This topic interest me, because I bought a Worx 36V electric mower last year - it was cheap because no battery was available to even test it and later I found out why - the motor controller was totally burned out....
So, I need to decide to either build a pack that can run the mower without controller since it has a PM motor (probably somewhere around 30V) or re-create the 36V control loop that the burned-out controller had. On the motor shaft is a magnet and hall sensor, so that all the controller needs to do is increase throttle until a setpoint of RPM is reached (the mower has a speed select switch for "silent" operation at moments you do not want to disturb others) So that would mean taking the hall sensor signal, triggering a monostable multivibrator with it, then integrate the output or select the length of the pulse so it can control the feedback for the throttle - allowing use of a DC bike/scooter controller. For pack, I will probably try to assemble something from the Li-Ion tool batteries that I bought a bunch of some time ago, or a series-parallel set of 5Ah packs that I got at another time, but I am not sure that those can sustain several C discharge... Luckily my lawn is pretty small, but if I judge my new neighbors correctly then they might want to try the mower too, so I will need to make sure it has a decent BMS. Charging fast means also little time for balancing, which makes it a challenge to keep everything in check. My own preference is to charge slow and if needed overnight, to give everything the time to balance right even if the bypass current is in the 0.1 Amp range. I know that I should not keep the cells at max voltage continuously or they will overcharge, but that is a matter of detecting the last bypass circuit turning on to switch the charger off. Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.com Skype: cor_van_de_water XoIP: +31877841130 Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 -----Original Message----- From: [email protected] on behalf of EVDL Administrator Sent: Fri 3/22/2013 2:27 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] headway cells fr 36 volt mower On 21 Mar 2013 at 10:08, Peakfoto Digital Photo Still n Video wrote: > can they build to certain custom size dimensions ? As long as they can use the same cells, yes, they'll build a custom battery. I don't know what (if anything) extra they charge for customization, however. There's an email link on the website (in "about us") to inquire. Tell them the dimensions of the space you have available, and they should be able to suggest something. David Roden EVDL Administrator http://www.evdl.org/ _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
