After 5 years, it finally gave up.
Symptom: Turn key, would not start, and the battery indicator came on.
after 2 or three turns of the key, it would start.
Checked the voltage (idle, no load) = 13.5v.

Took to sams club, they load tested it. - 112 CCA. (vs 500).

$85 for an ever-ready, had good luck with these in the past.

Does the electrical system really need over 112 CCA to energize the circuits?
Im not very knowledgeable of the starting ciricuits, thought the HV battery did all the work, just thought I'd throw out to you experts.....

 

I would like to know the answer of this as well.

I too just replaced the original 12v battery with a Bosch (only battery i found close by with a 3yr free replacement) 2006 MMH with 48k miles, original battery

Funny thing is, I changed it when we were headed out of town. Changed the battery and drove 400 miles, then 3 days later came home. After 800 miles, I decided to check the battery with my automatic battery conditioner/charger/maintainer. I put it on and it charged for 4 hours before saying the battery was full. I would have thought the battery would have been full after 800 miles of driving. I did drive home the last 3/4 mile in EV mode though. Perhaps that is why.

 

You have to test your 12v battery with the key out, or else you get a false test result as the 330v to 14v comverter instantly comes on when you turn the key.
The battery does not need many amps, but it needs strong voltage.

 

The first part makes sense, but the last sentence makes no sense at all, if you have 112CCA, then you probably have several amps and the volts to show for it.
Im suprised none of you guru's out there havn't come forward with a more technical spec on what the 12v battery needs to actually support the startup.

 

Amps and volts do not depend on each other.
You can have high amps and low voltage at the same time.

Amps = flow.
Volts = pressure
Amps x Volts = watts = power

A river may have high flow and low pressure, and still have a lot of power.
A 1" pipe may have high pressure, and low flow, and still have lots of power.

The starter relay needs less than 5 amps.
The starter relay needs more than 12 volts.
If you don't have 12 volts, 115 amps at 11 volts won't start the car.

There is your technical info,
Make sense now?

A river

 

Somehwat, Where are you getting your specs on the relay?
My assumption from what I've ready on this forum is that the HV battery does 99% of the work for startup.
I would think that 11V at 115amp would still be enough for the relay to engage. Most 12v relays are spec'd down to 9 or 10v, but again no one has come forward with the real specs.
BTW: I did check my voltage with the "key out" as you mentioned. Thats what I meant by "no-load". Idle may of been a bit misleading, it was engine off. -- It read 13.5v.
thanks for the info...

 

Sometimes things are just a little bit more complex. for instance when you said your battery voltage was 13.5 volts when you tested it then us in the know people know thayour voltmeter was off or the battery just came off a charge as a fully charged battery will read 12.8 volts after it is "rested" meaning that it has been off a charger for a good while and there is no load. A 13.5 volt reading means it is on charger or just came off charge. Volts VS amps is more of a function of load resistence. 12 volts with a 12 ohm load will cause 1 amp of current to flow. 12 volts with 1 ohm load will cause 12 amps to flow. 12 volts at .1 ohm will cause 120 amps to flow.
The question is can your battery maintain 12 volts with .1 ohm and put out 120 amps. if your battery is low it will go down to (for the sake of argument) 6 volts and will only put out 60 amps instead Amps=volts/resistence. This is where a load test from the autoparts store will help you.

General rule of thumb. Charge battery at 14 volts untill the current goes down to about 5% of capacity. Just know that you need to begin this test with battery fully charged. leave it disconnected for 2 hours then read voltage. 12.8 100% 12.6 75% 12.4 55% 12.2 33% 12.0 20% 11.8 volts pretty **** close to dead. Again rule of thumb, don't forget to facter in temps and check SG if you want to be more exact.

 

Yes I agree and understand that,(thank you), but what really confused me is that we are talking very low amp requirements to enagage the relay. For example I was able to turn my lights on, honk the horn, lock and unlock the doors, etc which all require a few amps give or take. So I would think that activating the 12v relay as explained by GPSman would be no problem. Thats why Im interesed in the actual spec/requirement for the 12v batterys role in the engine startup process.

 

Yes I agree that if you can turn on headlights and honk the horn you should have enough juice to close the relay. I do not know how many amps are required to operate the relay but I would think it would only be a few amps.

I would also like to know how much 12 volt current is needed to get the 330 to 12 volt converter charging the 12 volt battery as once I left my lights on and when it wouldn't start I thought that if I left the key on the 330 volt batteries would charge the 12 volt, didn't happen had to get a jump just to close this relay then it started nice and strong. Maybe we should call this a contactor as that implies more current then a relay for operation.

 

On the SG I'm reading 11.8vdc before starting the ICE after the FEH sits overnight. Reading 11.5vdc with the headlights on before starting.

Does this mean my OEM battery is going to die soon? So far everything is normal with no starting or running issues. I'm carrying a booster pack just in case.