Batteries

[bigcol]

I've screwed mine to the wall only yesterday. Lol

[smileypete]

Would help if the OP shared a bit about their budget, their electrical needs and type of boating they're planning on doing - eg marina based, continuous cruising, off grid liveaboard etc.

 

As Julynian says, one of those handheld DC clamp ammeters can be very handy, common models are the Unitrend UT203 or Mastech MS2108A, £40 from Maplins and £25 online.

 

I don't think the Smartgauge is totally fule proof coz it won't warn about persistent undercharging.

 

cheers, Pete.

~smpt~

Edited April 21, 2014 by smileypete

[Theo]

Initially when first on the water with our solar and new batteries the SOC became a bit of a worry almost to a point of paranoia LOL, I could have well paid £100 +++ for a battery monitor around that time, fortunately I didn't.

 

Now having lived with the system for 8 months I can pretty much judge how the batteries are faring by looking at the original analogue needle gauge on the 12v panel.

 

We do have a fitted amp meter too and don't take too much notice of that either.

 

Just through a couple of months trial & error I reckon I can judge the batteries SOC as well as any gadget gadget. I do try not to let batteries go over 50% SOC, but in reality I'm not going to lose sleep over it, we went 4 days a couple of weeks ago with poor weather and hardly any input from solar, batteries would have been well below 50% SOC but I didn't need to burn expensive fuel to recharge them either, so I might lose a tiny fraction of battery life, but how much would the fuel cost and wear & tare on engine against a possible tiny amount of lost battery life.

 

Our analogue volt gauge has in the past read Empty but ample power on the boat, if I disconnect all loads from the batteries, within a couple of hours they're back up to 12.4/5v

 

I really don't think spending money on these type gadgets gains anything. Our MPPT controller also logs how many amps gleaned so some simple maths keeps us on top of things, learning how you use and judge your own energy use accordingly is much more interesting. Having not ever drained batteries to the point of setting of inverter alarms I reckon we're doing pretty well.

 

We do use a clamp meter a lot through the winter though for charging purposes, really useful for assessing amps input to better select appropriate charge methods.

I can identify with that philosophy but you do need to be pretty confident in the basic theory.

 

N

[bottle]

I know the theory can use the meters and interpret them but still have a Smartgauge.

 

Used in its most basic form, two wires to connect and one buttons to press.

 

and with respect, the other half can understand it.

[Ex- Member]

I can identify with that philosophy but you do need to be pretty confident in the basic theory.

 

N

 

Well basic as in knowing amps and volts and what certain readings mean.

 

The point I'm making is when you live with something day on day you get used to how it behaves. (well if you investigate like I tend to do) We basically know on average how many amps we use and how many amps we put into the batteries at the end of the day. That along with what the volts reading means I can confidently predict weather I need to charge the batteries. Through trial and error previously I now know that if the volt meter is reading a certain voltage whilst equipment is still running, that will relate ball park to a SOC. It won't be as simple as 12.2v = 50% SOC

 

I've previously had voltage readings well below 12v in the evening, almost empty on analogue gauge but then isolated the BB and 2 hours later have a reading around 12.5v I can have the needle reading empty for several hours even over night and in the morning after resting will still be reading 12.1/2v

 

Basically the actual voltage reading whilst under load or charging is next to useless. But over time getting to know your system it's just like I've described, it all just becomes so simple. I generally only look at the battery level once a day and confirm how many amps have been gleaned from solar. Anything between 150 and 200 amps on a previously fully charged battery means I can confidently go 24 hours without even having to think about any additional charging other than solar. We have often lasted 3 days from fully charged batteries in poor weather, in fact a few weeks ago we lasted 4, but they were pretty low so I did knock the fridge and inverter off over night, just in case LOL

 

Today's been good 240amps, yesterday we only gleaned 53amps from solar, batteries read 11.8v after solar finished last night, we ran 2 laptops and had a Tv running till 2am, not a problem, I simply new there was enough energy to cope.

 

6 months ago I would have been getting a genny out, or shutting everything down and going to bed early LOL That's when I realised though that just because your volts read 11.6 doesn't mean you're under a 50% SOC When I used to over react and do this and then find the batteries back to half or /3/4 full next morning I just made a point of learning as I went along.

 

Having to charge from engine and generator through winter was a good learning curve too. This is where the clamp meter comes into it own.

[Theo]

 

Well basic as in knowing amps and volts and what certain readings mean.

 

The point I'm making is when you live with something day on day you get used to how it behaves. (well if you investigate like I tend to do) We basically know on average how many amps we use and how many amps we put into the batteries at the end of the day. That along with what the volts reading means I can confidently predict weather I need to charge the batteries. Through trial and error previously I now know that if the volt meter is reading a certain voltage whilst equipment is still running, that will relate ball park to a SOC. It won't be as simple as 12.2v = 50% SOC

 

I've previously had voltage readings well below 12v in the evening, almost empty on analogue gauge but then isolated the BB and 2 hours later have a reading around 12.5v I can have the needle reading empty for several hours even over night and in the morning after resting will still be reading 12.1/2v

 

Basically the actual voltage reading whilst under load or charging is next to useless. But over time getting to know your system it's just like I've described, it all just becomes so simple. I generally only look at the battery level once a day and confirm how many amps have been gleaned from solar. Anything between 150 and 200 amps on a previously fully charged battery means I can confidently go 24 hours without even having to think about any additional charging other than solar. We have often lasted 3 days from fully charged batteries in poor weather, in fact a few weeks ago we lasted 4, but they were pretty low so I did knock the fridge and inverter off over night, just in case LOL

 

Today's been good 240amps, yesterday we only gleaned 53amps from solar, batteries read 11.8v after solar finished last night, we ran 2 laptops and had a Tv running till 2am, not a problem, I simply new there was enough energy to cope.

 

6 months ago I would have been getting a genny out, or shutting everything down and going to bed early LOL That's when I realised though that just because your volts read 11.6 doesn't mean you're under a 50% SOC When I used to over react and do this and then find the batteries back to half or /3/4 full next morning I just made a point of learning as I went along.

 

Having to charge from engine and generator through winter was a good learning curve too. This is where the clamp meter comes into it own.

Yup. But as Bottle says %age is something that we all understand and if it is on a little red display at the push of a single button it means that everyone can use it.

 

(By the way, and not intending to give offense or be picky, most of the statements about amps in the above do not relate to current but to charge. The correct unit for this is ampere-hours (Ah) which is amperes x hours. I just thought that I ought to make sure that the uninitiated were aware of this)

[nicknorman]

Of course, being familiar with the difference between amps and amphours would be a good start.

 

Ed:curses, beaten by Theo!

Edited April 21, 2014 by nicknorman

[Ex- Member]

I do it deliberately Nick to piss off the pedants LOL

Yup. But as Bottle says %age is something that we all understand and if it is on a little red display at the push of a single button it means that everyone can use it.

 

(By the way, and not intending to give offense or be picky, most of the statements about amps in the above do not relate to current but to charge. The correct unit for this is ampere-hours (Ah) which is amperes x hours. I just thought that I ought to make sure that the uninitiated were aware of this)

 

% costs over £100, learning your own system Free LOL

 

Yeah AH blah blah, I've been told numerous times LOL Most everyone gets the gist though

[ditchcrawler]

That's why you need Smartgauge. Within the limits of its accuracy the percentage reading is always the fraction of the actual capacity of the batteries. It takes account of their condition.

 

N

But it only tells you what percentage full the bucket is, not how big the bucket is.

[Theo]

I do it deliberately Nick to piss off the pedants LOL

 

% costs over £100, learning your own system Free LOL

 

Yeah AH blah blah, I've been told numerous times LOL Most everyone gets the gist though

I could almost feel a ChrisW moment coming on. I feel that it is important to get this right or those who really don't know abut electricity will have no chance of understanding the principles of a fascinating subject. Everything discussed will be just one item in a list of unrelated facts instead of part of a beautiful organised and comprehensible system.

 

N

[nicknorman]

But it only tells you what percentage full the bucket is, not how big the bucket is.

Yes that is true, but surely that is also what is most pertinent. An amphour counter tells you how full a bucket of imaginary size might be, not how full your bucket is. Having both types is best, but if you only want /can afford one, then it should be the SG.

[Fazandgil]

Thanks all for your input I have two new views to research after the smart gauge :-)

[ditchcrawler]

Yes that is true, but surely that is also what is most pertinent. An amphour counter tells you how full a bucket of imaginary size might be, not how full your bucket is. Having both types is best, but if you only want /can afford one, then it should be the SG.

I think I may well agree with that. I don't have a Smart Gauge, I don't feel one would be of any use to me, but I am sure its a great help to a lot of boaters. I will say no more. (for a little while)

[peterboat]

I went for the overkill method 1500 amp hours of full traction batteries and 1K watts solar panels also the wispergen for winter when solar doesnt cut it. I use a lot of power dishwasher auto washer kettles etc etc etc. It works for me I look at the meter attached to the tracer as long as when I go to bed it reads 12.2 or so all is well. The other day full sun the solar was clearly in de-sulphation mode 15 odd volts showing every so often yet hardly any amps going in . I check my batteries regularly and hope to get 20 odd years out of them ( one bank is 9 years old already so who knows? I know that I am lucky to afford my setup but everyone on a boat should have solar it keeps your batteries alive

 

Peter

[junior]

I have to say I think it is rather unhelpful to the OP, who (and I hope she will forgive me if I am wrong here) doesn't seem to have much knowledge of battery electrics, and probably not much interest in gaining such, when posters can't resist saying how clever they are to be able to know their battery state by performing complex differential calculus on the number of hydrogen atoms in their batteries (that they have personally counted), applying a factor acquired by oberving their tea leaves, and then running the whole thing through an analogue computer that uses seaweed as the ALU.

 

For someone whose hobby is not staring at their batteries all day, the Smartgauge is the obvious choice for a fit-and-forget solution to having a pretty good idea how the batteries are doing, at a glance, without needoing to have a degree in subatomic physics.

 

Clever:yes. Helpful:no

As so often on here, the voice of reason LOL.

[smileypete]

Ah, c'mon what's hard about reading a voltmeter or ammeter?

 

It's pretty well impossible to diagnose problems or issues without them.

 

cheers, Pete.

~smpt~