Amp Hour counting with the OBDIIC&C Gauge

[AClewell]

What numbers should we be expecting when doing the AH test? I forced my pack full yesteday and depleted it on the way to work this a.m. and the gauge shows only about
+0.13 -0.78 for a net of -0.65 total used. This seems really low compared to what I was expecting. I think I have a healthy pack and have never had any recals other than after grid charging.

Alan

[retepsnikrep]

You should be looking for a max of around 4ah for a pack in great condition.

The gauge at present only counts current when in the main display screen. So after you have cleared the ah/time etc before setting off you must return to the main screen for the actual drive/trip. Only when stopped at other end should you go into the ah screen to check the results.

I haven't checked ah/wh counting so we need some others to do the pack test to check it's not got a bug.

[Eli]

Like Peter says, the theoretical maximum for a pack in excellent condition is 3.9Ah(60% of 6.5Ah), but I think in practice it will be more like 3.3Ah since our cells are rated at 5.5Ah with current of 32A or more.

I'll try and remember to compare the OBDIIC&C Ah/Wh numbers with the BCM Gauge.

[AClewell]

OK, Thanks Peter.

I was on the SOC reset screen most of the time. LOL

That makes testing a little more tricky. So when I go to bump the SOC to high each time I need to engage my clutch switch so that I don't have any lost AH data.

I will test again tomorrow.

Thanks,
Alan

PS. I guess I should have figured that out as the LB LED stayed on when I was on the SOC screen, even when I was using assist.

[retepsnikrep]

Originally Posted by AClewell

That makes testing a little more tricky. So when I go to bump the SOC to high each time I need to engage my clutch switch so that I don't have any lost AH data.

That's a good plan. Eventually gauge will count in background/any mode as well.

[AClewell]

I started out this a.m. with the battery grid charged to 174v and depleted it on the way to work this morning trying not to allow assist by useing the clutch switch. Wow a lot more capacity than I expected. BTW I did check my config bits and they are all 1's except for the temp is set to 0 for F.

[racer26]

Here's what I did to come up with this pic:

Used SOC reset mode to set SOC to 40%, repeatedly, until the car recal-ed to 75% almost immediately.

Reset the Ah/Wh display

Use max assist as much as possible (WOT and coastdown cruising over a 50-65mph speed range), use clutch switch to avoid regen as much as possible. When assist is locked out, use SOC mode to reset SOC to 75% until it immediately recals down.

This is an OEM pack that was replaced an estimated 2 years before I bought the car in May 2011. The 100A fuse was replaced by me in September 2011.

[Eli]

Hmm. Alan's reading seems a little anomalous. It could be partly because of the grid charge? Did you forget to reset it after your last test?

5.32 - 0.78 on your first test - the 0.46 input gives you 4.08Ah, which is a more believable number, but I find it highly suspect that any stock pack could be giving anywhere near 5.0Ah.

Like I said, the maximum theoretical amp hours from a stock, healthy pack is 3.9Ah(60% of 6.5Ah). In reality, it should be closer to 3.3Ah as stock cells are only rated for 5.5Ah @ 32A of discharge or more.

The BetterBattery has 8Ah cells, and gives 4.8Ah(60% of 8Ah) and 0.66kWh. We need to verify that the Ah/Wh counting is correct, though it should be if it's essentially the same code the BCM Gauge uses.

Racer's numbers are more in line with what I would expect from an aged pack. I was pretty surprised to see that my believed to be healthy 1.5 year old stock pack was only giving 3Ah(0.38kWh) - and that's after a grid charge.

What we should actually be paying attention to more than amp hours is the watt hours. This is actual power output: Volts * Amps. Amp hours alone only gives you half the picture, but it's still a useful number.

We should probably start a Capacity spreadsheet.

[AClewell]

I was very careful to reset everything this morning. This test was good. My previous test was not due to not being on the main display screen during testing per Peter.

[Eli]

I'm not really trying to doubt you, just don't understand how that's possible. When was your pack replaced?

According to your test, your pack is outperforming the BetterBattery.....

We need to get you setup with some logging action, I'd need to see the full picture to believe that.

I know you said the +32% mode isn't enabled, but.. double check? lol

Really needs to be put into a secret menu, or make it so two bits have to change to enable it. Adds too much uncertainty.