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Training a new Smartgauge


Capnbob

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Fitted a new set of 3 batteries, cruised for 4 hours and moored. Should be 100% charge assuming the "fully charged ex factory" claim is correct.

 

Four days later (during which time I operated very little electrics) fitted a Smartgauge. This initialises itself to a default 75% SOC until it learns more accuracy over time, but I overrode this and set it manually to a nominal 93%.

 

According to the manual it will learn accuracy over the first few charge/discharge cycles, but the manual presumes I've got an accurate SOC charge meter connected to guide that process - but of course I haven't (which is why I bought the Smartgauge in the first place).

 

I've only got the engine for charging at the moment, so my instinct is to wait until the SG drops below, say, 90% and run the engine until the SG says 100% (and then another, what, half-hour?) Then repeat...

 

Does that sound like a reasonable plan?

 

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Just ignore it for the next week, charge as much as you can and discharge as normal, then this time next week have a look and it will tell you how much is in your batteries. In the mean time fit a cheap ammeter to measure tail current for  when you think your batteries are charged, should read 1-2% of battery Ah when batteries fully charged and its time to stop charging.

Edited by Loddon
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8 minutes ago, Capnbob said:

Fitted a new set of 3 batteries, cruised for 4 hours and moored. Should be 100% charge assuming the "fully charged ex factory" claim is correct.

 

Four days later (during which time I operated very little electrics) fitted a Smartgauge. This initialises itself to a default 75% SOC until it learns more accuracy over time, but I overrode this and set it manually to a nominal 93%.

 

According to the manual it will learn accuracy over the first few charge/discharge cycles, but the manual presumes I've got an accurate SOC charge meter connected to guide that process - but of course I haven't (which is why I bought the Smartgauge in the first place).

 

I've only got the engine for charging at the moment, so my instinct is to wait until the SG drops below, say, 90% and run the engine until the SG says 100% (and then another, what, half-hour?) Then repeat...

 

Does that sound like a reasonable plan?

 

No, you don’t need any other gauge, I think you must be misreading the manual. Just fit and forget. It will read accurately when you need it to, so for example if you only cycle it between 95% and 100% it won’t “learn” as it really needs deeper cycles, but then again it’s reading doesn’t matter. If you fit it to fully charged batteries having set the SoC to roughly 100%, the first time you significantly discharge down to say 60-70% or lower it will read fairly accurately and certainly will let you know when you need to recharge. Further cycles will refine it but it will read fairly accurately on the first cycle, provided you set the correct battery type.

 

The other thing to bear in mind is that new batteries can take a few cycles to settle down (a lot of cycles in the case of something like Trojans) so again, there is no point in expending energy trying to get the SG to “Learn” batteries that are still bedding in.

 

Just fit and forget.

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To the OP:

 

What made you buy the Smartgauge? What did you think it was going to do?

 

The manual tells you that Smartgauge is not accurate when charging. When mine reads 100% there is an hour or two to go before the tail current is low enough to consider the batteries full. If I stopped charging each time as soon as the Smartgauge reached 100%, I would destroy my batteries fairly quickly.

 

Even the designer has been said to say that it is not even accurate when discharging until it reads less than 80%. He apparently went on to ask why anyone would want to know if their batteries were above 80% when discharging.

 

A Smartgauge is useful for telling you when you should start charging. You obviously need to have your own rules for this, but many don’t let their batteries go much below 50% - and don’t forget to charge them to 100% as often as possible. Some would say every day, others might say at least every second day. Many seem to consider once a week is enough, as long as you get them to about 80% or so every day.

 

As some have said above, in order to establish that your batteries are as good as full, you need some kind of ammeter. I have a NASA BM2, which also tells me the instantaneous amps flowing, charging or discharging, as well as cumulative Ah.

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I've not got the manual in front of me, but thought when I got involved in a similar discussion in the past someone said that the SG would really only start to fully sort itself out once I had gone below an indicated 75%.

Perhaps I'm remembering that wrongly - please correct me if I am.

 

All I know is that at the moment most of the time my boat is on the mooring with nothing powered on (240V or 12v) when we are away from it, but with the 240V connected and an a Electroquest 30A 3 stage charger switched on continually when we are.

Our demands on 12V when there are low, (only some LED lights - the most used ones are 230v, plus pumps - nothing else).  However the last time there for 4 or 5 days, I think the SG only crept up from 85% to 86%.

 

As the charger seems to consistently think it only needs to be in "float", I'm sincerely hoping the SOC is better than the SG wants to record, because if the batteries really are stuck at an SOC in the mid eighties, I doubt it's doing them a heap of good.

7 minutes ago, Richard10002 said:

Even the designer has been said to say that it is not even accurate when discharging until it reads less than 80%. He apparently went on to ask why anyone would want to know if their batteries were above 80% when discharging.

So not much use at all in the situation I have just described then?

Perhaps I should have saved my money.

 

EDIT: So need I worry about my batteries f the SG never falls below 80%?

Edited by alan_fincher
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Well, thanks people... Really helpful.

 

Putting it all together it seems I've got the wrong device, or maybe not, but given what I have got then the best move forward is to also fit either a nasa bm2 (thus doubling the cost of battery monitoring) OR a cheapo ammeter (which is much more appealing), and use the latter to know when to stop charging, and the Smartgauge for all other monitoring, especially to know when to start charging.

 

Is that a reasonable summary?

 

If so, can anyone point me to a wiring diagram to tell me how to connect up a cheap ebay ammeter?

 

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3 minutes ago, Capnbob said:

Well, thanks people... Really helpful.

 

Putting it all together it seems I've got the wrong device, or maybe not, but given what I have got then the best move forward is to also fit either a nasa bm2 (thus doubling the cost of battery monitoring) OR a cheapo ammeter (which is much more appealing), and use the latter to know when to stop charging, and the Smartgauge for all other monitoring, especially to know when to start charging.

 

Is that a reasonable summary?

 

If so, can anyone point me to a wiring diagram to tell me how to connect up a cheap ebay ammeter?

 

Yes, it will increase your cost of battery monitoring, but should hopefully decrease your battery outlay due to increased lifespan.

 

You will need an ammeter and shunt.

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25 minutes ago, alan_fincher said:

I've not got the manual in front of me, but thought when I got involved in a similar discussion in the past someone said that the SG would really only start to fully sort itself out once I had gone below an indicated 75%.

Perhaps I'm remembering that wrongly - please correct me if I am.

 

All I know is that at the moment most of the time my boat is on the mooring with nothing powered on (240V or 12v) when we are away from it, but with the 240V connected and an a Electroquest 30A 3 stage charger switched on continually when we are.

Our demands on 12V when there are low, (only some LED lights - the most used ones are 230v, plus pumps - nothing else).  However the last time there for 4 or 5 days, I think the SG only crept up from 85% to 86%.

 

As the charger seems to consistently think it only needs to be in "float", I'm sincerely hoping the SOC is better than the SG wants to record, because if the batteries really are stuck at an SOC in the mid eighties, I doubt it's doing them a heap of good.

So not much use at all in the situation I have just described then?

Perhaps I should have saved my money.

 

EDIT: So need I worry about my batteries f the SG never falls below 80%?

Whatever the SG says, If you don’t regularly charge them to 100%, they will sulphate and lose capacity.

 

The easiest way to tell the they are charged to 100% is to look for a low tail current and, for that, you need an ammeter, probably shunt based.

 

Trusting your charger to decide whether your batteries are OK on float is another method for early destruction :( With some/many you have to turn them off and on to reset them, and start the bulk, absorption, float process again. With my Sterling inverter charger, it often goes into float after an hour, because that’s what it’s algorithm tells it to do. In reality, it needs several hours to get to a low tail current, so I set a 55 minute alarm, and turn it off and on several times.

 

Having said that, given your boating experience, if your batteries don’t cause you concern, why change something that’s working for you :)

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28 minutes ago, alan_fincher said:

I've not got the manual in front of me, but thought when I got involved in a similar discussion in the past someone said that the SG would really only start to fully sort itself out once I had gone below an indicated 75%.

Perhaps I'm remembering that wrongly - please correct me if I am.

 

All I know is that at the moment most of the time my boat is on the mooring with nothing powered on (240V or 12v) when we are away from it, but with the 240V connected and an a Electroquest 30A 3 stage charger switched on continually when we are.

Our demands on 12V when there are low, (only some LED lights - the most used ones are 230v, plus pumps - nothing else).  However the last time there for 4 or 5 days, I think the SG only crept up from 85% to 86%.

  

As the charger seems to consistently think it only needs to be in "float", I'm sincerely hoping the SOC is better than the SG wants to record, because if the batteries really are stuck at an SOC in the mid eighties, I doubt it's doing them a heap of good.

So not much use at all in the situation I have just described then?

Perhaps I should have saved my money.

 

EDIT: So need I worry about my batteries f the SG never falls below 80%?

Our battery charger and also the solar controller (fairly basic PWM one) behave similarly, going to float far too early. The charger wll go back to absorption for a few minutes if there is some demand, so, on shore power, the batteries get to a higher state of charge if the fridge is turned up or frequent showers are taken? or the invertor is left on (Sterling one with a fairly high standby current).

The solar controller does a fixed absorption time after absorption voltage is reached, which is a real waste as it goes to float before midday, so most of the available sun power is wasted,

 

The Smartgauge does agree with the Amphour counter (MerlnPowergauge), once starting conditions of the counter are taken into account, and is also consistent with alternator current if the engine is fired up.

I'd believe the Smartgauge, despite the  inaccuracies when charging. (Despite others' experience, I find mine to be fairly accurate when charging)

 

So the answer to the EDIT is "Yes"

 

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18 minutes ago, Capnbob said:

Well, thanks people... Really helpful.

 

Putting it all together it seems I've got the wrong device, or maybe not, but given what I have got then the best move forward is to also fit either a nasa bm2 (thus doubling the cost of battery monitoring) OR a cheapo ammeter (which is much more appealing), and use the latter to know when to stop charging, and the Smartgauge for all other monitoring, especially to know when to start charging.

(snip)

 

Yo/ve got the right device, but the information is incomplete. An ammeter will tell you when to stop charging, which the Smartgauge isn't good at.

I added a Smartgauge to the Merln Powergauge which was fitted on our boat. The Smartgauge is FAR more accurate than the Powergauge, whose "State of Charge" reading is a load of mince most of the time. I use the Powergauge mainly as an ammeter, With our boat usage, charging usually stops when we moor up.

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22 minutes ago, Richard10002 said:

Whatever the SG says, If you don’t regularly charge them to 100%, they will sulphate and lose capacity.

 

10 minutes ago, Iain_S said:

So the answer to the EDIT is "Yes"

 

Yes, this us my fear, though other than by changing the equipment in use, it is very hard to see how to solve the problem.

Although the Electroquest 30A charger, (almost certainly the same as the Numax 30A charger), has been a regular "fit and forget" recommendation on CWDF for situations where you are consuming 12 volts when on shore-power, I'm now far from convinced it is that suitable.

It is documented behaviour that it will switch to float once charging current is at 10% of the specified maximum, (i.e. 3 Amps), and it doesn't either seem to be possible to change that value or in any other way force the charger to stay in bulk for longer.  I don't think my unit is faulty - it seems to work as specified.

I have wondered whether introducing a deliberate load on the 12 volts that drew more than 3 amps might force the charger to start delivering more than 3 amps, and hence not go into float, but deliberately introducing a drain on your batteries when you are trying to charge them seems counter-intuitive.  Could this work?

If not can anybody recommend a charger that is an alternative to the Electroquest, (it needs to have a similar footprint), that can be tricked into not going into float too soon?

 

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6 minutes ago, alan_fincher said:

If not can anybody recommend a charger that is an alternative to the Electroquest, (it needs to have a similar footprint), that can be tricked into not going into float too soon?

 

The Sterling Pro Charge Ultra allows you to set your own asbsorption and float voltages. That stops the effect you get with the electroquest. 

 

It also stops there being a final, low, true float voltage for leaving it on for weeks on end however....

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22 minutes ago, alan_fincher said:

 

 

Yes, this us my fear, though other than by changing the equipment in use, it is very hard to see how to solve the problem.

Although the Electroquest 30A charger, (almost certainly the same as the Numax 30A charger), has been a regular "fit and forget" recommendation on CWDF for situations where you are consuming 12 volts when on shore-power, I'm now far from convinced it is that suitable.

It is documented behaviour that it will switch to float once charging current is at 10% of the specified maximum, (i.e. 3 Amps), and it doesn't either seem to be possible to change that value or in any other way force the charger to stay in bulk for longer.  I don't think my unit is faulty - it seems to work as specified.

I have wondered whether introducing a deliberate load on the 12 volts that drew more than 3 amps might force the charger to start delivering more than 3 amps, and hence not go into float, but deliberately introducing a drain on your batteries when you are trying to charge them seems counter-intuitive.  Could this work?

If not can anybody recommend a charger that is an alternative to the Electroquest, (it needs to have a similar footprint), that can be tricked into not going into float too soon?

 

My Electroquest can be tricked into staying at 14.3 Volts by leaving some LED Striplights on ,Approx 45 Watts in total.

ETA have verified the effect by turning Lights off one by one and when the load is reduced the Charger drops down to 13.4-6 Volts . 

Edited by cereal tiller
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32 minutes ago, cereal tiller said:

My Electroquest can be tricked into staying at 14.3 Volts by leaving some LED Striplights on ,Approx 45 Watts in total.

ETA have verified the effect by turning Lights off one by one and when the load is reduced the Charger drops down to 13.4-6 Volts . 

Thanks

 

Sounds like it's worth a try.

I only have LED lights internally, but suppose I could eave the tunnel light on, (with a sack over it, to stop countless people telling me I have left it on!

I've a thought that I might have a large ceramic based variable resistor in the shed somewhere, that might be the right number of ohms, and OK to pass 3 amps continuously.

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4 hours ago, alan_fincher said:

I've not got the manual in front of me, but thought when I got involved in a similar discussion in the past someone said that the SG would really only start to fully sort itself out once I had gone below an indicated 75%.

Perhaps I'm remembering that wrongly - please correct me if I am.

 

Only if you fit it and leave the default start up SoC at 75%. The SG will synchronise when the actual SoC falls to the indicated SoC. The indicated SoC doesn’t move upwards unless the batteries are being charged at a bulk or absorption voltage. Probably your charger is on float which isn’t enough to get the SG indication climbing. The first time you actually use your boat off mains for a day or two, taking the SoC down and up significantly, it will become synchronised.

 

Had you set the indicated SoC to 100% when you installed it, it would have been fine straight away.

Edited by nicknorman
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4 hours ago, Capnbob said:

Well, thanks people... Really helpful.

 

Putting it all together it seems I've got the wrong device, or maybe not, but given what I have got then the best move forward is to also fit either a nasa bm2 (thus doubling the cost of battery monitoring) OR a cheapo ammeter (which is much more appealing), and use the latter to know when to stop charging, and the Smartgauge for all other monitoring, especially to know when to start charging.

 

Is that a reasonable summary?

 

Yes.

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1 hour ago, nicknorman said:

Only if you fit it and leave the default start up SoC at 75%. The SG will synchronise when the actual SoC falls to the indicated SoC. The indicated SoC doesn’t move upwards unless the batteries are being charged at a bulk or absorption voltage. Probably your charger is on float which isn’t enough to get the SG indication climbing. The first time you actually use your boat off mains for a day or two, taking the SoC down and up significantly, it will become synchronised.

 

Had you set the indicated SoC to 100% when you installed it, it would have been fine straight away.

No, I don't think that covers it. 

 

When last we returned to our moorings after an extensive cruise, it was either at 100% or very close to it. Since it has been back on the moorings, with us spending periods on board, the reading has ended up where it is now. 

 

Of course I realise that if the SG is telling the truth My charger isn't keeping up with what we are taking out.

 

However if the bank is genuinely at only 86% SOC wouldn't you expect a 30 amp charger to want to be putting more than 3 amps into it? The problem is that if it can be urged out of float it will quickly drop to just 3 amps, then as it is specified to do, drop back to float. 

So is it really at only 86%?I really don't know whether to believe it or not. 

EDIT: (To add a clarification in case anybody still wants to discuss....)

I don;t actually know if it has ever read less than 75% since it was last connected up.  It is possible that even when out boating that it never did.  I'm really not sure one way or the other.

Edited by alan_fincher
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12 minutes ago, alan_fincher said:

So is it really at only 86%?I really don't know whether to believe it or not. 

 

C'mon now Alan. As I've been told on here 1000 times, a smartgauge does not accurately report the state of charge during charging. 

 

As yours ably demonstrates. 

 

 

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11 minutes ago, Mike the Boilerman said:

 

C'mon now Alan. As I've been told on here 1000 times, a smartgauge does not accurately report the state of charge during charging. 

 

As yours ably demonstrates. 

 

 

But perhaps it is?  The indicated SOC certainly will not change dramatically if I switch the charger off!

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