Has anyone tried these out yet, Do they need fan cooling at full spec output? I am thinking of putting 4 of them in series across the battery (Iam assuming that when turned off they do not present a load to the battery) in the Insight and running an AC plug out the back with a relay the turns on the battery fan anytime 120V is applied to the power supply inputs. I will just set them to 43 + or - volts each and let the current fall where it may. When I use 172volts on my my present charger the current stays below 400 ma so I shouldnt need any current limiting at all. I might have to play with the adjustments a bit, but Ill bet I can set them where they dont exceed 570 ma under any conditions...except a bad battery.....thats what fuses are for..... If they can cool satisfactorily I can mount them inside the battery compartment (they are so small it wont take any space to speak of) along with the relay and have only a coiled AC cord out the back. What a deal.
__________________
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."
Has anyone tried these out yet, Do they need fan cooling at full spec output? I am thinking of putting 4 of them in series across the battery (Iam assuming that when turned off they do not present a load to the battery) in the Insight and running an AC plug out the back with a relay the turns on the battery fan anytime 120V is applied to the power supply inputs. I will just set them to 43 + or - volts each and let the current fall where it may. When I use 172volts on my my present charger the current stays below 400 ma so I shouldnt need any current limiting at all. I might have to play with the adjustments a bit, but Ill bet I can set them where they dont exceed 570 ma under any conditions...except a bad battery.....thats what fuses are for..... If they can cool satisfactorily I can mount them inside the battery compartment (they are so small it wont take any space to speak of) along with the relay and have only a coiled AC cord out the back. What a deal.
I should be able to do some testing in the next week or so. It would be nice if they can be run w/o current limiting or extra cooling. I guess it depends if they self current limit at 540mA or if they just trip off.
An easy to get to 1/2 amp Slow Blo fuse would be a simple solution. But my experience, even when the battery is depleted, putting 172 volts across it does not create more than 400 ma of current. BUT....my power supply may be increasing its resistance as the current goes up and self limiting.
__________________
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."
A pack can run from 140-170V during the charging process.
A fixed voltage supply current will ramp up very quickly as the voltage differential between the pack and the charger increases, so without a resistor in series, you will be adjusting the supplies every few minutes if you hope to keep the charging under control.
A diode on the output of the series charger is a good idea as it will eliminate any back current into the supplies.
One $20 CC supply, and you can just connect it and forget it.
You saved money on the 48V supplies, invest in a CC supply and you have a nice CC charger.
The supplies do not need fan cooling unless they are run at max in a closed box.
The supplies have a hiccup mode output protection, where they pulse on, and if the current gets too high they turn back off, and they try again. Don't know if they will tolerate a big overcurrent when in this mode? It is always best to work well within the specified ratings of any electronics, so I would not recommend using the supplies without at least a power resistor to soften up the output, and the best solution is to add a CC supply to the string as in my original design.
Don't forget the 12V for the battery fan, and you should be using a DC rated fuse, as a bad short across the battery could arc through a standard 250VAC fuse, or a 12V automotive fuse.
This is what I will use as an output protection fuse on the dual charger, as it is rated at 125VDC http://www.schurterinc.com/pdf/english/typ_umt_250.pdf
I should be able to finish the dual charger prototype today, and begin operational testing.
Thanks for the info, I'll pick up a few current limiting supplies, less work and cleaner than building 2 more lm 317 circuits. Plus that will give me 2 spare 48v supplies.
For the fans, I am using a 120v AC / 9v DC power brick rated at 2 or 3 amps. It does the job and takes up very little space.
Mike, would there be any reason not to connect a wall wart type supply when doing this? It might not be an elegant solution but I do have a few laying around that seem to be decent smaller switching type AC to 12v DC adapters.
Jim, the rating on the Meanwell site for the RS-25-48 is displayed as "Over Load Protection 110 ~ 180% rated output power" I'm not sure how long it will allow, say a 110% overload, or what the voltage hysteresis for its power output. I'm not sure if the pack was around 150 volts under if it would pump loads of amperage in to meet the voltage exactly or if there is some play in it, looking at a 20+ volt jump all depends on the internal resistance of the cells, your experience however is more experience than I have though, if it works out, that would be sweet.
I should play with 5 sticks connected to one 48 volt supply adjusted appropriately to see what my ammeter says when the supply drops out, I hope not but I do after all have an extra supply since I only really need 3 if I end up buying a CC charger for the pack so I do have one available to be a guinea pig. I'm a bit busy as of late but if I can get the time to play with one I might learn a little about how much they might stretch off their specs.
Disclaimer for this post(especially the previous paragraph): Don't burn your equipment up or kill your pack based on what I say I am doing or might do, be safe, do your own due diligence with high voltage, electricity in general, and expensive batteries.
The LED was a late addition Mike made to the circuit to lower the voltage about 3 volts and let you know current was flowing. The least expensive LED in stock was $10 where I was buying the parts so I didn't get one. I think you can do without.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
