Battery mod not working out?

[California98Civic]

Many thanks guys. I have some reassurance, two more strategies to figure out my problem, and an excuse to buy a tool! I like it.

[deathtrain]

my question is why dont you go with two of the batteries and put them in parallel? cost?? maybe?

[California98Civic]

Originally Posted by deathtrain

my question is why dont you go with two of the batteries and put them in parallel? cost?? maybe?

Not cost. But there were two reasons. First, a desire to fit the battery and its charger into the former battery's space in the car rather than relocating. Second, it is part of a general program of shaving weight in small measures across multiple places. That weight program has shaved nearly 250 lbs for a car that started at 2262lbs and that is driven heavily through pulse and glide techniques. This battery mod removed 12 pounds, without losing enough CCA to start the engine. It is a motorcycle battery, but my 1.59cc four cyl Civic is not all that much more than a motorcycle in some ways. That's especially true because I reduced electrical loads so much: CD player replaced with a battery-operated mp3 player, LED bulbs, HID headlamps. Night driving kills the battery still. And I have a little more I can do to reduce electrical load.

If I had two like batteries in-line, would the ability of my Odyssey 6 amp charger to fully recharge both batteries be reduced?

[oil pan 4]

That battery charger would charge 2 deep cycles no problem as long as they had enough time.

[California98Civic]

I think maybe my alternator is dieing, and I wonder if the low voltage in the deep-cycle battery is a culprit. Sometimes, my voltmeter will show under 12volts and yet the alternator does NOT turn on. Other times the voltmeter shows momentary charging but then the alt appears to cut-out again. Looks like a bad alt maybe. I need to test it tomorrow. But I wonder if I over taxed the alt with this deep-cycle battery? Anybody had that experience?

[3dplane]

You could only over tax your alternator if you allow it to charge up a severely discharged battery. However you are running a small capacity battery so that should pick up voltage faster causing the amp load on the alt.to decrease before it overheats. Who knows what exactly is going on?

I would put a regular battery in there, hook up an accurate voltmeter and go for a ride,monitoring the voltage. Turn on lights too to make sure it works.

If it's still acting up and all your connections are good you can call it an alternator. (maybe the PCM or ECM or ECU whatever Honda calls it can also manipulate the alt. but I would not go there yet)

I recently tested a voltmeter in my car and discovered weird things. (94 mazda protege 1.8L manual SOHC). When I take off with a cold engine,the alternator will not charge regardless of electrical load until I'm about 3-4 miles down the road! (morning or evening).
When it starts charging or coolant temp is beyond a certain point,I can do "regen" key off if I let the clutch out and the engine rpm hits at least about 2000 rpm the alt. WILL charge all the way down to very low rpms like 15 mph in 4th gear for example. Full output regardless of electrical loads! This is confirmed by three different volt meters and an ammeter. Weird!

Back to your case,your alternator might be just going out regardless of your mods!
Barna

[California98Civic]

Originally Posted by 3dplane

You could only over tax your alternator if you allow it to charge up a severely discharged battery.... your alternator might be just going out regardless of your mods!

I have also seen odd charging behavior by the ghost in the machine. But testing today at the battery posts with engine off, engine warm and idling, and engine idling with extra elect load showed normal operating ranges for the alternator. What could cause intermittent (one time only) high voltage DTCs in the coolant temp sensor, Electric Load Detector, O2 sensor, and MAP sensor each? Could the battery mod have effected the electric load detector in a way that is creating voltage spikes?

[3dplane]

I don't think so (voltage spikes)!
However in general, low voltage conditions will cause all electronic equipment to go nuts.So knowing what you are doing,I would not pay much attention to the codes. If I wanted to diagnose them,I would reinstall the original battery,clear the codes and drive the car to see who's back if any codes come back!
Barna

[oil pan 4]

Yeah you dont want to unhook the battery with the engine (and alternator) turning.
I have seen alternators put out over 20 volts when the battery was unhooked and with little to no load.
I had one alternator put out 48 volts at no load but it worked fine when installed into the electrical system.

[California98Civic]

Well... alternator passed test as did battery... but my ignition coil just failed a test, and an ICM/igniter "input test" from the manual also points to a failed coil. But here's the kicker: testing as soon as the coolant reached running temps indicated the coil was fine when I tested it a few weeks ago. The coil seems to fail only after the distributor gets hot after 15 mins or so of driving. Hahaha!! I am hoping this solves it, but I'll test the ICM and the spark itself once I have the coil replaced.

BTW, honda-tech's moderator RonJ@HT is guiding and querying me via a thread their. Great know-how and advice there. Hope this is the beginning of the end of my running problems...