Thanks Cor, for the information. I thought I would like to play with these,
but maybe not due to some of the concerns you bring up.
I currently have 16 60ahr calb cells I am learning with on my motorcycle with
no BMS. The investment in this small of pack is not huge and hands on
learning is worthwhile, so I don't mind being my own BMS in this case. I would
eventually like to put Calb cells in my truck. I will likely install a BMS in
my truck as that will be a larger investment and more cells to try and keep
track of manually. Right now I am leaning towards Orion. So the Zener
balancers were just going to be for experimenting and observation.
I understand the risks of not installing a BMS, but it is always interesting
comparing that against the risk of having something permanently wired across
your cells.
damon
> Date: Tue, 23 Jun 2015 11:18:42 -0700
> To: [email protected]
> Subject: Re: [EVDL] Lee Hart Zener Regulator for Calb cells
> From: [email protected]
>
> Lee has discussed this in the past, it is likely in the archives.
> I see three main issues:
> - at lower voltage, the zener knee gets very soft so unless you use
> additional electronics to amplify, the zener itself does not work very well
> on a single cell as you already indicated, two cells might indeed be better
> since around 6V the zeners have the best characteristics but that introduces
> issues with imbalance between the two cells
> - Voltage differences while charging are very small with most types of
> Lithium. 3.2V at rest but 3.5V is over-charging a LiFePO4 cell whereas a
> flooded/AGM lead-acid battery can easily go from 12V to 15V and it does not
> hurt them to be sitting at 15V while balancing for an hour.
> - leakage and failure: while zeners are supposed to go "on" at a certain
> voltage, they will leak below that voltage so you are introducing extra
> "self-discharge" which can very per cell with the properties of the zener, so
> in a sense you are making the situation for Li-Ion worse. Also zeners can
> fail (shorted typically) and mechanically fail and the Lithium cells will not
> take well to being over-charged due to a failure
>
> 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 damon henry via EV
> Sent: Tuesday, June 23, 2015 10:37 AM
> To: EV List
> Subject: [EVDL] Lee Hart Zener Regulator for Calb cells
>
> Hi,
> I am wondering if anyone has adapted Lee Hart's Zener regulators for lithium
> cell use. I don't think the voltage of one cell is high enough to use this
> type of device on, but I think proper values can be found to regulate two
> cells in series. I would love to experiment with some of these and would
> like full bypass at 6.8 volts. I believe the 12 volt model can be tweaked by
> picking appropriate replacement Zener diodes, but I don't do a lot of this
> type of design, so I am not familiar with what is available or where to
> source the parts. Any help would be appreciated.
> thanks Damon
> Here is a link to Lee's
> design.http://www.sunrise-ev.com/LeesEVs.htm#zenerlamp
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/2b159354/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)
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/212b619a/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)
