replaced battery-still won't start

[svalleynsx]

As the title states, I replaced my stock '91 battery with an Optima Red. Still getting the clicking and engine turn over with no start. I was assured those batteries come fully charged, ready to go. My question is could it be the starter or something else in the ignition/electrical system causing this? All connections are secure. Radio comes on, seats still slide back/forth(although weakly), windows work.

I don't own a battery tester or VOM and I'm not even sure now it's the battery I needed to replace in the first place.

 

[TyraNSX]

Try jumping it (at the fuse box by coolant tank). If that cures it, you must have a weak battery or bad connection(s). It helps to push down on the battery post clamp with a thick bladed screwdriver while tightening the nut so it actually grabs the post & doesn't ride up. From your description, it sounds like it's almost dead. If jumping fixes it, get a Battery Tender on it asap & see what happens.

 

[D'Ecosse]

The battery clamps are notoriously bad on the NSX as is also the ground wire connection at the bulkhead.

Ifyou can move the terminals on the posts all, they're probably not tight enough. As TyraNSX suggests, try to push down on the clamp as you tighten to get it on the 'fatter' part of the tapered post; you may also have to insert a piece of copper wire or similar between the post & the clamp to get a tighter clamp on it.

Once you are confident it is tight on the post, turn on ignition (don't attempt to start) & check the indicated voltage on the instrument panel gauge - it should be ~ 12V. Turn on your lights (high beam) & see what the volatge reads then, it shouldn't drop by much if it's fully charged. Attempt to start it if this is your situation.

If it's significantly lower, probably needs to be charged. If it drops only a little, you may try to start it but if there is not enough juice you might be reolved to charge it. If you can get it started, a good run will help to charge the new battery up from the alternator without having to remove it.

 

[svalleynsx]

Ackkkk! I should've known better and looked at the ammeter to see if I was getting ~12V. Good tip D'Ecosse. But as TyraNSX suggested it WAS a weak battery the parts store sold me in the first place. Took it back to them and had them put it on the tester and it came up reading 10.3V

Made sure the last one they had in stock was 12V before I exchanged it. It was. 12.6V:smile:

Guess it just goes to show, "never trust the claim by battery companies that most come off the shelf fully charged already".

One thing still bothers me though. The Optima Red35 leaves about a 2" gap on each side of the battery container, side to side. Is it necessary or have most people on here that have went to this battery used spacers to take out this space some way? I suppose I can wedge some styrofoam in there but bolting in the spare tire crossbracket snugly seems to keep the box very secure with no movement at all.

 

[Veleno]

I have the Optima Yellow Top and if I remember correctly it wasn't as wide as the OEM battery box. No problem though with it being short, just make sure it's secured with the tie-down.

 

[Hugh]

Dali makes a nice billet mount for the Optima Red.

http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1918

This is a pic of the same mount for an Odyssey

 

[svalleynsx]

That looks pretty cool, but what are those two screw-looking things on top of the bracket? Are they just for adjustment?

 

[Hugh]

Looks to me like they secure the small horizontal piece that holds the battery down.

 

[svalleynsx]

Well it looks like I have a drain on the electrical system somewhere.:frown: Went to start it this morning and could not even adjust the seat or turn on the radio let alone the ignition. I checked the cabin light and this was not left on accidentally. This, after I've installed two Optima red top batteries this past weekend.:frown: Any suggestions would be greatly appreciated.

 

[Briank]

First guess would be the trunk light is staying on. Do you have a DVM and know how to use it. The best way to find where the drain is to connect up a DVM to mesure amps at the battery and start pulling fuses. When the power drain goes away you will know what circuit you need to look at.

 

[svalleynsx]

I can safely eliminate the trunk light since I haven't been in there in weeks.:biggrin: I'm assuming just a cheap volt-ohm-milliammeter will suffice in place of a DVM? One of those $5 jobbies from K-Mart? Yes, I'm familiar with electric test devices so I will give it a try this weekend. Thanks.

 

[D'Ecosse]

... I'm assuming just a cheap volt-ohm-milliammeter will suffice in place of a DVM?

Here's even a cheap ($20) digital one from RadioShack

 

[svalleynsx]

I guess my question is, and I hope it doesn't sound too stupid is, does it matter if you use an analog or digital voltmeter? If I hook it up to read current across the posts and start pulling fuses, what should I expect to see? A sharp drop? Gradual? What should the "steady-state" current read on a fully charged battery?

 

[TyraNSX]

Wouldn't you stick the amp meter between the positive terminal & positive battery cable to measure current, and look for it to drop as you yanked fuses? It is probably easier to buy a battery tender or trickle charger & be done with it.

 

[D'Ecosse]

.... does it matter if you use an analog or digital voltmeter?

No

If I hook it up to read current across the posts...

You don't read current across the posts (you read voltage across or between the posts) - you disconnect one terminal (the -ve) then connect one lead to the terminal & one to the battery post it was removed from and it will measure the return current to the battery through the meter. Do not connect the leads across the battery when in current mode! Only in voltage mode should it be connected across the terminals.

...and start pulling fuses, what should I expect to see? A sharp drop? Gradual? What should the "steady-state" current read on a fully charged battery?

Not sure exactly - 'normal' drain should be less than 0.1A (100mA) I would expect.

 

[svalleynsx]

Yes, temporary "brain-fade" there for a second.:biggrin: Always measure voltage in parallel, current in series.

 

[svalleynsx]

It is probably easier to buy a battery tender or trickle charger & be done with it.

Correct me if I'm wrong, but aren't the Battery Tender and Trickle just advanced battery chargers? How would they actually diagnose faults in the charging system?

 

[TyraNSX]

Correct me if I'm wrong, but aren't the Battery Tender and Trickle just advanced battery chargers? How would they actually diagnose faults in the charging system?

They won't. They will just keep it charged unless you have a really big draw somewhere. Which I imagine would've caught fire by now if there was a short or you would have noticed something not working or smelling burnt.

 

[D'Ecosse]

Well it looks like I have a drain on the electrical system somewhere.:frown: Went to start it this morning and could not even adjust the seat or turn on the radio let alone the ignition....

They (trickle charger) won't. They will just keep it charged unless you have a really big draw somewhere. Which I imagine would've caught fire by now if there was a short or you would have noticed something not working or smelling burnt.

There has to be a fairly significant draw to discharge a new battery in <48 hrs. It doesn't mean necessarily there is a 'short' of a power wire to ground but a component or device that is not being turned off with ignition/accessory key switch - could be something as simple a sticking relay or as briank suggested maybe an interior or trunk light being left on.

With that kind of drain I think it is important to identify & resolve rather than ignore & try to compensate with a trickle charger.

 

[TyraNSX]

Wouldn't anything staying on & drawing a lot of juice make some degree of audible noise? Like a humming motor or clicking solenoid or relay? Assuming it's not a light somewhere. I don't know if the NSX alternator has one, but if the diode in the alternator is bad, it allows backwards current flow & kills the battery fast. This happened in my Scorpio, as it was explained by the mechanic who finally figured it out. Car charges when running, drains when shut off. If you can't find any obvious draw, it may be worth having the alternator diode tested. I didn't mean a battery tender will fix the problem, just that it would hopefully prevent having a dead battery every day.

 

[svalleynsx]

The only thing out of the ordinary I've noticed is that after installing the new battery, the left front headlamp bulb has once again gone out. Just had it replaced almost a year ago.