[ausev] charger help

[Marc Kohler]

Erik,

I measured the output of the charger without a load: 105V

Since that is the open circuit voltage of my 8 batteries, no output current
will flow.

I then hooked the charger across 7 batteries (92V) and the charger put out
current (just like it should).  So at least I know the charger works.

I opened up the charger to look at the programming resistor.

It is 86.6k (which is set up for 108V) just like the previous owner had
said.

The manual shows about 5kohm increase for each step (76.8kohm for 96V,
82.5kohm for 102V, 86.6kohm for 108V, etc)

So which begs the question, should I buy a potentiometer at Radio Shack and
just increase the resistance until I get to my 112V desired output?

The internal setting is for a 108V system, but the output is only 105V max.
My thought is instead of trying to figure out why it's not working the way
the manual says it's supposed to, just to change the values until the unit
acts the way I need it to.

Marc

 

 

  _____  

From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
Behalf Of Erik
Sent: Sunday, March 22, 2009 9:50 AM
To: AustinEV News Announcements and General Discussion
Subject: Re: [ausev] charger help

 

Have you messed with the programming resistor inside the K&W?  I don't have
the values handy, but I might be able to find them. 

What's the open circuit voltage on the K&W? ie. what voltage does it make
when it's not trying to charge? The good news about the K&W chargers is that
they're pretty simple.

Erik

2009/3/21 Marc Kohler <mkohler at austin.rr.com>

Hi Guys,

I've been slowly getting my ElectraVan road worthy.  Now that it is, I'm
having problems with my chargers.

Background:  I have two chargers that came with the van, a K&W BC-20 and a
Lester (transformer version).

Both supposedly worked last time the previous owner used the van (1998).

 

The K&W BC-20 works on 120VAC input.  Its fuse is good, the breaker switch
is not thrown, and the GFI tests out.  When plugged in the Green ON light
comes on and the fan spins, but no current seems to flow (it has an
ammeter).  At first I thought that it did not allow current to flow because
my open circuit voltage was too high.  But I've dragged the battery voltage
down enough that it should have come on.

 

The Lester is a dual output version (108V and 12V) and can accept 120V or
240VAC.  When I plug it in, the Charger ON light does not come on, nor does
anything change when I push the Press To Reset button.  The 3 fuses appear
to be good.  The thing shows no signs of life.  There is no fan.  I took the
cover off to see if there was anything obvious, but everything looks normal
(no burns or broken wires).  I suppose the printed circuit board could be
bad after sitting for so long, but I don't know how to troubleshoot it.

 

It's killing me to finally have an operational vehicle but I can't drive it
until I get a charger working (using my 12V charger takes me 8 days to
charge the batteries up individually).

 

Does anyone have any experience with either of these types of chargers?  I'm
thinking that the problem with the K&W is something simple.  I have no
desire to send the Lester off to get fixed as it weighs over 60 lbs and
shipping alone wouldn't be worth it, so I hope to be able to repair it
locally (or at least determine the problem locally).

I like it for its dual input voltage capability.

 

Any advice would be appreciated.  My only other option is to purchase a new
charger.

Thanks,
Marc Kohler

 

 

 

  


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