a DC-DC to charge li-ion... GREAT!!

[frodus]

i keep looking for something smaller or something more sealed... might have to build it

 

[317537]

http://www.ebay.com.au/itm/DC-DC-Converter-75W-48V-5V-15A-JW075A1-Qty-3-/370227871055?pt=LH_DefaultDomain_0&hash=item56334cfd4f

Not sure if these have been posted, Ive been sent here from another thread.

This one for may be good for lipo's 5v @ 15amps. 3 * DC converters for $25USD each lot making them around $8.30USD each, Has a 40% trim down capability.


http://datasheet.octopart.com/JW075A1-Lucent-datasheet-10725116.pdf

40% should be adequate for most LI apps

To provide protection in a fault (output overload) condition,
the unit is equipped with internal current-limiting
circuitry and can endure current limiting for an unlimited
duration. At the point of current-limit inception, the
unit shifts from voltage control to current control. If the
output voltage is pulled very low during a severe fault,
the current-limit circuit can exhibit either foldback or tailout
characteristics (output current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.

Looks Good to me for Lipo as the voltage aint going to get pulled down too much anyway.. These converters are usually very reliable in so many situations.
If one can get something that can handle over 25 amp to the paralleled DC converter inputs, EG a welder trasnformer, there is no reason these DC converter wont work for high current battery chargers.

 

[317537]

I Picked up an old AC welder for a song that can do 48v @ 80 amps with no sweat, you just need to rectify it. Those 3.3v and 5v DC conveters work most efficient at 36v anyway

You can controll the current on welder transformers just fine to over 120 amps..

The above pic is a DC welder. But you could do an AC welder cheaper and some 60 amp rectifiers and big caps, Mwahahahah.

 

[317537]

http://www.ebay.com.au/itm/IGBT-ZX7-200-DC-INVERTER-MMA-ARC-MACHINE-manual-welder-/310283616856?pt=AU_Welding&hash=item483e584258

For a main PSU people who dont want to put too much into the work, $160 for a 10A to 200A adjustable DC supply @ 67v @ no load. Limit to 24A and load it up it will Vdrop on the output nice.

 

[megacycle]

I Picked up an old AC welder for a song that can do 48v @ 80 amps with no sweat, you just need to rectify it. Those 3.3v and 5v DC conveters work most efficient at 36v anyway

You can controll the current on welder transformers just fine to over 120 amps..

The above pic is a DC welder. But you could do an AC welder cheaper and some 60 amp rectifiers and big caps, Mwahahahah.

Could quite a few of those little critters possibly live inside that case
Or would there be space cooling issues, could make a nice integrated charger/welder
Was your thoughts going that way with that lid off nice lot of space.

 

[bzhwindtalker]

I would like to find lower powered ones, like 5-10w per, at a very low price. Someone has an idea?

 

[splash]

There are lots of adjustable dc to dc converters on ebay from china. Also there are power supplys 120vac to 12 vdc to drive the dc-dc modules. They are not expensive. I think I may build one. A charge rate of 2 amps is plenty...even 1 amp. Also will need an 18 pin connector...male and female. For over discharge protection...I can set my cycle analyst to limit current at any set voltage. In my case i set it for 43 volts (48v battery)
Splash

 

[megacycle]

Think might as well get an ac/dc to 5v and cut out the middle stage.
Losses n1 x n2 equals 70ish %.
One times big PSU.

 

[splash]

120vas to 3.6 vdc ? ........looked on ebay....could not find any.

 

[fechter]

There are lots of adjustable dc to dc converters on ebay from china. Also there are power supplys 120vac to 12 vdc to drive the dc-dc modules. They are not expensive.

Most of the adjustable dc-dc converters on eBay are not isolated, so won't work for pack charging. I'd like to find some cheap isolated ones. Even 500mA or 1A would be great for pack balancing.

 

[megacycle]

Found a 200W@3.3V, how many amps do you need. Obviously could look at 5V's might be more available.
http://www.aliexpress.com/fm-store/403243/211495926-546863944/Genuine-MeanWell-Mean-Well-MW-3-3V-60A-198W-Regulated-AC-DC-Switching-Power-Supply-NES.html.