Rectified mains charge lead

NeilP

NeilP

1 GW
Joined
Nov 27, 2010
Messages
5,012
Location
49.17303, -2.05354 Jersey, Europe
In another thread, I saw mention of using mains power as a quick and dirty boost charge lead.

The idea seemed to be rectify the mains, and pass it through a halogen bulb to drop voltage and limit current . I am thinking that carrying halogen bulb is going to be a pain, and it is just going to get vibrated to bits, the filament just wont last

Am looking to charge 20s LiPo pack, so need 82 volts or so
Thinking may be half wave rectify to give a lower rectified voltage than full wave
Who els has done this ? What else is needed.. am working on 240 volt mains here in uk,not 120 so have more volts to loose than you guys is USA
 
Now you've gone off the deep end.. lol

EV car guys are doing this, they call it a 'bad boy charger'. Go google it.
 
Will do a google,
Am sure somone on here does it for a bike pack

Not looking to go to within a whisker of full charge with this, just to take a low ish 75 v pack back up to 80 or 8/ volt would be good, just a quick boost if I have opportunity
 
Seeing mention of using phase angle controllers..... I know I have a 3kW one down the farmmfrom the days when I tried a bit of distilling..... but the it suddenly starts getting bulky again and you are suddenly back up to a box the size of a Meanwell
 
amberwolf said:
As I am pretty sure I mentioned before, Liveforphysics does it; he's posted about it so you could search his posts. ;)
Click to expand...

If liveforphysics does it, it is ALWAYS a good idea :lol:
 
I'm going to be putting some information up soon on an open source charger, that uses a very powerful unisolated buck converter - target is 1500-2000W, to do it correctly requires some pretty high ripple current rated caps though, this is the sticking point at the moment.

Its actually designed for charging EV's (open circuit voltage will be regulated to 150V) but could be used for larger Lipo battery packs folks use here.

Also designed to be reasonably (!) safe and efficient.
 
Its my 1000w peak charger that weighs a few ounces.
 
Hehe, I'm thinking about making my next bike close to 415 V charge so I can use a 3-phase pair to bulk charge :twisted:
 
keep a small , hi power halogen lamp in your pocket?
i had a setup for this ,when i used lead.its in a box "somewhere"...
the " i i " below is a mains jack. the brackets are a rectifier bridge.
mains plug,rectifier,outlet box,and battery plug(HUBBELL)...
the outlet box as a switch/breakout....a plug if i was using a regulated supply,
and a plug to screw-in lamp device ,or ammeter....
(direct,lamp-limited,or monitored.)

<-------------------[~ +]----------(i i)----------->to pos batt lead
line power input!
<-------------------[~ -]------------------------->to neg batt lead

at the time i was using stage lamps,some kilowatt types!
i had seen this in an audels book,for use on the farm 70 years ago.
(different rectifiers though)
it was one of my favorite books when i was a kid , in the 60s,and 70s.

it cant easily be calculated,so you start with a smaller bulb,and like an led,do not forget the
voltage of the "load".
this is not safe for anyone,and if you do this you should have your battery
DISCONNECTED FROM ALL OTHER CIRCUITS.
the device was 1 lb,and i was commuting 4 miles...this way,i could
"take the long way home"....

today,i would use a cap,in place of the lamp,did i read somewhere(here?),
that 24 uf is roughly 1 ampere.......?
reactance can run COLD.....not the same as a lamp.....
cant you use a line and ground in your system ? seems you could have a deluxe
2 settings version!
 
probably not as simple over here in UK

We have 240 v mains, so rectify that and the dc volts will be up to ... errrr 1. times is it ? RMS and all that
So 340 volt or so, down to 84 or so, that is lots of volts to drop
 
Found this while researching dirty chargers:
http://itee.uq.edu.au/~mmme2104/Lecture%209%20-%20Power%20electronics.pdf

Very nice little summary of single and three-phase AC-DC rectifiers, DC-AC inverters, PWM, DC-DC converters etc. :mrgreen:
 
Hey, I charge at 425 Volts every day off a 120 volt mains on my TWIKE. It was designed for 240v mains from Europe and was converted to 120v by using a 1-2 step up transformer (internally mounted) but with a bit of work, I can put in a J1772 and charge faster off the free chargers going up all around here in Portland. I can easily pull enough amps to pop a 20 amp breaker on 120v (it is adjustable from the keypad). I can fully charge in 2 hours though which helps.
 
NeilP said:
probably not as simple over here in UK

We have 240 v mains, so rectify that and the dc volts will be up to ... errrr 1.3 times is it ? RMS and all that
So 280 to 300 volt, down to 84 or so, that is lots of volts to drop
Click to expand...

You've got 240v lightbubs still. This means its equally easy, just a little less efficient (which doesn't matterfor a dirty power stealing charger)
 
Well yes, as long as i can drop the voltage ...but the idea of having to carry a halogen lamp around...I can see that as being more agro than carrying a meanwell around. Probably end up with a broken filament by the time you come to actually use it ..the bulb idea does not do it for me..if the filament does not get trashed, then sure the glass itself will get smashed
 
I'm sure you could use something else that is not as breakable, such as a travel hair dryer or other small device.

What if you mounted the halogen on the bike for a source of light while dirty charging in the dark?

Good luck!
 
neobeam said:
keep a small , hi power halogen lamp in your pocket?
i had a setup for this ,when i used lead.its in a box "somewhere"...
the " i i " below is a mains jack. the brackets are a rectifier bridge.
mains plug,rectifier,outlet box,and battery plug(HUBBELL)...
the outlet box as a switch/breakout....a plug if i was using a regulated supply,
and a plug to screw-in lamp device ,or ammeter....
(direct,lamp-limited,or monitored.)

<-------------------[~ +]----------(i i)----------->to pos batt lead
line power input!
<-------------------[~ -]------------------------->to neg batt lead

at the time i was using stage lamps,some kilowatt types!
i had seen this in an audels book,for use on the farm 70 years ago.
(different rectifiers though)
it was one of my favorite books when i was a kid , in the 60s,and 70s.

it cant easily be calculated,so you start with a smaller bulb,and like an led,do not forget the
voltage of the "load".
this is not safe for anyone,and if you do this you should have your battery
DISCONNECTED FROM ALL OTHER CIRCUITS.
the device was 1 lb,and i was commuting 4 miles...this way,i could
"take the long way home"....

today,i would use a cap,in place of the lamp,did i read somewhere(here?),
that 24 uf is roughly 1 ampere.......?
reactance can run COLD.....not the same as a lamp.....
cant you use a line and ground in your system ? seems you could have a deluxe
2 settings version!
Click to expand...

Could you post some pictures of your charger? At 24uF 1amp seems a lot. What input voltage do you have and what's your battery voltage?
 
i cant,it was just a harness i built at a lab.
but at 60 hz,i get "Xc" of 110 "ohms".
in this case at a 110 line you get 1 amp thru(maximum) for a series cap placed in the input of a bridge rectifier.

i.e. series cap
--------------)i---------[~ +]------------------->
[ bridge ]
-------------------------[ ~ -]--------------------->


if this cap is 24uF,then never can more than 1 amp flow..RMS!
if you know the load is 50 volts it will be less,(there is only 60 volts difference)
60 volts/110 Ohms=etc
but if you need to "add some" charge ....it will work....
I was using a common outlet,and would have used a cap if i had
thought about it!
the lamp got very hot,caps will not.

here,the first and second circuit are the basis of my assumption.
http://www.bowdenshobbycircuits.info/page10.htm#lineled.gif
i love this stuff ,and tho it could not pass any standards testing ....
i have a rep for this kinda thing!
LOL...
 
Doesn't the pulsating current damage the battery? I know the internal resistance of Lipo is very low, so the voltage fluctuations are minimal, but at 50 or 60Hz that could be a factor...
 
It can damage them - the noise you hear in the cells when charging with pulsating DC is the plates deforming.

I've heard similar noises from capacitors before dying under extreme conditions (like when somebody parallels too many W bins onto a PA amp, and you could hear the bass in the capacitors - this was on a ~5Kw amp though).
 
So how does the theory of 'Pulse charging ' fit in to this?
I had heard about it but not read up, so it is just words to me..
 
Two new threads on this:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=31384
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=31428
 
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