[dberns]

We've got this nifty display showing how much electricity is going in/out of the battery for IMA, but... I'm wondering what those bars really mean.

Has anyone hooked up a meter and seen how much amperage is really going through? And... whether the numbers are the same/bar at different times (and also how the charge and assist sides compare?)

I've noticed, for example, that the amount of retardation (sorry....) I "feel" has very little obvious correlation with the number of bars in the "charging" field - and don't think I've ever bumped into what five horsepower of engine drag should be doing.

(My car uses the CVT so that would tend to reduce the obvious effects, but the differences are still enough to make me wonder).

Thanks.

 

[Insightful Trekker]

The IMA gauges are software driven, none make "direct" measurements. Armin did precisely what your asking quite a while back. The Charge and Assist gauges algorithm are quite complex.

What can always be accurately stated is that if its showing Assist (Asst) then current is flowing _out_ of the IMA pack. Conversely so with Charge (Chrg).

The complexity begins let's say for example the indicator initially showing full assist and the current corresponding to 90A, but after a few seconds the amount of current ramps down. (Actual rates of flow do not reliably correlate to the number of bars shown) Its a good thing. High sustained rates of charge or discharge for any battery will cause damage.

The gauges response reads like the average "dumbed down" versions that most all cars use these days. It costs too much to try and convince customers that spikes with their temperature gauge are normal (But such _IS_).

See Armin's post:

http://www.insightcentral.net/forum/viewtopic.php?t=582

Also see:

Recals, Forced Charge, IMA Battery & thermal mgmt - long
http://www.insightcentral.net/forum/viewtopic.php?t=750

for probably more than you want to know about the IMA system.

retardation (sorry....) = Regeneration, as in regenerative braking or on deceleration. Regen for short. But your word works for the gauges too, in a different context.

HTH!

 

[Dougie]

I was driving along in town last night with fully charged batteries. The car is so light and nimble once you get out of background charging! It just seems so much more responsive and light-footed. I seriously think than when/if my IMA system gives up the ghost that I will just rip it out and drive a lightweight car with a small ICE.

The point is that the charge bars don't even show the background charging, which is in effect MOST of the time if you use the IMA system at all. It takes quite a while to get the batteries so completely charged that the system just leaves them alone.

I'm tempted to put a real ammeter into the system.

 

[JoeMultihuller]

Regarding IMA current measurement, a current shunt certainly works and I have one installed for my 12V battery, but for the IMA battery something electrically isolated would be desirable. I wanted something completely independent of the built-in IMA sensor, so I got this split-type Hall Effect sensor and associated meter http://www.semarine.com/meters_lights/meters.shtml Unfortunately, I haven't found a place to mount it as I want to only read the current going to/from the IMA battery. MIMA already does this using the Insight's sensor - interesting to note the occasional disparities between the instrument panel display and what the MIMA LEDs show. :shock: For example, if the engine is idling and I hit the MIMA regen joystick, the instrument panel immediately shows four green bars whereas it may take 5-10 seconds before the the battery actually starts receiving any current. :roll: JoeS.