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Mike the Boilerman

My third SmartGauge...

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17 minutes ago, nicknorman said:

I’ve never noticed a tendency to stick at 94%. But then we have a modern alternator that charges at around 14.5v. We go from say 65% on starting the engine in the morning, to 100% by early afternoon. As has been said, perhaps your charging voltage is on the low side?

Very possibly.

Here’s the post I referred to:

 

 
   blackrose said: 

Has anyone actually bought one of these things and would you recommend it?

 

http://www.smartgauge.co.uk/selector.html

 

(I'm just thinking about the smartguage, not the smartbank)

 

 

Strangely enough I have one :(

It makes battery monitoring real simple you dont need to know the size of the bank and subtract what you have used just look and so long as its above 50% you are OK.

Hasnt really changed how I run my system but I worry less as I can see its still above 50%.

I tried to confuse it by running the tumble dryer off the inverter whilst boating which gives me a net loss from the batteries of 50Ah ( TD draws 100A alternator is 50A) it came up with the correct answer, after a couple of hours boating and drying my 400Ah battery bank had dropped from 75-50%.

It doesnt always get to 100% it levels off at 94%charged however that could be my charging system :(

Its a small unit 90x60x25mm the only downside is that as mine is an early one it has no mounting brackets so its fixed to the wall with DS tape.

Other than that it does what it says.

What it will do is control external relays according to voltage so if you havent got a system linking your alternators to charge the domestic bank at a higher rate it should be possible to do this (ask Chris at SG).

 

 

Would I buy another one?

I am about to for the 12v system (first one is on the 24v system)

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3 minutes ago, rusty69 said:

Leaving lots of lights on our boat wouldn't make a dent in the batteries...... They're all leds:)

You beat me to it. I can remember years ago having to always go round switching lights off. Nowadays with these new fandangled diodey thingies, you dont have to bother.

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8 hours ago, Peter Thornton said:

Very possibly.

Here’s the post I referred to:

 

 
   blackrose said: 

Has anyone actually bought one of these things and would you recommend it?

 

http://www.smartgauge.co.uk/selector.html

 

(I'm just thinking about the smartguage, not the smartbank)

 

 

Strangely enough I have one :(

It makes battery monitoring real simple you dont need to know the size of the bank and subtract what you have used just look and so long as its above 50% you are OK.

Hasnt really changed how I run my system but I worry less as I can see its still above 50%.

I tried to confuse it by running the tumble dryer off the inverter whilst boating which gives me a net loss from the batteries of 50Ah ( TD draws 100A alternator is 50A) it came up with the correct answer, after a couple of hours boating and drying my 400Ah battery bank had dropped from 75-50%.

It doesnt always get to 100% it levels off at 94%charged however that could be my charging system :(

Its a small unit 90x60x25mm the only downside is that as mine is an early one it has no mounting brackets so its fixed to the wall with DS tape.

Other than that it does what it says.

What it will do is control external relays according to voltage so if you havent got a system linking your alternators to charge the domestic bank at a higher rate it should be possible to do this (ask Chris at SG).

 

 

Would I buy another one?

I am about to for the 12v system (first one is on the 24v system)

 That looks like something I wrote 12 years ago and the reference to the charging system was probably to the Victron I had at the time that was using adaptive charging not to the alternator.

I realise the way its worded could be misread. As for SG I did get another one with a SB to control the 12v system. Since then I've changed boats and have a SG on here.

I am not a member of the battery boiler club, I prefer to source a decent OEM regulator for whichever alternator i have on a boat when I got this boat both alternators had Sterling units on them first thing I did was remove them and change the regulator on the starter battery alternator to one that gives 14.4v and adjust the domestic alternator to 14.4v (sealed batteries).

 

J

 

Edited by Loddon

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10 hours ago, Dr Bob said:

What voltage were you charging at as you finished your cruise?

And equally important, what was the charging current?

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19 minutes ago, WotEver said:

And equally important, what was the charging current?

Absolutely, but I thought he only had a Smartgauge.?

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4 minutes ago, Dr Bob said:

Absolutely, but I thought he only had a Smartgauge.?

Indeed he has!

Having read the back posts from over 10 years ago I’m amazed at the emotions that this little device stirs up ..........

 

I can only say that we have, for some time, just used a digital voltmeter to monitor our batteries and the Smartgauge is streets ahead of this. Remember that this is a share boat and some of our owners don’t want to have to have the interest that we have in this. They just want to enjoy the boat whilst not wrecking the batteries. Smartgauge seems to be just the job for this.

 

I think I might suggest that we also fit an Ammeter so that we can better monitor the charging system and decide whether we need to fit some kind of smart box to encourage a higher charging rate from the alternator - but I guess that this is a whole new subject ........

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13 minutes ago, Peter Thornton said:

I think I might suggest that we also fit an Ammeter so that we can better monitor the charging system...

Yes you should. An ammeter is the ideal companion to a SmartGauge. 

14 minutes ago, Peter Thornton said:

I’m amazed at the emotions that this little device stirs up ..........

Have you noticed that the detractors are exclusively non-owners?

25 minutes ago, Dr Bob said:

Absolutely, but I thought he only had a Smartgauge.

Then he needs to get an ammeter fitted. About a fiver from eBay. 

  • Greenie 1

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31 minutes ago, Peter Thornton said:

 

 

I think I might suggest that we also fit an Ammeter so that we can better monitor the charging system and decide whether we need to fit some kind of smart box to encourage a higher charging rate from the alternator - but I guess that this is a whole new subject ........

For a start, just check your charging voltage as you get over 90% SoC or near the end of your run. If it's below 14.0V then you charging will be too slow and you need to get it higher. You can see that with the kit you have.

Edited by Dr Bob

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23 hours ago, nicknorman said:

No it doesn’t just smooth the voltage out, that wouldn’t really work. As we know, SoC can be determined from rested no load voltage. If you now turn on a load, the voltage takes a step change, and then slowly decreases as the battery discharges. Turn other thing on or off, you get different step changes and rates of voltage decrease. You can make a stab at a relationship between voltage step change and current (as a % of capacity) and hence SoC. At some time the voltage may stabilise (everything off) and the box can re-evaluate the SoC using rested no load voltage. If the answer is different from that calculated so far, it can modify the constants used to link step change with %current (learning process). Obviously the reality is much more complicated than that.

One thing I've often pondered about is whether or not the change in voltage when something is turned on is indicative of battery capacity due to sulphation.  E.g. suppose my rested battery voltage with no load is showing 12.7V.  I now turn on something that draws three amps, e.g. a fridge.  The voltage drops to 12.4V.   I'm sure in the past I've had sets of batteries where the drop in voltage is much less, and I have a feeling that the current batteries are getting clogged up.  So does the drop from 12.7V to 12.4V suggest that the batteries are losing capacity, and if so, is this a way to determine the degree of sulphation?

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1 minute ago, dor said:

So does the drop from 12.7V to 12.4V suggest that the batteries are losing capacity, and if so, is this a way to determine the degree of sulphation?

Well it will be related to capacity which when compared to the original capacity will give a clue to sulphation. The snag is you will also need to know the current in/out as well as the voltage. So for a given draw, the rate of change of voltage will be related to capacity in some way. I am not sure if you could do it just on voltage, dV/dt, or d(dV/dt)/dt, but someone will be along in a minute to say you can.

 

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25 minutes ago, dor said:

One thing I've often pondered about is whether or not the change in voltage when something is turned on is indicative of battery capacity due to sulphation.  E.g. suppose my rested battery voltage with no load is showing 12.7V.  I now turn on something that draws three amps, e.g. a fridge.  The voltage drops to 12.4V.   I'm sure in the past I've had sets of batteries where the drop in voltage is much less, and I have a feeling that the current batteries are getting clogged up.  So does the drop from 12.7V to 12.4V suggest that the batteries are losing capacity, and if so, is this a way to determine the degree of sulphation?

I think the general consensus is that a sulphated battery behaves much like a battery of lower capacity. So at a rough guess I’d say that there will be a link between step voltage change and sulphation. What it is exactly, anybody’s guess! In the mean time one way to measure sulphation is to check the fully charged specific gravity against the manufacturer’s stated value. Tricky if they are sealed batteries! If so, the only other way (apart from gaining access by force) is to check the capacity by making a controlled discharge. If the batteries are not that old, a reduction in capacity is most likely to be due to sulphation.

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1 hour ago, dor said:

So does the drop from 12.7V to 12.4V suggest that the batteries are losing capacity, and if so, is this a way to determine the degree of sulphation?

To an extent only. The drop in voltage is caused by a rise in the internal resistance of the battery, which is itself dependant upon several factors including temperature, sulphation, and corrosion. The latter two are directly related to reduced plate area due to age. If you’ve avoided sulphating the batteries then they will be suffering from grid corrosion. Quality batteries such as the ever-popular T105s are very robust and have deep wells in the cells, thereby resisting the effects of corrosion for many cycles. So while they may not suffer from internal shorts they will nevertheless have a reduced plate area to work with, which leads to an apparent rising of the internal resistance: the chemical reaction not being able to ‘keep up’ with the discharge rate due to the reduced plate area. 

 

 

Edited by WotEver
Clarity. It’s still not quite right but it’s near enough.

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2 hours ago, WotEver said:

Have you noticed that the detractors are exclusively non-owners?

 

Not true. I have three Smartgauges and I have plenty of criticisms, should anyone be interested to hear them....

 

 

Shall I run through them again?

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22 minutes ago, Mike the Boilerman said:

 

Not true. I have three Smartgauges and I have plenty of criticisms, should anyone be interested to hear them....

 

 

Shall I run through them again?

Yes please. It would save having to read the thread again... 

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2 hours ago, Dr Bob said:

For a start, just check your charging voltage as you get over 90% SoC or near the end of your run. If it's below 14.0V then you charging will be too slow and you need to get it higher. You can see that with the kit you have.

I do have a clamp meter with me so at 94% this morning it was at 14.1 (read on the Smartgauge) and hovering around 5 or 6 amps  on the clamp meter. Upon transferring to the Sterling Pro on board charger it also charges at about the same rate. So maybe our charging system isn’t that bad?

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Another thought on this: Our syndicate of 5 owners spends, on average, around £100 a year on batteries. I.e. 4 batteries that last 4-5 years. That’s £20 each, a little more than a pumpout. You can see why most owners don’t want to have to watch gauges and make calculations but just prefer a simple % readout telling them when to recharge.

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41 minutes ago, Peter Thornton said:

I do have a clamp meter with me so at 94% this morning it was at 14.1 (read on the Smartgauge) and hovering around 5 or 6 amps  on the clamp meter. Upon transferring to the Sterling Pro on board charger it also charges at about the same rate. So maybe our charging system isn’t that bad?

14.1 is really too low. Perhaps you could look at fitting a different regulator to the alternator? Although as a share boat it is probably mostly cruising long days, I think never charging above 14.1v will lead to sulphation. Modern batteries have calcium in the plates to reduce gassing, and these really prefer a much higher voltage say 14.6 or more.

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1 hour ago, nicknorman said:

14.1 is really too low. Perhaps you could look at fitting a different regulator to the alternator? Although as a share boat it is probably mostly cruising long days, I think never charging above 14.1v will lead to sulphation. Modern batteries have calcium in the plates to reduce gassing, and these really prefer a much higher voltage say 14.6 or more.

^^^^^ wot he said. 

 

5A at 14.1V is still a bit below 100%; probably close to that 94% that SmartGauge was telling you. You’re aiming for about that current or a little less if possible at 14.4V+.

 

14.6V or 14.8V showing <5A would be great. 

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