HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 12, 2009, 06:38 AM
Registered User
roewe's Avatar
Joined May 2008
10 Posts
Help!
DC/DC Step up converter - 12V/48V @ 300-600w

Hello,

im looking for a DC/DC converter to step up the 12-14V from my car to 48V.
I will use it to charge my 12S A123 pack.
If the cut-off voltage is reached, round about 46V, the "DIY charge cut out" will cut off the pack from the converter.

The converter should have a P(out) of round about 500 watts (or 2* 300W). Is this possible to build, and does anybody have some information?

So it would be very easy and cheap to load a 12S A123 very fast.
Thanks a lot and...
best regards

Malte from germany



all information at one view:


- DC/DC converter
- 12V to 48V
- ~ 12A I(out) or 7A I(out)
- ~ 576W P(out) or 336W P(out)



edit: Can any mod transfer this thread in the DIY forum?
roewe is offline Find More Posts by roewe
Last edited by roewe; Dec 13, 2009 at 05:04 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 12, 2009, 07:10 AM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
3,045 Posts
You should try this in the DIY forum. That is were most of the electronic designs end up.

Highflier
highflier is offline Find More Posts by highflier
Reply With Quote
Old Dec 12, 2009, 08:02 AM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
13,148 Posts
That is going to be a somewhat expensive item. 48 volts at 500watts means the DC-DC step up converter will be drawing at least 40 to 45 amperes out of a 12vdc battery.
You are going to suck the power out of a 12vdc battery fast. You don't even want to leave the engine running on your car at that rate, it could overload the alternator.

Generally the solar power and wind generator users use something like this already.
Some new automotive applications use 48v too. I have seen some 100w boost converters from places like this: http://www.powerstream.com/dcdc.htm
Here is a short article from a wind generator person:
http://s4wsbox.com/?q=node/26
Now these guys happen to sell some 600w boost converters with 12v in and 48v out.
http://zahninc.com/su1.html?gclid=CN...FRQhnAod0nnGsA
earlwb is online now Find More Posts by earlwb
RCG Plus Member
Latest blog entry: My new Gaui X5 Rc Helicopter
Reply With Quote
Old Dec 12, 2009, 09:09 AM
jrb
Member
jrb's Avatar
Edina, MN, USA
Joined Oct 1999
11,430 Posts
What do you use at home?

When away from my Club's field and there's no AC, I power my MasTech 5020 via a Vector 2000W modified sine power inverter (has DC to DC unit inside!) running off my 2007 Explorer.

Here's a few threads with more info

http://www.rcgroups.com/forums/showp...74&postcount=5

http://www.rcgroups.com/forums/showp...2&postcount=59
jrb is offline Find More Posts by jrb
Reply With Quote
Old Dec 12, 2009, 10:03 AM
Registered User
roewe's Avatar
Joined May 2008
10 Posts
at home i have a lot of time and use my 270W Charger. So a "12V to 220V converter" would be not the only thing i would need. But thanks...

I would leave the engine running at loading my accu.
I mention that the alternator is a little bit biger than original and for 5 or 10 minutes, some times a week, i dont think that the alternator will be killed.

Thank you for the links, thats very intressting. My dream is, to build by own way But a cheap converter would be an alternative.

One question more: Is there a problem when ill use two 12V to 24V converter to use them in serie to get 48V?
roewe is offline Find More Posts by roewe
Reply With Quote
Old Dec 12, 2009, 11:02 AM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
13,148 Posts
Yes there is a problem in that normally that doesn't work as the power supply cases are grounded and thus you are likely to short everything out if you try to connect them up in series.
I vaguely remember something else, but I forget what the problem was at the moment.
earlwb is online now Find More Posts by earlwb
RCG Plus Member
Latest blog entry: My new Gaui X5 Rc Helicopter
Reply With Quote
Old Dec 12, 2009, 11:28 AM
Registered User
SteveM732's Avatar
United States, OR, Beaverton
Joined Feb 2008
1,976 Posts
Why not use four 3S packs? Then to charge put them in parallel and zip charge from a deep cycle battery. I do it all the time with a 9S setup that I have.
SteveM732 is offline Find More Posts by SteveM732
Reply With Quote
Old Dec 12, 2009, 12:46 PM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
13,148 Posts
I thought if a question. Who makes a 12s 500w LiPo battery charger?
That you would need a 48v DC source to feed it with.
earlwb is online now Find More Posts by earlwb
RCG Plus Member
Latest blog entry: My new Gaui X5 Rc Helicopter
Reply With Quote
Old Dec 12, 2009, 06:24 PM
Registered User
roewe's Avatar
Joined May 2008
10 Posts
nobody do this...

Hyperion built a 360W charger up to 10S.
So i would need one more charger... mh.
I know the problem by power supplies. But: It is a problem too, when a DC source (CarBattery) is used? I hope not but it seems so
roewe is offline Find More Posts by roewe
Last edited by roewe; Dec 12, 2009 at 06:32 PM.
Reply With Quote
Old Dec 13, 2009, 09:59 AM
jrb
Member
jrb's Avatar
Edina, MN, USA
Joined Oct 1999
11,430 Posts
I've shopped some links for Dc to DC in the past w/o luck based on voltage and price.

The MasTec was about the same price as anything I could find; and the Inverter can be used for many things!
jrb is offline Find More Posts by jrb
Reply With Quote
Old Dec 13, 2009, 01:39 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,812 Posts
This site has more buck / boost units than most but not cheap

http://www.powerstream.com/Wire_Size.htm

an example

http://www.powerstream.com/high-power-DCDC.htm
everydayflyer is online now Find More Posts by everydayflyer
Reply With Quote
Old Dec 13, 2009, 05:32 PM
Registered User
roewe's Avatar
Joined May 2008
10 Posts
Quote:
Originally Posted by jrb View Post
I've shopped some links for Dc to DC in the past w/o luck based on voltage and price.

The MasTec was about the same price as anything I could find; and the Inverter can be used for many things!
you are right....round about $300.
In germany a 900W power supply cost around $250 but..its not cheap
roewe is offline Find More Posts by roewe
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale MPI AC/DC Converter T_MECO Aircraft - Electric - Batteries & Chargers (FS/W) 0 Dec 10, 2009 10:26 AM
Sold TWINFLY AC/DC power converter 110-220AC to 12V DC 12.5 amp $35 shipped USPS ground be69ar Aircraft - General - Miscellaneous (FS/W) 3 Mar 10, 2009 05:26 PM
Discussion DC-DC step-up JF1980 DIY Electronics 3 Mar 07, 2009 09:34 AM
Wiring a DC-DC converter for 12v Camera! eyedoc Aerial Photography 8 Apr 02, 2004 04:33 PM
AC-DC Converter for 12V Charger Gerry Santos Power Systems 5 May 21, 2002 02:31 PM