battery monitoring

[WotEver]

 

I think you might need to read up on the BMV 602 it has high and low voltage alarms...

I don't believe I do, nope. Please tell us how does it differentiate between a low voltage caused by a temporary heavy load and a low voltage caused by a low SoC.

 

The above is precisely my point. Because SmartGauge is aware of the actual SoC of the battery you can be aware that your charge status is down to 50%. With an Ah counter that is much more difficult for a novice with an unknown bank capacity.

[Graham.m]

Think we might have scared the OP away, he has been back but not posted

I don't believe I do, nope. Please tell us how does it differentiate between a low voltage caused by a temporary heavy load and a low voltage caused by a low SoC.

The above is precisely my point. Because SmartGauge is aware of the actual SoC of the battery you can be aware that your charge status is down to 50%. With an Ah counter that is much more difficult for a novice with an unknown bank capacity.

 

Suggest you tell me as you seem to know evidence and all that.

 

As I don't believe the OP wants genny starting etc and does not have any exotic equipment aboard I am not going to clutter the thread

[nicknorman]

Oh dear Nick!

Hate to nitpick, but there IS a definition of fully charged, and it can be found in The Battery FAQ.

 

Smpt

Yes you right there is a definition there, In fact it gives several. All different and there are lots of other definitons.

 

It says when the charge current has stabilised, without giving an actual dI/dt figure. That is pretty vague as the dI/dt doesn't suddenly go to zero, it tails off gradually leaving the reader to decide when it is fully charged.

 

It gives 2% tail current. Some on here would say 1%, Victron would say 4%.

 

It mentions specific gravity, which is only useful if the correct concentration of acid remains and the battery is in good condition (not sulphated)

 

It mentions rested open circuit voltage but that is tricky to get whilst charging!

 

So yes you are correct, there ARE definitions of fully charged, lots of them, and all different.

 

Perhaps I should have said there is no definitive definition, or is that tautological?

[Tony Brooks]

 

 

Think you missed that I did not say used the BMV to measure SoC. I said measure the Ahs used on it, different I think you might agree

 

I agree, probably with 100% accuracy but what will the OP do with the answer. He does not know his actual battery capacity and probably does not know how discharged it was. All he can do is make a guess, might a swell fit an ammeter and monitor tail current.

[nicknorman]

Think we might have scared the OP away, he has been back but not posted

 

 

I'm sure he knew what he was starting!

[WotEver]

 

I think you have miss the flow of the thread. We are talking about charging...

Yes, I'm fully aware of that. I suggest you read my post again.

 

Tony

I'm sure he knew what he was starting!

Absolutely ?

[mrsmelly]

Live aboard for umpteen years I would go for the BMV over the not so smart gauge but actualy prefer the NASA because I can read it without my glasses.

( there are others )

Tim

[Graham.m]

I don't believe I do, nope. Please tell us how does it differentiate between a low voltage caused by a temporary heavy load and a low voltage caused by a low SoC.

 

The above is precisely my point. Because SmartGauge is aware of the actual SoC of the battery you can be aware that your charge status is down to 50%. With an Ah counter that is much more difficult for a novice with an unknown bank capacity.

 

Well looking at the smartgauge manual

 

"For a low voltage alarm:-

The battery voltage has to fall below the activation voltage to trigger the alarm.

The battery voltage has to rise to the deactivation voltage to kill the alarm.

So if the activation voltage is set to 12.00 volts then the battery voltage will have to fall to 11.99 volts to

trigger the alarm.

For a high voltage alarm:-

The battery voltage has to rise to the deactivation voltage to trigger the alarm.

The battery voltage has to fall below the activation voltage to kill the alarm."

There is no delay mentioned so as soon as the voltage dips the alarm goes off

I'm sure he knew what he was starting!

 

So maybe we go away and leave it as it is until he gives us some more info like battery type etc

 

Edited January 20, 2016 by Graham.m

[destinyjon]

Thanks guys.

I think for me, the smartgauge will suit my requirements. It seems to be a popular choice on the whole.

Found them for £120 + £5.95 postage at cactus navigation and marine. It appears they have a uk distributer, so no import taxes!

[Graham.m]

Thanks guys.

I think for me, the smartgauge will suit my requirements. It seems to be a popular choice on the whole.

Found them for £120 + £5.95 postage at cactus navigation and marine. It appears they have a uk distributer, so no import taxes!

 

Enjoy and I hope it truly meets your needs

[mrsmelly]

Thanks guys.

I think for me, the smartgauge will suit my requirements. It seems to be a popular choice on the whole.

Found them for £120 + £5.95 postage at cactus navigation and marine. It appears they have a uk distributer, so no import taxes!

 

Cactus are first class thats who I use.

 

Tim

[smileypete]

Yes you right there is a definition there, In fact it gives several. All different and there are lots of other definitons.

 

It says when the charge current has stabilised, without giving an actual dI/dt figure. That is pretty vague as the dI/dt doesn't suddenly go to zero, it tails off gradually leaving the reader to decide when it is fully charged.

 

It gives 2% tail current. Some on here would say 1%, Victron would say 4%.

 

It mentions specific gravity, which is only useful if the correct concentration of acid remains and the battery is in good condition (not sulphated)

 

It mentions rested open circuit voltage but that is tricky to get whilst charging!

 

So yes you are correct, there ARE definitions of fully charged, lots of them, and all different.

 

Perhaps I should have said there is no definitive definition, or is that tautological?

 

I think that you're in danger of missing an important point here, that the charge voltage needs to be correct for the battery type and temperature.

 

Of course, the definition is the only one for the battery while being charged, and it's common sense in a way.

 

Paraphrasing the above definition, I'd say that if the tail current falls to a steady low level, usually below one or two percent of battery capacity, then the battery can be considered fully charged. At a rough guess, I'd say that a drop of less than 0.5% over an hour, though not perfect, is more than enough.

 

Maybe you or others could help us out, and when charging your batteries, towards the end of charge record the Smartgauge reading and the tail current every 30 minutes or so, it would be interesting to compare the two.

 

cheers, Pete.

smpt

Edited January 20, 2016 by smileypete

[Tom and Bex]

As I've mentioned before on here, we live off grid with solar and generator for battery charging. I find the Smartgauge very useful as an instant glance to see if we need to charge or not, also at this time of year it's very good at seeing how we are managing on solar during the day or if a top up charge is needed.

 

We also have a cheap shunt based ammeter from ebay that had its uses, but for us the Smartgauge is definitely the best in off grid situations. If I had the money I would have both gauges but to be honest don't think I could be bothered with the setup and adjustment of the BMV and just want the simple fit and forget of the Smartgauge.

 

As to accuracy during charge, I find ours seems to be a bit slow getting to 100% but would rather that than show 100% too early. As said it is hard to define 100% anyway.

 

All the above information is based on practical day to day use in real life as opposed to theoretical best practice.

 

Tom

[nicknorman]

I think that you're in danger of missing an important point here, that the charge voltage needs to be correct for the battery type and temperature.

Of course, the definition is the only one for the battery while being charged, and it's common sense in a way.

Paraphrasing the above definition, I'd say that if the tail current falls to a steady low level, usually below one or two percent of battery capacity, then the battery can be considered fully charged. At a rough guess, I'd say that a drop of less than 0.5% over an hour, though not perfect, is more than enough.

Maybe you or others could help us out, and when charging your batteries, towards the end of charge record the Smartgauge reading and the tail current every 30 minutes or so, it would be interesting to compare the two.

cheers, Pete.

smpt

"Considered fully charged" and "falls to a steady low level", "at a rough guess... 0.5%/hr" etc - I can agree with those but they are not exactly a precise reference one could use to calibrate a gauge against.

 

As to the last para, yes it's something I intend to do next time we are on the boat (this weekend) - not only record the current vs Smartgauge SoC but also vs AH counter SoC and, in discharge, Smartgauge SoC vs AH counter SoC. Not promising it but I'll do it if I have time / remember.

[WotEver]

 

Well looking at the smartgauge manual <lots of boring writing>

 

User looks at SmartGauge. SmartGauge reads 50% (or whatever level the user decides). User starts charging.

 

No alarms, no spurious voltage readings, no calculations. Just a glance at a gauge.

 

Tony

[nicknorman]

Well looking at the smartgauge manual

 

"For a low voltage alarm:-

The battery voltage has to fall below the activation voltage to trigger the alarm.

The battery voltage has to rise to the deactivation voltage to kill the alarm.

So if the activation voltage is set to 12.00 volts then the battery voltage will have to fall to 11.99 volts to

trigger the alarm.

 

For a high voltage alarm:-

The battery voltage has to rise to the deactivation voltage to trigger the alarm.

The battery voltage has to fall below the activation voltage to kill the alarm."

 

There is no delay mentioned so as soon as the voltage dips the alarm goes off

 

Incorrect on two counts, one is that had you read further, yes there is the option to assign a time delay to the low voltage alarm, but more importantly why would one want the alarm based on voltage? Reading further still reveals that you can also set the alarm to operate on SoC which is surely the correct thing to do for generator control.

[Graham.m]

"Considered fully charged" and "falls to a steady low level", "at a rough guess... 0.5%/hr" etc - I can agree with those but they are not exactly a precise reference one could use to calibrate a gauge against.

 

As to the last para, yes it's something I intend to do next time we are on the boat (this weekend) - not only record the current vs Smartgauge SoC but also vs AH counter SoC and, in discharge, Smartgauge SoC vs AH counter SoC. Not promising it but I'll do it if I have time / remember.

 

Have you fully set the Ah counter up?

Incorrect on two counts, one is that had you read further, yes there is the option to assign a time delay to the low voltage alarm, but more importantly why would one want the alarm based on voltage? Reading further still reveals that you can also set the alarm to operate on SoC which is surely the correct thing to do for generator control.

 

Personally I would want to do it on voltage as taking most batteries into and below 10.5 is not a good thing as is not drawing heavy currents off batteries not designed for them

User looks at SmartGauge. SmartGauge reads 50% (or whatever level the user decides). User starts charging.

 

No alarms, no spurious voltage readings, no calculations. Just a glance at a gauge.

 

Tony

 

You know it is rude to alter someone's writing in that way either quote it or not

 

Stop being rude

 

So I will quote it in full for you

 

 

 

Well looking at the smartgauge manual

 

"For a low voltage alarm:-

The battery voltage has to fall below the activation voltage to trigger the alarm.

The battery voltage has to rise to the deactivation voltage to kill the alarm.

So if the activation voltage is set to 12.00 volts then the battery voltage will have to fall to 11.99 volts to

trigger the alarm.

For a high voltage alarm:-

The battery voltage has to rise to the deactivation voltage to trigger the alarm.

The battery voltage has to fall below the activation voltage to kill the alarm."

There is no delay mentioned so as soon as the voltage dips the alarm goes off

 

So maybe we go away and leave it as it is until he gives us some more info like battery type etc

 

Edited January 20, 2016 by Graham.m

[blackrose]

 

On the Sterling charger there are two displays the left volts and the right amps and viewing that will again show the current (amp) being supplied to the battery and hence the tail current can be read there, again so long as nothing else is drawing current. I am naughterly assuming a Sterling Pro charger

 

 

I have a Sterling Pro-digital charger but it doesn't have these features? It's 10 years old - I guess they've upgraded it since then. Exactly which Sterling Pro charger are you referring to?

[Graham.m]

 

I have a Sterling Pro-digital charger but it doesn't have these features? It's 10 years old - I guess they've upgraded it since then. Exactly which Sterling Pro charger are you referring to?

 

This series http://sterling-power.com/products/pro-charge-ultra

[cuthound]

Back in the 70's, when BT had manually charged systems, the decision to stop charging was taken when specific gravity readings and tail current had remained steady for two consecutive readings, with each reading taken every 30 minutes throughout the charge.

[blackrose]

I have a Smartgauge AND a BEP DC monitor.

 

Even Gibbo thought it was a bit over the top when I spoke to him about ordering a Smartgauge and told him I already had the BEP monitor.

 

BUT, I have everything I need and I don't need to take sides in these discussions because they're both useful - even though they cost me a small fortune! It's the the battery monitor equivalent of having a cassette and a pump out.

 

The DC monitor does volts on 3 battery banks (start, domestics and BT) and amps in/out on the domestics, while the Smartgauge is just connected to the domestics. I never bother looking at SoC on the DC monitor.

 

 

 

Looks like it was a bit warm in the boat that night!

 

Edited January 20, 2016 by blackrose

[blackrose]

 

This series http://sterling-power.com/products/pro-charge-ultra

 

Very nice. Mine looks like it was built in the 80s compared to that!

[WotEver]

 

Very nice. Mine looks like it was built in the 80s compared to that!

Even if you had it, reading current off a charger while you're using other equipment is pretty pointless. Of course, you could turn everything off and find a torch I suppose. Preferably in the other order ?

[Graham.m]

Even if you had it, reading current off a charger while you're using other equipment is pretty pointless. Of course, you could turn everything off and find a torch I suppose. Preferably in the other order ?

The Sterling has a light display so just switch the master of and count 10 and read the current.

[johnmck]

Hi all.

Before i start embarking on what appears to be an emotive topic to some(!), i have read a number of threads on the forum regarding this subject, but being a novice with boat electrics and a relatively new boater, i have found a lot of threads somewhat overwhelming! (no disrespect to any forum members)

Having been on my boat for 8 months or so, i have managed so far by charging regularly either by engine power generating or my external 2.6Kw kippor generator. I would consider myself not to be a high power consumer, no toasters, electric kettle, etc.

The system charges through a sterling charger, which indicates when battery bank is either in fast charge, absorbtion or flood. I think the only issue with this approach is uneconomic regarding fuels, ie, would like to know the battery state before having to charge.

 

Therefore, i would like to install a battery monitor and probably do it myself, in order to keep the cost to a minimum!

The system comprises of a bank of 3 batteries (110ah i think!) and 1 engine battery. Additionally, one solar panel.

My primary requirements are:-

Ease of use and not necessarily over complicated

Ease of installation

Cost.

Many thanks all.

 

 

 

 

oh, should say, the two i am looking at are the smartgauge and the victron bvm 602.

thanks

I am your original electrical numpty.

 

For me the Smartguage does the trick. I want a guide and anything that is more complicated would Flummox me.

 

I try not to go below 75% SOC on the Smartguage, and charge up to 100%.

 

Still on the original batteries after five years. Works for me, no argument!