Smartgauge question

[NB Alnwick]

We have relied on our Smartgauge for the last decade or so but recently, after changing the batteries and re-setting our Smartgauge back to its original factory settings we have noticed that we get variable and inaccurate voltage readings from the second battery bank. The Smartgauge typically fluctuates between 22 and 25 volts (our boat runs on 24 Volts) but when I take a reading with my multimeter directly from the batteries I get a combined voltage of 27 Volts and each battery measured individually indicates 13.6 Volts.

Could this be a sign that the Smartgauge is on its way out or might it be a poor connection somewhere?

Edited December 10, 2022 by NB Alnwick

[blackrose]

I don't know if your problem is due to a poor connection but I think I've got a bad connection somewhere as power to the Smartgauge seems to be lost every time I touch any cables around the batteries. 

[Tony Brooks]

The only comment I can make is that Gibbo (and I think the instruction) was insistent that the cables go direct to the batteries so I suspect they are very sensitive to voltage drop on the wiring. Are you both certain the battery terminals and connections are clean and tight, I think you shoudl have afuse neat the batteries in the positive so is this clean and tight.

[IanD]

1 hour ago, Tony Brooks said:

The only comment I can make is that Gibbo (and I think the instruction) was insistent that the cables go direct to the batteries so I suspect they are very sensitive to voltage drop on the wiring. Are you both certain the battery terminals and connections are clean and tight, I think you shoudl have afuse neat the batteries in the positive so is this clean and tight.

The Smartguage draws very little current, there's no voltage drop in the wires *to* the Smartguage (voltage sensing). Gibbo insisted that the wires go direct to the batteries -- preferably the terminals -- so that it sees the actual battery voltage, not a lower voltage because of drops in the high-current cables and connections if it taps off somewhere else.

 

A bad connection in the wires to the Smartguage or a faulty Smartguage would explain the symptoms described.

[Tony Brooks]

1 hour ago, IanD said:

The Smartguage draws very little current, there's no voltage drop in the wires *to* the Smartguage (voltage sensing). Gibbo insisted that the wires go direct to the batteries -- preferably the terminals -- so that it sees the actual battery voltage, not a lower voltage because of drops in the high-current cables and connections if it taps off somewhere else.

 

A bad connection in the wires to the Smartguage or a faulty Smartguage would explain the symptoms described.

 

I would point out that dirty battery terminals would cause a low voltage to the Smartgauge when any significant charging or discharging was taking place.

[NB Alnwick]

I think I need to re-check all the connections before blaming the Smartgauge.

[IanD]

8 minutes ago, Tony Brooks said:

 

I would point out that dirty battery terminals would cause a low voltage to the Smartgauge when any significant charging or discharging was taking place.

 

That's true, the only way to get round that is Kelvin/4-wire sensing -- voltage sense connections from the Smartgauge direct to the actual terminals, separate from the connections that carry the current.

 

Either way, it's still much better to connect them there (right at the battery) than further away... 🙂

Edited December 10, 2022 by IanD

[Bod]

Can you take multi meter readings direct from the rear of the smart gauge?

If the reading agree, duff connection. 
Different readings, check calibration of both meter and smart gauge. 
 

Bod

[NB Alnwick]

22 hours ago, Bod said:

Can you take multi meter readings direct from the rear of the smart gauge?

If the reading agree, duff connection. 
Different readings, check calibration of both meter and smart gauge. 
 

Bod

 

Good advice - sometimes the obvious answer is easily missed. So I did as suggested and the readings were different but the Smartgauge has now become even more eratic in its readings and the engine bank is now constantly reading "Lo" on the Smartgauge despite my multimeter confirming that there is 27.9 VDC at the terminals. Gibbo always warned not to tamper with the internals of the SG and I respect his warning so it looks like I need a new one! Does anyone have a spare SmartGauge that they no longer need?

Edited December 11, 2022 by NB Alnwick

[Tony Brooks]

4 hours ago, NB Alnwick said:

 

Good advice - sometimes the obvious answer is easily missed. So I did as suggested and the readings were different but the Smartgauge has now become even more eratic in its readings and the engine bank is now constantly reading "Lo" on the Smartgauge despite my multimeter confirming that there is 27.9 VDC at the terminals. Gibbo always warned not to tamper with the internals of the SG and I respect his warning so it looks like I need a new one! Does anyone have a spare SmartGauge that they no longer need?

 

Mike might but I would not touch it with a barge pole 😀

[blackrose]

On 10/12/2022 at 15:13, NB Alnwick said:

I think I need to re-check all the connections before blaming the Smartgauge.

 

Yes me too. 

[MtB]

15 hours ago, Tony Brooks said:

 

Mike might but I would not touch it with a barge pole 😀

 

 

Yeah I still have one faulty one left. Make me an offer for it!

 

[rusty69]

Just now, MtB said:

 

 

Yeah I still have one faulty one left. Make me an offer for it!

 

One pound. 

[MtB]

Just now, rusty69 said:

One pound. 

 

Nah, I'd be embarrassed to take yer money.

 

Besides, I'm using it as a door stop and if I sold it to you, I'd have to buy another doorstop.

 

But to be fair I did buy another Smartgauge a couple of years ago and it was perfectly calibrated, straight from the box. One out of three ain't bad, eh?

 

 

[rusty69]

1 minute ago, MtB said:

 

Nah, I'd be embarrassed to take yer money.

 

Besides, I'm using it as a door stop and if I sold it to you, I'd have to buy another doorstop.

 

But to be fair I did buy another Smartgauge a couple of years ago and it was perfectly calibrated, straight from the box. One out of three ain't bad, eh?

 

 

Why don't you perfectly calibrate the doorstop. 

 

If you do, I will up my offer to 2 pounds as long as that includes delivery, installation and after sales service. 

Edited December 12, 2022 by rusty69

[MtB]

18 minutes ago, rusty69 said:

Why don't you perfectly calibrate the doorstop. 

 

If you do, I will up my offer to 2 pounds as long as that includes delivery, installation and after sales service. 

 

I'll give you a 12 month guarantee too! I guarantee it won't be working in 12 months....

 

 

[GUMPY]

 

1 hour ago, MtB said:

 

 

Yeah I still have one faulty one left. Make me an offer for it!

 

I could take it from you and to save you any embarrassment I won't offer you anything for it, you can also pay for the postage to me if you like🤭

Edited December 12, 2022 by Loddon

[IanD]

20 hours ago, NB Alnwick said:

 

Good advice - sometimes the obvious answer is easily missed. So I did as suggested and the readings were different but the Smartgauge has now become even more eratic in its readings and the engine bank is now constantly reading "Lo" on the Smartgauge despite my multimeter confirming that there is 27.9 VDC at the terminals. Gibbo always warned not to tamper with the internals of the SG and I respect his warning so it looks like I need a new one! Does anyone have a spare SmartGauge that they no longer need?

 

You could always replace the SG with a Balmar... 😉

[NB Alnwick]

Just an update - I purchased a new Smartgauge direct from Merlin and fitted it this morning.

It is working as it should and is reporting the correct voltages on both battery banks.

It is interesting that before the old one failed completely by just displaying "LO" insead of the correct voltage on the engine batteries it had briefly displayed an error code E04 which I now know to be "above the voltage range" - an unlikely situation that had I known what it meant might well have been a clue that the unit had failed.