Think of the thermistors as self adjusting current limiters. You will not be able to put more than 25-50ma through them without them heating up and increasing resistance.
Since they are between the battery voltage taps and the measuring circuits, they allow measuring with a high impedance measuring circuit with virtually no voltage drop, but if the BCM inputs that they plug into shorted, they would control current so nothing burns up.
I'll be putting that to the test shortly. UPS crushed the tap plug on a civic battery and the pins were shorted together. I'll let you know the condition of the cells.
If the wires are not cooked, the thermistors worked.
I wired up the two stage grid charger and powered it up.
Put a switch on each of the four 48V supplies, and a master switch that turns on the two CC supplies.
A 6A diode across each of the power supplies output terminals so current has a way to get back to the CC power supply negative when the 48V supply is off.The diode drop about 2 V when all of the supplies are off.
Each of the 48V fixed supplies can be adjusted from 40-53V.
With all of the 48 supplies turned off, we have a 350mA and 700mA CC supply that has 4 diodes in series with it.
This gives us a choice of 350mA, 700mA, or 1050mA.
The current can be supplied over a CC range of ~6V to 46V.( 2V lost in diodes)
A single subpack to 5 subpacks.
Turn on one of the 48V supplies, and we add an adjustable 40-54V
Total CC range ~40V within a range of ~43 to 100V
Half of an Insight pack
two supplies ~83-154V Insight 2 pack
three ~123-208V Whole Insight pack
four ~163-262V Prius pack
5 or more to do any hybrid battery out there.
The CC supplies work perfectly in parallel, so in theory one could put 10 or more in parallel to get a 6-48V 7A+ power supply.
Lots of possibilities.
Weird, because had tested them by measuring resistance while heating them with a soldering iron and the resistance fluctuated then than 10 ohms.
It was also me who tried using a oven, but that was for testing PTC strips. I ended up using a pot of water on a stove to get proper readings on the strips.
I thought it was you that did the test. I suspect that the PTC effect is not linear, and accelerates as the temperature rises. A resistance check with a hot air gun blowing on the devices also shows a strong PTC effect once the part gets hot.
Maybe the soldering iron test did not heat it enough?
I have a civic battery terminal strip, so I will do the same test on that to see if they behave the same.
I finally got the RS-15-12 supplies yesterday, and will be finishing up the dual stage supply.
I am thinking of connecting the 12V supply to the charger pack negative for the test.
That will allow me to power the voltage detect circuit and relay for turning off the 700ma CC when at nearly full charge from the same supply as the fan.
Since the car will be off, and the fan relays off, I should be able to do it without problems?
I still need to add adigital volt meter, so I can see where the chartge is, and adjust the switch off of the 700ma at different voltages dependiing on the pack voltage.
The problem with selling ready made HV grid chargers to people that don't understand electricity is that the likely hood that they will hear a buzz and get killed is pretty high.
Sorry I could not resist!
The published parts list and schematic is pretty clear for anyone that has the skill to install it.
I will be offering a dual rate grid charger that will let you condition the pack and do a more rapid overnight charge so you can do a limited PHEV by starting with a full pack each morning.
The same charger can charge the Insight 2 pack, or individual subpacks.
I hope to get the prototype finished this month.
You still will have to install it.
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