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Discussion Starter #1
I just bought a 2002 Insight with 17,000 miles on it. Having just spent over four years living on a boat off-grid, I've become very attuned to 12v battery happiness.

Inasmuch as I'm an Insight newbie and am experiencing some fairly significant IMA battery level variations (perhaps normal, as I live in the hills), I thought I'd first monitor the 12v battery voltage level just to get an idea of its normal behavior. So we went for a pleasant 80-mile drive in the country (av'g. 64.3mpg - I'm still learning)...

I simply plugged in a digital voltmeter into the accessory socket and expected to see a fairly steady float voltage somewhere around 13.5v. I was shocked by the results: this voltage VARIES RAPIDLY and ranges from 13.6v down to 9.8v, often sitting in the 10v range for minutes at a time. I couldn't correlate this to either IMA level or IMA charging/discharging status nor to engine revs nor lights/accessories. Made me suspect that I have an intermittent shorted cell or two in the 12v battery. After letting the car sit overnight in the garage, I measured 12.37v across the 12v battery without turning anything on. Perhaps a little low, and maybe time to search for a battery replacement...

Our Insight came with a factory-original "Maintenance Free" wet-cell semi-sealed battery which I presume contains plates which are lead-calcium. These batteries are optimally charged at14.8v and prefer float voltages of 13.1v-13.4v (a little lower than the 13.6v I measured).

(deleted long-winded technical discussion comparing all sorts of battery types)

The favored replacement for our Insight's stock battery is the Hawker Odyssey which is an AGM VRLA. The OdysseyFactory.com website recommends charging at 14.4v-14.7v and floating at 13.6v-13.8v. Not a problem, and should be quite compatible with whatever the voltage regulation is from our DC-DC Converter (i.e., if it works with the MaintenanceFree battery then it's just fine for the AGM, presuming it's got a current limiter which will accommodate the AGM's lower internal impedance).

So far so good, and I'm about to place an order for the smaller (lighter) Odyssey PC545 , together with custom aluminum mounting bracket and terminal adapters. This smaller battery was selected since I live in a mild climate, we don't need deep-cycle capability (playing the stereo while parked for a few hours won't deplete it), and if we have to crank for more than five seconds using the starter, something else is wrong.

Before I do that, however, has anyone else monitored their 12v? If so, what are the voltage variations experienced?

Thanks in advance, and thanks to those who previously discussed and showed pictures of their replacement 12v batteries, and sorry for being so long-winded.
 

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I think the PC545 is the best choice. I have had one for several years in my airplane, and it does a SUPER job. It has plenty of cranking power for my 105 hp engine, even in sub-freezing temps. It already has lasted longer than a standard lead-acid battery........Billy
 

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I have a "Battery Gauge" permanently mounted in my Insight. It is connected to one of the hot lead on the cig. lighter.
In the AM (first start) and the first position on the ignition switch shows 12.5 volts. Second position on the switch shows 11.7 (No load other than the computer loading, etc.)
While running, (idle) the voltage will indicate between 13.5 and 13.9 volts, even with a "max. load" (lights, radio, fan, AC) the gauge reads 13.8 most of the time and never below 13.5 volts.

I use a "Hawker" Genesis 12V13A, weight 10.8 pounds and it was installed on 12/3/03 after being used on a "heart monitor" machine for 2 years. (Bought used) for $15.00. Have started the engine 4 times with the 12V battery when the IMA battery "overheated" during a summer trip. No problems since installation.

PS
Haven't seen a factory installed battery that is maintenance free. The "eye" of the battery is deceiving.

Hope this helps.
 

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Discussion Starter #4
Hi Billy and Willie,
Thank you both for your feedback. You're right, even though it says "Maintenance Free Battery" right on its case, a lead-acid wet cell needs occasional nourishment. Off to buy the PC545...
Joe
 

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Discussion Starter #5
Installed a Hawker Odyssey PC545 battery using a battery box from West Coast Batteries (http://www.odysseybatteries.com/pc680hd.htm) and my own two custom anodized aluminum brackets. Removed the original Insight battery box. The pieces can be seen on http://www.KatieKat.net/Vehicles/Insigh ... gParts.jpg
The installation:

The only permanent mods to the Insight are two 6x1.0 screw holes I drilled and tapped into the box crossmember. Used all eight of the original battery-mounting screws and added two 1/4x20 stainless screw/washers/locknuts (don't have any metric SS on hand).
The longer bracket also attaches with two screws to a control bracket underneath (the two screws just visible in the photo).
Placed a piece of foam between the battery and the crossmember.
The original battery ground cable was excessively stretched, so I replaced it with a longer one (12" would be fine, but all the local autoparts store had was 19"). Kept the original ground cable (attached redundantly) in case I need an on-the-road battery replacement.
A brief test run showed no more excessive 12v voltage variation, with the voltage hovering around 13.6-13.8v when the dc-dc converter is kicked in, but dropping to about 12.2v when it occasionally opens up (haven't figured out its logic yet).
Thanks to all who contributed to the previous Forum 12v battery discussions and mods.
JoeS.
 

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Hey Joe,

Nice install! I will look into the Hawker battery as I know my 12V is close to shot.

Also, hello from another LAH resident (Robleda Road). I will keep an eye out for another silver Insight around town...

Jay
2000 Silver
 

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DC-DC cycling

Joe,

I have a theory for the DC-DC turning on and off seemingly at random:

A) at very low loads, the DC-DC is very inefficient. It draws at least 1.5A from the 144V system in addition to what it needs to supply the 12V side. (This is common for SMPS)..

B) Maybe Honda was concerned about constantly floating the 12V battery at the fairly high level they use. So they turn off float when there is no or little load and only turn it back on when the voltage drops below a certain point (I seem to remember it was 12.0V, but I don't have my notes handy).

In either case, with the engine running or in auto-idle-stop, I have never seen the 12V side drop as badly as you reported. Where do you measure the voltage? Maybe it's the drop across a fuse or wire?
 

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Discussion Starter #8
Hi Guys - thanks for the notes.
Jay, I sent you a PM.
Armin - I am simply measuring the battery voltage at the accessories connector which looks like a cig. lighter outlet, but with no load I would expect it to be reading the battery voltage reasonably accurately (depending where their pickoff point is - I just received the service manual and haven't delved into it yet). On my list of things to do to the Insight is to put in some decent battery monitoring instrumentation; e.g., http://www.katiekat.net/Cruise/KatieKat ... ifications
I hope to be much smarter about the car when I return from a 2Kmile trip in a couple of weeks - barely driven it since I bought it - it's been raining :) Don't get the wrong idea - all my other cars get washed once every five years, whether they need it or not - and the original paintjob on my '67Saab is still good - waxed it once, back in '68
JoeS.
 

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The info in this thread is starting to raise concern, as next week’s cold weather in the northeast could possibly necessitate 12 start(s).

I have the original 12V battery, to which I added distilled water about 7 months ago. I’m not aware of any specific problems, as the period between re-cals has often been several months.

Since “Sputnik” doesn’t have A/C, I sometimes operate an interior 12V fan in the summer. I’ve noticed the fan speed changes frequently and significantly, with a consistent correlation to driving conditions. (I don’t remember all the specifics, but regenerative braking is one of the events that always ramps up the fan speed. I’d thought this was normal for the Insight.) I haven’t checked the voltage yet (while driving) with a DVM, but my guess would be that the voltage is varying by at least 10%, probably more.

If I have a chance to make some measurements (with and without fan motor load) I’ll post the results.
 

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Please reference the previous messages for context of the following observations.

The following voltage measurements were made on the 12V accessory connector (traditional “lighter”) with approximately 30 degrees F outdoor temperature. The garage temperature at initial starting was approximately 45 deg. F. All but one measurement was rounded to the nearest 0.1VDC.
‘Apologies to fellow engineers for not presenting this in spread-sheet format.

Start switch on, engine off: 12.3VDC
Start switch on, engine off, peripheral 12V fan on: 12.1VDC
Engine on, peripheral fan off: 14.0VDC
Engine on, peripheral fan on: 13.95VDC
Normal driving conditions: 14.0VDC +/- 0.4%
This includes:
Headlights on;
Regenerative braking;
Auto Stop (engine temporarily off)

I stopped the car and turned off the engine after approximately 10 miles and made the following measurements:

Start switch on, engine off: 12.6VDC
Engine on, normal driving conditions: 14.0VDC +/- 0.4%
This includes:
Headlights on;
Peripheral fan on;
Regenerative braking;
Auto Stop (engine temporarily off)
Maximum battery (IMA) assist;
Headlights, internal fan, peripheral fan, and tape player on.

Quite unlike my observations last summer, there were no noticeable variations in the peripheral fan speed under any of the conditions listed above.

Conclusions:

Considering that the “12V” battery voltage was very stabile (at 14 volts) under nearly all typical driving conditions after the engine ran for over 1 minute;
 The OEM 12V battery performance may possibly be maintained for 3 years + with the addition of distilled water, and/or;
 Variations in battery voltage (12V) are less likely at northern USA winter temperatures.

Hopefully, with the help of a passenger, I’ll have a chance to check and post measurements next summer.

CAUTION: As a safety consideration, please don’t attempt to read peripheral instruments while driving.

Despite hesitant periods of contemplation, “Sputnik” had no 12V starts this past week, despite 2 days where the daytime temperatures in my workplace parking lot didn’t exceed 10 degrees F.
 

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Your observation of the fan speed is correct. The Dc to DC converter will boost the 12v system voltage to 14 volts but it is not always on. If the electrical load is light the 12v battery supplies the power until its voltage falls triggering the DC to DC converter to pump up the 12v battery. If the electrical load is high (everything is on) then the DC to DC converter will stay on as the demand is high. This is a power saving technique as a DC converter charging a full 12 volt battery is wasting energy. Have fun, RIck
 

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Discussion Starter #12
Nemystic, thank you for taking the readings and identifying the test conditions.The significant parameter is temperature, as the voltage regulator within our dc-dc converter does appear to compensate (as it should), as evidenced by your higher voltage at low temperatures.

Thus, I'm no longer concerned about the actual voltage we're measuring, provided it's not much below 12v nor above 14.4v. BTW, I compared the voltage readings with a dvm clipped directly to the battery simultaneously with those measured at the accessories socket, and they were within 50millivolts of each other even when I played with various car loads (lights, radio, etc.); the conclusion is that measuring the car's 12v voltage at the accessories socket is ok.

I do not know where the temperature sensor for the dc-dc converter regulator is actually located, and about all I've been able to glean from the manual is that there is an overheat protection circuit which will turn off the dc-dc converter if it gets too hot. But isn't the battery exposed to a far different temperature than the dc-dc converter? In cars with alternators and external regulators, the regulator is in close proximity of the battery.

Rick, addressing the point you made, from what I've seen so far, most of the time (>95%) the dc-dc converter's regulator keeps the battery float voltage around 13.8v at around 60degF, normal for lead-acid and just fine for my new AGM PC545 Hawker Odyssey. It seems to continuously maintain ("regulate") this voltage irrespective of 12v loads, although I need to spend a lot more time looking at this ... hmmm, one of the parameters monitored by the Davis CarChip? - darn, they don't have Mac software for it!

What is unusual, however, is that every once in a while the dc-dc converter does TURN OFF, and the voltage reading drops suddenly to around 12.1v (60degF). I've noticed this occurrence when, e.g., I've floored it and full IMA assist kicked in when the IMA battery was 2/3 full. Nice of them to do that as it allows full use of the IMA battery to drive the motor.

Although the 12.1v is disconcerting at first, I would consider it normal for my lightweight battery under nominal loads. On the ToDo list is to put in a shunt to measure the actual battery in/out current.

Armin, you mentioned that you thought the dc-dc converter no-load current draw is 1.5amps from the 144v battery - that would be over 200 watts! - perhaps you meant from the 12v battery? I would expect our dc-dc converter to be pretty darn efficient and perhaps not even draw that much.... another thing to measure.

Measuring the 12v battery voltage directly allows us to tell when the dc-dc converter is either on or off (there doesn't seem to be an in-between). It's now of only academic importance, but does anyone know of a table listing the specific conditions when converter cuts off? - or is this another one of our car's mysteries we need to decode for ourselves? :)
 

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I have a carchip and when the engine load increase and the timing advance drops the voltage usually does also. Have fun, Rick
 

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What's a carchip and what does it do?
Thanks,
Robert
 

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Discussion Starter #15
The Davis CarChip is a portable plug-in device which stores the info available at the diagnostic connector for future retrieval on your PC. See

http://www.davisnet.com/drive/products/ ... oducts.asp

Unfortunately, they don't have software for a Macintosh. Anyone know if it will work with a Mac running VitualPC?
 

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I should add that the carchip isn't completly compatible with hybrids. In my case it starts a new trip log everytime autostop is engaged. I have pasted the logs together in excel but thats not what its supposed to do. I also recall someone with a newer insight saying it would only save until the first autostop but I have not had that problem. I have also used the autoxray scantool. Both have their advantages. The scantool can show you parameters as you are driving but I am fairly certain that the carchip records more parameters. Neither do anything with the IMA. Have fun, Rick
 

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Thanks Joe,
I guess I need to contact Rick and see if there are any true benefits of having it. It is strange on their website that it says:

Vehicle Exclusions

All Hybrid Gas/Electric Vehicles
CarChip is not supported in Hybrid Gas/Electric vehicles.

I wonder why? and if it just doesn't tell us any info about the batteries and charging, just engine info.
robert
 

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Re:

JoeMultihuller said:
Installed a Hawker Odyssey PC545 battery using a battery box from West Coast Batteries (http://www.odysseybatteries.com/pc680hd.htm) and my own two custom anodized aluminum brackets. Removed the original Insight battery box. The pieces can be seen on http://www.KatieKat.net/Vehicles/Insigh ... gParts.jpg
The installation:
I'm needing to replace my exisiting 12V (has a dead cell). I'm interested in isntalling a Hawker, and am really impressed with Joe's installation shown in the picture above. However, I know nothing about making custom anodized aluminum brackets. How would I go about making these, or getting them made? Joe, are you still around? How did you make yours? What are other people's ideas for mounting a Hawker?

Thanks,
Bryan
 

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The west coast battery box will bolt up just fine without the extra customization. I have the same installed in my Insight.
(see the rather poor angle pic of the same on the Hot air mod segment of my web pages (pic #1))

But measure twice :!: Drill once. ;)
(unless you also want to have to modify the length of the B- cable)

HTH! :)
 

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Insightful Trekker said:
The west coast battery box will bolt up just fine without the extra customization.
Thanks John. I can't tell from your photo . . . did you leave the original battery box in place and simply bolt the PC545 box to the inside wall of the original box? That seems like it might be the best option, if that works.

Thanks,
Bryan
 
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