“Riddle me this Batman”

[SeanC]

When is a “good” battery, not a “good” battery?

A quick re-cap. Two mornings camping on Moreton Island, even with a Traxide SC80 the cranking battery (wet lead acid) wouldn’t turn the engine over.

Got home. Put on charge. 3hrs later 12.68v. 24hrs later 12.62v. Wouldn’ turn over. Checked charge after. 11.2v.

So new battery in, old battery out. Old battery had been on charge. 13.1v. 5 days later still 13.1v. (A bit high for a wet lead acid battery?)

Took to Battery World. Tested. Battery good. 720cca down from 770cca. 13.0 volts.
“I don’t think it is good”
”Ok. Bring out the Durst” Same result.

Back home. Put old battery back in. Turns over no problem. 24hrs later barely turns over once.
10.66v after.???

[discomatt69]

Its a Land Rover thing................

[Ean Austral]

It's a battery thing ....


Cheers Ean

[Redback]

To be honest 770CCA is not enough, our battery(same as the Factory) is 900CCA, old battery is dead, new battery isn't up to the task, also I would check your auxiliary battery also, failing that it could be your SC80 is faulty.

I'm sure Drivesafe will be along soon to give you the answer you need, or PM or phone him really easy guy to deal will, be warned though he likes a chat[biggrin]

[Ferret]

When is a “good” battery, not a “good” battery?

When it won't crank 1 day after being charged regardless of what battery tests say.

[matti4556]

6 years ago I purchased an $50k battery tester.
It has been 100% correct on 2 occasions.
The brand and model of the battery tester is "Landrover Discovery 3".
I'm of the opinion you can navel-gaze battery theory until the cows come home - but one thing I know for sure is the car will definitely tell you the battery will just not do its job any longer. (and it has a huge task to provide energy for the systems in a modern car with "stuff-all tolerance" for low voltages)
Fit a new battery - problem goes away for another few years.
Matti

[SeanC]

6 years ago I purchased an $50k battery tester.
It has been 100% correct on 2 occasions.
The brand and model of the battery tester is "Landrover Discovery 3".
I'm of the opinion you can navel-gaze battery theory until the cows come home - but one thing I know for sure is the car will definitely tell you the battery will just not do its job any longer. (and it has a huge task to provide energy for the systems in a modern car with "stuff-all tolerance" for low voltages)
Fit a new battery - problem goes away for another few years.
Matti

Have an Odessey PC1350 in there now. Just interesting that the old battery could crank the motor without hesitation the barely turn it over the next day but sit for 5 day at 13.1volts.
I just don’t like not knowing why. Must be the scientist in me.

[matti4556]

Yeah I know where you are coming from Sean. I was like that until recently. I could tell you how to tune in your new VCR (remember them) because I would read the owners manuals back to front - all of them! I KNOW! = what a weirdo!? https://www.aulro.com/afvb/images/smilies/Smile.png but working in an appliance test laboratory did this to you - you knew exactly what factory made the magnetron for a particular model Sharp microwave oven but be stuffed if you could remember your wedding anniversary!
These days, remembering the wedding anniversary seems much more important for me https://www.aulro.com/afvb/images/smilies/SmileBigEye.png

But to theorize your battery issue in my "special" way - I would hazard a guess that the "crank one day and not the next" is related to internal resistance. It will read an ok-ish voltage with no load, but when push comes to shove it cant deliver more than once - sort of like when a pretty girl walks by - "suck the stomach in" to look good (battery terminal voltage), and hope to hell she doesn't hang about too long before you cramp up. Have a read of the terminal voltage when cranking.

[SeanC]

But to theorize your battery issue in my "special" way - I would hazard a guess that the "crank one day and not the next" is related to internal resistance. It will read an ok-ish voltage with no load, but when push comes to shove it cant deliver more than once - sort of like when a pretty girl walks by - "suck the stomach in" to look good (battery terminal voltage), and hope to hell she doesn't hang about too long before you cramp up. Have a read of the terminal voltage when cranking.
Love the analogy.[bigrolf]

[Russrobe]

Speaking of batteries, Supercharge Gold Plus MF88h 900CCA batteries are currently on special at AutoBahn for $223 bargain. Mines 5 years old and still last as long and still runs like new. Tempted to buy another just because they're so cheap! Don't like buying batteries online... Haven't had much luck with warranty in the past with other, more expensive ones.

[DiscoJeffster]

Speaking of batteries, Supercharge Gold Plus MF88h 900CCA batteries are currently on special at AutoBahn for $223 bargain. Mines 5 years old and still last as long and still runs like new. Tempted to buy another just because they're so cheap! Don't like buying batteries online... Haven't had much luck with warranty in the past with other, more expensive ones.

I paid $263 a few weeks ago for the same battery on “special” “30%” off from Repco which was the cheapest I could find at the time. That’s a great price! That was to go in my Audi. I use the Varta AGM in my D4 however that set me back $500 at the time.

[DiscoMick]

One recharge is not enough to know for sure. You may want to leave the dodgy battery on a multi stage charger for several weeks of conditioning before you will know for sure if it can be recovered.

[SeanC]

When not in use the battery was always connected to my c-tek charger. Regularly on charge for 1-2 weeks between use. The old battery which has been out of the vehicle for a week is still @ 13.2 volts and the charge indicator is green. From what I can find a fully charged wet lead acid battery should settle at about 12.7v. Does 13.2v indicate some sort of problem?

[Ferret]

...Does 13.2v indicate some sort of problem?

Probably surface charge (https://batteryuniversity.com/index.php/learn/article/water_loss_acid_stratification_and_surface_charge) .

[Markus1]

I believe that's surface charge Sean.

[SeanC]

Probably surface charge (https://batteryuniversity.com/index.php/learn/article/water_loss_acid_stratification_and_surface_charge) .

After a week?

[Russrobe]

Easy to tell, if you connect up a light load overnight like a single led or something, it should drop back down to 12.7V.

Tim (Traxide) recommends not leaving batteries connected to any charger for long periods of time (more than 24 hours). I found that out after i nearly destroyed one from over charging it after constantly running a smart charger for 6 days at a time.

I just put it on for 12 hours once a week if it's not being driven.

[DiscoMick]

A small solar panel is good as it charges during the day and lets it rest at night.

[SeanC]

Easy to tell, if you connect up a light load overnight like a single led or something, it should drop back down to 12.7V.

Tim (Traxide) recommends not leaving batteries connected to any charger for long periods of time (more than 24 hours). I found that out after i nearly destroyed one from over charging it after constantly running a smart charger for 6 days at a time.

I just put it on for 12 hours once a week if it's not being driven.

The c-tek supposedly won’t overcharge the battery. Was one of the reasons I bought one.

CTEK’s smart chargers move into a pulse maintenance mode once the battery is fully charged. Rather than sending in a charge and estimating what the battery needs, a CTEK charger will stay in constant communication with the battery, reacting and charging only when it is needed.
In pulse maintenance mode, the battery will be allowed to naturally self discharge to a certain level before being fully charged once again. Not only does this avoid the risk of overcharging but, as the battery is being exercised as it would be during normal use, the lifespan of the battery is extended considerably.

[DiscoJeffster]

The c-tek supposedly won’t overcharge the battery. Was one of the reasons I bought one.

CTEK’s smart chargers move into a pulse maintenance mode once the battery is fully charged. Rather than sending in a charge and estimating what the battery needs, a CTEK charger will stay in constant communication with the battery, reacting and charging only when it is needed.
In pulse maintenance mode, the battery will be allowed to naturally self discharge to a certain level before being fully charged once again. Not only does this avoid the risk of overcharging but, as the battery is being exercised as it would be during normal use, the lifespan of the battery is extended considerably.

Yep. I’ve left my Ctek on a car permanently for over a year at a time and the battery was never an issue in its ownership. They’re a cut above the norm for sure.

[Ferret]

After a week?

Possibly. Surface charge will dissipate naturally over time, how fast it dissipates probably depends upon the internal state of the battery. People talk about 'internal resistance'. A good battery will have low 'internal resistance' so probably allows that surface charge to dissipate fairly quickly ~12-24h. A bad battery will have a high 'internal resistance' That high internal resistance may not allow the surface charge to dissipate as quickly. But just my guess.

Batteries are funny things. The chemistry is relatively simple but real world conditions related to the physics of the chemistry like 'transport', 'kinetics' and 'equilibria' together with the physical properties of the electrodes themselves makes them much more complicated things.

[DiscoMick]

Put a load on the battery and the surface charge should dissipate.
My Projecta behaves similarly to the C Tek, I think.

[scarry]

Put a load on the battery and the surface charge should dissipate.
My Projecta behaves similarly to the C Tek, I think.

We had battery trouble with one of the vans recently,the battery showed 12.5V on a multimeter,but wouldn't turn over the engine.

With the meter on the battery,hit the starter and it dropped to 6.5V.

Surface charge.

This battery actually failed in the middle of the day.
The tech had turned off the engine only 20minutes before,and it wouldn't start.
It had been fine before turning it off.

[DiscoMick]

Sounds right. We had a similar experience with a camper trailer battery at Christmas and had to replace it while on Straddie. Read OK, but with the fridge on it dropped to 9.9. I have it on the Projecta right now, hoping to revive it, but probably won't work.

[DiscoMick]

The battery in my 9 year old iPod is similar. Works fine plugged into a running vehicle, but loses charge when left.

[Russrobe]

Interesting, I was using a CTEK too. Tim recommends ditching it in place of a small $30 solar panel from ebay.

It's especially the case if you accidentally forget to turn your fridge off or have something extra daining from the battery, which is easily done.

[DiscoMick]

The thing about solar is it excites the cells when the sun is shining and then let's them rest at night.

[SeanC]

Interesting, I was using a CTEK too. Tim recommends ditching it in place of a small $30 solar panel from ebay.

It's especially the case if you accidentally forget to turn your fridge off or have something extra daining from the battery, which is easily done.

The reason I leave it on the charger is that randomly and infrequently I get something that is draining the battery. I’m talking a near new battery going from fully charged to the central locking won’t operate in 3 days. Only happened a couple of times. No joy from the auto-electrician. So I keep it on charge when it isn’t being used. Hasn’t happened while camping touch wood.