# [EVDL] Dumb to smart charger converter



## EVDL List (Jul 27, 2007)

John,
Tho I am far from chargers and battery purchases, this sounds very 
intrieging to me.

Kelly Hales

PS Done anything with those bus motors yet?

Sent from my iPhone



> Neon John <[email protected]> wrote:
> 
> >
> > I'm about to start the design of a box to convert the many dumb
> ...


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## EVDL List (Jul 27, 2007)

John,

This sounds intrieging to me also.



> Kelly' Hales <[email protected]> wrote:
> 
> > John,
> > Tho I am far from chargers and battery purchases, this sounds very
> ...


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## EVDL List (Jul 27, 2007)

Sounds good!
I would be interested in either a kit or build plans.
Bill


> Neon John wrote:
> > I'm about to start the design of a box to convert the many dumb
> > (transformer/rectifier) chargers into smart chargers. What this box will do
> > is monitor the battery voltage and vary the line input voltage to the charger
> ...


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## EVDL List (Jul 27, 2007)

I built a dumb charger using a pair of toroid transformer secondaries to 
limit the peak current spikes.I am using a triac dimmer circuit to control the 
output voltage/current. It works on 220VAC and 110VAC.

I would like to make it smarter but first I have to find out why I keep 
blowing the 60 amp 400 volt triac. It is not getting hot. It blew before the 30 
amp circuit breaker opened.

I did buy a smarter charger, the PFC-20b but that is being fixed and I hope 
to get it back soon.

Dave Delman
electricDeLorean.com
evalbum.com/1482


**************Looking for a car that's sporty, fun and fits in your budget? 
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## EVDL List (Jul 27, 2007)

I've got a big old variac for a similar purpose.
I'd figured on pretty dumb electronics, too- enough to
save the pack, not so much that it actually thinks for me...

I'd be quite curious as to what you come up with.

Toby



> Neon John <[email protected]> wrote:
> 
> >
> > I'm about to start the design of a box to convert the many dumb
> ...


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## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > I built a dumb charger using a pair of toroid transformer secondaries to
> > limit the peak current spikes. I am using a triac dimmer circuit to control the
> > output voltage/current. It works on 220VAC and 110VAC.
> ...


----------



## EVDL List (Jul 27, 2007)

> Neon John wrote:
> > I'm about to start the design of a box to convert the many dumb
> > (transformer/rectifier) chargers into smart chargers. What this box
> > will do is monitor the battery voltage and vary the line input
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Lee,

> That makes good sense. I prefer to see more isolated chargers. 
> Non-isolated chargers are dangerous in ways that aren't obvious to 
> beginners or the careless.

I am both a beginner and a little careless! Could you please explain (or
post a link) to some of these dangers? I have often wondered how the
safety of:

1) A non-isolated charger with a GFI breaker.
2) A transformer isolated charger.

compare, say when charging an EV pack that is isolated from the vehicle
chassis. 

Hmmm, thinking about it - with non-isolated charger (1), if I touched
one side of the pack while standing on the ground a current could pass
through me to ground. The GFI may trip but I imagine some people might
be tempted to leave it out of their charger design.

However with (2) current can't pass through me unless I touch both sides
of the pack. Is that correct?

> 5. Build a KISS bulk charger that is just a big transformer and
> rectifier. Set the taps so it outputs slightly less than the
> desired DC output voltage.

One other question - how much ripple can EV type batteries handle
comfortably? For example if the charger was simply a transformer/bridge
with no smoothing capacitor, would this damage batteries? Or would we
just see the charge current vary over the AC ripple cycle?

I was wondering - if a high ripple is acceptable (at least for the bulk
current charging phase) would it perhaps help Power Factor? Without
significant smoothing capacitors AC current is being drawn at all parts
of the mains AC cycle. More current would still be use at the higher
parts of the cycle, but the the shape of the AC current waveform would
be smoother than compared to a non-PFC-corrected charger which has a
bank of smoothing capacitors.

Need to add one of the clever ideas in this thread to make the charge
algorithm smart at the end of the cycle. Lee your idea of a smart 12V
charger in series with a dumb bulk-current source might also be used to
actively smooth the AC ripple during the constant voltage phase. The
smart 12V charger could "fill in the gaps" in the ripple voltage if the
bandwidth of the control loop was high enough. 

But perhaps I am getting too complex. Maybe a bank of smoothing
capacitors is not a significant expense.

Thanks,

David


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## EVDL List (Jul 27, 2007)

>> I prefer to see more isolated chargers. Non-isolated chargers are
>> dangerous in ways that aren't obvious to beginners or the careless.



> David Rowe wrote:
> > I am both a beginner and a little careless! Could you please explain
> > (or post a link) to some of these dangers? I have often wondered how
> > the safety of:
> ...


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## EVDL List (Jul 27, 2007)

I built a dumb charger using a pair of toroid transformer secondaries to 
limit the peak current spikes. I am using a triac dimmer circuit to control the 
output voltage/current. It works on 220VAC and 110VAC.

I would like to make it smarter but first I have to find out why I keep 
blowing the 60 amp 400 volt triac. It is not getting hot. It blew before the 30 
amp circuit breaker opened.

I did buy a smarter charger, the PFC-20b but that is being fixed and I hope 
to get it back soon.

Dave Delman
electricDeLorean.com
evalbum.com/1482



**************It's only a deal if it's where you want to go. Find your travel 
deal here. 
(http://information.travel.aol.com/deals?ncid=aoltrv00050000000047)
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## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > I built a dumb charger using a pair of toroid transformer secondaries
> > to limit the peak current spikes. I am using a triac dimmer circuit
> > to control the output voltage/current. It works on 220VAC and 110VAC.
> ...


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## EVDL List (Jul 27, 2007)

To smarten the dumb charger, I have been pleased with Harry Landis
charge controller (described fully on my blog). I have since learned
that several commercial "smart" chargers use this same technique. It
was the best $50 I spent on my EV. It was designed for flooded
batteries, but I suspect that it would work fine on sealed batteries.
The fact that I have not had to add any water for months of daily use
would indicate that the seals on sealed batteries wouldn't be blown.



> <[email protected]> wrote:
> > I built a dumb charger using a pair of toroid transformer secondaries to
> > limit the peak current spikes. I am using a triac dimmer circuit to control the
> > output voltage/current. It works on 220VAC and 110VAC.
> ...


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## EVDL List (Jul 27, 2007)

How does one know when their snubber is working properly?

Lee Hart said...Another possibility: Triacs need a snubber circuit. This is 
usually a 
resistor and capacitor in series, connected directly across the triac's 
MT1 and MT2 terminals. A typical light dimmer circuit is intended for 
resistive loads like a light bulb, which need minimal snubbing; like 100 
ohms and 0.05uF. But for an inductive load like your big toroids, a much 
stronger snubber is needed; try 10 ohms 2 watts and 1uF.




Thank you,

Dave Delman
1981 Electric DeLorean Project
electricdelorean.com
http://evalbum.com/1482



**************It's only a deal if it's where you want to go. Find your travel 
deal here. 
(http://information.travel.aol.com/deals?ncid=aoltrv00050000000047)
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## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > How does one know when their snubber is working properly?
> 
> The parts don't blow up.
> ...


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## EVDL List (Jul 27, 2007)

> On 1 Sep 2008 at 13:12, storm connors wrote:
> 
> > To smarten the dumb charger, I have been pleased with Harry Landis
> > charge controller (described fully on my blog). I have since learned
> ...


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## EVDL List (Jul 27, 2007)

You've insisted before that the Landis controller doesn't work. If you
read the US Battery information they lead off with "There are many
ways to properly charge a battery." I can only report that after a
year of controlling my war surplus dumb charger with the Landis
controller:
-My batteries are in balance
-The pack reaches full charge
-It never overheats
-Although you think it is a bad thing, I haven't needed to add any
water for over 6 months.

I could babysit my charger and charge them "properly", but normal
distractions would lead to inattention which could cause irreversible
harm to the pack. The controller is a simple replacement for a timer
which eliminates the need to guess.

I thought I might end up extending the length of time it took to
charge the pack, but that does not seem to be the case.

No one else has suggested it, but I thought it might work for sealed
batteries because of this gentle treatment which results from only
charging for 5 minutes. How much damage could you do to a 500 pound
pack with 5 minutes of charging? (Assuming reasonable household amps.)

It isn't smart, but it seems to be smart enough.



> EVDL Administrator <[email protected]> wrote:
> > On 1 Sep 2008 at 13:12, storm connors wrote:
> >
> >> To smarten the dumb charger, I have been pleased with Harry Landis
> ...


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