Quote:
Originally Posted by RobertSmalls
"Meanwell RS-25-48 Switching Power Supply 25W, 48V, 0.57A"
That would give a 570mA charge rate, not 350mA, right? Which would mean you should be able to get a full charge in 12 hours or so.
MeanWell's largest RS-series power supply appears to be the 3.3A RS-150-48, $45 from Jameco.
Mike, how/when does your dual-rate charger switch from its fast rate to the 350mA rate?
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I had to read the site and this thread a few times myself because I was a little mixed up to. The power supplies can provide 570mA but they are constant voltage power supplies so they need to have their current limited because they won't do it themselves, instead they would overload and trip themselves off and would provide more than 570mA for the short period before they trip, possibly enough to cause some damage to the pack if the power supplies were larger or the overload goes well beyond their output rating before tripping. The charge rate comes from the constant current power supply that is in series with the other 3 constant voltage power supplies. Since they are in series the 350mA constant current supplies limit the current to the 350mA rate which is low enough to allow overcharge to not damage the cells provided that it isn't left on for too long after the whole pack is charged up. To have the higher rate, he takes the constant current supply that he has and connected it with another constant current supply that is rated to provide 700mA. So he can turn them both on and get 350+750mA = 1050mA (1.05 amps), or just one and get the 350 or 750mA.
...but to incorporate a larger constant current supply to be able to use higher than the 350mA you would need larger than the 570mA CV power supplies, or a daring nature to overload them to 700mA and possibly burn them up which could take the whole car. I checked and the CC power supplies come in 350mA 700mA and 1050mA for the ones that can provide up to 48 volts.
I was thinking of skipping the .57 amp supplies and going bigger but for the price I'll stay put and just get a 350mA CC supply for now to go with the cheap $20 ebay 4 pack. At 350mA they can more safely balance an out of balance pack but if I choose to go with a booster pack(or two), I might upgrade and get a 1050mA CC supply or two and larger 48v CC supplies when the time comes as long as I figure out the latching circuit that Mike is working out to drop it to 350mA to finish the charge safely. If I end up with a lithium PHEV system, depending on what I run into, I might work out an appropriate charger with these as I could setup a relay ramp-down for the current and termination when the pack reaches max charge voltage. Might be too much work though considering that ready made custom voltage 1500 watt chargers can be had for around $400 and I could work it into a BMS that would cut it off if something went awry with the charger.
