What does this hydrometer reading mean?

[woodfin]

My hydrometer acid level for all three domestic batteries is exactly on the line between green and white. Does this mean that the batteries are on the way out? I had charged the them the previous day and the charge reading was about 12.3.

 

George

[alan_fincher]

My hydrometer acid level for all three domestic batteries is exactly on the line between green and white. Does this mean that the batteries are on the way out? I had charged the them the previous day and the charge reading was about 12.3.

 

George

I suspect you mean 1.23, not 12.3 !

 

It means the electrolyte is 1.23 times more dense than pure water. (If it were 12.3 times the density of water, that would be impressive, as a lot of it is water!)

 

I assume your particular one is divided something like Red/White/Green ? (They are not all the same).

 

They don't sound fully charged to me, but how do you know you have charged them completely, before assuming they are starting to fail.

 

It could just be that your charging regime never gets them fully charged.

 

(The experts will know, but I suspect 1.23 equates to around three quarters charged - I could be wrong, though).

[Wiltshire Moonraker]

I had charged the them the previous day and the charge reading was about 12.3.

 

.... or do you mean 12.3 volts?

[chris w]

Either way (12.3v or 1.23SG) the batteries are about 60% charged only.

 

Chris

[Gibbo]

My hydrometer acid level for all three domestic batteries is exactly on the line between green and white. Does this mean that the batteries are on the way out? I had charged the them the previous day and the charge reading was about 12.3.

 

George

 

Assuming that's 12.3 volts then they're almost half flat.

 

Gibbo

[Tony Brooks]

My hydrometer acid level for all three domestic batteries is exactly on the line between green and white. Does this mean that the batteries are on the way out? I had charged the them the previous day and the charge reading was about 12.3.

 

George

 

If you really did fully them it may well mean you have lost capacity due to sulphation. The sulphur from the acid may be bound into the lead plates and thus the lower than fully charged reading. It would help if we also had the voltage reading after being charged, then stood overnight with nothing being drawn from them.

 

Whether they are only 60% charged or you only have 60% of the original capacity does not matter if they are performing well enough for you. The things to watch fro when using a hydrometer is discoloured liquid or a difference between any two cells in a battery of more then 0.03. Both are signs of failure - as is the need to constantly top up just one or two cells.

[alan_fincher]

Sorry,

 

As the question was about hydrometers, I assumed it was an attempt to quote a hydrometer reading.

 

Either way, as Chris says 12.3 volts probably ain't far from 1.23 SG on the hydrometer.

 

It would be interesting to know what the actual reading is "in the line between the green and the white though".

 

And what's being used to measure 12.3 volts, because if it's a panel meter it's probably not even close to accurate.

 

Just off to do mine, so I'll see what it is on my hydrometer.

[Tony Brooks]

Sorry,

 

As the question was about hydrometers, I assumed it was an attempt to quote a hydrometer reading.

 

Either way, as Chris says 12.3 volts probably ain't far from 1.23 SG on the hydrometer.

 

It would be interesting to know what the actual reading is "in the line between the green and the white though".

 

And what's being used to measure 12.3 volts, because if it's a panel meter it's probably not even close to accurate.

 

Just off to do mine, so I'll see what it is on my hydrometer.

 

 

Just checked mine - 1.250

[Gibbo]

Ahhhh but.........

 

The SG and voltage (assuming a long enough rest period) both roughly show the same state of charge ie about 60% or thereabouts.

 

If the battery had lost capacity the SG and the voltage wouldn't tie up. For instance, a battery that has lost 25% of its original capacity will show, when fully charged about 60% between the flat SG and the full SG, but the voltage will still show the battery to be fully charged (which it is, it's just now a smaller battery).

 

So I don't think they have lost capacity, I think they are just flat. It's possible they are broken, but no way to tell without seeing them.

 

Gibbo

[woodfin]

.... or do you mean 12.3 volts?

Yes

[woodfin]

Many thanks for the help so far. Forgive me for not expressing the details better. To try to be a little clearer: I charged the batteries on the previous day, (40amp 3 stage charger which indicated 90% full) and switched ithe charger to power mode. I took the SG and multi-meter readings on the next day. I would have expected the SG float to have been half-way up the green colour (it was on the charger battery) but, instead it was on the line between the green and white on the cells of the 3 domestic batteries. It leaves me suspecting that these batteries are on the way out. Am I right?

 

George

Edited May 11, 2009 by woodfin

[Gibbo]

Many thanks for the help so far. Forgive me for not expressing the details better. To try to be a little clearer: I charged the batteries on the previous day, (40amp 3 stage charger which indicated 90% full) and switched ithe charger to power mode. I took the SG and multi-meter readings on the next day. I would have expected the SG float to have been half-way up the green colour (it was on the charger battery) but, instead it was on the line between the green and white on the cells of the 3 domestic batteries. It leaves me suspecting that these batteries are on the way out. Am I right?

 

George

 

Where do you get the 90% from following the charge?

 

If the charger was on power pack mode why were the batteries only at 12.3 volts?

 

That indicates that the batteries don't charge when in powerpack mode, so what loads could have been on the batteries?

 

Gibbo

[woodfin]

Where do you get the 90% from following the charge?

 

If the charger was on power pack mode why were the batteries only at 12.3 volts?

 

That indicates that the batteries don't charge when in powerpack mode, so what loads could have been on the batteries?

 

Gibbo

 

The charger indicated, I think 90 or 100% charged. There was about 2 hours TV use on the previous evening and a fridge running continually. The charger has separate switches for power and battery charging. so probably does not charge in power mode. Could it be that the batteries are not holding the charge? They are over three years old.

 

George

[GSer]

It's just my opinion of course, but if the batteries are doing what you want don't try and chase perfect textbook sg/V readings/figures.

 

There are so many variables involved that the technical side is best left to the more 'anal' amongst us

 

Mind you if you are having problems that's a different thing. Good luck!

 

Paul

[Gibbo]

The charger indicated, I think 90 or 100% charged. There was about 2 hours TV use on the previous evening and a fridge running continually. The charger has separate switches for power and battery charging. so probably does not charge in power mode. Could it be that the batteries are not holding the charge? They are over three years old.

 

George

 

If the charger has separate switches for power pack mode then presumeably it also has separate outputs for the loads to be connected to. If that is the case then have you actually done this?

 

If that's not the case then it clearly isn't charging the batteries when in power pack mode and your fridge would easily account for the lowered state of charge.

 

It's all very unclear on what is connected to what so it's all pretty much guesswork.

 

Gibbo

[woodfin]

If the charger has separate switches for power pack mode then presumeably it also has separate outputs for the loads to be connected to. If that is the case then have you actually done this?

 

If that's not the case then it clearly isn't charging the batteries when in power pack mode and your fridge would easily account for the lowered state of charge.

 

It's all very unclear on what is connected to what so it's all pretty much guesswork.

 

Gibbo

 

Thanks for still considering this. The charger plugs into the mains and its leads are connected to the domestic batteries. I had left the charger on 'charging' all night, switched to power mode and took the readings the next morning. Perhaps I should begin again when next on board by leaving the charger on for a day or two and taking a fresh SG reading.

 

George

[Gibbo]

Thanks for still considering this. The charger plugs into the mains and its leads are connected to the domestic batteries. I had left the charger on 'charging' all night, switched to power mode and took the readings the next morning. Perhaps I should begin again when next on board by leaving the charger on for a day or two and taking a fresh SG reading.

 

George

 

But where are the loads connected when it is "switched to power mode". If they are still connected to the batteries then it's not doing what it supposed to do. The voltage should not have fallen that low.

 

There are two types of chargers with "power mode".

 

In one type the loads remain connected to the batteries. When the charger goes into "power mode" it effectively just holds the batteries at around 13.4 volts and it should never drop below that.

 

The other type have a separate pair of terminals where the loads are connected. When switched to "power mode" the loads are powered directly from the charger without any involvement from the batteries.

 

From what you have said so far yours is either broken or not wired up correctly.

 

Give us an owners manual or at least something to go on.

 

Gibbo

[woodfin]

But where are the loads connected when it is "switched to power mode". If they are still connected to the batteries then it's not doing what it supposed to do. The voltage should not have fallen that low.

 

There are two types of chargers with "power mode".

 

In one type the loads remain connected to the batteries. When the charger goes into "power mode" it effectively just holds the batteries at around 13.4 volts and it should never drop below that.

 

The other type have a separate pair of terminals where the loads are connected. When switched to "power mode" the loads are powered directly from the charger without any involvement from the batteries.

 

From what you have said so far yours is either broken or not wired up correctly.

 

Give us an owners manual or at least something to go on.

 

Gibbo

 

Thanks. Will get details when I go on board next week. Details of the charger are at the site in the link below.

 

http://caravantechnology.com/CandL40ABatteryCharger.aspx

 

George

[Gibbo]

Thanks. Will get details when I go on board next week. Details of the charger are at the site in the link below.

 

http://caravantechnology.com/CandL40ABatteryCharger.aspx

 

George

 

It looks to me like the charger isn't working in power pack mode because of it was working it wouldn't have let the voltage drop that low.

 

Gibbo

[woodfin]

It looks to me like the charger isn't working in power pack mode because of it was working it wouldn't have let the voltage drop that low.

 

Gibbo

 

Thanks, I'll get it checked.

 

George