I already have a 300ma charger with adjustable voltage to set the current anywhere I want. But this deal of four power supplies for $25 is too good to pass up, so I ordered the set of 4. Now I will figure out how to use them.
__________________
Jim Isbell
2000, 5 speed, 250,000 miles
"If you are not living on the edge, well then,
you are just taking up too much space."
Does anyone know where I can buy a LPC-20-350 power supply? Jameco will be out of stock until the end of April. Peak to Peak has a $50 min. order and I already got the e-Bay deal.
If three of us have the same problem maybe one of us could buy 3 from Peak to Peak and sell the 2 extra to the other 2 guys?
Last edited by JuiceMcGoose; 03-16-2010 at 08:08 PM.
I plan on connecting all four of the power supplys in series and setting them to the minimum setting of 42 volts which would then give you 168 volts for the charger with a current capability of 570ma. If the initial charge is from a very low battery that might streach the current capability. but I think a switched in and out series resistor or a variac feeding the power supplys could solve that until you get the battery up to 155 or so. Then after the current drops as you approach 168 volts, just adjust one of the supplys upward to maintain the current until charged. Just adjusting one of them, and leaving the other three at the minimum of 42 volts, would allow you to get the voltage up to 180 volts which is MORE than enough.
If you go the variac route then all you need to do is set them all at 48V or thereabouts and use the variac to lower or raise the output.
When I do this with my present supply I find that I dont have to change the voltage setting at all from bottom to top and the current stays about 200 to 300 ma. So I am not expecting to have a bit of adjusting to do if I just set the power supplys to deliver 173 to 175 volts ALL THE TIME and just monitor the current for my own curiosity.
__________________
Jim Isbell
2000, 5 speed, 250,000 miles
"If you are not living on the edge, well then,
you are just taking up too much space."
The Meanwell supplies are output voltage regulated over a 90-250VAC input range, so the variac will not work, but Jims other technique was what Peter did on his first grid charger. The resistor will need to have some power dissipation 10-25W, and that will all be lost as heat, so the charge efficiency will be poor.
The advantage of the LPC-20-350 is that it is efficient, and does not need adjustments after the initial setup.
My battery testing is showing me that in an unbalanced subpack, the best cell may reach the delta V full charged point several AH before the weakest cell will get there, so having the charge rate decrease as the fully charged point approaches could really stretch out that balancing time, thus the 350MA CC.
I have had to put as much as 9AH into a subpack to get it charged fully for the first time. At 350ma, that could take several days.
My test are done with 4-6A charge rate, and I still see as much as 20 minutes for the last cell to reach delta V after the first has done so, and this is only 6 cells.
Running the battery fans during the topping stage is a good idea, as when all the cells are full, all of the input energy is going to heat.
I buy my power supplies from Powergate, and even if they have no stock, it usually only takes a week.
I ordered from TRC Electronis. It was about $30 with shipping. $16.57 plus $5 handling plus $8.50 shipping.
I was about half way through the ordering process when up pops the warning that they do not sell retail. I typed in the name of the company that I work for, in the Company name field, with my home address in the address field. I assume in your case that would be Juice Goose Enterprises.
I too will have an extra RS-25-48. Mike (and many others) has contributed so much to this board, I think I will put mine in an evelope and mail it to Mike. Otherwise, it will go to waste. Mike, what is your address?
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2000 MT 146,000 miles
Bought 1/23/2010
I jumped on 2X of the 4 ea deal this weekend. I'm not exactly sure how I will implement them yet. One consideration is one charger per pack, current limited using the LM317HVs like with my variac charger. Just unsure if I will use 3 or 4 of the ebay special power supplies or if I will use 3 and a third current limit supply like Mike suggests.
Btw, quickly approaching the 2 year mark on plugin charging. That will make ~600 full cycles and no issues to date. Mpgs will also be going up as I am moving and will have a 30 mile daily commute vs my current 2 mile commute.
In the future, for anyone looking at this thread later, do a search for this supply misspelled as SR-25-48 and in case he ever corrects the mistake or he isn't selling them, the correct spelling is RS-25-48.
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