Thank you Joep! I'm pretty familiar with LiPO because I'm also an
RC passionate. I have carbon fiber racing 1/10 touring cars, CF helicopters
and racing RC boats. I have also LiPO packs and a specialized Lipo
balancer/charger/discharger that I had to modify because it was not
measuring right the upper voltage threshold, instead of 4.2 volts it was
displaying 4.1, so the charge process was not terminated at 4.2 but at 4.3
which is not so good.
Anyway, I think I'm gonna go with specialized IC for battery capacity
measuring and MPPT solar charger, as I just told Vasile. Because it is an
industrial process automation and it has to work at least 3 years without
maintenance, I can't take to much risks!
Still have some questions left. I will start with the most needy.
Can you advise me about the best choice for an LCD that works with JAL
routines for graphic lcd without problems. I have selected a few from
Farnell but it's my first time that I have to display data onto a COG
display.
Thank you again for your time!
joi, 9 august 2012, 18:49:22 UTC+3, Joep a scris:
>
> Hi,
>
> Lipo charge/discharge is not complicated, just keep the current within the
> bounadies until certain voltage levels are reached. But these cells are
> quite sensitive to overcharging ( resulting in fire risk) and deep
> discharge (destroying the cell). When puting cells in series, balancing
> and/monitoring of each cell is required.
> So proper testing and reliable circuit (including the watchdog Vasile
> mentioned) are manatory.
> I'm note sure about failure prediction, but i guess capacity measurement
> during a significant charge part of a charge cycle os a good indication for
> any battery. For nimh, reduced discharge curreny is a failure mode too.
>
> Joep
>
> Op donderdag 9 augustus 2012 schreef vasile surducan
> ([email protected]<javascript:>)
> het volgende:
>
>> Hi Bogdan
>> In my opinion, failure predicament for Lead Acid accumulators is not too
>> complicated, but I do know nothing about LiFePO cells so I can't
>> pronounce... I've designed and manufactured as prototype, about five years
>> ago (if I don't wrong) a charger-discharger for NiMH with one channel
>> using a simple PIC12F675 and a PC for analyzing data.. I think you have to
>> implement two things: a charging algorithm and a discharging algorithm on a
>> known load. Both are quite simple. You can also measure dV on dt with load,
>> but this might need more than 10 or 12bit AD resolution.
>> The biggest problem I've faced over the time since I'm playing with PIC
>> micro is not the algorithm itself, but the problems of long time running.
>> For such application you'll have to consider deeply how a watchdog should
>> help you against bottlenecks.
>>
>> best wishes,
>> Vasile
>>
>> On Tue, Aug 7, 2012 at 5:56 PM, Bogdan Mihai Octavian <
>> [email protected]> wrote:
>>
>>> Hello everybody! I'm not new into microcontrollers, actually all
>>> my projects, personal or those built for the company I'm working for, were
>>> built around PIC family. Now I'm working at a project that involves battery
>>> management and battery failure predicament. It is a industrial process
>>> automation powered from a Solar panel (UPS with MPPT charger and all the
>>> other stuff involved). Because it has to work without the Sun, sometimes,
>>> from the internal UPS powered from one or two LiFePO cells, I have not
>>> decide yet, I have to know the battery condition. The automation it is
>>> remotely located and it is visited by the maintenance stuff once a week or
>>> in case that something goes wrong (radio communication also implemented). I
>>> have founded some hardware solutions, battery gas gauge, provided by Linear
>>> Technology or Texas Instruments or Maxim, but those are little too
>>> complicated. I was thinking do do that myself and this is where I will
>>> need some help.
>>> So, does anybody have an idea how to do that? Measure the battery
>>> capacity and predict battery failure.....
>>>
>>> Thanks for your time!
>>> (Allocated to read this)
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