SOC Gauge after New Battery

[Mobiloman]

I recently had my battery replaced by Honda under warranty at 9 years 11 months and 5 days (whew!). Before the replacement my SOC gauge would only go from 16-20 bars, when it got to about 16 it would drop to zero and then force charge up. Now with the new battery it is often at 19 bars and never drops more than two bars from that. I can tell that all the background charging to keep the battery topped up is costing me ~3 MPG (at least). The MPG loss isn't as much of a worry as the fear of damaging my new battery by not cycling it properly. I tried pulling the 4th bottom row fuse and re-learning the SOC at idle but that had no effect. Should I try and do some long IMA runs without Regen to try and get the battery down to a force charge state?

I've already read similar threads but no one had a clear answer. Anyone know for sure how to fix this?

Thanks for the help

[Willie Williford]

The battery has probably been sitting for a long time from the time it was refurbished by Honda. (Which is not good for the battery)
Try not to use any assist, use a lot of regen and see if that will top it off. A grid charger is the best bet. Put your location in your signature and maybe someone has a grid charger that is close by and will assist you.
HTH
Willie

[retepsnikrep]

Did they change the bcm as well as part of the warranty fix?
That has different characteristics to the original and is more conservative trying to keep the battery charged more I understand.

[E27006]

The battery gauge is does not seem to be much more than an indicator of the state of charge of the pack, the new OBDII gauge might be worth having for peace of mind, the OBDII gauge reports battery SofC to .1 decimal, SofC can be down 60% and only a couple of bars off full on the dash gauge.

[Mobiloman]

Originally Posted by Willie Williford

Try not to use any assist, use a lot of regen and see if that will top it off.
Willie

I'm not quite sure what you mean, my problem isn't getting the battery to 20 bars, it does that frequently. I want my insight to let the battery discharge a bit more deeply and charge up through regen rather than what seems like constant background charging. Having the SOC gauge work better would be nice but Im really more concerned with the amount of background charging.

RE: Peter Perkins:
Yes they did replace the BCM under warranty, that is an interesting theory, that perhaps later model/replacement BCMs are more active at keeping the battery topped up via background charging. Has anyone else experienced this to be the case?

Also any thoughts on the risks or potential benefit to trying to use a lot of assist to get my battery depleted so that it will force charge back up?

Thanks for all the help

[Eli]

Yes, later BCM revisions are more aggressive with trying to keep the battery full.

Full overall is a good thing. If you can keep the battery at 19-20 bars and avoid forced regen, you should be able to get your MPG back.

[E27006]

Head into the city and do stop start driving with autostop engaged, the series of IMA restarts and first gear pull aways will deplete the pack to the low level that you are seek.

I repeat my intended advice that the SofC gauge is either inaccurate or very non-linear at the top end, as follows.

Today I set off on a trip with 17 bars SofC and 65% SofC OBDII, the 17 bars never changed on a 38 mile trip yet OBDII SofC ranged between 60 and 66%.

The battery temperature was a rather cool 9 C but rose to about 15 celsius at the end.

I did use regen and assist when possible, 25 to 30 amps peak, but typically 10 to 15 amps (4 bars on the charge assist gauge).

There are quite a few things going on in the background the standard gauges do even hint to the driver, today I observed the IMA system letting the pack slip down several % and then on a level stretch of road, with FCD reading high it pushed 4 to 6 amps back into the pack over a duration of a minute, nothing on the charge gauge to show this happening, this event occured 3 times in thetrip. I also saw similar discharges of about 1 amp, aagain no evidence on the assist gauge

Although your SofC is showing a high level , your pack may be charge cycling far more than the instrument cluster is telling you.

For the record, my car is a 2000 model manual transmission with the original BCM.

[randomfire]

Originally Posted by Mobiloman

...Now with the new battery it is often at 19 bars and never drops more than two bars from that...

Never drops below 17 bars? I wish I had your problem.

If you really want to cycle your battery, then maybe you have to sacrifice your mpg for a few miles and just floor the pedal. Even with an aggressive BCM, if the gauge is showing "Assist," then it shouildn't be charging. But then again, I don't have the new BCM in my 2000 so I could be wrong.

[gilbertguy]

I recently had my pack replaced under warranty, now that summer is over and the AC is not running the new pack I just got was always reading 19/20 bars. Part of this is how I drive, use very little or no assist leaving the lights but put as much back into the battery as possible with regen when slowing down.

My last battery was just like yours, would seem fine and after a few bars of use it would negative recal to nothing and start charging. So I wanted to see this battery actually drop in charge so I could see the system function to make sure everything is working right.

I started using lots of assist to launch and would coast to stops with no regen, actually took a long time to use up enough battery but it slowly dropped bar by bar down to about 2/3 of SOC. System finally kicked in and charged it back up by 1 bar enough to be happy. Once I saw this I went back to my normal way of driving, it is almost charged back up to full again without any actual system charging and just me using regen.

[jeff652]

Originally Posted by E27006

The new OBDII gauge might be worth having for peace of mind, the OBDII gauge reports battery SofC to .1 decimal, SofC can be down 60% and only a couple of bars off full on the dash gauge.

What is the OBDII gauge that you are referring to? Can I get this readout on a Ultragauge? I scanned through the menus but did not see it.