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Re: [EVDL] final email about "problems Electro Automotive"

Hi Evan,

That does not help the current owners
unless someone gets into a business of building
compatible control boards that will swap into
existing chargers.

If you send me the schematic then I can see if it
is possible to add a switch on a misbehaving charger
to disable the equalization (for example by setting
the voltage level at float voltage) so the user can
toggle the switch once per month to get his pack
equalized at high current charge and omit it all
the other days.

It will either require voiding the warranty by
opening it yourself or by someone else to get such
a mod, but if this is what it takes to get an
already purchased charger to work....


Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation
Email: [email protected] Private:
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Evan Tuer
Sent: Tuesday, November 02, 2010 5:00 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] final email about "problems Electro Automotive"

On Tue, Nov 2, 2010 at 11:16 AM, Collin Kidder <[email protected]>
> On Tue, Nov 2, 2010 at 12:11 AM, EVDL Administrator <[email protected]>
>> The only solution I can see is for some open-minded hacker (in the
>> good
>> sense) to reverse engineer the Zivan firmware so users can tweak it
>> themselves.
>> David Roden - Akron, Ohio, USA
>> EVDL Administrator
> Well, there's two possibilities:
> 1. Rewrite the firmware
> Usually people go to great lengths to protect the firmware in their
> products. It's not, in general, possible to tweak or get at the
> existing firmware. A totally new firmware has to be written based just

> on how the circuit board looks and what components appear to be on it.

> The bottom line is that we'll never know for sure what the real
> situation is until someone decides to have a warranty voiding day. Any

> takers? ;-)

Paul Compton reverse engineered one of these chargers several years ago.
I think I have a copy of his schematic somewhere. Anyway, the point I
want to make is that, based on my recollection, the microcontroller has
fairly limited control over the charge profile, I think it basically
acts as a timer to switch between different steps of voltage and current
that are set in hardware. I guess it "evolved"
from earlier chargers which had hardware timers as well.
Not flexible or easy to work with, and that's one reason these chargers
were never well suited for charging AGM batteries like Optimas.

The sensible option looked like making a new, simpler logic board which
allowed a modern micro with built in ADC and EEprom to read the actual
voltage and current and control the PWM more directly, and be properly
user configurable. I don't think anyone has done that however.

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