I do have a brake vacuum pump with a sizeable reservoir (holding vacuum) and my truck can stop pretty well, though I often use the brakes so little and so gentle that from time to time I have to force myself to make a harder stop, just to keep the brakes from getting stuck.
On my previous EV truck, the vacuum pump was drawing so much current on 12V and my battery so weak (the DC/DC went out) that I disabled the vacuum pump and simply pushed harder on the pedal. I could still make an emergency stop, I just had to *stand* on the pedal, but it still worked and I never had a collision in that vehicle. The problem the vacuum pump in that vehicle had was that there was no reservoir and the pump was not entirely up to keeping the brakes fully powered, so when braking with the vacuum pump the brakes first engaged too forceful, but then lost pressure and slowly faded so you had to keep pushing harder during the stop, while the start was too grabby. I noticed that in one incident where it had just freshly rained, I was driving on city streets doing maybe 35 and the light turned red close before me. I started to brake, but all I got was locked up wheels from the grabby brakes and I floated through the intersection, aquaplaning with locked brakes. Luckily it was empty. After that I disabled the pump and had no more "incidents". I like the Prius braking and it is very similar to the Leaf - it gives you plenty of stopping power when planning ahead and only if a light unexpectedly changes or another surprise happens, do you need the friction brakes. Since regen can typically only give you around 50% back, it is better to anticipate with your speed long before even using the brakes. Regards, Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: cwa...@proxim.com Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Willie2 via EV Sent: Tuesday, August 12, 2014 10:29 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Regen : Conversion advice On 08/12/2014 09:12 AM, brucedp5 via EV wrote: > Regen is much more to me than just regaining some range. It is a safety item > that I would use for dynamic braking. Since my physical size is large, I > physically fit better in a larger heavier vehicle (why I chose to have a > S-10 Blazer converted). So, regen would be quite useful to me in a heavier > EV. After driving my regenless conversion quite a distance, then driving a Leaf (with relatively poor regen) and then the Tesla (with really great regen), I can say that I MUCH prefer regen. Regen makes it easier and more convenient to drive. Aside from putting a little energy back in the battery. I doubt that the Tesla will ever need any brake work. That's amusing because the Tesla has these enormous brakes visible through the wheels. In my experience, one of the most common failures on conversions is the brake vacuum pump; my conversion spent perhaps 30% of it's life being driven without power for brakes. My wife refused to drive it in that condition. Reasonably so; it was quite exciting never knowing for sure that you could make an emergency stop. Though I did mange to avoid rear end collisions. _______________________________________________ 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)
