I know its not a hybrid, but...

[user removed]

Best way to test a battery is to charge it then turn on your headlights. A new battery will keep headlights on for 3+ hours before it dumps. A weak battery will not even come close to that, some as low as 20 minutes when they are on their last lags.

9 holes of golf and I was OK, 18 and I was in trouble .

I have seen batteries pass the quick load tests and be dead the next morning.

Charge it, turn on the headlights and wait an hour, test the voltage.

regards
Mech

[nemo]

Originally Posted by Old Mechanic

Charge it, turn on the headlights and wait an hour, test the voltage.

regards
Mech

Mech
What would you expect the voltage to be after 1hr.

The last four batteries that had (three vehicles) to replace were all working went parked over night or in one case several hours won't crank the engine later. Never any indication there was a problem, like slow cranking. None were recoverable. Is this the typical failure mode in your experience or a local phenomena?

[Ryland]

Originally Posted by Sheikz2

So the battery won't charge completely under normal conditions (no EOCing)?

I would say that you need to let your engine run for at least 2 minutes for every use of the starter, 3-5 minutes would be better to get the battery charged back up, but you are going to be lacking the absorption part of the charging cycle, so no, it's not going to charge completely under any short trips, that is why if you are not letting your battery charge up fully that it's a good idea to put it on a regular battery charger, it's very rare for me to leave town, so my car never runs for very long either, because of this every few months I put a charger on and my battery is going on 6 years old and starts up even on the coldest days without issue.

[Daox]

You should buy a scangauge or at least put a voltmeter on the battery to monitor it. The scangauge will also give you feedback to really help improve your driving technique.

[euromodder]

Originally Posted by Old Mechanic

If it is the original battery and it's 4 years old, it may be time for a replacement anyway. Maybe an upgrade to handle the engine off operation.

Dunno if they already made it to the USA, but with ever more start-stop systems being introduced in Europe, we're now also seeing batteries that are designed to take more frequent starts and that can cope better with running the auxiliaries while the engine is off.

[euromodder]

Originally Posted by nemo

The last four batteries that had (three vehicles) to replace were all working went parked over night or in one case several hours won't crank the engine later. Never any indication there was a problem, like slow cranking. None were recoverable. Is this the typical failure mode in your experience or a local phenomena?

It's been typical for me.

In one case, I drove out to the cash machine in the next village, then couldn't start the car again. Click (starter relay) - nothing.


Hägar has been going strong on it's OEM / Varta battery for 81 months so far - and he's spending the night outside, all year.
If the battery remains as good as it's been, I'll replace the car before the battery ...

[MetroMPG]

Originally Posted by Daox

You should buy a scangauge or at least put a voltmeter on the battery to monitor it.

Seconded! And thirded.

I see this point frequently overlooked by people who are either new to engine-off coasting OR disabling their alternators.

You NEED to monitor battery voltage to prevent damage!

10.5 volts is the absolute lowest a 12v battery should be subjected to with a load on it. Below that, you risk irreversable damage and shortened battery life. Deep discharges may save gas, but buying a new battery every year kind of negates that!

[christofoo]

Originally Posted by MetroMPG

Seconded! And thirded.

I see this point frequently overlooked by people who are either new to engine-off coasting OR disabling their alternators.

You NEED to monitor battery voltage to prevent damage!

...

+1

Even if the battery seems okay one day it can be dead the next, I think that cranking speed is not a very good indicator of State Of Charge, V monitor is better although I've been unlucky on the accuracy of my monitors (including the SGII). Best to recharge if in doubt. Charger current gives a good figure of SOC, and the asymptote gives an indicator of battery health.

EOC/FAS is definitely hard on batteries. Even with my V monitors and charger I have a hard time pushing more than 3 years from a battery given my restarting habits.

There's a list of solutions: on-board trickle charger or solar charger (do solar chargers need a controller to prevent overcharging?), deep cycle batteries, desulfating charger.

My latest thing is a desulfator/charger. (BatteryMINDer, not totally sure it works yet - will get back to you later.) I'm hoping it will extend battery life beyond the typical 3-6 years. Assuming it works I believe it's the most cost-effective option, particularly since I can use 1 BatteryMINDer for multiple cars, and since it (should) save multiple batteries in the long-term.
Amazon.com: BatteryMINDer Model 12117: 12 Volt 1.33 Amp (12V 1.33A) Charger/Maintainer/Desulfator: Automotive

[Mustang Dave]

It's the middle of Summer in the Northern Hemisphere. Your commute is about 5 miles one way. Why are you not walking or bicycling part of the time? it would be better for you and the environment. :shrug: