From: bretcahill@aol.com   
      
   The angle had been mangled in previous projects so the electrodes could not be   
   positioned close together enough to get below 20 ohms. I had to spend $5 for   
   lump charcoal. (Always try these things outdoors next to the grill with some   
   steaks in case of a    
   fire.) Adding pulverized charcoal to the brine, or rather, adding the brine to   
   the charcoal, got the "resistance" down below the equivalent of 2 ohms. It's   
   not really a pure resister so the ohm meter was worthless. I measured current   
   from a 3.6 volt    
   battery which was ~ 1 amp. This isn't an ohmic load so when I hooked up the   
   36v battery it drew 18 amps for the 1 or 2 seconds I was willing to keep the   
   test going.   
      
   Eventually I raised the electrodes out of the slurry until it drew less   
   current.   
      
   I blew a 15 amp fuse and used 1 cm wide al foil instead. Steam soon boiled out   
   the top of the sch 80 PVC pipe container but I held in there for a full   
   minute. No hot spots anywhere on the battery.   
      
   I had charged up 0.6 v earlier -- half an hour at 1.18 amps -- and the voltage   
   dropped 0.4 v in about the minute and a half I was actually zapping the thing.   
      
   This comes out to be an average of 18 amps.   
      
   I'm not going to bother with the 5 minute test with BMS. Hardly any hills in   
   the valley take much more than a minute anyway.   
      
   The original BMZ looked like a prototype, like no one had done a thorough   
   analysis of the possible wear from possible vibration that could short the   
   battery. So BMZ adopted a throw eberthang ya got at them approach. The battery   
   was held together by    
   dozens of cool tapes and sealants -- a Maginot Line.   
      
   Now I'm starting to wonder if I took enough care.  My reasoning was the down   
   tube should be the battery holder. Stuff that battery tightly enough in the   
   down tube and there is no intra battery rubbing. Sure would hate for it to   
   short out a year from now.   
      
      
   > > >Need to draw 18 Amps from a 36 v battery.    
   > > >    
   > > >For 5 minutes.    
   > > >    
   > > >2 lugs in a brine solution?    
   > > >    
   > > >Drive rebar into the ground?    
   > > >    
   > > >    
   > > Well, that's 2 Ohms, 648 Watt.   
   > Not sure if the sprinkler system is de facto flood irrigation or not.   
   Probably get pretty good current with all the Ca and Na in lower Colorado   
   River water.   
   > > Brine works, although you must measure the Amps    
   > > and regulate the electrodes manually.   
   > Meter only goes to 10 amps so play with that then extrapolate off when the   
   15 amp fuse blows.    
   >    
   > Is this an inverse square relation with distance?    
   >    
   > If concentration is linear if may be easier to 3X the salt of 6.7 amps.   
   > > Make sure not to short circuit the current.   
   > Two 15 amp fuses in parallel.   
   > > One bucket of water, 10 liters,   
   > I might use something taller to accommodate the rods.   
   > > and 1/4 Kg of salt.   
   > Get $1.25 of Na salt as I'm not going to waste $3 of lite salt on this   
   project.   
   > > 40 cm of aluminium rod electrodes.   
   > The two Al angles happened to be 1 m away cluttering the desk, one 35 cm and   
   one 40. I may cut the test after 2 min if they corrode too much. I'm a great   
   believer in useless clutter.   
   > > Starter cable of the Olde Times, not the Chinese ones.   
   > I'll just use the 4 X 16 AWG I use for the spot welding rig. In 2 years I'll   
   replace the cells again so I'm not going to ruin my cables.   
   > > Done this a 1000 times.   
   > Thanks.    
   >    
   > The 40 new cells were left over from a 7p X 10s cut to make a 3p range   
   extender and were sitting for 7 months. They are now are all at 32 v. I'll   
   charge up half way with the BMS attached then discharge test a minute w/o BMS.   
   Then 5 minutes with BMS.    
   >    
   > The bike stays out doors until after several charge cycles.    
   >    
   > I stopped by the Glamis Store asking if I could use their outlet to   
   recharge.    
   >    
   > "We are not responsible if your bike burns up."    
   >    
   > They didn't care if if the ebike burned their wooden store down, just   
   getting sued.    
   > It took awhile to realize they got sued everytime anyone flips a dune buggy.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)