Jeremy Harris
100 MW
I've just found these on eBay: http://cgi.ebay.com/SynQor-PQ48050QNA20NNS-DC-DC-Converter-48V-5V-Out-/380224535349?pt=LH_DefaultDomain_0&hash=item588725fb35 They look interesting for building fairly high current (20amp) LiPo balance chargers.
The spec on these SynQor converters is more interesting than most, as the trim down range is 20%, meaning that they'll go from a nominal 5V out to 4V. This looks to make them ideal as LiPo charge modules. They are isolated, so you can hook a load of them up to a big 48V DC supply and charge as many cells in a pack at once as you like.
The crude and simple way to stop them going into current limiting with a near-flat cell is to just fit a low value resistor (something like 0.1 ohm) in the output lead. This will add enough of a volt drop to limit the maximum current to under the 20 amp rating for a cell that's right down at around 2.2V (with the DC DC converter set to 4.2V output voltage).
I've just bought a bunch of these to build a kick-ass charger. I'll keep people posted as to how they work out (as I've had mixed experiences with DC DC converters in the past - some work great, others are not so good).
The data sheet link is here, if anyone's interested: http://synqor.com/datasheets/PQ48050QNA20_Datasheet.pdf
They'll need fan cooling for sure, but that shouldn't be too big a problem. A 350 watt, 48V Meanwell would run maybe three of these, so it looks like I'll have to get some bigger PSUs. Luckily, there's some rather affordable 500W ones here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380071301709&ssPageName=STRK:MEWAX:IT and the chap is only an hours drive away, so I can save on postage. To charge my proposed 15S pack I think I'll need three or four of these, with 15 DC DC converters. A 1500 watt charger should do the job nice and quickly..........................
Jeremy
The spec on these SynQor converters is more interesting than most, as the trim down range is 20%, meaning that they'll go from a nominal 5V out to 4V. This looks to make them ideal as LiPo charge modules. They are isolated, so you can hook a load of them up to a big 48V DC supply and charge as many cells in a pack at once as you like.
The crude and simple way to stop them going into current limiting with a near-flat cell is to just fit a low value resistor (something like 0.1 ohm) in the output lead. This will add enough of a volt drop to limit the maximum current to under the 20 amp rating for a cell that's right down at around 2.2V (with the DC DC converter set to 4.2V output voltage).
I've just bought a bunch of these to build a kick-ass charger. I'll keep people posted as to how they work out (as I've had mixed experiences with DC DC converters in the past - some work great, others are not so good).
The data sheet link is here, if anyone's interested: http://synqor.com/datasheets/PQ48050QNA20_Datasheet.pdf
They'll need fan cooling for sure, but that shouldn't be too big a problem. A 350 watt, 48V Meanwell would run maybe three of these, so it looks like I'll have to get some bigger PSUs. Luckily, there's some rather affordable 500W ones here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380071301709&ssPageName=STRK:MEWAX:IT and the chap is only an hours drive away, so I can save on postage. To charge my proposed 15S pack I think I'll need three or four of these, with 15 DC DC converters. A 1500 watt charger should do the job nice and quickly..........................
Jeremy