I've finally gotten tired of looking at the weed infested plot of land other people would call a front yard. To wit, I've managed to install half a volt pack module in my Ariens Amp Rider electric riding lawn mower. I was hoping to put both split modules in place, but there's just not enough room. The alleged 47 ampere-hours should be enough for three full cuts, dropping me down to about 30-35 percent SOC. Ball park figures, they are, as I've only done one cut so far, but the module is many magnitudes stronger/stiffer than the VRSLA blocks that were removed. About two hundred pounds (US$260) removed by recycling the VRSLA pack and maybe a quarter of that put back in with the Volt module. I detected no difference in handling, but at 2-6 mph, what would you be able to detect? Splitting a 96v module into two 48s wasn't particularly difficult. It started to reverse-accordian when I released the through bolts, and I wasn't comfortable with hoping to manage loose-leaf volt cells, so back together it went. It was a relatively easy matter to engineer two individual module clamps that kept each set secure. Adding a set of end plates purchased from eBay provided the necessary security to split them, along with a knocked-together top clamp for each block. I also purchased matching balance connectors for the Volt proprietary leads sticking up from the module. A bit of defective work on the multimeter allowed me to determine which leads had to go where to mate with my 25 ampere balancing charger and I was in like Flynn. I'm not sure who he is, but if he was ghosting me, all went well. Now to the crux of the biscuit (the apostrophe). I've seen figures for maximum charging voltage in the range of 48 volts (4 volts per cell) and a number of them that go beyond 49 volts. To be on the safe side, I configured the charger to the 4 vpc limit. In this particular instance, I figured I could have gone higher, because I would be cutting the lawn as soon as the charge was complete. Conversely, I'd like to avoid the one-hundred percent charge figure that today's automotive manufacturers also avoid. Our Rav4EV does about an eighty percent charge unless extended is selected when configuring. What number should I be using for the maximum voltage to attain about an eighty (or ninety?) percent state of charge? I use a CycleAnalyst amp-hour monitor on the mower to ensure I'm not pulling the pack/module below a safe limit. If I'm only loading to ninety percent (47 * 0.9 = 42.3 ah) and I don't want to drop below 20 percent SOC (47 * 0.2 = 9.4 ah) that should give me about 33 amp-hours running capacity. I can easily limit my use to 30 ah and be happy with the results. What voltage would represent 90 percent charge? Would it be practical to use the maximum safe voltage to top-balance the modules/pack and start my math from there? Suggestions are greatly appreciated. I'm running this R/C-grade charger on a 24v power supply connected to 110v house current. The power supply is supposed to be capable of 60 amperes. The charger can push 25 amps at 48 volts into the battery, but in so doing, it overloads the power supply. I've dropped the setting to 20 amps and the power supply is indicating a draw of 51 amps. This little package is moving some electrons at a pretty good rate, but clearly not stressing the Volt modules. No liquid cooling in my mower but with a 20 amp charge rate and a continuous draw of 25 amps from the mower, peaking at maybe 40 amps, I don't think I'm going to cook the module. It was rewarding to have everything work the very first time I plugged it in and figured out the charger. Read the manual carefully! -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20190421/bfb98239/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
