Smartgauge question.

[ROBDEN]

Morning all.

 

I have 4x110 amp sealed batteries. 3 years old. Used every day.

The Smartgauge connection has not been broken for at least 2 years.

 

Now, when the Sg reads, soc 100%, could this be verified by breaking open one of the sealed batteries and taking a specific gravity reading (I think it should be about 1.26-1.27 (?)) or would I have to check all the cells on all the batteries?

 

Thanks as always for any replies.

Rob….

[Murflynn]

I understand that the SG is self adjusting for a new installation, taking a few charge/discharge cycles to settle down.

Could you disconnect it and then connect again as in a new installation?

[ROBDEN]

I understand that the SG is self adjusting for a new installation, taking a few charge/discharge cycles to settle down.

Could you disconnect it and then connect again as in a new installation?

I could...but why?

[BargeeSpud]

Tony Brooks in the Back Cabin section of the latest Canal Boat mag (Nov), gives a very good way of determining this.

 

I've had my SG for nearly a year now, & whilst its very good, I'm reluctant to rely solely on what it tells me because a battery bank's SOC will drop off over time & you can almost never reach 100% SOC anyway. I believe that SG will give you a reading of 100% of the actual SOC the batteries are capable of achieving, which could only be 80% in reality, so the SG reading is really a self fulfilling prophecy in practice.

 

So long as you remember that, you'll get the best out of a very good instrument & my only regret is trashing my Adverc Battery Monitor when I fitted the SG. I should've run them both in tandem for a complete picture.

[nicknorman]

During charge, the Smartgauge essentially works by integrating charge voltage and time (there's a bit more to it than that). In other words, it holds a presumption that if you (for example) hold the battery voltage at 14.4v for x hours (x depending on the SoC when charging started) then the battery will be fully charged.

 

Fully charged as in it will take virtually no more charge. Not fully charged as in Specific Gravity at the manufacturer's original value of 1.27 or whatever. A sulphated battery will stop taking charge current before the specific gravity reaches ~1.27.

 

It would be interesting if you did measure that specific gravity at 100% SoC - almost certainly it will be below the 1.27 to 1.28 you expect, but doing an equalising charge may improve this, and if you have the lid off you will be able to top up any lost water.

 

As to whether you need to check just one, or all cells, it depends on what you are trying to achieve. No doubt all cells will be down on specific gravity, with some worse than others, but not sure what measuring that will achieve.

Edited October 6, 2014 by nicknorman

[ROBDEN]

During charge, the Smartgauge essentially works by integrating charge voltage and time (there's a bit more to it than that). In other words, it holds a presumption that if you (for example) hold the battery voltage at 14.4v for x hours (x depending on the SoC when charging started) then the battery will be fully charged.

 

Fully charged as in it will take virtually no more charge. Not fully charged as in Specific Gravity at the manufacturer's original value of 1.27 or whatever. A sulphated battery will stop taking charge current before the specific gravity reaches ~1.27.

 

It would be interesting if you did measure that specific gravity at 100% SoC - almost certainly it will be below the 1.27 to 1.28 you expect, but doing an equalising charge may improve this, and if you have the lid off you will be able to top up any lost water.

 

As to whether you need to check just one, or all cells, it depends on what you are trying to achieve. No doubt all cells will be down on specific gravity, with some worse than others, but not sure what measuring that will achieve.

Thanks Nicknorman.

 

I can't do an equalising charge as I can only charge from my alternator.

 

Wouldn't the specific gravity reading still be 1.26ish if the batteries are fully charged no matter what number amps remain?

I thought, that reading, was for any battery whether a 50 amp or a 235 amp battery.

 

OH! Have I just answered my own question?

 

Rob....

[nicknorman]

Thanks Nicknorman.

 

I can't do an equalising charge as I can only charge from my alternator.

 

Wouldn't the specific gravity reading still be 1.26ish if the batteries are fully charged no matter what number amps remain?

I thought, that reading, was for any battery whether a 50 amp or a 235 amp battery.

 

OH! Have I just answered my own question?

 

Rob....

Just to clarify, the specific gravity gives an indication of how complete the chemical reaction is. So when a new battery is fully charged, all the chemicals that could react to store charge, have done so, and thus the specific gravity should be 1.27-ish. But if a battery is sulphated, that means that some of the chemical is locked into hard sulphate crystals, so even though the battery won't take any more charge, the specific gravity remains below 1.27 due to the "lost" chemicals locked up in the sulphate crystals. Also there may be a tendency for the acid in the batteries to stratify, with a stronger concentration (hence higher specific gravity) of acid near the bottom, and a weaker concentration (hence lower specific gravity) nearer the top. Equalisation can help with both these things. If your alternator only goes to 14.4v or so, it might be worth contemplating some sort of external alternator controller to increase the voltage.

 

But first, check the specific gravities to see if you do actually have a problem.

[ROBDEN]

Just to clarify, the specific gravity gives an indication of how complete the chemical reaction is. So when a new battery is fully charged, all the chemicals that could react to store charge, have done so, and thus the specific gravity should be 1.27-ish. But if a battery is sulphated, that means that some of the chemical is locked into hard sulphate crystals, so even though the battery won't take any more charge, the specific gravity remains below 1.27 due to the "lost" chemicals locked up in the sulphate crystals. Also there may be a tendency for the acid in the batteries to stratify, with a stronger concentration (hence higher specific gravity) of acid near the bottom, and a weaker concentration (hence lower specific gravity) nearer the top. Equalisation can help with both these things. If your alternator only goes to 14.4v or so, it might be worth contemplating some sort of external alternator controller to increase the voltage.

 

But first, check the specific gravities to see if you do actually have a problem.

 

Thanks again for the clarification, now I understand.

 

I do have an old Sterling PAR (?) unit that someone gave me a while ago but don't know why it was removed in the first place or that it even works.

 

I seem to remember reading somewhere, that by connecting a wire from somewhere on the alternator, to the batteries, with a resistor and pot, you can have battery sensing for not a lot of money. I'll have to do some searching on the interweb.

 

Thanks. Rob....

[Proper Job]

Rob

 

Can I ask the question, why do you think the Smartgauge is give you wrong information?

[ROBDEN]

Rob

 

Can I ask the question, why do you think the Smartgauge is give you wrong information?

 

I don't. In fact I probably rely on it too much. I still think it's the best bit of kit I've bought for some time.

 

I was just wondering if it can be verified is all.

 

Rob....

[ROBDEN]

 

Thanks again for the clarification, now I understand.

 

I do have an old Sterling PAR (?) unit that someone gave me a while ago but don't know why it was removed in the first place or that it even works.

 

I seem to remember reading somewhere, that by connecting a wire from somewhere on the alternator, to the batteries, with a resistor and pot, you can have battery sensing for not a lot of money. I'll have to do some searching on the interweb.

 

Thanks. Rob....

 

Just found an old post by Arnot regarding the above but that was for a Lucas A127 alternator.

 

As yet, I don't know what breed my alt' is, as it's on a Vetus 4.19. So that's expensive then.

 

Rob....

[Phil.]

I have a similar issue. SG is showing C100 but I have just checked all the cells of six trojan T105s. Most cells gave a reading of 1.23 with a couple of cells showing 1.22. This I believe is about 80% not the 100 the SG is showing. I think from reading the other posts I need to equalise them so I have two questions

1 can I equalise using my mastervolt combi with the travel power or does it have to be shorepower and if so how do you get the combi to do the charging rather than the engine alternator.

2 after equalising does the smartguage re calibrate itself automatically

Thanks and hope I have not hijacked OP

[dmr]

There should be no difference between the electricity made by Travelpower or that from the shore, but the Travelpower only works when running the engine so equalisation will cost a few litres of diesel.

After equalisation the Smartgage goes a bit daft for a day or two then it sorts itself out.

 

(Before the electrikery pedants get me there is a little difference with TravelPower but it should not concern you, however I know nothing about the Mastervolt so hopefully somebody else will confirm)

 

.............Dave

[nicknorman]

I have a similar issue. SG is showing C100 but I have just checked all the cells of six trojan T105s. Most cells gave a reading of 1.23 with a couple of cells showing 1.22. This I believe is about 80% not the 100 the SG is showing. I think from reading the other posts I need to equalise them so I have two questions

1 can I equalise using my mastervolt combi with the travel power or does it have to be shorepower and if so how do you get the combi to do the charging rather than the engine alternator.

2 after equalising does the smartguage re calibrate itself automatically

Thanks and hope I have not hijacked OP

You are in the same situation I was recently - despite 100% on both the Smartgauge and an amphour-counting gauge, the specific gravities were low (not as bad as your's). I was limited on time but having equalised for 3 hours the gravities were back up approaching 1.270.

 

Yes you can equalise from your TravelPower via the Mastervolt Combi, but of course you will have to have the engine running for several hours, and first of all you need to ensure the batteries are fully charged (ie 100% on the Smartgauge).

 

To get the Combi to do the equalising, and assuming it is fed from the TravelPower, you need to increase the Combi's charging voltage to be 15.5 volts or so. With the Combi voltage above the alternator's regulated voltage, the alternator's output current just falls to zero and the Combi takes over seamlessly.

 

There are a couple of ways to get the Combi to equalise. The easiest is to operate the DIP switch inside (read the manual!) which puts the Combi into a timed equalise. The trouble I have found with this is that on ours, this equalise mode seems to be automatically stopped after quite a short time, and it has to be manually activated again and again at roughly 30 minute intervals.

 

A much better way is to connect to the Mastervolt Combi with a laptop or a remote panel like the Masterview and then increase the bulk and absorption voltages to 15.5v. Of course you have to return these settings to their normal values after you decide to stop the equalise process (no more increase in specific gravity). Whilst in my experience this is a much better way of doing it, it does of course come at the cost of, as a minimum, a MV Combi to USB interface (assuming you already have a laptop). Although I do have one which, since I got the Masterview, is not needed...

Edited October 6, 2014 by nicknorman

[ROBDEN]

You are in the same situation I was recently - despite 100% on both the Smartgauge and an amphour-counting gauge, the specific gravities were low (not as bad as your's). I was limited on time but having equalised for 3 hours the gravities were back up approaching 1.270.

 

Yes you can equalise from your TravelPower via the Mastervolt Combi, but of course you will have to have the engine running for several hours, and first of all you need to ensure the batteries are fully charged (ie 100% on the Smartgauge).

 

To get the Combi to do the equalising, and assuming it is fed from the TravelPower, you need to increase the Combi's charging voltage to be 15.5 volts or so. With the Combi voltage above the alternator's regulated voltage, the alternator's output current just falls to zero and the Combi takes over seamlessly.

 

There are a couple of ways to get the Combi to equalise. The easiest is to operate the DIP switch inside (read the manual!) which puts the Combi into a timed equalise. The trouble I have found with this is that on ours, this equalise mode seems to be automatically stopped after quite a short time, and it has to be manually activated again and again at roughly 30 minute intervals.

 

A much better way is to connect to the Mastervolt Combi with a laptop or a remote panel like the Masterview and then increase the bulk and absorption voltages to 15.5v. Of course you have to return these settings to their normal values after you decide to stop the equalise process (no more increase in specific gravity). Whilst in my experience this is a much better way of doing it, it does of course come at the cost of, as a minimum, a MV Combi to USB interface (assuming you already have a laptop). Although I do have one which, since I got the Masterview, is not needed...

 

What an idiot. Me not you.

 

I've got travel power. So if I buy a suitable charger, I could equalise my batteries when travelling for a few ours?

Any recommendations as to which charger?

 

Rob....

 

I have a similar issue. SG is showing C100 but I have just checked all the cells of six trojan T105s. Most cells gave a reading of 1.23 with a couple of cells showing 1.22. This I believe is about 80% not the 100 the SG is showing. I think from reading the other posts I need to equalise them so I have two questions

1 can I equalise using my mastervolt combi with the travel power or does it have to be shorepower and if so how do you get the combi to do the charging rather than the engine alternator.

2 after equalising does the smartguage re calibrate itself automatically

Thanks and hope I have not hijacked OP

Thanks for the hijacking, it's made me realize something.

Rob..

[Phil.]

Thanks dmr and nick.

That has answered it for me. I knew that a dip switch in the mastervolt puts it int equalise mode I just did not know that the alternator would just drop out of charging automatically.

One last question. Before doing this I assume I switch off everything whilst equalising but do not isolate the battery. Will things directly connected to battery terminals be ok i.e. smartguage and bilge pump etc.

[nicknorman]

Thanks dmr and nick.

That has answered it for me. I knew that a dip switch in the mastervolt puts it int equalise mode I just did not know that the alternator would just drop out of charging automatically.

One last question. Before doing this I assume I switch off everything whilst equalising but do not isolate the battery. Will things directly connected to battery terminals be ok i.e. smartguage and bilge pump etc.

You will get the E05 (?) on the smartgauge - over voltage alarm - but it will clear once you remove the high voltage and press any button on it. For other stuff, I wouldn't worry about pumps or fridge, they will be fine. I would avoid turning on other stuff such as lights (unless they are the LED type that can cope with up to 30v) and other things like TVs that might be connected direct to the 12v system.

 

You will be able to keep an eye on the charge voltage using the Smartgauge and I suspect you may find, like me, that the equalise mode exits fairly quickly after around 30 minutes and has to be re-triggered. Obviously you want to avoid running the engine for hours thinking you are doing an equalise when it dropped out hours ago!

Edited October 6, 2014 by nicknorman

[Phil.]

Thanks Nick will give it a go as no access to shorepower for at least 3 more weeks will update with the outcome

[by'eck]

I apologise if speaking out of turn here but it seems that many people use conservative charge voltages then find they have to equalise their batteries regularly to recover lost capacity.

 

Forum opinions seem to err on the side of caution where absorb charge voltages are concerned, e.g. max 14.4 volts with sealed batteries at least because that's what the dealer/sales info tells them. Others simply follow advice given regularly on this forum that because they have modern alternators the regulated charge voltage of 14.4 volts is fine.

 

If using lead/acid batteries, particularly those of lead/calcium construction, I would advocate using higher either via a cheap diode mod to your alternator as suggested here by Gibbo, or using an external regulator (Sterling/Adverc) providing greater control whilst set to a higher absorb voltage. If you have a mains charger that too can usually be set to a higher voltage.

 

As I've said before the 14.8 volt absorb voltage used on my current sealed batteries has done them no harm and didn't with previous sets after five years or more of use (tell-tales still working indicating electrolyte reserve), providing the higher voltage is only maintained during the absorb phase. Tail current when fully charged is so minimal gassing is never an issue.

[nicknorman]

I apologise if speaking out of turn here but it seems that many people use conservative charge voltages then find they have to equalise their batteries regularly to recover lost capacity.

 

Forum opinions seem to err on the side of caution where absorb charge voltages are concerned, e.g. max 14.4 volts with sealed batteries at least because that's what the dealer/sales info tells them. Others simply follow advice given regularly on this forum that because they have modern alternators the regulated charge voltage of 14.4 volts is fine.

 

If using lead/acid batteries, particularly those of lead/calcium construction, I would advocate using higher either via a cheap diode mod to your alternator as suggested here by Gibbo, or using an external regulator (Sterling/Adverc) providing greater control whilst set to a higher absorb voltage. If you have a mains charger that too can usually be set to a higher voltage.

 

As I've said before the 14.8 volt absorb voltage used on my current sealed batteries has done them no harm and didn't with previous sets after five years or more of use (tell-tales still working indicating electrolyte reserve), providing the higher voltage is only maintained during the absorb phase. Tail current when fully charged is so minimal gassing is never an issue.

I think you are right. However I am wary of Sterling products because they seem so "home made" and old fashioned. You only have to look at the brochure picture of the PDAR and see the row of wired LEDs all at different angles - very amateurish and if that represents the company's attention to detail...

 

I plan to leave the Combi set to 15v but 10A next time we go out cruising. That way the 12v alternator will do the bulk of the work but towards the end of the charge the voltage will rise to 15v (if the TravelPower is on) which seems a cheaper and more robust way of doing it (cheaper when you already have a TP and Combi that is!).

[dmr]

Thanks dmr and nick.

That has answered it for me. I knew that a dip switch in the mastervolt puts it int equalise mode I just did not know that the alternator would just drop out of charging automatically.

One last question. Before doing this I assume I switch off everything whilst equalising but do not isolate the battery. Will things directly connected to battery terminals be ok i.e. smartguage and bilge pump etc.

 

You need to turn off anything that is going to be damaged by 15.5v. I can't be bothered and nothing has blown up yet, though I did check the data sheets of the more expensive items. The Jabsco water pump runs a bit faster on 15.5v, I try not to have a long shower whilst equalising.

 

Smartgage is fine and hopefully your bilge pumps won't be running.

 

...........Dave

[by'eck]

I think you are right. However I am wary of Sterling products because they seem so "home made" and old fashioned. You only have to look at the brochure picture of the PDAR and see the row of wired LEDs all at different angles - very amateurish and if that represents the company's attention to detail...

 

I plan to leave the Combi set to 15v but 10A next time we go out cruising. That way the 12v alternator will do the bulk of the work but towards the end of the charge the voltage will rise to 15v (if the TravelPower is on) which seems a cheaper and more robust way of doing it (cheaper when you already have a TP and Combi that is!).

 

Sterling - cheap and cheerful but reliable as well in my opinion, based on using their products (Chargers, Combi's, Inverters, DAR's and Splitters) for over 15 years.

 

I have to say they are no more resilient to direct lightning strikes though, which is the only time I've had to replace

[Phil.]

I plan to leave the Combi set to 15v but 10A next time we go out cruising. That way the 12v alternator will do the bulk of the work but towards the end of the charge the voltage will rise to 15v (if the TravelPower is on) which seems a cheaper and more robust way of doing it (cheaper when you already have a TP and Combi that is!).

Are you able to do this by configuring the mastervolt without a laptop and would this cause the batteries to gas at that voltage as this is only half a volt below equalising.

 

 

Edit - I think just answer own question reading the manual it looks as if you can change voltage between 8 and 16 if read correctly. Having said that this is not an area I would feel happy tinkering with. Is it something that I could get professionally done.

Edited October 6, 2014 by Phil.

[nicknorman]

Are you able to do this by configuring the mastervolt without a laptop and would this cause the batteries to gas at that voltage as this is only half a volt below equalising.

Edit - I think just answer own question reading the manual it looks as if you can change voltage between 8 and 16 if read correctly. Having said that this is not an area I would feel happy tinkering with. Is it something that I could get professionally done.

No, you have to use a laptop or other interfacing device such as a Masterview in order to set any voltage between 8 and 16. Once you have the communication set up though, it is trivially easy to change. But also I note that using the DIP switches you could select battery type to "Traction" which gives an additional 0.7v at bulk charge and 0.4v at absorption which would go a long way to helping the situation.

 

Yes it might cause the batteries to gas a bit and I certainly wouldn't want to leave the Combi set to that when on shore power unattended, but it would be OK to select from time to time. My experience with lead-calcium "leisure batteries" is that the calcium raises the gassing voltage substantially and even at 15.5v, the fully charged current is just a few amps (maybe 1.5A per 110AH battery) so although it is gassing, it is not using much water.

Edited October 6, 2014 by nicknorman

[Phil.]

Thanks I have today set the dip switch to traction mode so I will equalise them then see if things are a bit better if not I will have to spend some money on a masterview.