and RPM sensor are mandatory. Not to use in mountainous areas with long (steep) descends;
- Originally meant to replace the petrol motor, mount it on the gearbox with an adapter plate, add some batteries and there you go: and this is how simple it should be.
In the lower power ranges, there is a lot of choice, mostly in combination with a Curtis, Inpower or Sevcon controller. Some motors are completely sealed, which makes them suitable for off-road fun. But, for higher output, the mass-cooled AC motor becomes heavy, and the max. of this type is about 15kW continuous kW power IF you want to stay below 100kg. If you need more power, AC liquid cooled motors are the only option and they are expensive. A 37kW continuous power rated, liquid cooled AC motor will cost at least three times the price of it’s brushed DC equivalent.
The next 10 arguments are based our experiences with HPEV’s, Siemens DMOC and AC PM motors.
Advantages of AC systems:
- All AC controllers support regen. braking;
- AC systems have 3-4% better efficiency then DC;
- High IP rating for AC induction, suitable for off-road applications and boats;
Integrated RPM and temperature sensors which allows the controller to prevent damage from overloads and over-revving;
- In lower power ranges (up to 15kW continuous rated motors) there is lot’s of choice;
- Because of the easy reverse forward switching, AC systems are very suitable for boat conversions, or direct drive applications;
- Most controllers have many parameters which can be alternated;
- Most permanent magnet motors are extremely light weight. We have seen examples of 12kg liquid cooled PM AC motor rated at 30-50kW continuous power (!!), depending on RPM
- AC offers motor/controller options up to 700V suitable for DIY;
- World wide services options for strong brands like Curtis and Sevcon.
Disadvantages of AC:
- Most AC systems are 20-30% more expensive than DC alternatives In higher voltage ranges, prices quickly doubles or triples the price of a DC motor/controller combination. High KW AC motors are even more expensive;
- Input voltage ranges which AC controllers can handle are limited;
- The installation and setting the right parameters in the controller can be quite a hassle: Handhelds and dongles are extra investments. sometimes needed to do a proper installation;
Summary on AC:
AC systems can be regarded as more advanced regarding weight, efficiency and prevention from overheating and over-revving. But that comes with a price. Especially at high performance levels AC systems for DIY purposes are very expensive. Regen braking is nice to have but do you really need it? If you’re really aiming to meet the automotive standard then go for PM AC, and increase your budget!
For medium to heavy weight cars: make your dream come true and take brushed DC for a reasonable budget and a lots of fun scenario. If you know what you’re doing it’s worth saving the money.
For the rest, especially light weight cars and boats: go for the efficient and relatively safe AC options. The extra costs will compensate for the comfort.
For offroad-, mountainous-, and heavy city traffic the only option is AC.
Calculating the optimal EV conversion kit for an Oldtimer Citroen HY Streetfood Wagon in the Low Countries
- By ivovandenbrink
A few years ago, some crazy businessman asked us: ‘What electric drivetrain would you put in my restored oldtimer HY bus? It’s for selling honest streetfood!’ He kept coming back and was serious after all. So we started our calculations. This is our challenge:
- the bus should do 100km range in every situation (frost, wind, rain, whatever) at 70-80km/hr max.
- the wagon will be driving in The Netherlands, flat country, no regen. breaking necessary
- the weight of a full street food wagon including the conversion will be 2200kg, as a consequence a standard keyway shaft will not be strong enough for this application
- there will be more HY conversions coming from this customer, continuity is an important factor
- the HY drivers are probably not technicians, the bus has to be very reliable
- the budget for the conversion has to be realistic: not low budget but not carte blanche either
Batteries and BMS
For a 2200kg car to do 100km on one charge even in bad weather, we would need 35kWh of batteries. We suggested 60 cells of Calb CA180ah (adding up to about 190V together) with an Orion BMS here. The Calbs have a minimum loss of capacity in winter and the Orion BMS is the only DIY system that supports DC fast charging (Chademo). For the future this could be an interesting option.
AC or DC
Then there is the choice between AC and DC, which is often made emotional instead of rational. AC seems more sophisticated, because most systems support regenerative breaking and have a better temperature control. It is appealing to modernize an oldtimer into the 21st century with an AC drivetrain. But it tends to be more expensive so we had to be rational. We compared a few possible setups:
1. Siemens AC motor – Azure Dynamics Controller
A Siemens AC motor in combination with an Azure controller would do the job just fine. The Siemens motor has a tooth splined shaft as a standard, which is the preferred driving shaft coupler, given the weight of this van. Both the motor and the controller have great automotive quality, we’re a fan. Aftersales is a big problem though, because there are only a few sets left from the bankruptcy. Doing a series of the HY bus would be a problem. Getting into the Azure controller and programming it to the right settings is a real pain, so not a pro in this discussion. This combination is now for sale at around €6.500, including Rebbl’s EMC certification which is necessary in Europe.
2. Emrax 268 AC PM motor – Unitek Bamocar D3 controller
An Emrax motor with a Unitek Bamocar controller would be an awesome solution. The Unitek controller is already EMC certified, the question is whether this will be accepted in combination with the Emrax motor. The Emrax motor is very promising because of it’s power and very small size (20kg), but according to the website ‘first customers are part of a fieldtest’. That might not be a problem for a DIY conversionist and we can’t wait to start experimenting with it, but for an entrepreneur selling streetfood on a daily basis this is might be a bit to early. The Emrax does not have a tooth splined shaft, so this has to be engineered as a special option. The heavy van really needs a sturdy coupler. The combination will cost at least €10.000, which is about 80% more than the solution we finally choose for.
3. Double HPEV AC motor – 2 Curtis controllers
The HPEV AC Motor and Curtis controller do great in smaller cars with a small to medium range. For the streetfood wagon there is the possibility of a twin HPEV setup in combination with two Curtis controllers, to give it enough power and enough voltage intake. Both are thoroughly tested and reliable. Also aftersales is great on these products, as is programming and finetuning settings. Drawback is the budget, our customer would need a minimum of €12.000 for this. Another drawback is the shaft, which is not tooth splined. This has to be engineered as a special option. This set is available including Rebbl’s EMC certification for the Curtis 144V/500A controller in a HPEV 51 or 75 set up.
4. Kostov Alpha DC motor – EVNetics Soliton1 controller
The Kostov Alpha 11” aircooled DC motor and the Soliton1 from EVNetics is a combination that can do the job on the DC side. The Soliton1 has an wide battery voltage inputrange of 9-340V DC and can deliver 1000A to the motor. Experience and aftersales on both products is good, and programming the controller is easy. Because the Kostov Alpha is well cooled it has a continuous power rating of 50kW, which is the best weight/power ration. This DC motor also has the necessary tooth splined shaft as a standard option available. This set is an investment of €5.750 including the Rebbl’s necessary EMC package.
We came to the conclusion that the quality/price ratio of the DC set would be highest for our customer, and so was our advice. We configured a kit that will serve as a model for future HY conversions from the same client, and other clients living in flat countries like The Netherlands. This includes the tooth splined shaft and coupler. But if you have the same plans in the mountains of Switzerland for example, your optimal kit will be quite different.
- By ivovandenbrink
The electric quad from our customer Robbie Fuhren in The Netherlands made its maiden ride! What an exciting machine this has become, great craftsmanship by Robbie. Take a look at his video or visit his blog.
The EV Conversion Kit that was used for this quad:
- By ivovandenbrink
We did some amazing conversion projects together with universities and schools the past two years. We worked with Hanze Racing Division, Friesche Poort, HAN, Hanzehogeschool Groningen, Drenthe College, Satakunta, Flensburg University, Technicka University and Queens University Belfast. Teaching students is great, they want to participate in the electric revolution and really appreciate hands-on experience. Are you a teacher, or do you know a teacher, who would like to start a conversion project in Europe? We can help! Contact firstname.lastname@example.org for more info.