Another Smartgauge question.

[ROBDEN]

I have 4 x 110amp batteries. They are charged via the alternator.

When charging starts, the alternator reads 14.8v-14-9v and about 80-90amps.

 

Over time this gradually drops to around 14.4 volts and the current drops to

1 - 3 amps. Fully charged?

After turning off the engine the SmartGauge is only showing about 80-85 soc.

 

Which is correct?

Should I just re-set the SG?

 

Thanks for any help/advice.

 

Rob….

[Graham.m]

I have 4 x 110amp batteries. They are charged via the alternator.

When charging starts, the alternator reads 14.8v-14-9v and about 80-90amps.

 

Over time this gradually drops to around 14.4 volts and the current drops to

1 - 3 amps. Fully charged?

After turning off the engine the SmartGauge is only showing about 80-85 soc.

 

Which is correct?

Should I just re-set the SG?

 

Thanks for any help/advice.

 

Rob….

 

Think the first question is how long is over time?

 

Do you know what the battery voltage was before you started charging?

 

Have you any idea how many Ahs you had taken out of the battery?

 

What is the battery voltage say an hour after you stop charging?

Edited December 7, 2015 by Graham.m

[blackrose]

How many discharge/charge cycles have the batteries had since you've had the smartgauge? If it's new I think you need to discharge the batteries below 74% on the SG then recharge, and do that cycle 4 times for it to sync properly.

 

Just a thought.

Edited December 7, 2015 by blackrose

[ROBDEN]

SG fitted about 5 years ago.

New batteries 4 months ago.

Voltage before charging was 12.25v.

Voltage an hour or two after charging (dark outside) 12.75-12.8.

 

Rob....

[Graham.m]

SG fitted about 5 years ago.

New batteries 4 months ago.

Voltage before charging was 12.25v.

Voltage an hour or two after charging (dark outside) 12.75-12.8.

 

Rob....

 

What are the new batteries seal or open batteries (you can top the water up)

 

12.25 suggests a SOC of 60%

 

12.75-12.8 after an hours suggest the batteries were very close if not fully charged

 

So 40% of 440 suggest 176 Ahs used

Edited December 7, 2015 by Graham.m

[Graham.m]

Did you happen to note the SG read an hour or so after charging?

[Tony Brooks]

"Drops to around 14.4". This sounds a bit odd to me unless there is a smart regulator in use OR the alternator temperature is being monitored, just maybe the battery temperature.

 

Anyway 14.8 to 14.9 sounds very high straight after the first start although I think Beta did fit some 14.8 volt alternators.

 

Is this reading from an accurate voltmeter and if hand held is its battery still OK?

[nicknorman]

Where and how are you measuring the voltage and current? The initial voltage seems very high. Perhaps it is a battery-sensed alternator and/or it has a fancy regulator? What size alternator? Even so to get 14.8v at what is presumably max current seems surprising. Final question, what are the Smartgauge wires connected to?

 

So you started at a little over 50% SoC and so if the batteries have their original capacity you would need to add 200AH or so which is quite a lot. It would take many hours to do that, maybe 6 or 8.

[Graham.m]

My alternator's initial charge voltage is in the area of 14.7 volts and drops eventually to about 14. I suspect this is a function of the regulator.

 

My big concern is the batteries have been changed from Floods to sealed. In which case the charge voltage could be too high and might be damaging the batteries.

[Graham.m]

The boat listing suggests a 42hp engine and a boat possibly 5 or more years old. could be a Beta engine

 

Downeaster Built by Price, Fallows & Company Ltd - Length : 17.37 metres ( 57 feet ) - Beam : 2.08 metres ( 6 feet 10 inches ). Metal hull N/A power of 42 HP. Registered with Canal & River Trust number 511347 as a Powered Motor Boat. ( Last updated on Wednesday 22nd May 2013 )

 

The Duchess Built by Price, Fallows & Company Ltd - Length : 17.37 metres ( 57 feet ) - Beam : 2.08 metres ( 6 feet 10 inches ) - Draft : 0.01 metres ( 0 feet ). Metal hull N/A power of 42 HP. Registered with Canal & River Trust number 511347 as a Powered Motor Boat. ( Last updated on Sunday 11th April 2010 )

[by'eck]

I have 4 x 110amp batteries. They are charged via the alternator.

When charging starts, the alternator reads 14.8v-14-9v and about 80-90amps.

 

Over time this gradually drops to around 14.4 volts and the current drops to

1 - 3 amps. Fully charged?

After turning off the engine the SmartGauge is only showing about 80-85 soc.

 

Which is correct?

Should I just re-set the SG?

 

Thanks for any help/advice.

 

Rob….

 

Very surprised at the initial voltage readings. Would have expected them to be closer to the reverse at beginning and end of charge. When you say the alternator reads 14.8-14.9 volts how are you reading this, and could you confirm the voltage at the batteries at that point using say an accurate multi-meter.

 

Out of interest what output alternator do you have and does it have an external regulator?

Edited December 7, 2015 by by'eck

[nicknorman]

My alternator's initial charge voltage is in the area of 14.7 volts and drops eventually to about 14. I suspect this is a function of the regulator.

 

My big concern is the batteries have been changed from Floods to sealed. In which case the charge voltage could be too high and might be damaging the batteries.

Is that the voltage at the alternator, or at the battery terminals? In the OP's case and if it is the voltage at the battery terminals, something doesn't stack up because when our alternator first gets going it will be putting in 175A, with a terminal voltage of sub-14v. To get the battery voltage straight up to 14.8 the alternator would need to be putting in several hundred amps.

[Graham.m]

Is that the voltage at the alternator, or at the battery terminals? In the OP's case and if it is the voltage at the battery terminals, something doesn't stack up because when our alternator first gets going it will be putting in 175A, with a terminal voltage of sub-14v. To get the battery voltage straight up to 14.8 the alternator would need to be putting in several hundred amps.

 

Mine is at batteries, of course, although the volt drop is less than 0.1V A to B

 

We don't know what alternator this is. Initial is given at 14.8 @ 80A. Remember this is memory and could be a red herring, could be an hour after start of charge.

 

Either way concerned the new batteries are seal and the old were floods and there could be battery damage and life shortening

[Tony Brooks]

As I said, the drop in voltage could be to do with temperature monitoring within the regulator BUT that does not explain the high charging voltage on initial start up because with more than about 10 to 20 amps output the alternator design (not the regulator) will depress the charging voltage. Then as the batteries charge and the current falls the voltage creeps up. This has nothing to do with any internal or external regulator.

 

In both cases above something seem very odd.

 

The only advice one can give Graham is to check with the battery distributor/importer because the initial voltage seems high for sealed flooded cells but may well be perfectly OK or certain designs of AGM. However as it takes maybe 20 minutes to start gassing as long as the voltage has fallen within that time it could all be fine.

[Graham.m]

Rob,

 

My suggestion the next time you charge

 

Note the SG reading at the beginning of charge, end of charge and an hour or so later

 

Note the voltage at the battery if possible at start of charge, end of charge and an hour or so later

 

If the SG has not reset itself I would do a reset and watch for a repeat next time you charge

 

 

The only advice one can give Graham is to check with the battery distributor/importer because the initial voltage seems high for sealed flooded cells but may well be perfectly OK or certain designs of AGM. However as it takes maybe 20 minutes to start gassing as long as the voltage has fallen within that time it could all be fine.

 

Sorry I do not understand your comment why would I need advice?

Edited December 7, 2015 by Graham.m

[ROBDEN]

This the same set up as my last set of batteries. They lasted over 4 years and were charged/discharged every day.

 

Batteries are sealed due to access.

Vetus 4.17 engine. 100 amp Iskra alternator with a Sterling reg' thingy on. ( Can get 100 amps at start up but have to rev to about 1400revs.)

 

Current measured with multi-meter and engine ammeter....both read the same.

SG fitted directly to battery posts.

 

I'll start the engine now and give you the readings.....back in a tick.

 

Right then. SG reads 12.25v/soc60.

Engine at 1000 revs. After 2 minutes 14.5v@78amps. After 5 minutes, 1000 revs, 14.8/14.9v@63 amps.

 

Anyway. What ever condition the batteries are in, if they can't take any more power ie: reading 1-3 amps, shouldn't the SG read 100% soc?

Regardless of whether 400 amps or 100 amps available?

 

Rob....

Rob,

 

My suggestion the next time you charge

 

Note the SG reading at the beginning of charge, end of charge and an hour or so later

 

Note the voltage at the battery if possible at start of charge, end of charge and an hour or so later

 

If the SG has not reset itself I would do a reset and watch for a repeat next time you charge

 

Sorry I do not understand your comment why would I need advice?

I think Tony has you confused with me......Bless.

Edited December 7, 2015 by ROBDEN

[Tony Brooks]

Rob,

 

My suggestion the next time you charge

 

Note the SG reading at the beginning of charge, end of charge and an hour or so later

 

Note the voltage at the battery if possible at start of charge, end of charge and an hour or so later

 

If the SG has not reset itself I would do a reset and watch for a repeat next time you charge

 

Sorry I do not understand your comment why would I need advice?

 

This from post 13:- " Either way concerned the new batteries are seal and the old were floods and there could be battery damage and life shortening"

 

Snip

I think Tony has you confused with me......Bless.

 

Not unless you used Graham's name for #13 or the forum screwed the names up.

[ditchcrawler]

So is it the Stirling giving the voltage changes acting like a smart charger

[ROBDEN]

 

This from post 13:- " Either way concerned the new batteries are seal and the old were floods and there could be battery damage and life shortening"

 

Not unless you used Graham's name for #13 or the forum screwed the names up.

I beg you pardon Tony.

 

Rob....

[Tony Brooks]

I beg you pardon Tony.

 

Rob....

 

No probes, whatever turns up I am as interested as you in the outcome, especially as it APPEARS that two members have similar charging voltage profiles.

[nicknorman]

This the same set up as my last set of batteries. They lasted over 4 years and were charged/discharged every day.

 

Batteries are sealed due to access.

Vetus 4.17 engine. 100 amp Iskra alternator with a Sterling reg' thingy on. ( Can get 100 amps at start up but have to rev to about 1400revs.)

 

Current measured with multi-meter and engine ammeter....both read the same.

SG fitted directly to battery posts.

 

I'll start the engine now and give you the readings.....back in a tick.

 

Right then. SG reads 12.25v/soc60.

Engine at 1000 revs. After 2 minutes 14.5v@78amps. After 5 minutes, 1000 revs, 14.8/14.9v@63 amps.

 

Anyway. What ever condition the batteries are in, if they can't take any more power ie: reading 1-3 amps, shouldn't the SG read 100% soc?

Regardless of whether 400 amps or 100 amps available?

 

Rob....

 

I think Tony has you confused with me......Bless.

The voltage and current readings you give here are more "believable" however you started at 60% SoC and within 5 minutes had 14.9v at 63A, that means the batteries are totally shagged. Perhaps as Graham said they are out of water. To confirm this, we are still missing the vital information which is roughly how long did it take to go from 60%SoC to the 1-3 Amps condition?

 

Basically what you are saying is correct in that once the current is down to 1-3A (presuming this is measured accurately) the batteries are fully charged. The Smartgauge tends to "see" the nature of the charger rather than the nature of the batteries during charge, and so it's charging algorithm is more along the lines of a voltage time integral, ie if you hold the voltage at X volts, starting from y SoC, it must be charged after z hours:minutes. However if the batteries are badly damaged this tends to not work very well. The designer was known to have said that the SG starts to not work well once batteries are damaged to below 50% of their original capacity, although in my experience it remains reasonable until well below this figure.

 

Have you noticed a significant reduction in the time it takes to get to the 1-3A condition and/or the SoC declining much more quickly than it used to? Both are indicative of knackered batteries.

[Graham.m]

 

 

Anyway. What ever condition the batteries are in, if they can't take any more power ie: reading 1-3 amps, shouldn't the SG read 100% soc?

Regardless of whether 400 amps or 100 amps available?

 

Rob....

 

Rob,

 

I agree with you and it looks as if it is out of sync. As I suggested above next time you charge note the readings and see if the SG gets back in sync within an hour or so. If not do a resync. On the next charge watch for a repeat, if it does fail to sync let us know.

 

Obviously the batteries you have have been matched to your system and need be not worry to us if yopu are totally happy. It is just some sealed batteries will be damaged if charged at voltages above about 14.4V, obviously does not apply to you.

Edited December 7, 2015 by Graham.m

[Graham.m]

 

This from post 13:- " Either way concerned the new batteries are seal and the old were floods and there could be battery damage and life shortening"

 

 

Tony, Sorry I still do not understand you, think you are misreading the posts and thread. You seem to think I am taking about my batteries if so you are incorrect

[ROBDEN]

The voltage and current readings you give here are more "believable" however you started at 60% SoC and within 5 minutes had 14.9v at 63A, that means the batteries are totally shagged. Perhaps as Graham said they are out of water. To confirm this, we are still missing the vital information which is roughly how long did it take to go from 60%SoC to the 1-3 Amps condition?

 

Basically what you are saying is correct in that once the current is down to 1-3A (presuming this is measured accurately) the batteries are fully charged. The Smartgauge tends to "see" the nature of the charger rather than the nature of the batteries during charge, and so it's charging algorithm is more along the lines of a voltage time integral, ie if you hold the voltage at X volts, starting from y SoC, it must be charged after z hours:minutes. However if the batteries are badly damaged this tends to not work very well. The designer was known to have said that the SG starts to not work well once batteries are damaged to below 50% of their original capacity, although in my experience it remains reasonable until well below this figure.

 

Have you noticed a significant reduction in the time it takes to get to the 1-3A condition and/or the SoC declining much more quickly than it used to? Both are indicative of knackered batteries.

Thanks for that. I'll let you know after this run.

 

Rob....

[MtB]

Charging a 440Ahr bank at 80-90 Amps seems in the high side too.

 

ISTR reading Gibbo saying charging batteries at a far higher rate than the 10% 'rule of thumb' works fine, but at a cost of much shortened battery life.