Is the Optima Yellow Top a good batt?

In the immortal words of Rodney King, "Can't we all just get along?"

 

Sam Spade rules

 

No not really. There are a LOT of conditions which will cause the engine to come on and a low state of charge in the 12 V battery is just one.

As a matter of fact, I don't actually remember anybody actually saying that a low 12 V , by itself, will trigger the engine to run.
Since the 12 V charges off the big battery and NOT off the engine directly.......I suspect that the 12 V getting low will just ramp up the DC-DC inverter and won't have any direct impact on the engine running.

 

Meaning what exactly ?

You don't like to hear the truth ??

 

Yes, but if the 12v is bad/weak and NEVER FULLY charges, the system continues to use energy out of the HV battery and so needs to run the ICE more (because it is always WASTING energy from the HV battery TRYING to charge the 12v fully, it has to replace that energy). I have not had this experience with my Prius, but I absolutely did experience it with my used 2005 Ford Escape Hybrid (same design as Prius), when I bought it, the battery was weak, but hard to notice since it is not used to start the ICE. I replaced it and immediately got 3-5 MPG better mileage.
Also, the lower than normal voltage may affect some readings/settings in the car, possibly causing the ICE to run more.

 

Well put. That's the point I was trying to make. Even with a good, but low-charged battery, it uses energy out of the HV battery until it achieves the proper charge level.

 

Even when my 12 volt was weak the charging system still kicked down to 13.6 after driving a bit. Only stayed at 14.2 when the headlights or AC where on. Think that's why that battery didn't last.
I have a yellow top now and trickle charger it couple times a week to be sure.

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And I think it didn't last because it was worn out or defective.
A failing battery often LOOKS like it is fully charged and will even "fool" the charger.....but then it can't actually produce enough current do it's job.

 

Definitely didn't hold a load. Headlights alone dropped it bellow 11 volts.

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Next birthday, Christmas or whenever, ask for one of these:

 

Those got to be the most mismatched size of terminal clamps versus the size of the wire that I have ever seen.

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LG-H918 ?

 

The BatteryMINDer 1510 is an excellent tool.

 

I think if everyone got/used a decent battery smart charger, an electronic battery load tester tester, and gave up on trying to figure out how much gas was left when the gauge read empty, this site would fall apart, lol.

We could get back to cleaning our $(*!@ EGR circuits every month or two.

 

Is that a good test of battery strength? If so, what should the minimum voltage be with oem headlights?

 

Akin to checking tread depth with a penny? At least that sort of works.

 

What I use.

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Ok dumb question....what is the 'proper' way to attach a BatteryMinder in a Prius? I've seen talk of using an under the hood hot point. Is this the'correct' method? Why can't you attach directly to the battery?

 

Since it's a permanent installation I attached directly to the battery. You can close the hatch with the cord hanging out.

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That is what I was thinking. I'm going to install a ring adapter kit at the battery terminals ( which are obviously at the rear of the vehicle ).

However, nearly every post I see on here when I search seems to imply using the 'boost point' under the hood...which is why I was asking.

Thanks for your help!

 

No reason to pop the fuse box and positive terminal to hook up the charger. I just leave the connector plug hanging out the back corner for easy hook up. I don't understand the Prius charging system. I've drove the car a half hour and the charger still charged for like 45 minutes to top the battery off.

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