I re-read the original mentioning of the 40Ah cells that also said that he paid $5k for 95 cells. That is about right, the CALB were typically going for $1.25 per Ah so that means that he really is using 24 sets of 4 *in series* since that gives the roughly 300V that is expected. I suspect that his 90 miles range is incorrect, or it may be "up to" 90 mi which can only be achieved by driving constant 30 MPH for 3 hours straight. Since he has 40Ah cells and the sporty acceleration needs more than 200A, he is loading his cells with more than 5C and that is outside the spec for the cells, as far as I know, so I think that the worry about the longevity of the cells is valid.
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 This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:[email protected]] On Behalf Of Cor van de Water via EV Sent: Friday, June 12, 2015 10:41 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] EV Digest, Vol 32, Issue 18 Hi David, Something is not correct in the numbers that you give us. If there are 24 modules of 4 parallel cells, then the pack voltage is about 77V (24 x 3.2V) which makes no sense in a 300V vehicle, so I suspect that there still are 96 series cells. The 40Ah is incapable of giving the truck a spiffy acceleration because typical for this type of vehicle is at minimum 250A current limit (which is what my US Electricar S10 truck had and it is similar to the Ranger) and since the recommended max draw on these batteries is 3C the 40Ah cell would need to be limited to 120A so my guess is that there are 2x 40Ah cell in parallel or there actually are 80Ah cells in use, but size constraints may have made 40Ah necessary and they are buddy-paired, but still 96 cells in series. That would give a total max pack capacity of 24.6 kWh and at a typical consumption of 300 Wh per mile for a truck, that gives 82 miles of range. Drive it careful (slower) and you can get up to 90 miles of range in practice. That would mean that a total of 192 cells of 40Ah capacity are used. As I said before - it makes more sense to use the 80Ah cells (half the terminals to connect) but of course I do not know the reason to select 40Ah. 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 This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:[email protected]] On Behalf Of David Miller via EV Sent: Friday, June 12, 2015 9:38 AM To: Alan Arrison Cc: Electric Vehicle Discussion List Subject: Re: [EVDL] EV Digest, Vol 32, Issue 18 Hi Alan. Thanks for the insight! I do worry about the batteries. It's not my Li conversion. So, I'm short on many details. Here is what I know. It ranges 90 miles per charge under easy use. 45 miles per charge when driven aggressively. The 40 AH Lithiums are packed into 24 4-cell parallel modules. So, these modules are 160 AH with 1/4 of the total current flowing through each cell? Does this explain the good range? Does this significantly improve the Lithium longevity? My 13 year old NiMHs still get ~70 miles. But my power is uncomfortably low. Thanks! -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150612/49dfc231/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) _______________________________________________ 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)
