charger specs for 24v scooter

[Soundguy]

My cousin has a 24v scooter for her kids. they use sealed lead acid batteries. They managed to smoke the charger (lightening?) It lists output as 24v 1.6a on the ul tag.. but I know if it is charging a 24v battery.. it is realizing a higher voltage output. Since I'm building it from scratch..and don't have a reference unit to test under load, i was thinking of shooting for 27.6 volts, etc. , perhaps a 'charged indicator as well.. all the usual stuff. filtering/basic surge/over voltage.. fused.. etc..

Any comments on my target charging voltage?

Soundguy

 

[DFW]

Soundguy, I have an off-grid power system for my house which is 24v. Mine calls for 28.8 for bulk charging and floating at 26.6.

Hope this helps.

David

 

[Soundguy]

Looks like I was right in the middle. I can bump this circuit up to a max of 29.4v so 28.8 is doable.

thanks

Soundguy

 

[slowrev]

Davids numbers figure out like mine. I used to do installation and maintenance on Phone company battery backup strings.

Are you using a 3 terminal regulator ? I have made a few of those little trickle chargers to work with about any surplus wall transformer I happen to have.

Also do you have any info on how to build or how the desulfator float chargers work ? Probably got the stuff to build a few, just don't know exactly how they work.

Ben

 

[KennyV]

Ben…
You should find what you are looking for, Battery Desulfation Pulse Generator, At
http://www.shaka.com/~kalepa/desulf.htm
KennyV.

 

[slowrev]

Thanks Kenny. Looks like I can fing enough info there to run with.

Ben

 

[slowrev]

Thanks again for that link Kenny. Been looking the schematics and such over and believe I have everything to make one or two of those. Not sure I want to play with the mains driven high power one though /forums/images/graemlins/ooo.gif
Now if I could just get time to play with my electronics stuff.....

Ben

 

[KennyV]

Ben,
I know what you mean… /forums/images/graemlins/crazy.gif I have been cutting back on the things I ‘have to do’ for the last year and a half… It still seems like I cannot find time to do the fun electronics projects I have been putting off. I guess there is always tomorrow /forums/images/graemlins/smirk.gif…. KennyV.

 

[Soundguy]

</font><font color="blue" class="small">( Are you using a 3 terminal regulator )</font>

I wasn't going to.. but was instead going to build a seirs pass regulator usin a to-3 component.. though.. I suppose I could use a 78xx regulator and biase it a few votls up.. or use one of dip package variable regulators.

</font><font color="blue" class="small">( Also do you have any info on how to build or how the desulfator float chargers work )</font>

If I had a schematic i would /forums/images/graemlins/grin.gif

I've reverse engineered the OEM charger.. it's fairly simple.. ac in.. fuse, full wave bridge.. filter, 1st stage regulator.. drps it to intermediate voltage using a tip style device. Then it has a secondary stage regulator using a dip packaged variable regulator and support hardware. Has a rectifier for reverse current protection, Has a low ohm value power reistor in series line with load to limit charge current as well as an "L" filter setup. Secondary circuit consists of a bi-color led to indicate charging / charged level. Output section has an mov across the reverse current diode, as well as an mov on the ac line side as some simple surge protection.

I see lots of 'at factory' point to point wiring and resistor add-ins. i take it the circuit board design is faulty, or the primary design was inadequate. I count at least 3 're-work' components added in on the secondary stage voltage regulator.. probably to fine tune the regulation.. etc.

MY design should be much simpler.. more robust, and just as good.

Soundguy

 

[slowrev]

Mains driven ? I guess I am just old fashoned and like transformers for such projects. Getting harder to find them though.
Some of the rework might have been to meet UL specs, or to keep it from flaming up /forums/images/graemlins/smile.gif
Ben