Dear all, I am from Denmark and my German is not so good, so I hope it is OK that I write in English. I have a Kewet 3 which I have parked in the garage for several years. During the last couple of weeks, I installed an 48V 200 Ah Hunsienk LFP battery pack and a new LFP charger (58.4V, 25A). Unfortunately, I cannot swich the car in reverse. When I swich the cables on the relays next to the motor, the car can run in reverse. The contact switch next to the steering wheel also seem to work. So there must be a relay or something between the main forward/reverse relays and the switch that does not work. I am disassembling the car to find the malfunctioning relay, but if someone could guide me, I would be grateful. Thank you all for a nice active forum. Cheers, Søren
Kewet 3 - upgrade to LFP batteries and a problem with reverse driving
- Themenstarter SorenHJ
- Datum Start
Sure it is
Afaik, there is no extra relay to switch the direction solenoids, its all activated by the manual direction (F/R) switch. But you can help if you take a few photos of the rear box where the Curtis and the solenoids are located. Do the reverse lights light up when selecting R?
Unfortunately, my website has no circuit diagram for the El-Jet 3. All i know is that there was a problem with the 3 when towed, burning the motor because of a wiring problem. This could easily be fixed by re-wiring.
You should also be able to measure voltages at the F/R switch.
Hi Matzetronics, thank you for your answer
A couple of years ago I changed the old 48V El-Jet 3 motor to a 72V El-Jet 5 and inserted a new 72V Curtis controller, so it looks more like the Kewet 5 on the power train (see photo). I kept the old 48V circuit and added the thick black cables for addition of 24V behind the seats. The 24V lead acid batteries had their own Lead acid charger. Currently I have only purchased four 12V LFP batteries and want to see how that works before I add another 24V LFP batteries behind the seats. The car has been running about 1000 km in both F and R with the 48V+24V lead acid system. At some point the lead acid batteries died and I did not want to replace them with new lead acid batteries that only had around 200 cycles.
Yes the F/R switch lights up when selecting R (see photo). When selecting F, I measure 13.2V across the switch (earth to "3") and 0V from earth to "4". When selecting R, I measure 12.9V from earth to "3" and earth to "4".
When selecting F on the switch, I measure 53.8 V on the left relay (see photo). On the right relay I measure 0V.
The difference in voltage between the switch and relay makes me believe there must be a contactor between the switch and the relay.
Interestingly, right now the system works again. I have not done anything but disconnecting and re-connecting the sockets on the relays, so either it has been a poor contact on the sockets or the mysterious "contactor" has revived.
Best,
Søren
A couple of years ago I changed the old 48V El-Jet 3 motor to a 72V El-Jet 5 and inserted a new 72V Curtis controller, so it looks more like the Kewet 5 on the power train (see photo). I kept the old 48V circuit and added the thick black cables for addition of 24V behind the seats. The 24V lead acid batteries had their own Lead acid charger. Currently I have only purchased four 12V LFP batteries and want to see how that works before I add another 24V LFP batteries behind the seats. The car has been running about 1000 km in both F and R with the 48V+24V lead acid system. At some point the lead acid batteries died and I did not want to replace them with new lead acid batteries that only had around 200 cycles.
Yes the F/R switch lights up when selecting R (see photo). When selecting F, I measure 13.2V across the switch (earth to "3") and 0V from earth to "4". When selecting R, I measure 12.9V from earth to "3" and earth to "4".
When selecting F on the switch, I measure 53.8 V on the left relay (see photo). On the right relay I measure 0V.
The difference in voltage between the switch and relay makes me believe there must be a contactor between the switch and the relay.
Interestingly, right now the system works again. I have not done anything but disconnecting and re-connecting the sockets on the relays, so either it has been a poor contact on the sockets or the mysterious "contactor" has revived.
Best,
Søren
Anhänge
Well, the photos don't tell me much but i'm glad you narrowed down the problem. Sorry, i can't tell anything about that brown box as it is a device only found in your El-Jet 3. The older models had a gearbox with reverse gear and no solenoids and the later models are controlled by a computer - the car controller.
If the problem persists - i have a lengthy instruction from Kewet Industri on how to change an El-Jet 3 to a model with car controller. But i never scanned it and have to look it up if the brown box is mentioned somewhere in this document if further questions arise.
Just a thought - maybe the box contains the circuit to forbid switching direction as long as the car is still rolling. That would mean that some kind of speedsensor is involved and connects to this box.
If the problem persists - i have a lengthy instruction from Kewet Industri on how to change an El-Jet 3 to a model with car controller. But i never scanned it and have to look it up if the brown box is mentioned somewhere in this document if further questions arise.
Just a thought - maybe the box contains the circuit to forbid switching direction as long as the car is still rolling. That would mean that some kind of speedsensor is involved and connects to this box.
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Hi again, the brown box is indeed the gear box. And the problem was loose connections in the socket pins soldered to the print. I soldered the pins and removed the loose connection. The green contactors are the ones that manage switching from F to R. I believe the two green contacts close to each other governs the F and R, and the third is the one you mention that prevents switching to R when the car is driving.
Anhänge
May i use the photos from the board on my website kewet.de? It would be a valuable addition as i have very little material on the El-Jet 3.
Yes you are welcome to use the photos. The car is now assembled and I hope to get some number plates next week. But I took some more photos in a higher quality and I am happy to send them to you. If you write an email to me on sorenogkamilla@gmail.com, I can send you the high quality version of the photos. Happy to share the other photos on this site as well.
Anhänge
I think the current set will do well, i mostly use moderate quality and resolution for the images.
Thank you very much! You might want a sneak peek:
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Was die alles macht konnte ich noch nicht rausfinden, mit Rückwärts kann es hier nichts sein da Schaltgetriebe mit Rückwärtsgang. Habe aber das Gefühl das der auch in die Steuerung eingreift strommäsig irgendwie. Da es so funktioniert werd ich hier ohne Not nichts anfassen. JME ist Jürgen Mittnacht, diesen Menschen gibt es glaub noch
JME built the Battman as improved batterymanagment. Funny enough it uses the same connector as the Gearcounter. There should be a display of some kind in your cockpit.
JME hat damals den Battman als Batteriemanager verbaut. Lustigerweise hat der genau den gleichen Verbinder wie der Gearcounter. Es sollte aber noch eine Anzeige existieren.
kewet.de
JME hat damals den Battman als Batteriemanager verbaut. Lustigerweise hat der genau den gleichen Verbinder wie der Gearcounter. Es sollte aber noch eine Anzeige existieren.
Battman
In einigen Kewet waren sogenannte Battmann von der Firma JME, Jürgen Mittnacht. Der Battman von JME war ein Batteriekontroller, der Anfang der 90 er Jahre entwickelt wurde. Anders als viele andere...
kewet.de JME surely used common available displays back then, so probably it would be not a very hard job to repair this. Those displays are not made for the harsh environments of a car in the sun, so the LCDs will fail over time.
JME hat sicher damals handelsübliche Displays verwendet, so das eine Reparatur vermutlich möglich wäre. Diese einfachen LCDs sind nicht besonders geeignet für die Anwendung im sonnendurchfluteten Auto, so das die Anzeige über all die Jahre immer weniger funktioniert.
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