Battery charging circuit

[Damn Dan]

(snip)


Wouldn't an external charger be the way to go in any case? In other
posts you've mentioned that 1) driving to work consumes 10% of the
battery charge, and 2) when the battery goes below 50%, the car starts
recharging it, reducing your gas mileage. From this, it seems the solar
panel is an unnecessary complication -- if you can make a round trip
commute to work with only 80% loss, you're not triggering the recharge
cycle, so why not just top off the battery at home every night from a
wall socket and forget about fickle and expensive solar panel?

Meet the pseudo-environmentalist in me. I like the thought that the energy
I'm using to charge the battery is completely renewable. Besides, solar
panels are just way cooler than wall sockets.

(Don't bother yelling at me about how much energy and resources solar panels
take to make... I know my logic is flawed, but hey, I'm having fun right?)

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

(snip)


Wouldn't an external charger be the way to go in any case? In other
posts you've mentioned that 1) driving to work consumes 10% of the
battery charge, and 2) when the battery goes below 50%, the car starts
recharging it, reducing your gas mileage. From this, it seems the solar
panel is an unnecessary complication -- if you can make a round trip
commute to work with only 80% loss, you're not triggering the recharge
cycle, so why not just top off the battery at home every night from a
wall socket and forget about fickle and expensive solar panel?

From what I've read, the all electric vehicles have to have a massive,
special charger installed at your home. That's not cheap, something
like $5k, plus you then have to pay for the electricity.

 

[Clarence]

From what I've read, the all electric vehicles have to have a massive,
special charger installed at your home. That's not cheap, something
like $5k, plus you then have to pay for the electricity.

Really?
Why so much?
A 200 Amp 12 Volt Charger can be bought new for $120.00

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

message
Really?
Why so much?
A 200 Amp 12 Volt Charger can be bought new for $120.00

Well, for one thing, if one expects to get up in the morning and find
his car fully charged, it will have to be higher capacity than that.
And we're discussing about battery voltages closer to 200VDC.

Remember that we're talking about all electric vehicles. I.E. a 5 or6
kVA charger. http://www.autoworld.com/news/Toyota/RAV4_EV.htm

 

[William P.N. Smith]

A 200 Amp 12 Volt Charger can be bought new for $120.00

Really, where? Or are we talking about a battery booster at the local
gas station to dump some uncontrolled charge into the battery?

 

[William P.N. Smith]

I'll probably try charging the battery once
without waking up the BCM and see what happens. The worst it'll do is

.... confuse the onboard computer as to the state of charge of the
battery and cause it to overcharge it significantly, reducing it's
lifetime while voiding the warranty. 8*|

 

[William P.N. Smith]

Good point. I'm definitely going on faith that the many onboard sensors
(serveral voltage, current, and temperature sensors) will pick up the change
and react accordingly.

NiMH batteries have a very flat SOC/Voltage curve...

 

[Clarence]

Really, where? Or are we talking about a battery booster at the local
gas station to dump some uncontrolled charge into the battery?

I did a Google search, there were many hits and the one I priced as an example
was a 'three level' charger with a 500 Amp "booster" mode for starting.

There were 47,800 hits for a 200 Amp Charger and many were duplicates.
I am sure that many were the gas station variety.
The one I priced was among the cheapest, but there were MANY more to choose
from.

 

[Clarence]

Well, for one thing, if one expects to get up in the morning and find
his car fully charged, it will have to be higher capacity than that.
And we're discussing about battery voltages closer to 200VDC.

Remember that we're talking about all electric vehicles. I.E. a 5 or6
kVA charger. http://www.autoworld.com/news/Toyota/RAV4_EV.htm

WOW, quite a hit on the electric bill if you charge for 10 hours a night.

 

[Ross Herbert]

|
|I live in Arizona. If you do a little research, you'll find that the
|Southwest receives some of the highest solar energy per square foot in the
|country. The change of seasons and weather do not change the ambient solar
|energy all that much around here.
|
|My hybrid battery has a mere 6.4Ah capacity. The internal circuitry limits
|the available capacity to the middle 60%, thus there is a realistic capacity
|of 3.84Ah. On my drive to work, I use between 5-10% of that capacity.
|That's .384Ah. By keeping my battery charged, I prevent the electric
|generator from sipping energy off of my forward momentum to recharge the
|battery. I have calculated through observation that I get about 10mpg less
|when the battery is charging itself while I drive. So yes, acheiving .384Ah
|a day will save a lot of gas.

It would perhaps have saved some misunderstanding all around if the
above information had been included in the first post... It is
difficult to make suggestions with none of the important information
being provided.

 

[Damn Dan]

|
|I live in Arizona. If you do a little research, you'll find that the
|Southwest receives some of the highest solar energy per square foot in the
|country. The change of seasons and weather do not change the ambient solar
|energy all that much around here.
|
|My hybrid battery has a mere 6.4Ah capacity. The internal circuitry limits
|the available capacity to the middle 60%, thus there is a realistic capacity
|of 3.84Ah. On my drive to work, I use between 5-10% of that capacity.
|That's .384Ah. By keeping my battery charged, I prevent the electric
|generator from sipping energy off of my forward momentum to recharge the
|battery. I have calculated through observation that I get about 10mpg less
|when the battery is charging itself while I drive. So yes, acheiving ..384Ah
|a day will save a lot of gas.

It would perhaps have saved some misunderstanding all around if the
above information had been included in the first post... It is
difficult to make suggestions with none of the important information
being provided.

In general, I fully agree, but a complete description of my project wasn't
the intention of my original post. I gave a very broad description in the
beginning just to familiarize the reader with the general concept of what I
was doing. Then I asked one specific question at the end (about two sources
interacting in the same circuit), which was the whole purpose of the post.
If people want to discuss other aspects of the system, that's wonderful and
I look forward to reading their replies. But I feel Mike quickly and
harshly judged my post without bothering to gather the facts he was missing.
His sarcasm was directly aimed at making me look like an idiot, and I didn't
appreciate that, especially since the majority of his points were based on
assumptions. I feel my response to him was an appropriate response based on
the tone of his post.

 

[Ross Herbert]

In general, I fully agree, but a complete description of my project wasn't
the intention of my original post. I gave a very broad description in the
beginning just to familiarize the reader with the general concept of what I
was doing. Then I asked one specific question at the end (about two sources
interacting in the same circuit), which was the whole purpose of the post.
If people want to discuss other aspects of the system, that's wonderful and
I look forward to reading their replies. But I feel Mike quickly and
harshly judged my post without bothering to gather the facts he was missing.
His sarcasm was directly aimed at making me look like an idiot, and I didn't
appreciate that, especially since the majority of his points were based on
assumptions. I feel my response to him was an appropriate response based on
the tone of his post.

I wasn't making any comment on your response to Mike since I would
probably have done the same were I in your shoes. It's just that when
it comes to asking for advice on complex subjects such as battery
charging the first thing anyone giving advice wants to know is "how
big is the battery (capacity) and how quick do you want to charge it?"
and that info is most useful when supplied in the original post. Some
people may not be familiar with the equipment in which the battery is
used either so that makes it a little more difficult as well.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

is

... confuse the onboard computer as to the state of charge of the
battery and cause it to overcharge it significantly, reducing it's
lifetime while voiding the warranty. 8*|

If the subject is a personal pronoun (him, her, it, you, me, them), no
apostrophe is used.
http://tranchant.plus.com/notes/apostrophe

I enjoy reading your posts and I'm not trying to pick on you, I'm just
trying to show how easy it is to remember a simple rule. Thanks.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

NiMH batteries have a very flat SOC/Voltage curve...

Well, the cheap ones I got from Fry's and other stores don't seem to
discharge without a significant V drop. But then I don't use them to
run my vehicles.

 

[Clarence]

If the subject is a personal pronoun (him, her, it, you, me, them), no
apostrophe is used.
http://tranchant.plus.com/notes/apostrophe

I enjoy reading your posts and I'm not trying to pick on you, I'm just
trying to show how easy it is to remember a simple rule. Thanks.

Actually he likes to pick on everyone, so don't feel your being singled out for
special treatment. After a while you learn to ignore him!

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

I did a Google search, there were many hits and the one I priced as an example
was a 'three level' charger with a 500 Amp "booster" mode for starting.

There were 47,800 hits for a 200 Amp Charger and many were duplicates.
I am sure that many were the gas station variety.
The one I priced was among the cheapest, but there were MANY more to choose
from.

We had an electric vehicle "golf cart" at work for a year, and I read
the manual for it. They esxplained that the three pronged plug had one
pin for the onboard computer to control the charger. This was for a
48VDC lead acid system. So the trend today seems to be towards more
intelligent chargers, and hence the higher prices.

Interestingly, the book also explained that when the yellow "low
battery" light on the dash lit up, you had two hours or 36 holes of
golf left(!) )

 

[Clarence]

We had an electric vehicle "golf cart" at work for a year, and I read
the manual for it. They esxplained <typo?> that the three pronged plug had one
pin for the onboard computer to control the charger. This was for a
48VDC lead acid system. So the trend today seems to be towards more
intelligent chargers, and hence the higher prices.

Interestingly, the book also explained that when the yellow "low
battery" light on the dash lit up, you had two hours or 36 holes of
golf left(!) )

Having designed some chargers for Golf carts and fork lift trucks, I can tell
you that More intelligent does not mean more expensive. My last design was one
third the cost to build for the simple single control unit it replaced.

 

[Damn Dan]

I wasn't making any comment on your response to Mike since I would
probably have done the same were I in your shoes. It's just that when
it comes to asking for advice on complex subjects such as battery
charging the first thing anyone giving advice wants to know is "how
big is the battery (capacity) and how quick do you want to charge it?"
and that info is most useful when supplied in the original post. Some
people may not be familiar with the equipment in which the battery is
used either so that makes it a little more difficult as well.

Granted, but like I said, I made the original post to get one specific
question answered (regarding multiple sources in the same circuit). I
honestly thought the thread wouldn't turn into more than 3 or 4 posts at
most. I've been pretty thrilled by the discussion it has produced, though.
It was unexpected.

 

[William P.N. Smith]

"Watson A.Name - \"Watt Sun, the Dark Remover\""

I enjoy reading your posts and I'm not trying to pick on you, I'm just
trying to show how easy it is to remember a simple rule. Thanks.

The rule I've never been able to figure out is "Does Anal-Retentive
have a hyphen?"

Thanks for your input.

 

[William P.N. Smith]

"Watson A.Name - \"Watt Sun, the Dark Remover\""

We had an electric vehicle "golf cart" at work for a year, and I read
the manual for it. They esxplained that the three pronged plug had one
pin for the onboard computer to control the charger. This was for a
48VDC lead acid system. So the trend today seems to be towards more
intelligent chargers, and hence the higher prices.

I've got two 48V Club Car golf carts, and the "intelligence" in the
charger is the relay on the end of that third pin. The onboard
computer on the golf cart watches battery voltage and current {into,
out of} the battery pack, and adjusts the "automatic" charge cycle
accordingly.

Strangely, the price of these 48V, 20A chargers (transformer,
half-wave bridge, 'magnetic' ammeter, connectors) is on the order of a
buck a watt! Unfortunately, the 200A, 12V charger isn't real...