>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>Sent: 04 September 2006 17:02
>To: Microcontroller discussion list - Public.
>Subject: Re: [EE] charging a 12V battery with solar array
>
>
>>> > http://www.tunecharger.com/
>>>
>>> Not overly cheap.
>>> PIC16F675 based boost converter
>>> Circuit on page 10.
>>>
>>> 
>>> 
>http://www.tunecharger.com/2006_t_0001_mtc_3-330.2%20%20reva%20techni
>>> cal%20reference%20manual.pdf.
>>
>> By a strange coincidence I found the above recently (have you been
>> hacking my gargoyle [tm] searches? :-)
>
>The manual is dangerously naive when discussing battery charging 
>needs - both lead acid, which it is mainly intended for, and NiCd and 
>NimH. It is dangerously underspecified for any of these tasks. As a 
>panel to battery energy transferer it may do a good job.
>
>Their comments on multiple sources in parallel are correct but 
>generally do not represent means of using more than one source at once 
>which may confuse the technically inexperienced. .
>
>I am uncertain of the merits of their two stage charging process and 
>it seems to reduce efficiency. They first use a boost converter to 
>charge a capacitor to above battery voltage and then discharge the 
>capacitor into the battery using a separate FET switch. I don't see 
>that not using the boost converter directly is an advantage. 
>Discharging a capacitor into a lower voltage load will necessarily 
>cause I^2R losses (even if it's not evident where the R is it still 
>exists). They would probably be better off using the second FET as a 
>synchronous flyback diode to get better efficiency.

I'm wondering if the resulting pulsed current delivery offers simmilar benefits to those claimed by reflex or "burp" chargers.  The designer of this circuit seems to claim that it can revive dead batteries....

Regards

Mike

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