Jerry, The 4 parallel packs that you quote as nominal 48V are in fact 60V at 3.5V per cell and 17 in series. The extra module of 8 could be split in 4 parallel 2-series pairs to increase the voltage of your Total pack from 60 to 67V, but at 19 cells in series the top charging voltage then goes to 19 x 4.1V = 78V, I don't know if your charger and controller will be happy with that, or better to Stay at the max 70V with the 17 series cells - depending on your existing component specs.
Success, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com -----Original Message----- From: EV [mailto:[email protected]] On Behalf Of jerry freedomev via EV Sent: Monday, February 02, 2015 5:48 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Volt pack arrives Hi Adam and All, Thanks for your part helping me get these as time I got into lithium light batteries to go with my lightweight EV's. Yes I understand the current limits and a major reason for the e controller. Though the first set up with have 4 in parallel at 48vdc nom likely too much amps available!! I'll run lighter cables to limit max amps too. With just another 24vdc group I can go 2 strings of 120vdc nom. Or another 5kwhr and do 156vdc nom pack might give me 150 mile range. Looking at the bus bars, etc 120amp cont looks right. It's good we didn't break up the pack. I'll fuse each 48cell set though I make my own fuses. Not hard if you understand them. On voltage I have your earlier post on it and seeing what others might have experienced. So anyone else have experience with Volt batteries? I was thinking using the BMS cables getting a couple model airplane 7 cell BMS' IC's with meters that have a balancing function plugging them in say 1/month to equalize. Mostly just relying on monitoring. It has motivated me to get the Ewoody and FreedomEV going now I have batteries that will give it good range. The fact the weather is getting warmer helps as in Fla mid Feb to June is building season . Looks like my front suspension design, double A frame, is good so mostly a matter of getting stuff mounted, skin on and electrical. By then my wthr meters, etc for battery charging will be in and I'll have a chance to put some cycles on them. It's going to be strange having so much data to work with as until now it's just been volts, amps and AC charging wattmeter. I just happy good wthr meters have dropped so much in price, Lightobject 404, with so many great features like charger turn off when 95% charged, fuel gauge, volts, amps, high/low alarms, etc. Thanks, Jerry Dycus From: Adam Chasen <[email protected]> To: jerry freedomev <[email protected]>; Electric Vehicle Discussion List <[email protected]> Sent: Monday, February 2, 2015 12:28 AM Subject: Re: [EVDL] Volt pack arrives Glad you are enjoying your cells! I have been using 4.1 as my top and 3.5 as my bottom voltage. The Volt battery module was not designed to provide more than 120A current continuous based on the components found in the battery (specifically the relays in the head unit are rated for 120A continuous, but much higher surge). Or course hooking yours up in parallel multiplies that current by the number of packs you have. I strongly encourage you to invest in some "semiconductor fuses" to protect the packs from one another when hooking up in a parallel scenario. Note: These fuses are likely to be incompatible with using a contactor style controller. The fuses are available in various amperages on ebay (new old stock). In the case of a cell failure (cells usually fail short), one pack will have lower voltage. This will result in the other parallel packs dumping current into the failed pack's remaining good cells. This can cause a dangerous situation due to overvoltage and thermal runaway on the failed pack. I believe these fuses will provide some protection from this situation in addition to providing some protection to an electronic motor controller (they are actually designed to protect high power diodes and transistors from catastrophic failure). Keep those tops on and any liquids away from them! You are correct in that they are very dangerous to work around. I strongly encourage using rubberized tools (not that it should be treated as the only safety measure). Adam -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150203/d3fd42ef/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) _______________________________________________ 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)
