NiMH battery conditioning
#11
11-07-2007, 01:21 PM
Re: NiMH battery conditioning
Mike:
I really do not wish to blow this issue out of proportion and cause people to fear the batteries they've got. However, this should also be something that we should all be aware of... since this issue is not without precedents. If there's a chance to manage the SoC in regular mountain driving then much of this fear is trivial and almost insignificant. But, if the climbs are prolonged to such an extend that the SoC is depleted at the top or even earlier then IMO the best recourse is to have a solid extended warranty at hand.
Harold:
There's nothing more that I would like than to be wrong on this issue.
Sadly, I fear history may continue to prove that folks who live and drive in mountainous areas may experience battery failures well before those of us who live in flatter regions. As a matter of fact, I do not expect a single failure out of my batteries on any of my cars, and yes, I intend to keep them for a long time.
...
MSantos
I really do not wish to blow this issue out of proportion and cause people to fear the batteries they've got. However, this should also be something that we should all be aware of... since this issue is not without precedents. If there's a chance to manage the SoC in regular mountain driving then much of this fear is trivial and almost insignificant. But, if the climbs are prolonged to such an extend that the SoC is depleted at the top or even earlier then IMO the best recourse is to have a solid extended warranty at hand.
Harold:
There's nothing more that I would like than to be wrong on this issue.
Sadly, I fear history may continue to prove that folks who live and drive in mountainous areas may experience battery failures well before those of us who live in flatter regions. As a matter of fact, I do not expect a single failure out of my batteries on any of my cars, and yes, I intend to keep them for a long time.
...
MSantos
Occasionally, it will recal on the way up the hill, with the SOC dropping down from 5 bars to 1 bar in a second or two, yet the IMA was showing no boost on the way up. At the top of the hill, it will not recharge right away, but after a short while, it recharges normally.
Maybe the instrumentation is not the best.
#12
11-07-2007, 02:09 PM
Re: NiMH battery conditioning
Being I have a 2004 I have had several software updates, I suspect they are tweaks to the method of charge/ discharge protocol that " provides the conditions" to enhance battery life.
#13
11-07-2007, 05:03 PM
Re: NiMH battery conditioning
Medical carts with NiMh batteries are actually warrantied for 18 months or less. The carts we use recommend changing the batteries every 12 months.
Its interesting that Hybrids can go or be warrantied for 8 years. I could be the number of battery cells the Hybrids use that make it last longer, but 8 years seems exaggerated ...
Its interesting that Hybrids can go or be warrantied for 8 years. I could be the number of battery cells the Hybrids use that make it last longer, but 8 years seems exaggerated ...
#14
11-07-2007, 06:53 PM
Re: NiMH battery conditioning
It's the careful monitoring of the battery's State of Charge. Not allowing it to fully discharge or fully charge, or charge/discharge when the temperatures are too high/low, etc. Also, careful matching of individual cells in the pack. Much more scrutiny is given to the battery pack and its controlled charge/discharge patterns. This allows for a much longer battery life.
#17
05-08-2008, 08:18 PM
Re: NiMH battery conditioning
Medical carts with NiMh batteries are actually warrantied for 18 months or less. The carts we use recommend changing the batteries every 12 months.
Its interesting that Hybrids can go or be warrantied for 8 years. I could be the number of battery cells the Hybrids use that make it last longer, but 8 years seems exaggerated ...
Its interesting that Hybrids can go or be warrantied for 8 years. I could be the number of battery cells the Hybrids use that make it last longer, but 8 years seems exaggerated ...
Other electronics, like laptops and the medical cart, are run from 100% to near empty. That shortens the life of the nimh cells a lot.
Out here in California, the batteries are warrantied for 10 years, 150k miles.
#19
05-12-2008, 10:07 AM
Re: NiMH battery conditioning
Just so I understand this correctly: Are you saying that it is BAD or GOOD to allow it to fully discharge/charge ?
I'm a newbie here and trying to soak up all the tips I can. I just bought my HCH II a week ago and have already put 1000 miles on it (went on a road trip this weekend).
In the last week (1000 miles) the battery has hit 8 Bars (fully charged) ONLY ONCE. It stayed at 8 bars for just a short time (less than 2 minutes). That was on a long stretch of highway.
All other times it fluctuates between 3-7 bars. Usually hoovers around 5-6 bars.
Is that good - or should I be concerned that it is not working correctly? I was very surprised that over 1000 miles, it tapped 8 bars only once.
Thanks!
#20
05-12-2008, 03:13 PM
Re: NiMH battery conditioning
It's bad to fully charge or discharge. The car's computer won't let you do anything really bad to the batteries so no worries there but efficiency wise you want to avoid both. If you let it get too low the car will then do a force charge (usually around 4 bars) and you'll lose 10% to 20% efficiency while it is doing that. This will happen from time to time so no worries. If you let it go too high then it won't charge the batteries at all and then you lose the ability of regaining the energy when you do have to brake.
Getting 8 bars isn't too hard to do if you've been on the highway a while. Just let her coast from 65 to 30 (if you're already around 6 or 7 bars which is most likely if you are on the highway). My trip to mom's always has this section where the traffic just slowly piles up and I usually hit 8 bars there and having to use the real brakes to slow down.
Getting 8 bars isn't too hard to do if you've been on the highway a while. Just let her coast from 65 to 30 (if you're already around 6 or 7 bars which is most likely if you are on the highway). My trip to mom's always has this section where the traffic just slowly piles up and I usually hit 8 bars there and having to use the real brakes to slow down.
