Xgauge battery settings

[jimsoh]

Of the 3 SOC state of charge ; BTA battery current ; BTV battery voltage, which is the most pertinent to mpg. You can't display more than 1 at a time & I wonder which would be the most helpful.

daily 30/70% hwy/city

TIA

[Bob64]

IMO: Battery current.

That way, you can control your acceleration as to avoid draining your battery, as well as avoiding charging your battery while trying to achieve super highway mode. Also, enable you to achieve "60 amp" braking for optimum regeneration efficiency.

[Neicy]

Bob,

I've been fascinated since I got my second SGII and have been watching BTA. What other tips can you give me WRT current flow? I had heard before to stay off the pack for best mpg, but I seem to be doing better using it sometimes. I know I'm losing some energy in the exchange but it seems sometimes it's better to just use battery when the pack is really full. Any suggested reading to help me learn more? Thanks Bob.

[Bob64]

Yeah sure, if your battery is "Green" go ahead and use it until it gets blue... but try not to drain it in one second too... try to spread the energy out - as well as the heatbuildup - as long as possible.

[JimboK]

To Jimsoh: I agree with Bob about current being the most valuable to monitor of the three options you presented.

To Neicy: Bob's advice to you is good as well. When my SOC is much above mid-60s (7 or 8 green bars), I will use EV mode or stealth a little more freely than usual. I also use it for low-demand situations of short duration, such as moving around the driveway or a parking lot, between closely spaced red lights, or extending a glide a short distance. In these low-demand instances my goal is to keep current flow out of the battery to less than 20 amps, and preferably less than 10A.

[archae86]

Originally Posted by Neicy

I had heard before to stay off the pack for best mpg, but I seem to be doing better using it sometimes. I know I'm losing some energy in the exchange but it seems sometimes it's better to just use battery when the pack is really full.

This is a really basic question from economics. The key question is not "what did the charge in the battery cost you?", nor really "what is the current state of charge?", but rather "what is the replacement cost of the charge I am considering using?".

If you are in a situation where the possibility exists optionally to use charge from the battery,and it will be replaced by burning gasoline in the internal combustion engine, you would lose on the deal, since you will be paying the "tax" imposed by extra inefficiencies in the entire loop. If, on the other hand, the charge will replaced by unavoidable hill descent or braking regeneration, then using the stored charge is a big win.

In economics people call this "ignoring bygones", and "considering replacement cost".

The reason that it is worth paying attention to the current state of charge despite what I said above is that the car will alter its future control strategy based on its future state of charge, which will in turn alter the answer in some cases to the questions I posed above.

[Neicy]

Originally Posted by JimboK

When my SOC is much above mid-60s (7 or 8 green bars), I will use EV mode or stealth a little more freely than usual. I also use it for low-demand situations of short duration, such as moving around the driveway or a parking lot, between closely spaced red lights, or extending a glide a short distance. In these low-demand instances my goal is to keep current flow out of the battery to less than 20 amps, and preferably less than 10A.

That's what I was looking for. Thanks Bob & Jim.

Next Q. When braking, how many amps should be going back and at what point (if any) can the battery not take in the charge from regen?

[JimboK]

Originally Posted by Neicy

That's what I was looking for. Thanks Bob & Jim.

Next Q. When braking, how many amps should be going back and at what point (if any) can the battery not take in the charge from regen?

Hi, Neicy. Sorry I missed this follow-up question earlier. Are you asking at what current flow is braking most efficient?

As for the second part of your question, as the battery approaches 80% the car will reduce regeneration. SOC actually will exceed 80% at times, and when it does the car does what might be called a "forced B mode" to avoid further regeneration. See this thread where several of us describe this.

[jps000]

From those in the know, would you mind describing in more precise detail HOW you use the amp meter for the goals you state. That is, you avoid charging battery while trying super highway mode (I imagine that's to avoid a loss of fuel energy; it's best to charge during regen moments) , so HOW do you do that (you watch for what meter flow number, or do you watch that with something else, or watch something else entirely and see that measure's impact on meter flow? Or in regard to controlling acceleration to avoid draining your battery, HOW do you do that with BTA, exactly. Isn't targeting low RPMs enough?

Are you actively using the BTA and adjusting accordingly or is that just confirming a good process...

Any other how's appreciated...

[nerfer]

Originally Posted by jps000

From those in the know, would you mind describing in more precise detail HOW you use the amp meter for the goals you state. That is, you avoid charging battery while trying super highway mode (I imagine that's to avoid a loss of fuel energy; it's best to charge during regen moments) , so HOW do you do that (you watch for what meter flow number, or do you watch that with something else, or watch something else entirely and see that measure's impact on meter flow? Or in regard to controlling acceleration to avoid draining your battery, HOW do you do that with BTA, exactly. Isn't targeting low RPMs enough?

I'm not sure how to use the amp feedback myself. I programmed it in, but haven't used it because it seems to vary quite a bit independently of my inputs. IGN (ingition advance timing) is more useful to me, I keep it under 20 at all times (some recommend 14 but it's hard to even maintain speed at that level). This is directly tied to acceleration, and when it drops to 5 you know it's in glide mode (if the engine is warm enough for gliding). So that's what I've been using, but if some of the others can give a good explanation of how to use the current, I'd be interested in learning.

If you're going for low RPMs only, you might need the BTA to make sure you're not getting battery assist (which lowers RPMs, but drains the battery). But I think the energy screen would also show you that.