Battery Fault

[Tony Brooks]

1 hour ago, rusty69 said:

If only there was an alternative

There is but I doubt you or I would afford it (Datacell). However if only everyone would understand the bets way to use such meters is to measure tail current to know when the battery is full and the Ah out to asses the actual capacity there would be no need to recalibrate the things. The lying part would then be ignored.

[Ianmc]

19 hours ago, Tony Brooks said:

No, I did not sorry. Still the advice I gave to IanMC hold good for him and as for Jddevel I await more info. What I said to him may or may not be good advice.

I wish people would not confuse the issues in this way. All it will take is starting the post by something like "I have another problem and it seem this is a good pace to ask about it" if the post has to go into the topic. Better still start another one because that keeps all the info for ONE problem in one place and runs no risk of confusing the issue.

Thanks for the advise,and I'm sorry for confusion.

[WotEver]

50 minutes ago, Mike the Boilerman said:

 

Yes.  One that could be relied upon to be correctly calibrated straight from the box, you mean?

If only there was! 

Ahh yes. That would be the SmartGauge. Reportedly, a few faulty ones appeared a while back, but the manufacturer will happily replace them if that’s the case

[MtB]

33 minutes ago, WotEver said:

Ahh yes. That would be the SmartGauge. Reportedly, a few faulty ones appeared a while back, but the manufacturer will happily replace them if that’s the case

 

If only they could just send them out right in the first place, they wouldn't be needing to make such helpful and generous offers.

[WotEver]

13 minutes ago, Mike the Boilerman said:

 

If only they could just send them out right in the first place, they wouldn't be needing to make such helpful and generous offers.

As far as any of us are aware that’s exactly what they’re doing

[MtB]

1 minute ago, WotEver said:

As far as any of us are aware that’s exactly what they’re doing

 

And how would you know otherwise?

Out of the few of us here who have taken the trouble to actually check ours for accuracy, five so far have been found to be wrong.

Five out of perhaps ten or fifteen of us who have actually checked?

[WotEver]

Just now, Mike the Boilerman said:

 

And how would you know otherwise?

Out of the few of us here who have taken the trouble to actually check ours for accuracy, five so far have been found to be wrong.

Five out of perhaps ten or fifteen of us who have actually checked?

So return yours for exchange (like we’ve been suggesting for months and months) and then you’ll KNOW how accurate they are instead of simply repeating the same tired lines. 

[rusty69]

1 minute ago, WotEver said:

So return yours for exchange (like we’ve been suggesting for months and months) and then you’ll KNOW how accurate they are instead of simply repeating the same tired lines. 

Lets go round again 

[MtB]

1 minute ago, WotEver said:

So return yours for exchange (like we’ve been suggesting for months and months) and then you’ll KNOW how accurate they are instead of simply repeating the same tired lines. 

 

Missing the point by a country mile!

Even if I bought another that turned out to be correct, I'd carry on countering the irrational hero worship on here for Smartgauge by recounting my own person experience with faulty ones.  

[WotEver]

18 minutes ago, Mike the Boilerman said:

Even if I bought another that turned out to be correct, I'd carry on countering the irrational hero worship on here for Smartgauge by recounting my own person experience with faulty ones.  

How pointless. 

[rusty69]

35 minutes ago, Mike the Boilerman said:

 

Missing the point by a country mile!

Even if I bought another that turned out to be correct, I'd carry on countering the irrational hero worship on here for Smartgauge by recounting my own person experience with faulty ones.  

I'll give you a tenner for your two

[cereal tiller]

1 minute ago, rusty69 said:

I'll give you a tenner for your two

 

1 minute ago, rusty69 said:

I'll give you a tenner for your two

I'll raise you £15

[ditchcrawler]

Just now, cereal tiller said:

 

I'll raise you £15

If they work on 24 volts I may join in, Is this plus P&P

[rusty69]

1 minute ago, cereal tiller said:

 

I'll raise you £15

For £25,they're yours

Just now, ditchcrawler said:

If they work on 24 volts I may join in, Is this plus P&P

They don't on mikes 24V

[cereal tiller]

2 minutes ago, ditchcrawler said:

If they work on 24 volts I may join in, Is this plus P&P

They DO work on 24 Volts, for everyone except MtB.

[cuthound]

5 hours ago, jddevel said:

Victron BMV 702

In which case the battery capacity will probably need resetting to the actual capacity the batteries are now AND the % charge will need resetting when the batteries are fully charged (tail current  has remained stable for 3 consecutive 30 minute periods with the charger in absorbtion mode (14.4 volts).

The BMV may also need it's battery fully charged  (tail current) default resetting from the factory default of 4% to 1%.

To assess the battery capacity now, firstly reset the default tail current to 1%. Then fully charge the battery, then synchronise the battery percentage meter to read 100%. This will reset the amp-hours out to zero. Details of how to do the above are  BMV manual.

Let the battery discharge until the open circuit voltage is 12.1 volts, which represents 50% charge. Note how many amp-hours have been discharged on the BMV, and double this reading.  This is the actual capacity of your batteries now, and the reading that should be entered in your BMV.

It is good practice to assess the capacity of your batteries every 3 months.

 

[WotEver]

2 hours ago, cuthound said:

Let the battery discharge until the open circuit voltage is 12.1 volts

For those that don’t know, this is the voltage with everything turned off (including the fridge) for at least half an hour. 4 hours is better if you wish to be more accurate. If you have a SmartGauge then this can tell you the SoC instantly of course, with no messing around. 

http://batteryuniversity.com/learn/article/how_to_measure_state_of_charge

Edited November 23, 2017 by WotEver
Added link to support my ‘4 hours’ claim

[ditchcrawler]

1 hour ago, cuthound said:

 

It is good practice to assess the capacity of your batteries every 3 months.

 

Is it

[WotEver]

3 minutes ago, ditchcrawler said:

Is it

It is if you want the BMV to give anything like accurate results I guess. 

Edited November 23, 2017 by WotEver

[nicknorman]

It is if you have crappo batteries and don't look after them. On the other hand our batteries are 4 years old and still have their rated capacity. <looking for smug, self-satified smiley!>

[Dr Bob]

1 hour ago, WotEver said:

It is if you want the BMV to give anything like accurate results I guess. 

..but watch out for the temperature effect.  The capacity reduces with temperature so checking it tomorrow is going to show a much worse result than you got if you measured it 3 months ago (tomorrow is going to be cold).

[ditchcrawler]

1 hour ago, WotEver said:

It is if you want the BMV to give anything like accurate results I guess. 

Are got you, I miss understood again, I thought you were doing it to check the batteries not sort the meter out 

[cuthound]

1 hour ago, WotEver said:

It is if you want the BMV to give anything like accurate results I guess. 

Yup, depending on battery type, capacity can drop rapidly, particularly if your charging regime is less than optimal causing your batteries to lose capacity through sulphation.

I'm almost as good as Nick, because my 10 year old Lifeline AGM's still have over half of their badged capacity. 

[jddevel]

God this has given me a head ache. I sometimes wish I hadn`t asked the question- but then I`d miss the repartee. I`ll work on the premise that if it doesn`t seem right then I`d better get someone in who may no a bit more. A fool and his money but then that`s the story of my life. Married with 4 children, horses and now a canal boat. Will never learn.

[nicknorman]

3 hours ago, Dr Bob said:

..but watch out for the temperature effect.  The capacity reduces with temperature so checking it tomorrow is going to show a much worse result than you got if you measured it 3 months ago (tomorrow is going to be cold).

No, the capacity doesn't reduce with temperature. Only the rate that the battery can give up charge reduces.

 Well OK it depends on how you measure the capacity. Capacity is normally measured by draining the battery at a constant current corresponding to some proportion of the AH capacity until it reaches the terminating voltage of typically 10.5v. A cold battery will reach that terminating voltage sooner, because towards the end the chemicals can't react fast enough. But the charge isn't lost, its just sleeping! If you leave the battery to rest and/or drain it slower, the remaining charge can be extracted. In other words, you can get just as much charge out of a cold battery as a hot one, it just takes longer if its cold. So in the case of the voltage check, you just have to leave it longer for the true open circuit voltage to become apparent.

Since boat batteries are not normally fully discharged at a constant rate, that measure of capacity is fairly irrelevant. Certainly if the desire is not to go below 50% for cycle life reasons, there is no need to take temperature into account to decide how much AH can be taken out.

Edited November 23, 2017 by nicknorman