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eid

Voltage on a new starter battery

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I have just replaced my starter battery. The voltage on the new one was 12.7v, which I read is normal for a rested battery. However, I'm a bit puzzled by it's behaviour when compared to my old one, and the bank of leisure batteries.

When on charge (engine running) for 2 hours, the voltage remained at 14.27/8 volts from start to finish. I'm sure my old one went slowly up to 14.40.

When I cut the engine, this battery went down below 13v within half an hour. The old one stayed over 13v mostly if I remember correctly. The leisure bank is till 13.03v after an hour and under a small load.

 

Do I need to put this battery on a long charge, or is there another explanation?

 

Thanks

 

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12.6/12.7V is the normal resting voltage of a nominal 12V lead acid battery once the surface charge has been removed. Anything above that is purely surface charge and meaningless wrt the battery’s health. 

 

Yes, give the battery a good long charge when you have the chance; who’s to say the store fully charged it prior to selling it?  Is it a wet battery? If so, take some specific gravity readings with a hydrometer. 

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18 minutes ago, WotEver said:

12.6/12.7V is the normal resting voltage of a nominal 12V lead acid battery once the surface charge has been removed. Anything above that is purely surface charge and meaningless wrt the battery’s health. 

 

Yes, give the battery a good long charge when you have the chance; who’s to say the store fully charged it prior to selling it?  Is it a wet battery? If so, take some specific gravity readings with a hydrometer. 

 

I need to move tomorrow anyway so I'll make sure to run the engine for hours and hours. It is wet, yes. I don't have a hydrometer yet but maybe it's time to get one.

 

Thanks WotEver.

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38 minutes ago, eid said:

I have just replaced my starter battery. The voltage on the new one was 12.7v, which I read is normal for a rested battery. However, I'm a bit puzzled by it's behaviour when compared to my old one, and the bank of leisure batteries.

When on charge (engine running) for 2 hours, the voltage remained at 14.27/8 volts from start to finish. I'm sure my old one went slowly up to 14.40.

 

 

I'd say you new batt is nothing LIKE fully charged. The 14.27v suggests it is sucking quite a current from the alternator so can't possibly be approaching tail current territory. 

 

This rhymes with my own recent new batt experience. I bought a pair of leisures by mail order. On arrival after spending 2 days in transit they too measured 12.70v on arrival. After installing them I started the engine and three hours later these two 100ah batts were still sucking 15a down from the alternator (approx) so like yours, mine were demonstrably part charged despite the 12,70v terminal voltage.

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2 minutes ago, Mike the Boilerman said:

 

I'd say you new batt is nothing LIKE fully charged. The 14.27v suggests it is sucking quite a current from the alternator so can't possibly be approaching tail current territory. 

 

This rhymes with my own recent new batt experience. I bought a pair of leisures by mail order. On arrival after spending 2 days in transit they too measured 12.70v on arrival. After installing them I started the engine and three hours later these two 100ah batts were still sucking 15a down from the alternator (approx) so like yours, mine were demonstrably part charged despite the 12,70v terminal voltage.

I did see you previous post while searching. I have no way of measuring the current going in, unless I plug in my 240v charger. I may well do this, just so I can be sure. There's a marina just over there ^.

I'm pretty sure the alternator on the starter charges at 14.4volts.

 

Thanks Mike.

 

 

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Whilst the rested voltage of 12.6 volts indicates a fully charged battery, the charging voltage of 14.27 with a 14.4 volts charging source indicates that it isn't.

 

This is because the plates on brand new batteries are not "fully formed", that is not all of the active material (lead oxide) in the negative plates has been fully cured yet. This is normal and your batteries are not yet at full capacity. Battery manufacturers do not supply "fully formed" batteries because to do so would reduce their cyclic life and also cost them more to manufacture.

 

Don't worry, your battery will gain capacity over the next few charge/discharge cycles, as the active material continues to cure and as it does the batteries will accept less current (tail current) when fully charged.

 

 

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2 minutes ago, cuthound said:

Whilst the rested voltage of 12.6 volts indicates a fully charged battery, the charging voltage of 14.27 with a 14.4 volts charging source indicates that it isn't.

 

This is because the plates on brand new batteries are not "fully formed", that is not all of the active material (lead oxide) in the negative plates has been fully cured yet. This is normal and your batteries are not yet at full capacity. Battery manufacturers do not supply "fully formed" batteries because to do so would reduce their cyclic life and also cost them more to manufacture.

 

Don't worry, your battery will gain capacity over the next few charge/discharge cycles, as the active material continues to cure and as it does the batteries will accept less current (tail current) when fully charged.

 

 

 

Thank you, that was interesting. I really have learnt a lot about batteries on this forum.

 

I'm relieved to know I haven't caused damage by using it like this.

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Just now, eid said:

I'm relieved to know I haven't caused damage by using it like this.

Not at all. You’ll be doing it good by exercising it. Like I said originally, it has a charge (otherwise it wouldn’t be sitting at 12.6V) but a good long charge or three will condition it nicely :)

 

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8 minutes ago, WotEver said:

Not at all. You’ll be doing it good by exercising it. Like I said originally, it has a charge (otherwise it wouldn’t be sitting at 12.6V) but a good long charge or three will condition it nicely :)

 

Great!

 

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I reckon its always worth trickle charging new batteries for a good few hours before putting them into service.

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12 hours ago, bizzard said:

I reckon its always worth trickle charging new batteries for a good few hours before putting them into service.

Well it's been used once now and will be again this morning but then it's going to get charged in the marina. What ampage would you consider a trickle though (110AM battery)?

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Ideally Charge it at 14.6 V until the input current is less than 3 A. (Approx 2% of capacity). Then float at 13.4 V overnight.

Otherwise sit it on a 3 stage charger until the current at stage 2 is less than 3 A then allow it to go to float overnight.  You may need to con the charger or adjust its settings to get it to stay in stage 2 long enough to get down to 3 A at the end.

N

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2 hours ago, BEngo said:

Ideally Charge it at 14.6 V until the input current is less than 3 A. (Approx 2% of capacity). Then float at 13.4 V overnight.

Otherwise sit it on a 3 stage charger until the current at stage 2 is less than 3 A then allow it to go to float overnight.  You may need to con the charger or adjust its settings to get it to stay in stage 2 long enough to get down to 3 A at the end.

N

Why 14.6v rather than 14.4v? I have a setting on my charger for 14.7v. I was wondering when I should use it.

.

I put it on charge this morning at 14.4v. It went into absorption quite quickly and showed it was charging at 14.4v but only 0.1A. The reading on the terminals was 14.27v, like yesterday.

I thought this rather odd so decided to phone the supplier for their opinion. While I was describing the above, I look up and see that the battery has suddenly gone to 14.5v. Thereafter it seemed to behave more properly (like my domestic bank) so I think all is well.

Perhaps all this is explained by cuthound's post above.

Edited by eid
+1*'

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5 minutes ago, eid said:

Perhaps all this is explained by cuthound's post above.

Most certainly. It’s often been mentioned as an example that Trojan Batteries (T105’s) will take a couple of weeks before they offer their full potential. 

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AA torch batteries are good too. I bought some fairy lights from Range a couple of years ago fo £4.99. There are about 100 LED lights. and everso long. The control box holds 2 AA batteries. The thing is solidly made., 6 different sequence settings, self timer, they turn off after about 6 hours from being switched on and come on again the next evening automatically. Last year I turned em on a couple of days before Christmas and left them on continually, they started to dim in April the following year, I then removed the batteries and put them in my oven alongside a Shepherds pie I was cooking for dinner to re charge them, put them back in the control box and got another 3 weeks illumination. The batteries were cheapo ones from Aldi. Its all wonderful magic.  Clever these Chinese.

Edited by bizzard

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35 minutes ago, WotEver said:

Most certainly. It’s often been mentioned as an example that Trojan Batteries (T105’s) will take a couple of weeks before they offer their full potential. 

Great.

 

 

14 minutes ago, bizzard said:

AA torch batteries are good too. I bought some fairy lights from Range a couple of years ago fo £4.99. There are about 100 LED lights. and everso long. The control box holds 2 AA batteries. The thing is solidly made., 6 different sequence settings, self timer, they turn off after about 6 hours from being switched on and come on again the next evening automatically. Last year I turned em on a couple of days before Christmas and left them on continually, they started to dim in April the following year, I then removed the batteries and put them in my oven alongside a Shepherds pie I was cooking for dinner to re charge them, put them back in the control box and got another 3 weeks illumination. The batteries were cheapo ones from Aldi. Its all wonderful magic.  Clever these Chinese.

 

How was the pie?

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3 minutes ago, eid said:

Great.

 

 

 

How was the pie?

Very energizing, thank you. My wristwatch won't work anymore.

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5 minutes ago, bizzard said:

Very energizing, thank you. My wristwatch won't work anymore.

Best put it in the oven then but remember to take it off first.

My grandad dropped his hearing aid in the toilet once then put it in the oven to dry. It didn't do the plastic any good at all. Good job there were no pies in with it.

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57 minutes ago, eid said:

Why 14.6v rather than 14.4v? I have a setting on my charger for 14.7v. I was wondering when I should use it.

Mainly because 14.6 V is pretty much always safe with an open FLA battery and I did not know about your particular battery's max charge voltage or chemistry ( calcium, antimony etc). 

It would be worth a check that your battery maker is OK with 14.7 but at worst, for one charge, you are only going to use more water than expected by charging at 14.7.

Fancy AGM etc batteries are something other and need lower voltages.

N

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15 minutes ago, BEngo said:

Mainly because 14.6 V is pretty much always safe with an open FLA battery and I did not know about your particular battery's max charge voltage or chemistry ( calcium, antimony etc). 

It would be worth a check that your battery maker is OK with 14.7 but at worst, for one charge, you are only going to use more water than expected by charging at 14.7.

Fancy AGM etc batteries are something other and need lower voltages.

N

 

My Lifeline AGM's can be equalised at 15.73 volts at 15°C. As you say, it is best to read the manual for any particular battery to determine charge voltage.

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1 hour ago, bizzard said:

Very energizing, thank you. My wristwatch won't work anymore.

Would you like to xplain why putting batteries in the oven works, I used to do this with my U2 Every Ready for my Raleigh bicycle, but I assumed things had moved on. AND its prolly dangerous, btw.

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1 hour ago, BEngo said:

Mainly because 14.6 V is pretty much always safe with an open FLA battery and I did not know about your particular battery's max charge voltage or chemistry ( calcium, antimony etc). 

It would be worth a check that your battery maker is OK with 14.7 but at worst, for one charge, you are only going to use more water than expected by charging at 14.7.

Fancy AGM etc batteries are something other and need lower voltages.

N

Thanks for the explanation.

 

 

34 minutes ago, LadyG said:

Would you like to xplain why putting batteries in the oven works, I used to do this with my U2 Every Ready for my Raleigh bicycle, but I assumed things had moved on. AND its prolly dangerous, btw.

 

I used to do it with crisp packets to shrink them, and used fireworks, for what reason I haven't a bloody clue.

 

Kids eh 🙄

Edited by eid

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1 hour ago, LadyG said:

Would you like to xplain why putting batteries in the oven works, I used to do this with my U2 Every Ready for my Raleigh bicycle, but I assumed things had moved on. AND its prolly dangerous, btw.

Danger is good for you, it keeps you on your toes. Anyway Lady G when you go train spotting a good torch is needed, a big powerful LED one with U2 batteries. As train spotting at night is full of various delights and happy excitment, At night unusual locomotives can be seen on freight trains and you need the torch to shine on their numbers and to enter them in your Ian Allen trainspotters book. Carlisle station is good for this at night, as is Crewe both being big junction stations.  but take your own bottle of Scotch and oat cake nourishment with you as the licenced buffet will probably be closed.

Edited by bizzard

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1 minute ago, bizzard said:

Danger is good for you, it keeps you on your toes. Anyway Lady G when you go train spotting a good torch is needed, a big powerful LED one with U2 batteries. As train spotting at night is full of various delights and happy excitment, At night unusual locomotives can be seen on freight trains and you need the torch to shine on their numbers and to enter them in your Ian Allen trainspotters book. Carlisle station is good for this at night, as is Crewe both being big junction stations.  but take your own bottle of Scotch and nourishment with you as the licenced buffet will probably be closed.

No worries I don't go anywhere without essential supplies.

Carlisle Station has a super bar which serves hot cider, and quick snacks, which served its purpose last year when  the scheduled Virgin train failed to materialise, and the replacement turned up four hours late.

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1 hour ago, LadyG said:

Would you like to xplain why putting batteries in the oven works, I used to do this with my U2 Every Ready for my Raleigh bicycle, but I assumed things had moved on. AND its prolly dangerous, btw.

Chemical reactions get more viperous when hot so in a nominally flat at outside temperature the reaction between the carbon, zinc, and weakened alkaline would not produce enough electricity to       illuminate the bulb, get it hot and the reaction increases ---------- until it cools down.

 

One things for sure is that if you got it hot enough to  melt the pitch in the end it would make a mess and if you manages to boil the semi-liquid inside it might blow up but probably safe enough in ver low oven settings.

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