Monitoring power Draw

[DanB]

What do folks recommend as a good way to monitor leisure power levels & usage? My boat doesn't have any sort of "fuel gauge" for the remaining power in the leisure batteries (4x 12v).

[Naughty Cal]

A simple ammeter and voltmeter. Then learn how to read them and what they are telling you.

[mrsmelly]

2 minutes ago, DanB said:

What do folks recommend as a good way to monitor leisure power levels & usage? My boat doesn't have any sort of "fuel gauge" for the remaining power in the leisure batteries (4x 12v).

M fave is the NASA bm 2. Tells you charge in/out voltage etc forget the a/h counter bit they are not needed and not accurate. Very big easy at all times to read screen and fully waterproof. I have had several other types all do well but non are as easy to read as the Nasa

[Tony Brooks]

Or if the "learning" bit is hard an ammeter to tell you when to stop charging and a Smartguage to tell you when you should start charging.

If you have to ask the question DO NOT rely on any meter that supposedly tells you how many amp hours you have left in the batteries. They lie in most boaters' hands and ruin batteries for you.

[DanB]

Is there a good general charge/batteries faq about?

[Tony Brooks]

Not FAQs but see Bro's topic just below this one and look here http://thunderboat.boards.net/board/27/practical-advice-guidance     

particularly the charging primer and why some charge meters tell lies. You can skip the ensuing discussions.

Just about every question on these topics have been answered here several times over but the search facility can be a pain.

Edited July 5, 2017 by Tony Brooks
Get poster's name right

[MtB]

49 minutes ago, Tony Brooks said:

Or if the "learning" bit is hard an ammeter to tell you when to stop charging and a Smartguage to tell you when you should start charging.

 

Frankly, this is wrong. Doing this lead to me wrecking a new set of expensive batteries.

[mrsmelly]

2 minutes ago, Mike the Boilerman said:

 

Frankly, this is wrong. Doing this lead to me wrecking a new set of expensive batteries.

I would concur. Tony is absolutely correct in one way but I think you and I as long term liveaboards concur that very frequent charging is more important than anything else.

[Tony Brooks]

46 minutes ago, Mike the Boilerman said:

 

Frankly, this is wrong. Doing this lead to me wrecking a new set of expensive batteries.

 

42 minutes ago, mrsmelly said:

I would concur. Tony is absolutely correct in one way but I think you and I as long term liveaboards concur that very frequent charging is more important than anything else.

 

Right, I was trying to keep it simple. For maximum life batteries should be fully recharged AS SOON as they are discharged. From the moment of discharge sulphation starts to take place that reduces the capacity of the battery. Also for maximum life you should minimise the depth of discharge before recharging. This, in effect, enhances the cyclic life of the battery. So we have the need for frequent recharging indicated by these two things.

Although it is not a hard and fast rule it is usually accepted that 50% is as low as it is wise to discharge a battery.

A cruising boat is likely to run the engine for battery charging every day and usually for several hours. With a  well specified system for their electrical use they will often  not get to 50% discharged overnight BUT if they suddenly develop high consumption habits they may so to prolong the cyclic life they would be wise to start charging at 50% discharge.

A livaboard boater may well be able to last several days before the 50% discharge figure is reached and all that time the batteries are sulphating and loosing capacity so to combat that the 50% "rule" may not be applicable so they might do better to start charging at some higher figure. Of course its better to fully recharge every day if you can but if not each boater can set their own discharge percentage as to when they start recharging and as far as I am concerned the easiest way to get that reading is with a  Smartguage. You will note that I did not give a figure as to when to start charging in my reply above so I think my reply stands.

I am concerned that at this time of year when we may go to bed and get up with a degree of daylight assessing the battery state of charge  with a voltmeter is likely to give an artificially high figure because of the solar voltage.

[mrsmelly]

4 minutes ago, Tony Brooks said:

 

 

Right, I was trying to keep it simple. For maximum life batteries should be fully recharged AS SOON as they are discharged. From the moment of discharge sulphation starts to take place that reduces the capacity of the battery. Also for maximum life you should minimise the depth of discharge before recharging. This, in effect, enhances the cyclic life of the battery. So we have the need for frequent recharging indicated by these two things.

Although it is not a hard and fast rule it is usually accepted that 50% is as low as it is wise to discharge a battery.

A cruising boat is likely to run the engine for battery charging every day and usually for several hours. With a  well specified system for their electrical use they will often  not get to 50% discharged overnight BUT if they suddenly develop high consumption habits they may so to prolong the cyclic life they would be wise to start charging at 50% discharge.

A livaboard boater may well be able to last several days before the 50% discharge figure is reached and all that time the batteries are sulphating and loosing capacity so to combat that the 50% "rule" may not be applicable so they might do better to start charging at some higher figure. Of course its better to fully recharge every day if you can but if not each boater can set their own discharge percentage as to when they start recharging and as far as I am concerned the easiest way to get that reading is with a  Smartguage. You will note that I did not give a figure as to when to start charging in my reply above so I think my reply stands.

I am concerned that at this time of year when we may go to bed and get up with a degree of daylight assessing the battery state of charge  with a voltmeter is likely to give an artificially high figure because of the solar voltage.

Agree with all of that of course. You are so right about solar completely throwing false readings into the equasion, realy there is no real substitute to years of experience and getting to understand your lifestyle, boat charging system and what any monitoring equipment is telling you in a real world scenario.

[MtB]

1 hour ago, Tony Brooks said:

A livaboard boater may well be able to last several days before the 50% discharge figure is reached and all that time the batteries are sulphating and loosing capacity so to combat that the 50% "rule" may not be applicable so they might do better to start charging at some higher figure.

 

I still disagree. Trojan say recharge immediately any discharge occurs, or words to that effect.

My battery bank was lasting 5 to 6 days before getting down to 50% at which point I recharged in line with the advice you gave in post 4 (and to be fair it was the same advice as pretty much everyone else on here was also giving back then). This wrecked the bank for the reasons you've just added, which I had no idea was happening until after I started posting here about the developing failure of my new battery bank.

My practical advice for off grid liveaboards in the light of experience would be to recharge when down to 50%, or recharge 24 hours after the last recharge, whichever happens the soonest. Still fairly simple advice but essential in the three winter months when solar does 0% of virtually nothing. Hard to comply with if you work full time though.

 

 

Edited July 5, 2017 by Mike the Boilerman

[Tony Brooks]

 

1 hour ago, mrsmelly said:

Agree with all of that of course. You are so right about solar completely throwing false readings into the equasion, realy there is no real substitute to years of experience and getting to understand your lifestyle, boat charging system and what any monitoring equipment is telling you in a real world scenario.

Really that's the problem. The whole thing is so  full of variations in every aspect it is all but impossible to produce simple guidance that suits boaters  in all situations.

Its all very well me just using an ammeter and voltmeter but then being ancient I have to get up in the wee small hours so taking a peak at the voltmeter is no great problem. However knowing if the batteries are really showing the rested voltage is down to experience and if they are not which way the error will be and how much to estimate any correction factor.

2 minutes ago, Mike the Boilerman said:

 

I still disagree. Trojan say recharge immediately any discharge occurs, or words to that effect.

My battery bank was lasting 5 to 6 days before getting down to 50% at which I recharged in line with the advice you have just given Tony (and to be fair it was the advice pretty much everyone else on here was also giving back then). This wrecked the bank for the reasons you've just added, which I had no idea was happening until after I started posting here about the developing failure of my new battery bank.

My practical advice in the light of experience would be to recharge when down to 50%, or recharge 24 hours after the last recharge, whichever happens the soonest. Still fairly simple but essential in the three winter months when solar does 0% of virtually nothing. 

 

 

I am not disagreeing with you in any way. I actually stated what Trojan say but in my own words.

I still say that a Smartguage is probably the best guide an inexperienced boater will get to tell them when they MUST start charging. Nothing wrong with doing it before any particular percentage is reached.

[mrsmelly]

2 minutes ago, Tony Brooks said:

 

Really that's the problem. The whole thing is so  full of variations in every aspect it is all but impossible to produce simple guidance that suits boaters  in all situations.

Its all very well me just using an ammeter and voltmeter but then being ancient I have to get up in the wee small hours so taking a peak at the voltmeter is no great problem. However knowing if the batteries are really showing the rested voltage is down to experience and if they are not which way the error will be and how much to estimate any correction factor.

I am not disagreeing with you in any way. I actually stated what Trojan say but in my own words.

I still say that a Smartguage is probably the best guide an inexperienced boater will get to tell them when they MUST start charging. Nothing wrong with doing it before any particular percentage is reached.

I had to laugh at this Tony  I am not the only saddo that when he gets up for a wee in the dark looks at his battery montor then!!

[rusty69]

Just now, mrsmelly said:

I had to laugh at this Tony  I am not the only saddo that when he gets up for a wee in the dark looks at his battery montor then!!

I'm sad enough to have positioned the smartgauge so i can see it from the bed, it being constantly illuminated. The mrs isn't too happy when i inform her at 2am what the reading is. 

[mrsmelly]

Just now, rusty69 said:

I'm sad enough to have positioned the smartgauge so i can see it from the bed, it being constantly illuminated. The mrs isn't too happy when i inform her at 2am what the reading is. 

[MtB]

2 minutes ago, rusty69 said:

I'm sad enough to have positioned the smartgauge so i can see it from the bed, it being constantly illuminated. The mrs isn't too happy when i inform her at 2am what the reading is. 

 

My smartgauge is in the saloon of my boat where I can see it at all times. 

Fat lot of good it is though.

[rusty69]

Just now, Mike the Boilerman said:

 

My smartgauge is in the saloon of my boat where I can see it at all times. 

Fat lot of good it is though.

Isn't it about time you recalibrate them both? 

[MtB]

Just now, rusty69 said:

Isn't it about time you recalibrate them both? 

 

And how will that help?

(Given I know how much they are out?)

[rusty69]

Just now, Mike the Boilerman said:

 

And how will that help?

(Given I know how much they are out?)

I dunno. 

The offer of a tenner for it still stands though 

[MtB]

Just now, rusty69 said:

I dunno. 

The offer of a tenner for it still stands though 

 

Even though the SmartGauge manual says not to rely on anything the display is telling you? (Or words to that effect.)

[rusty69]

Just now, Mike the Boilerman said:

 

Even though the SmartGauge manual says not to rely on anything the display is telling you? (Or words to that effect.)

Yep, love my one. So much that i would like two. 

[MtB]

If you bought my two, one would say 84% while the other says 100%.

Then 5 hours of solar later, they would both say 100%. Or rather 100% alternating with an E3 error massage (OR is it E4?) as the solar does an hour of equalising every day.  

 

[rusty69]

1 minute ago, Mike the Boilerman said:

If you bought my two, one would say 84% while the other says 100%.

Then 5 hours of solar later, they would both say 100%. Or rather 100% alternating with an E3 error massage (OR is it E4?) as the solar does an hour of equalising every day.  

 

Try recalibrating then and disabling the e03 error. What ya got to lose? 

Edited July 5, 2017 by rusty69

[MtB]

Just now, rusty69 said:

Try recalibrating then andcdisable the e03 error. What ya got to lose? 

 

An hour of my valuable time.

I'll offer you a tenner to nip over and do it for me...

[rusty69]

3 minutes ago, Mike the Boilerman said:

 

An hour of my valuable time.

I'll offer you a tenner to nip over and do it for me...

Took me about 5 minutes. 

 

Besides your time ain't that valuable. How many hours you spent on here moaning about your smartgauge? 

Edited July 5, 2017 by rusty69