about the plastic disk shearing off. replace it with a sheet metal disk to fit the motor shaft then place a disk of leather between the new drive disk and the blade hub, then when you hit a rock the blade slips and no damage is done.
*Dennis Lee Miles * *Director **E.V.T.I. Inc.* *E-Mail:* *[email protected]* <[email protected]> *Phone #* *(863) 944-9913* Dade City, Florida 33523 USA On Mon, Apr 28, 2014 at 3:45 PM, Michael Ross <[email protected]>wrote: > I have another battery from these people that seems just fine (after taking > it apart to see inside) > > > http://www.aliexpress.com/store/product/24V-40AH-LiFePO4-Battery-Pack-Electric-Bicycle-electric-Scooter-bicycle-E-Bike-Lithium-Ion-Long-life/328001_771068114.html > > This one is 24V 40Ah LFP and weighs 9kg. $500 including shipping BMS and > charger. 3 to 7 day delivery and the met that. These that 18650 cells with > welded straps for conducting the juice. > > I think I will try to get a used 24V B&D instead of reworking my old bottom > of the line MTD. > > I think my wife would love to have an electric mower. She hates asking me > to start them for her. It would be nice not having all the oil checking > and filling, And as the current mower works - the rod knocking and > smoking. We have an acre of mostly flat yard - 40Ah would go a long ways > and the charge time is about 2 hours. > > > On Mon, Apr 28, 2014 at 3:25 PM, Peter Eckhoff <[email protected]> wrote: > > > Hello Mike, > > > > I'll second what Cal is saying below. To get the nut off, you have to > > place a wrench on the nut and "impact" it until the nut loosens. I would > > **not** use a compressed air impactor tool. I use my fist. Be careful > > because everything is free wheeling. If you leave your knuckles in the > > path of the blade, your knuckles are going to get whacked. There is no > > other place to place another wrench unless you weld a nut to the top of > the > > motor shaft. > > > > Like Cal, I keep a set of several "small plastic blade insulators" on > hand > > which is how they are described in the User's Manual. The word > "insulator" > > may seem like a misnomer but it is to "insulate" the shock of hitting a > > rock from damaging the armature. > > > > I converted a corded B&D to cordless. It uses 9 - 5 amphr 12 volt LA > AGMs > > to power the mower. It is enough to do a 7K square foot lawn. What used > > to take me 1.5 hours to do when corded, now takes about 45 minutes. > > > > I use a 1.3 amphr AGM for the tripping a small contactor. This battery > > goes down faster than the pack. I would use about a 2 amphr battery for > > each hour the contactors are tripped. That should give you plenty of > > cushion. > > > > I wrote a two part article for the Electric Auto Association's Current > > Events magazine. I have the submittals in PDF format. The B&D motors are > > DC universal motors that operate at 120 volts. The corded version has a > > full rectifier bridge on a little heat sink. It was mainly a rewiring > job > > to bypass the rectifier. > > > > I think the AGMs are the wrong type of battery for this project. > Normally, > > when not cutting the lawn, the motor consumes about 4 amps. When cutting > > thick grass, the motor consumes about 8 amps. It can spike to 10 amps in > > real thick grass or when the mower clogs up in thick grass. > > > > I have been contemplating upgrading this mower to Lithium. A set of 40 - > > 3.2 volt 10 amphr would be about right for an hour's worth of cutting and > > still have some reserve. I saw an ad for Shorai 12Volt 12 Amphr > batteries > > for $117 each and they weigh about 1.7 pounds. My 5.0 amphr batteries > > weigh 3.5 pounds each for an added weight (starter + pack support + > > contactor) of 35 pounds onto a mower that weighs 47 pounds for a total of > > around 82 pounds. This is about the weight of an ICE push mower. Twelve > > Shorai batteries would be around 20 pounds. The mower would be lighter > and > > so would your wallet of $1400 plus shipping. > > > > I have thought about purchasing 4 - 100 amphr CALB batteries and then use > > a converter to step up the voltage to 120 volts. At an efficiency of > 85%, > > the amphrs to the motor would be about 8.5. I am not sure if a converter > > could handle that much amperage. I was going to do some more homework > > before asking the experts here. Four CALB batteries would be about 600 > > dollars and a converter would run in the lower several hundreds. The > > savings would be substantial but I am not sure if the electronics would > > handle the load. > > > > The other thought would be to run the 4 CALBs into an inverter and leave > > the rectifier bridge intact. The inefficiency of the inverter plus the > > inefficiency of the rectifier bridge would likely sap the pack of a lot > of > > useful energy. I think this would be a nonstarter. > > > > I know of someone using a self contained electric mower. You might want > > to shoot him an email at theadm *A*T* AOL. If you are in the RTP area, > we > > are both "local". > > > > Everyone else I see running an electric mower are running with a cord. > If > > you want me to, I will ask my neighbors their brand and opinions. > > > > > > On 4/28/2014 1:27 PM, Cal Frye wrote: > > > >> I'm on my second Black and Decker push mower, corded type. I have a > >> small lawn, so avoiding running over the cord is not a major problem. I > >> won't advise on motor or batteries, but I can say B&D has a plastic shim > >> in the stack of washers holding the blade to the motor shaft. Said shim > >> has raised edges which grip either side of the blade, and an opposing > >> pair of edges which grip in turn a keyed, square washer above the blade. > >> This square washer is driven by the motor, and the blade is driven by > >> the plastic shim. Hit too hard an obstacle, and the plastic edges shear > >> off and the blade rotates freely. > >> > >> This is effective, but is also a wear point, and I've learned to buy the > >> shims by the half-dozen. My eyes don't always find the rocks in the yard > >> before the blade does :-( > >> > >> Best regards, > >> -- Cal Frye, www.calfrye.com > >> /Be an Internet Sceptic/ Stop. Think. Connect. > >> www.stopthinkconnect.org - Be at least as safe on the > >> Internet as you are crossing the street! > >> > >> "I sincerely believe that banking establishments are more dangerous than > >> standing armies." -- Thomas Jefferson, letter to John Taylor. > >> > >> > >> > >> Michael Ross <mailto:[email protected]> > >>> April 28, 2014 12:58 PM > >>> I have an old simple ICE push mower, that might be worth converting. > >>> > >>> ... > >>> What about the shock of the blade hitting something nearly immobile? > That > >>> is a lot of shock that small engines are able to handle - special > >>> consideration in the regard with electric motors? > >>> > >>> -------------- next part -------------- > >> An HTML attachment was scrubbed... > >> URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/ > >> attachments/20140428/339eb705/attachment.htm> > >> -------------- next part -------------- > >> A non-text attachment was scrubbed... > >> Name: compose-unknown-contact.jpg > >> Type: image/jpeg > >> Size: 770 bytes > >> Desc: not available > >> URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/ > >> attachments/20140428/339eb705/attachment.jpg> > >> _______________________________________________ > >> 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) > > > > > > > -- > Put this question to yourself: should I use everyone else to attain > happiness, or should I help others gain happiness? > *Dalai Lama * > > Tell me what it is you plan to do > With your one wild and precious life? > Mary Oliver, "The summer day." > > To invent, you need a good imagination and a pile of junk. > Thomas A. Edison< > http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > A public-opinion poll is no substitute for thought. > *Warren Buffet* > > Michael E. Ross > (919) 550-2430 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > Phone > (919) 631-1451 Cell > (919) 513-0418 Desk > > [email protected] > <[email protected]> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140428/eefac1eb/attachment.htm > > > _______________________________________________ > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... 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