On 20 Oct 2005 18:23:08 -0700, "Too_Many_Tools"
wrote:

I would be interested in hearing a recommendation for a charger for
lead acid batteries.

I am looking for a charger that gives an indication of charging status
(no idiot lights please), capability for flooded cells, sealed lead
acid and any other options you have found useful.

Also, what do you use to charge your lead acid batteries?

You don't say what AH rating your batteries are but for my pair of
deep-cycle flooded batteries in my RV I use a homebuilt three-stage
charger.

Most (all) of the commercially available crap uses switch-mode
conversion/regulation that generates gobs of EMI/RFI.

I built a 30A, three-stage analog charger. Not wanting to reinvent
the wheel, I used an Astron RS-35M power supply

http://www.astroncorp.com/linear.shtml

for the transformer/rectifier/filter/pass trasistors and an A-A
Engineering

http://www.a-aengineering.com/

"smart charger" board that I modified, for charge control. The board
uses the Unitrode (now TI) UC3906 IC

http://www.ti.com/sc/docs/psheets/ab...ps/slua115.htm

that is specifically designed for this.

Sorry, there are a couple of idiot lights, but the supply also has
honest to goodness meters too.

On Fri, 21 Oct 2005 16:58:56 -0700, Wes Stewart wrote:

On 20 Oct 2005 18:23:08 -0700, "Too_Many_Tools"
wrote:

I would be interested in hearing a recommendation for a charger for
lead acid batteries.

I am looking for a charger that gives an indication of charging status
(no idiot lights please), capability for flooded cells, sealed lead
acid and any other options you have found useful.
(snip)

"smart charger" board that I modified, for charge control. The board
uses the Unitrode (now TI) UC3906 IC

http://www.ti.com/sc/docs/psheets/ab...ps/slua115.htm

that is specifically designed for this.

I use and freely recommend the UC3906 for SLA's, but have never investigated
their use on flooded cells. Very interesting .....

Any pictures of this homemade charger?

Sounds interesting.

TMT

On 21 Oct 2005 21:25:26 -0700, "Too_Many_Tools"
wrote:

Any pictures of this homemade charger?

Sounds interesting.

Befo http://users.triconet.org/wesandlinda/Figure_1.jpg

The circuit board has the 723 and other low power stuff and is removed
and discarded.

After: http://users.triconet.org/wesandlinda/Astron_A_A.jpg

This is not quite the final view. When I took this, I had yet to
receive the precision power resistor that I needed for the current
sampling shunt and was using the DC resistance of a piece of wire for
that.

Sorry no write-up or schematic at this time. I thought about doing it
by saw no market for an article.

Also, consider that this is set up for one max current condition that
is related to the AH rating of your battery and what fraction of same
you want to charge at. I have some ideas on how to make this
variable, but have not implemented them because this design fits my
requirements.

If you decide to use a '3906 here is a little spreadsheet I threw
together to calculate resistor values, etc. Disregard references to
"equalize voltage" as this is not a function of the IC.

http://users.triconet.org/wesandlind...eryCharger.xls

The stuff in the blue boxes is for user input.

Thanks for the information.

Frankly I am surprised by the lack of response on this question....I do
appreciate the comments I have gotten so far.

Do you think maybe some people just throw away their lead acid
batteries instead of recharging them? ;)

TMT

On 22 Oct 2005 08:49:47 -0700, "Too_Many_Tools"
wrote:

Thanks for the information.

Frankly I am surprised by the lack of response on this question....I do
appreciate the comments I have gotten so far.

Do you think maybe some people just throw away their lead acid
batteries instead of recharging them? ;)

Another vote for a 3 stage charger. But for best lifespan I'd shallow
cycle occasionally so the battery gets a topping charge (say a 30%
discharge every 3 months). See:

http://www.allegromicro.com/techpub2/cadex/index3311.htm
http://www.buchmann.ca/Chap4-page6.asp
http://www.google.com/search?hl=en&safe=off&client=opera&rls=en&q=sla+fl oat+charging+sulfation&spell=1

cheers,
Pete.