Battery charging

[Loafer]

To keep it simple the non tech way is the smartguage lots on here swear by them. I needed to know how many amps I was creating/using so went for a NASA BM2, which was roughly the same price as the smartguage. Now it is up to you to study the threads on here and make your own mind up as it really does depend on what information you require as to what device you fit

 

By far the cheapest is a voltmeter, and learn to read what is is telling you.

 

That does take time and observation though. I have used a BMV 600S for years, but don't really need it any more - it is used just for interest. It is normally left on the 'volts' display, occasionally 'consumed energy'.

[Arthur Brown]

A boat at say £30K is a cheap flat (£100K on land) BUT you take on he duties of water supplier, fuel supplier, waste remover (inc toilets) and electrical supply company. There ARE a few things you need to learn about and electrics is one of them.

 

Read the Victron book it's a free PDF download and it's right, OK it is based on the Victron range but the author is a real boater and knows real boat life.

 

Read the Smartguage.co.uk website and look at all the pages, study them til they make sense, again the author is(was) a real boater so knows boat electrics.

[Richard10002]

I tried to set up a simple system with separate volt meters, and ammeters, but it wasnt satisfactory without a cumulative reading of Amp Hours used... truly an example of "buy cheap, buy twice".

 

Thus, with a a choice of NASA BM2 and Smartguage in 2012, I chose the NASA as I definitely wanted to know Cumulative Amp Hours used, and instantaneous Amps being discharged, or charged. Its' stab at percentage state of charge is undoubtedly significantly innaccurate.

 

A few months ago, I decided I could justify £125 on a Smartguage, so now have the best of both worlds. I'm not convinced that SOC on the Smartguage is always accurate, but it seems much more accurate and much smoother than the NASA. Between 100% and about 85%-90% it is definitely not accurate... tonight it has fallen from 100% to 90% SOC after using only 17Ah, but after 3 or 4 days useage of about 200Ah, it shows 40% SOC. The first 10% useage suggests a capacity of 170Ah, but the 60% useage suggests a capacity of 330Ah. I have 4 x Trojan 105, so capacity should have been 450Ah when purchased in May last year. I dont doubt the capacity may have fallen, but it is more likely to be around 350Ah, than 170Ah, (given that I can use lots more than 200Ah over a long weekend, and I have never let the SOC on the Smartguage fall below 30%).

 

I'm tempted to let the SOC fall to 20% and see how many Ah are used, but that's probably too much for this thread...

 

Needless to say, based on my needs and experience, I would, and did, buy the NASA BM2 as my choice of battery monitor, if I could have only one.

[Loafer]

Nicknorman, over to you, I've been called to bed!

[peterboat]

I tried to set up a simple system with separate volt meters, and ammeters, but it wasnt satisfactory without a cumulative reading of Amp Hours used... truly an example of "buy cheap, buy twice".

 

Thus, with a a choice of NASA BM2 and Smartguage in 2012, I chose the NASA as I definitely wanted to know Cumulative Amp Hours used, and instantaneous Amps being discharged, or charged. Its' stab at percentage state of charge is undoubtedly significantly innaccurate.

 

A few months ago, I decided I could justify £125 on a Smartguage, so now have the best of both worlds. I'm not convinced that SOC on the Smartguage is always accurate, but it seems much more accurate and much smoother than the NASA. Between 100% and about 85%-90% it is definitely not accurate... tonight it has fallen from 100% to 90% SOC after using only 17Ah, but after 3 or 4 days useage of about 200Ah, it shows 40% SOC. The first 10% useage suggests a capacity of 170Ah, but the 60% useage suggests a capacity of 330Ah. I have 4 x Trojan 105, so capacity should have been 450Ah when purchased in May last year. I dont doubt the capacity may have fallen, but it is more likely to be around 350Ah, than 170Ah, (given that I can use lots more than 200Ah over a long weekend, and I have never let the SOC on the Smartguage fall below 30%).

 

I'm tempted to let the SOC fall to 20% and see how many Ah are used, but that's probably too much for this thread...

 

Needless to say, based on my needs and experience, I would, and did, buy the NASA BM2 as my choice of battery monitor, if I could have only one.

Same for me if I could be bothered I could connect my laptop to the Midnite solar controller to see how many amps solar is doing, however the BM2 does that as well as the wispergen and the alternator, and all the boats discharges at a glance. So for me I know how much my gain or deficit is on a daily basis. How accurate the SOC is however anybodies guess, but for me it doesnt matter as the wispergen will self start if battery level goes below a certain limit

[Robbo]

Same for me if I could be bothered I could connect my laptop to the Midnite solar controller to see how many amps solar is doing, however the BM2 does that as well as the wispergen and the alternator, and all the boats discharges at a glance. So for me I know how much my gain or deficit is on a daily basis. How accurate the SOC is however anybodies guess, but for me it doesnt matter as the wispergen will self start if battery level goes below a certain limit

Is the BM2 an amp counter? If the generator comes in on the SOC, this will change over time if you don't update the battery capacity.

[Loafer]

Is the BM2 an amp counter? If the generator comes in on the SOC, this will change over time if you don't update the battery capacity.

 

Er, how do you do that, Robbo? (<mischievous smile>)

[peterboat]

Is the BM2 an amp counter? If the generator comes in on the SOC, this will change over time if you don't update the battery capacity.

Everything goes through the BM2 and as I have a 1500 ah full traction battery bank and the bm2 doesnt go that high its all a bit of a guess.

[Richard10002]

Is the BM2 an amp counter? If the generator comes in on the SOC, this will change over time if you don't update the battery capacity.

 

It's an amp hour counter, and instantaneous amps meter and volt meter, and very good it is too!

 

As you say, you have to enter capacity for it to show SOC but, as you cannot know capacity with any accuracy, SOC cannot be accurate, although you can iterate towards it with a bit of thought and patience.

[Loafer]

 

It's an amp hour counter, and instantaneous amps meter and volt meter, and very good it is too!

 

As you say, you have to enter capacity for it to show SOC but, as you cannot know capacity with any accuracy, SOC cannot be accurate, although you can iterate towards it with a bit of thought and patience.

 

I'm completely convinced that you can iterate towards it very well, if you have good knowledge of battery tech and charging requirements, and in possession of a BM2, or BMV 600. Probably as good as the Smartgauge's 5%, although I don't have one. (I am a fan, though).

 

If I could get one for 50 quid from eBay, I'd get a Smartgauge, just to prove myself right or wrong. There doesn't seem to be one for sale second hand.

[Robbo]

Everything goes through the BM2 and as I have a 1500 ah full traction battery bank and the bm2 doesnt go that high its all a bit of a guess.

You could half it and enter that into the BM2, so SOC on the BM2 is from 0-100% but in real terms it's from 50%. My reason for the reply was that your battery capacity reduces over time so if you don't update the BM2 your genny will be kicking in at lower and lower SOC.

[peterboat]

You could half it and enter that into the BM2, so SOC on the BM2 is from 0-100% but in real terms it's from 50%. My reason for the reply was that your battery capacity reduces over time so if you don't update the BM2 your genny will be kicking in at lower and lower SOC.

Thats what I have done however the gennie kicks in on voltage, if it sits at a a certain low voltage for over an amount of time it starts. One of my banks was off last year for testing it was pronounced fit and that is at 10 years old! so clearly solar does something right

[Robbo]

Thats what I have done however the gennie kicks in on voltage, if it sits at a a certain low voltage for over an amount of time it starts. One of my banks was off last year for testing it was pronounced fit and that is at 10 years old! so clearly solar does something right

 

I'm doing something similar where I can start a generator based on alarm of SOC, or/and voltage. What voltage settings have you used, and do you find the generator kicks in on high loads?

[peterboat]

 

I'm doing something similar where I can start a generator based on alarm of SOC, or/and voltage. What voltage settings have you used, and do you find the generator kicks in on high loads?

Its built into the wispergen I think its 12.1 volts for over so many minutes. High loads dont trigger it. These were built for yachts at sea rather than canal boats although CRT does have a load of them. I will look at the manual and see what it says and send it to you

[Robbo]

Its built into the wispergen I think its 12.1 volts for over so many minutes. High loads dont trigger it. These were built for yachts at sea rather than canal boats although CRT does have a load of them. I will look at the manual and see what it says and send it to you

 

Cheers, I've got a Kohler genny and a Victron BMV so can configure it to start the genny on SOC or Voltage. The Voltage drops when a high load is applied so I could get it too start the genny.

[smileypete]

Thanks for all replies, took your advice n ordered solar panels, just need to get a monitor for battery charger now to get an idea of how much the solar is charging. Have read the vitron manual already.

Any tips on cheaper battery monitors? Cheers

 

A Smartguage is the simplest to use, but not the cheapest at £160.

 

You may be able to get by just fine with an accurate 4 digit voltmeter for £5 to £10, and some sort of ammeter like a 'DC clamp ammeter' for £30ish, BUT it does need a little learning and experience to use.

 

OK often people make out that using a voltmeter and ammeter is super complicated (WHY? ) but all it really needs is this:

 

1) Batteries in frequent use need a FULL charge at least weekly - other charging can be near full as practicable.

 

2) SO, what is a FULL charge, then? To paraphrase 'The Battery FAQ' :

 

a) Charge voltage has reached the correct level as required by the manufacturer or supplier.

 

b ) Charge current has tailed off to a steady low level, usually less than 1 to 2% of batt capacity in Ah - may take 6 to 8 hours!

 

c) If a non sealed battery, it helps if the battery acid is fizzing gently at the end - a quick peek once in a blue moon will do.

 

3) Recharge when the batt voltage no longer recovers above 12.2V, or say 12.1V if running a few LED lights or 12V fridge. If the inverter starts beeping it's definitely time to recharge!

 

That's about it really.

 

A Smartgauge gives a nice easy reading BUT it's not quite accurate enough at the end of charge, when the need for accuracy is greatest! . So even with a Smartgauge it's best to have an ammeter as well.

 

cheers, Pete.

~smpt~

Edited April 2, 2016 by smileypete

[Loafer]

 

A Smartguage is the simplest to use, but not the cheapest at £160.

 

You may be able to get by just fine with an accurate 4 digit voltmeter for £5 to £10, and some sort of ammeter like a 'DC clamp ammeter' for £30ish, BUT it does need a little learning and experience to use.

 

OK often people make out that using a voltmeter and ammeter is super complicated (WHY? ) but all it really needs is this:

 

1) Batteries in frequent use need a FULL charge at least weekly - other charging can be near full as practicable.

 

2) SO, what is a FULL charge, then? To paraphrase 'The Battery FAQ' :

 

a) Charge voltage has reached the correct level as required by the manufacturer or supplier.

 

b ) Charge current has tailed off to a steady low level, usually less than 1 to 2% of batt capacity in Ah - may take 6 to 8 hours!

 

c) If a non sealed battery, it helps if the battery acid is fizzing gently at the end - a quick peek once in a blue moon will do.

 

3) Recharge when the batt voltage no longer recovers above 12.2V, or say 12.1V if running a few LED lights or 12V fridge. If the inverter starts beeping it's definitely time to recharge!

 

That's about it really.

 

A Smartgauge gives a nice easy reading BUT it's not quite accurate enough at the end of charge, when the need for accuracy is greatest! . So even with a Smartgauge it's best to have an ammeter as well.

 

cheers, Pete.

~smpt~

 

 

[Richard10002]

 

A Smartguage is the simplest to use, but not the cheapest at £160.

~smpt~

 

£125 including delivery from Cactus Nav

 

http://www.cactusnav.com/advanced_search_result.php?keywords=smartguage&x=2&y=12

 

I couldnt justify one at £160, but at £125 I bought one almost immediately to join my NASA BM2.

[Leemc]

Yet another thread about electrics on boats that just confuses me even more. The problem must be my learning style and just reading information doesn't sink into my brain:(

I think I need to do this practically on a boat with someone showing/explaining ( slowly and more than once!) what exactly is happening.

Thanks to all contributors, you know your stuff.

[Alan de Enfield]

Yet another thread about electrics on boats that just confuses me even more. The problem must be my learning style and just reading information doesn't sink into my brain:(

I think I need to do this practically on a boat with someone showing/explaining ( slowly and more than once!) what exactly is happening.

Thanks to all contributors, you know your stuff.

 

No1 Son has the same problem - he just cannot absorb electrical 'stuff'.

 

I think its probably down to some 'syndrome' due to the fact when we had the farm, and he was very young. I used to send him across the field to check the electric fencing was working (by touching it) he has never really liked 'lecky.

[by'eck]

 

No1 Son has the same problem - he just cannot absorb electrical 'stuff'.

 

I think its probably down to some 'syndrome' due to the fact when we had the farm, and he was very young. I used to send him across the field to check the electric fencing was working (by touching it) he has never really liked 'lecky.

 

Funnily enough my Dad, a market gardner who kept pigs as a (profitable) hobby, tried something similar with me when I was knee high to a grasshopper.

 

My Mum who is still alive recalls the tale and disbelief when I grabbed hold of the pig fence wire and stepped over - without issue - could it have been the welly boots ? - talk about irrersponsible parents

[BruceinSanity]

Funnily enough my Dad, a market gardner who kept pigs as a (profitable) hobby, tried something similar with me when I was knee high to a grasshopper.

 

My Mum who is still alive recalls the tale and disbelief when I grabbed hold of the pig fence wire and stepped over - without issue - could it have been the welly boots ? - talk about irrersponsible parents

Many years ago at a Scout camp, one of the lads stepped over what he thought was a dead strip of electric fence. He was only just tall enough to get over and the wire pressed itself into the crotch of his Levi's. And it was live...

 

Until then, I hadn't realised you could jump vertically into the air when already standing on tiptoe

[Taslim]

Many years ago at a Scout camp, one of the lads stepped over what he thought was a dead strip of electric fence. He was only just tall enough to get over and the wire pressed itself into the crotch of his Levi's. And it was live...

 

Until then, I hadn't realised you could jump vertically into the air when already standing on tiptoe

My cuz from Yorkshire, where they farm 'right' visited & we niped of to town for 10 fags and a flagon, like you do as a grown up 13 year old. The cider worked, I warned John not to piss through the hedge, he said the wire was just to fool the cattle then executed a perfect (if P stained) back somersalt.

 

Back on topic S. Pete summed it up very well.

[smileypete]

Yet another thread about electrics on boats that just confuses me even more. The problem must be my learning style and just reading information doesn't sink into my brain:(

I think I need to do this practically on a boat with someone showing/explaining ( slowly and more than once!) what exactly is happening.

Thanks to all contributors, you know your stuff.

 

Do you have a decent digital voltmeter and some sort of ammeter fitted on the boat?

 

If so it makes it a lot easier to understand it by seeing how things work in practice. Otherwise it's a bit like trying to learn to ride a bike - without a bike.

 

Have to admit I have trouble with anything more than basic maths if I can't visualise it, it becomes too abstract for me.

[Leemc]

Thanks Pete still on land for a little while longer. But this stuff is very high up on my " get my head round list"