โFeb-25-2016 03:43 PM
โFeb-28-2016 01:17 PM
โFeb-28-2016 10:50 AM
Salvo wrote:
This is not a van. I get 16 - 17 mpg, usually driving at 62 mph.
โFeb-28-2016 10:10 AM
โFeb-27-2016 08:52 AM
LScamper wrote:
" I'd guess that the ripple there is more due to the starter motor hitting up against a compression stroke on the engine. That would also explain why each successive peak is a little less severe, as the engine gains momentum."
X2.
The first peak do to starter turning engine from dead stop. Like locked rotor current.
โFeb-27-2016 07:59 AM
โFeb-27-2016 06:14 AM
โFeb-26-2016 08:01 PM
SCVJeff wrote:Salvo wrote:That ripple out at 200A was what I was presuming was the back EMF of the starter coil collapsing
For the heck of it here's the starting current from my new toy: '16 Miata.
Charging current slowly increases to about 30A after 8 sec.
โFeb-26-2016 05:03 PM
Salvo wrote:That ripple out at 200A was what I was presuming was the back EMF of the starter coil collapsing
For the heck of it here's the starting current from my new toy: '16 Miata.
Charging current slowly increases to about 30A after 8 sec.
โFeb-26-2016 03:04 PM
Salvo wrote:
I see no signs of an inductive kickback. Here's a plot of the battery voltage during the cranking sequence. Data logging connections are at the battery. I would need some gummy arms to snake through the engine compartment to get to the starter. I'm fairly confident any inductive flyback would be evident at the battery.
Around 1.4 sec there's a little dip in voltage. That could be the solenoid getting energized. Shortly thereafter, the starter motor pulls battery voltage down to 9.4V. A little after 2.2 sec the solenoid releases. This is where the inductive voltage spike would occur. There isn't any evidence of one.
Voltage is measured every 1.5 ms.
Yeah, the Arduino data logger is amazing. All for about $20. The clamp-on current probe is a bit more pricey at $75. There's a few brave souls here that are getting into Arduino.
โFeb-26-2016 01:19 PM
โFeb-26-2016 11:02 AM
โFeb-26-2016 10:41 AM
โFeb-26-2016 09:27 AM
โFeb-26-2016 07:31 AM
tatest wrote:
That 700 is a spike fed by surface charge on the battery plates. Internal resistance in most lead-acid starting batteries limits deliverable current to 400 amps or less. NiMH could deliver more.