What chip would you recomend someone use if they were charging lead acid bats. ----- Original Message ----- From: "Lee Hart" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, October 09, 2002 2:19 PM Subject: Re: Tropica update/charger chip.
> [EMAIL PROTECTED] wrote: > > This chip uses an exernal shunt. Yes, the voltage drop required > > is .25V, but that works out nicely to an available 0.01R shunt > > for 25A - so the 6.25W dissipation is not a problem. > > OK, that helps. Be aware that the peak charging current may be several > times the average, when the charging is done at the peak of the AC line > cycle. Therefore, the peak voltage drop across the shunt may be also > considerably higher. Make sure the chip's current sense input has enough > dynamic range to cover the peaks. > > > the pack voltage sensing is independant from VCC. > > Again, that helps. Make sure you know its maximum voltage, and that you > don't run into trouble if the pack sensing pin is more positive than the > VCC pin (if, for instance, the power supply that is running the chip is > slow to come on). > > > The bq2031 uses an external NTC thermistor, on the end of a wire > > if you like. > > Again, that will help. Does it detect an open, shorted, or missing > temperature sensor? Or does the charging algoritm commit batricide if > the sensor is damaged or missing? > > > This one doesn't seem too bad (it is designed for lead acid, > > with the correct voltage/temperature compensation), in fact the > > Constant Current / Constant Voltage / Float profile looks > > similar to the Zivan - so, not ideal maybe but useable.. > > Sounds hopeful, at least. I am not criticising the BT2031 in particular; > I haven't used it (and don't have the time to pull out its data sheets > and learn it just to provide free engineering advice :-). I am just > offering some general comments on my experiences with other battery > charging chips. > -- > Lee A. Hart Ring the bells that still can ring > 814 8th Ave. N. Forget your perfect offering > Sartell, MN 56377 USA There is a crack in everything > leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen > >
