wrote:
>
>>
>> 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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