In my experience, charging at 200 ma or less will not require the fan be operated. I use 170 to 200 without any detectable heating at all.. However at 250 ma I can detect SOME heating, though not enough to worry me...except for the long run.
At 200 ma over night (10-12 hours) you are replacing a little over 1ah of charge. Since the Insight normally uses about 4ah from stop to stop, if you keep it above half on the SOC during the day, the overnight charge should be sufficient for daily use. This amount of charging will not hurt the battery in my opinion. If you want to "balance" the pack, give it 36 to 48 hours at 250ma and watch the charge curve on the "deepest" stick (the one that can hold the most charge) till it dips in voltage to indicate a full pack.
__________________
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."
In my experience, charging at 200 ma or less will not require the fan be operated. I use 170 to 200 without any detectable heating at all.. However at 250 ma I can detect SOME heating, though not enough to worry me...except for the long run.
At 200 ma over night (10-12 hours) you are replacing a little over 1ah of charge. Since the Insight normally uses about 4ah from stop to stop, if you keep it above half on the SOC during the day, the overnight charge should be sufficient for daily use. This amount of charging will not hurt the battery in my opinion. If you want to "balance" the pack, give it 36 to 48 hours at 250ma and watch the charge curve on the "deepest" stick (the one that can hold the most charge) till it dips in voltage to indicate a full pack.
Not to be picky, but 200mA @ 10 hours is 2aH minus losses, 12 hours bumps that up to 2.4aH.
36 to 48 hours @ 250mA puts you at 9aH and 12aH, again minus losses and self drain.
I charge my 2 packs for about 12 - 14 hours at 600mA (start charge) - 500mA (end charge) and do see a buildup of heat with the fans running on a cool summer night.
Remember that you do not want to fully charge the battery on a regular basis. It will shorten the life of the battery cells (while extending the usable life). What I mean by this is that it will wear out the cells - not depress them. There's no cure for that but replacement of the cells.
I read a very interesting article about our Insight batteries on Battery University, where the author recommended topping off the battery about 3 to 4 times per year.
My battery actually topped-off tonight, just as Mike has mentioned in several posts. My el-cheapo Radio Shack multimeter must be a little off calibration, because my pack made it to a maximum of 166.5 volts, then dropped off about 1.0 volt in the last two hours or so. I dropped the charge to 100 mA when I noticed the drop and kept it there for another hour, with no change in voltage.
It started out with a voltage reading of 151 and I *tried* to keep the variac adjusted with the current in the 150 to 200 mA range, but it took allot of baby sitting on my part to keep it there. Every hour or so, I would take a look and see that it had dropped to below 100 mA on numerous occasions.
I did not try the regulators that you and Mike have talked about, but maybe next time...
I think I may need to put a 1 ohm dropping resistor in series with the positive lead to the battery and monitor the voltage drop across it to determine the real mA current. I have three meters and each one gave a different reading, and not just by a difference of 5% either. Of course the resistor will need to be sized to properly dissipate the heat build-up and keep the resistance stable over temperature. But hopefully that will give me a better current reading than the meters I have when measuring current.
They have a supplier in US and you never know may be a discount for quantity. (Note I've e-mailed the UK supplier about a bulk purchase) See previous post on this thread for the US supplier. I suggest someone looks at that possibility over there.
Ron you could knock them up into grid chargers and flog them with your recon batteries.
In fact looking at them they could be easily installed in the IPU compartment with just a mains power input socket to the outside world.
I tested one and it will go from 40-54.5V no load.
Three makes that 163.5V Not quite high enough but four gives us a very nice range.
I havent tried them in series yet, but four would fit in a nice neat case and they look a good but as yet untested option.
With a 570ma ish output the re-balance grid charge could be done in one night easily.
They are very sweet and neat. And you can make a grid charger for £50!
<snip>
In fact looking at them they could be easily installed in the IPU compartment with just a mains power input socket to the outside world.
But doing so would make monitoring and adjusting the output voltage and current difficult. I suppose that these things could be set before installing, but would that be sufficient over the long run? Would having the grid charger external be a better design?
Quote:
Originally Posted by retepsnikrep
I havent tried them in series yet, but four would fit in a nice neat case and they look a good but as yet untested option.
I encourage you to consider this as a replacement for your single-psu design for which you were asking for potential customers.
[QUOTE=retepsnikrep;142920With a 570ma ish output the re-balance grid charge could be done in one night easily.[/QUOTE]
Wouldn't 570ma lead to excessive heating? Do these psu's have an adjustable constant current setting that could be set in the 250 - 300 ma range that those in the know have been suggesting? I suppose an ammeter would need to be part of the grid charger package to allow one to set the current level.
I'm looking forward to hearing your test results with these psu's.
Ron you could knock them up into grid chargers and flog them with your recon batteries.
That's my goal. I expect that most of my customers would be interested in them, and it's another step toward becoming a one-stop-shop. I ordered a dozen of them a week ago. I'll let you know when they arrive.
At 35 amps, a battery gives up about 4 ah in seven minutes.
At 10 amps, it takes about 30 minutes to put that charge back.
At 25 amps, a battery gives up about 4 ah in eleven minutes.
And, your point is???? I am trying to keep from overheating the battery at 200ma to 250ma. charge and at 4 amps the entire battery, taken one stick at a time, can be discharged in a day. The math is simple.
__________________
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."
And, your point is???? I am trying to keep from overheating the battery at 200ma to 250ma. charge and at 4 amps the entire battery, taken one stick at a time, can be discharged in a day. The math is simple.
And the point is that I'm giving you some independant verification of your numbers. Nothing more.
Did some calculations of the results of the Charge to Discharge ratio from the Battery balance I performed last April.
Using the figures for the last charge then discharge cycle (by which time the stick has stabilised with a steady final capacity) gives a Discharge over Charge ratio of about 93%.
Example: Subpack 15, Charged to 7138 mAh, then discharged giving out 6630 mAh, this works out to 92.9%
The test conditions are charge and discharge at 10 Amps, discharging down to subpack voltage of 5.4 volts (0.9v per cell)
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