# battery charger



## otp57 (Feb 7, 2012)

Have any one use this type of charger?
http://www.e-volks.com/capacith_charger.html
It is a good way to charge ?????????????????


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## otp57 (Feb 7, 2012)

otp57 said:


> Have any one use this type of charger?
> http://www.e-volks.com/capacith_charger.html
> It is a good way to charge ?????????????????


Ok have anyone use a charger like this.??????


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## major (Apr 4, 2008)

otp57 said:


> Ok have anyone use a charger like this.??????


Dude,

Maybe you're trying to go the cheap route, but be smart about it. This thing looks like crap. I can't believe some place is actually selling it. Stay away from it. Anything you plug into the wall (120 Volt AC utility power) has the potential for damage to you and your property and others. It can kill you or burn your house down. Get products with a known track record or the UL certificate.

major


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## otp57 (Feb 7, 2012)

major said:


> Dude,
> 
> Maybe you're trying to go the cheap route, but be smart about it. This thing looks like crap. I can't believe some place is actually selling it. Stay away from it. Anything you plug into the wall (120 Volt AC utility power) has the potential for damage to you and your property and others. It can kill you or burn your house down. Get products with a known track record or the UL certificate.
> 
> major


Ok but the only way to learn is to ask???? and now I know.


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## PStechPaul (May 1, 2012)

Only about 400W, and it's still $300! Definitely not isolated. And it might give a 1000A surge into the batteries when you plug it in. This would use about a 165 uF capacitor rated at 125 VAC, and a bridge rectifier. The capacitor might be about $12:
http://www.mouser.com/ProductDetail/Cornell-Dubilier/PSU13015/?qs=vqCChdBZyfj9oOusCKfquouIgzJJK4Sh


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## otp57 (Feb 7, 2012)

PStechPaul said:


> Only about 400W, and it's still $300! Definitely not isolated. And it might give a 1000A surge into the batteries when you plug it in. This would use about a 165 uF capacitor rated at 125 VAC, and a bridge rectifier. The capacitor might be about $12:
> http://www.mouser.com/ProductDetail/Cornell-Dubilier/PSU13015/?qs=vqCChdBZyfj9oOusCKfquouIgzJJK4Sh


I think I will stay with normal system for charging.


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## ricklearned (Mar 3, 2012)

PStechPaul said:


> .........Definitely not isolated........


And it doesn't have a 3 prong plug. I can't tell, is that two prong plug polarized?


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## otp57 (Feb 7, 2012)

ricklearned said:


> And it doesn't have a 3 prong plug. I can't tell, is that two prong plug polarized?


 that thing don't look safe


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## ricklearned (Mar 3, 2012)

It is also housed in the same plastic box that I purchased at Home Depot or Lowes. I used it for my solar connections. I would also aprefer a more accurate digital display of voltage, especially when charging Lifepo's


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## PStechPaul (May 1, 2012)

If you are willing to pay $5000 or more for batteries, it doesn't make sense to skimp on the charger, which could damage the cells. Actually it's probably not a big deal for the charger not to be isolated, especially if the common side is neutral, and if the charger is on a GFCI. It might also depend on how the batteries ar connected in the EV. If everything there is isolated, it won't be a problem. You shouldn't touch the electrical connections anyway, but if there is a connection to the vehicle frame, that could be a problem, although the GFCI would render it fairly safe.

I came up with a simple linear charger circuit that is designed to be connected directly to the AC line or even better to a variable transformer. The power in the series regulator can be reduced by adjusting the DC input to just above the float voltage. It provides a constant charge of about 8 amps into a 100V battery pack discharged to 80V as represented by the load side 80V battery and a 10F capacitor to allow the simulation to show a 28 second charge time. The battery voltage rises smoothly to 110V, and then drops to a float voltage of 100V, with a minimal residual current of 29mA. With some simple switching technology the same principle could be made much more efficient. In this case the series pass transistor Q3 dissipates up to 320W.


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## major (Apr 4, 2008)

ricklearned said:


> It is also housed in the same plastic box that I purchased at Home Depot or Lowes. I used it for my solar connections. I would also aprefer a more accurate digital display of voltage, especially when charging Lifepo's


Here's one with a digital display. http://www.ebay.com/itm/Capacitive-...15960?pt=Battery_Chargers&hash=item35b8792d98 

How can people sell crap like this


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## DJBecker (Nov 3, 2010)

major said:


> Here's one with a digital display. http://www.ebay.com/itm/Capacitive-...15960?pt=Battery_Chargers&hash=item35b8792d98
> 
> How can people sell crap like this


At least that one is in an honest wooden box. Looks like a grade above discarded pallet wood, and with screws rather than nails for extra strength. 

That meter is a Harbor Freight one. There are sometime coupons to get them for free, but you usually have to pay $2.99 or $3.99.

I'm only a little nervous about the exposed surfaces of the battery clamps. Not too nervous. Most of the time you'll be touching it with dry skin. It's not like there is a label "lick here".


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## PStechPaul (May 1, 2012)

Actually using capacitors may not be such a bad idea. You can make a voltage doubler which will produce a current-limited source of 300 VDC from a 120 VAC source, and it will generate virtually no heat even when the output is shorted. The biggest issue is power factor, and also there needs to be an active current limiter which absorbs the inrush when it's plugged in, or when there are power line transients. Here is a simple circuit that draws 15A from the 120 VAC power line and produces 1kW at about 250VDC into a 60 ohm load, at better than 95% efficiency:










It draws 36 amp peak current so PF = 1000/(36*120) = 0.23 but maybe that's not such a big problem for a simple home charger.

With the output shorted (well, a 1 ohm load), it draws 110 amps which is just enough to trip the breaker safely. Even under those extreme conditions it still puts 11kW into the 1 ohm load at 90% efficiency.

The only real expense is two motor capacitors which are $25 each:
http://www.mouser.com/ProductDetail...=0r35cIPu56F5iTigWzWS0ykKarYByq2vK69Bm8QjVjQ=

It's not isolated but a GFCI should make it touch safe.


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## otp57 (Feb 7, 2012)

PStechPaul said:


> Actually using capacitors may not be such a bad idea. You can make a voltage doubler which will produce a current-limited source of 300 VDC from a 120 VAC source, and it will generate virtually no heat even when the output is shorted. The biggest issue is power factor, and also there needs to be an active current limiter which absorbs the inrush when it's plugged in, or when there are power line transients. Here is a simple circuit that draws 15A from the 120 VAC power line and produces 1kW at about 250VDC into a 60 ohm load, at better than 95% efficiency:
> 
> 
> 
> ...


That very good thanks 
I will have to play with this.


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## njloof (Nov 21, 2011)

DJBecker said:


> I'm only a little nervous about the exposed surfaces of the battery clamps. Not too nervous. Most of the time you'll be touching it with dry skin. It's not like there is a label "lick here".


I use these on any equipment that warrants it:

http://www.ee0r.com/donotlick.pdf


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## otp57 (Feb 7, 2012)

njloof said:


> I use these on any equipment that warrants it:
> 
> http://www.ee0r.com/donotlick.pdf


I kile that....LOL


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