Is 805 AMPs enough to run 240 v fridge & 240 v freezer

[ditchcrawler]

Just to lighten things up a little, on Mrs Brown last week, she read out aloud from the newspaper "A Smart car previously reported as stolen was found to have been dragged into the drains by a rat" :-)

I've got a Mastervolt Mass combi with the MV monitor. With the batteries charged, it displays 100% and 13.1v but maybe that's down to gel batteries? Even after a couple of weeks. If a couple of lights are on and the water pump running, it still says 100%.

I have a Stirling battery monitor that is an amp in amp out counter and if you just leave it on the batteries with nothing switched the indication will be fuly charged batteries even if they are completely flat due to self discharge.

[Groundhog]

I've spent a lot of time reading posts on here about electrics over the last week or so and from what I've seen there's limitations to the SG and also limitations to shunt based monitors. It seems the only way to overcome those limitations is to install both which is what I've decided on and what the OP will have when their work is done. I think NickNorman's posts on the subject persuaded me it was the way to go but I've read that many I could be unfairly apportioning blame with that statement.

[nicknorman]

I've spent a lot of time reading posts on here about electrics over the last week or so and from what I've seen there's limitations to the SG and also limitations to shunt based monitors. It seems the only way to overcome those limitations is to install both which is what I've decided on and what the OP will have when their work is done. I think NickNorman's posts on the subject persuaded me it was the way to go but I've read that many I could be unfairly apportioning blame with that statement.

Nope, I totally agree with that.

[bottle]

I use a Smartgauge and a clamp ammeter.

[Slim]

That seems far too much. I would be surprised if it didn't cause an under-read. When you say you have "been assured this wouldn't affect SoC..." by whom was that? If Merlin then they don't actually understand how it works! Do you feel that it does affect the SoC reading - eg you can drain the batteries down to say 70% and then check the rested no-load voltage with one of your meters.

In fact it was someone on this forum about 6 months ago (give or take). If I recall correctly, at some point in the past Gibbo had been asked the question and that was his response. I've tried to find topic in question but can only go back to last December. To be honest I've never felt too comfortable with my SG. When I go back to the boat to fit the new Combi and MICC I've just ordered I'll do as you suggest regarding running the batteries down and measuring the at rest voltage. In the meanwhile I'll watch this topic with interest and hope the OP sorts his problem soon.

 

 

Frank

[Slim]

The very word Smart always worries me, it reminds me of Spivs, Jack the lads, clever dicks and Arthur Daley's. So I tend to avoid anything offered for sale which has Smart in its name. I even give all my Smarties away, which are bought for me because I couldn't face eating them. I also thought the price of em was a rip off for the measly amount the tube contained.

But I really liked my Smart car

[nicknorman]

In fact it was someone on this forum about 6 months ago (give or take). If I recall correctly, at some point in the past Gibbo had been asked the question and that was his response. I've tried to find topic in question but can only go back to last December. To be honest I've never felt too comfortable with my SG. When I go back to the boat to fit the new Combi and MICC I've just ordered I'll do as you suggest regarding running the batteries down and measuring the at rest voltage. In the meanwhile I'll watch this topic with interest and hope the OP sorts his problem soon.

 

 

Frank

My SG was 0.1v out. When I contacted Gibbo he said it should be within 0.05v - well that was the accuracy it should have been calibrated to. He went on to say that it shouldn't make any difference to SoC but in my experience, it caused the SoC to drop rather quickly to around 85%, before it became more accurate. I got it adjusted and afterwards it seems more accurate. I would certainly have thought 0.25v was excessive. Gibbo made a lot of smokescreen about how the SG worked and I think denying that it worked in voltage was part of that. PM sent.

[Arthur Brown]

The Smart gauge seems to be one of the best battery state meters, and I suspect that having sold the technology (to Merlin?) Gibbo wasn't at liberty to disclose details.

 

From the OP's original situation I worry that an 800AH battery was ever fitted to a system with a moderate alternator and there is little chance of a 100Amp alternator getting an 800AH battery charged -ever. OK the first hour may see 100AH gone into a flat battery but the tenth hour certainly will not.

[George94]

Read the manual, it says that the Smartgauge may be up to 10% inaccurate whilst the batteries are on charge.

 

It does not claim to tell you when the batteries are 100% SOC

 

It will tell you the SOC whilst the batteries are being used ie, being discharged.

 

Unfortunately it does claim this - by inference.

 

The Smartgauge shows SoC, and when it reads 100% most people would infer that the batteries are fully charged. If it can't say that the batteries are fully charged, then it shouldn't pretend to.

 

My battery manufacturer says batteries are fully charged when they are only accepting a charging current of 0.5% of battery capacity. Of course, you need to have everything switched off to measure this.

 

So it seems that I need to install an ammeter. It's a pity really, that one can't rely on the charger to do this, but my Victrons go into Float mode at approx 80% SoC, so I have to over-ride them to stay in Absorption mode.

 

It's all a real pain, and I am convinced my batteries have lost some capacity through being under-charged on occasion. However, it's almost impossible to measure without a gigantic upheaval.

[nicknorman]

Unfortunately it does claim this - by inference.

 

The Smartgauge shows SoC, and when it reads 100% most people would infer that the batteries are fully charged. If it can't say that the batteries are fully charged, then it shouldn't pretend to.

 

My battery manufacturer says batteries are fully charged when they are only accepting a charging current of 0.5% of battery capacity. Of course, you need to have everything switched off to measure this.

 

So it seems that I need to install an ammeter. It's a pity really, that one can't rely on the charger to do this, but my Victrons go into Float mode at approx 80% SoC, so I have to over-ride them to stay in Absorption mode.

 

It's all a real pain, and I am convinced my batteries have lost some capacity through being under-charged on occasion. However, it's almost impossible to measure without a gigantic upheaval.

You will find somewhere in the bumph that it specifically says that it is only accurate to within 10% during charge, therefore it does not claim to accurately indicate when 100% Soc is reached - whatever that might mean!

 

In the case of your battery manufacturer they have settled on 0.5% AH capacity. Not an unreasonable compromise, but it does not represent 100% SoC and of course the charge rate to reach an equivalent SoC will vary somewhat with temperature and in particular, battery health.

 

If you want to take your batteries to 0.5% AH capacity that is fine but it will require hours of charging at hardly any current and, when you take into account the cost of the engine or generator and its fuel, vs the cost of battery replacement, it is of questionable economics.

 

In my experience the SG normally shows 100% SoC at 1% to 2% AH charge rate, although it depends on the charging profile. If you wanted to get to 0.5% I think you could do that by waiting for 100% on the SG and then adding a couple of hours charging. The time could be determined from a £30 clamp-meter and would be reasonably repeatable so no need to actually install an ammeter - However most people don't want the "endless" engine running to get to 0.5%. That said, having an ammeter is very useful and I certainly look at ours frequently.

 

You have to bear in mind that all these methods of monitoring batteries are compromises, starting from the fact that there is no hard and fast definition of 100% charged. Different devices have different compromises. In the SG's case, accuracy on charge is not very good, whilst to offset that accuracy in terms of the real SoC on discharge is good, the device is pretty cheap and very easy to install. I think the expression is "pays your money and takes your choice"!

[Robbo]

 

So it seems that I need to install an ammeter. It's a pity really, that one can't rely on the charger to do this, but my Victrons go into Float mode at approx 80% SoC, so I have to over-ride them to stay in Absorption mode.

 

 

Is this because you can't config the Victron for the correct voltages? I know some of the cheaper chargers you can't, but on the combi's you can.

[bottle]

 

Unfortunately it does claim this - by inference.

 

The Smartgauge shows SoC, and when it reads 100% most people would infer that the batteries are fully charged. If it can't say that the batteries are fully charged, then it shouldn't pretend to.

 

My battery manufacturer says batteries are fully charged when they are only accepting a charging current of 0.5% of battery capacity. Of course, you need to have everything switched off to measure this.

 

So it seems that I need to install an ammeter. It's a pity really, that one can't rely on the charger to do this, but my Victrons go into Float mode at approx 80% SoC, so I have to over-ride them to stay in Absorption mode.

 

It's all a real pain, and I am convinced my batteries have lost some capacity through being under-charged on occasion. However, it's almost impossible to measure without a gigantic upheaval.

 

Set the VIctron up (laptop, Interface and softwarerequired ) correctly for your batteries, set the charge curve to 'fixed' and forget the 'adaptive' and 'adaptive + battery safe' settings as advised by Gibbo (Smartgauge designer)

 

You will need to do more monitoring, volt meter and ammeter whilst batteries are being charged.

 

As to all the other bits see post #110

[George94]

 

Is this because you can't config the Victron for the correct voltages? I know some of the cheaper chargers you can't, but on the combi's you can.

 

It's not a combi. It's a Phoenix - just a charger.

[Robbo]

 

It's not a combi. It's a Phoenix - just a charger.

The Phoenix voltage settings can be changed, for the Trojans you need to customise them for the correct ones.

[bottle]

george 94

 

it may depend as to your exact model and age.

 

"

Computer interface

Every Phoenix Charger is ready to communicate with a computer through its RS-485 data port. Together with our VEConfigure software, which can be downloaded free of charge from our website www.victronenergy.co and the data link MK1b (see accessories), all parameters of the chargers can be customised."

From this PDF document: http://www.victronenergy.com/upload/documents/Datasheet-Phoenix-Battery-Charger-EN.pdf

[Robbo]

 

george 94

 

it may depend as to your exact model and age.

 

"

Computer interface

Every Phoenix Charger is ready to communicate with a computer through its RS-485 data port. Together with our VEConfigure software, which can be downloaded free of charge from our website www.victronenergy.co and the data link MK1b (see accessories), all parameters of the chargers can be customised."

From this PDF document: http://www.victronenergy.com/upload/documents/Datasheet-Phoenix-Battery-Charger-EN.pdf

 

 

Looks like you can also do via some switches as well so you don't need the VEConfigure stuff. http://www.victronenergy.com/upload/documents/Phoenix-Charger.pdf

[George94]

Thanks, everybody, but the website has some rather conflicting information on it. In some places it says the Phoenix can be configured by VEConfigure, and in others it says it can't. The only way to find out for sure is to invest £50 in a cable.

 

I have two 50 amp chargers, and have over-ridden the first one (by switches) to stay in Absorption mode, and the other I have left to go into Float. If the batteries need charging, I turn off the first charger when the SG tells me the batteries are at 100%.

 

Recently I have moved to a mooring with mains power, so it's not really a problem now except when away from the mooring for a few days, and in that case the engine will be on quite a lot, and the solar panels which I installed in the summer are also a huge help.

 

But it's still irritating that there isn't a better way to ensure one's batteries are charged.

 

One thing I have observed is that even in Absorption mode, the current that the batteries will accept is very small when the batteries are charged. It makes me wonder whether there is any benefit in having a Float mode.

[nicknorman]

 

One thing I have observed is that even in Absorption mode, the current that the batteries will accept is very small when the batteries are charged. It makes me wonder whether there is any benefit in having a Float mode.

Yes there is (otherwise why would the manufacturers bother!). Even though the current in Absoprion is perhaps just an amp or two, if this is left on 24/7/365 then not only will water loss occur, but more importantly something called "plate erosion" (or corrosion) occurs, which will significantly shorten the battery's life. In float mode the current should be virtually zero. Edited January 8, 2015 by nicknorman

[Robbo]

Thanks, everybody, but the website has some rather conflicting information on it. In some places it says the Phoenix can be configured by VEConfigure, and in others it says it can't. The only way to find out for sure is to invest £50 in a cable.

 

Well an email to Victron is cheaper. Can't you configure using the micro switches inside the Victron?

Edited January 8, 2015 by Robbo

[bottle]

Thanks, everybody, but the website has some rather conflicting information on it. In some places it says the Phoenix can be configured by VEConfigure, and in others it says it can't. The only way to find out for sure is to invest £50 in a cable.

 

I have two 50 amp chargers, and have over-ridden the first one (by switches) to stay in Absorption mode, and the other I have left to go into Float. If the batteries need charging, I turn off the first charger when the SG tells me the batteries are at 100%.

 

Recently I have moved to a mooring with mains power, so it's not really a problem now except when away from the mooring for a few days, and in that case the engine will be on quite a lot, and the solar panels which I installed in the summer are also a huge help.

 

But it's still irritating that there isn't a better way to ensure one's batteries are charged.

 

One thing I have observed is that even in Absorption mode, the current that the batteries will accept is very small when the batteries are charged. It makes me wonder whether there is any benefit in having a Float mode.

 

Think of your battery as a bucket, with a small hole in it (self discharge). That you cannot allow to overflow

 

When it is empty you can fill it fast, as it get near to full you have to fill more slowly so as not to overflow, when it is absolutely full you have to fill it only as fast as it empties through the hole.

 

The float mode is to always keep the battery full to its maximum.

[cuthound]

Think of your battery as a bucket, with a small hole in it (self discharge). That you cannot allow to overflow

 

When it is empty you can fill it fast, as it get near to full you have to fill more slowly so as not to overflow, when it is absolutely full you have to fill it only as fast as it empties through the hole.

 

The float mode is to always keep the battery full to its maximum.

I have worked with batteries all my working life, and this is the simplest and most accurate description I have ever heard. Have a greenie!

[forsberg]

Hi!

Needs to be broken down in steps.

A : Are the batterys and charging OK? best way to check with a battery acid tester if possible, check all cells when fully charged.

if some cell differients thet battery is broken. If no batterys are fully charged somethings wrong with the charging.

if there is a short in one battery that could drain them very fast, on the other hand that battery would get very noticeble warm.

 

B : How much stuff do you run overnight ? the annual specification on fridge and freezer is just an estimate and it could well be more.

the inverter will at best have a 90% efficency so some Ah goes away there.

What kind of heating and hotwater do you have, some draw lots of Ah.

 

... Right 7 pages missed that but never mind.

 

Anyway there are no way to measure battery condition by electronics and get a trustworthy 0-100% reading.

It will always be a "good guess" at the best and with any parameter wrong it will be a bad guess.

 

Only testing the battery acid will give you a correct answer.

 

So except for a Amp-meter fitted correctly there are no way to decide when the batteries are as fully charged as their condition and temperature allows.

 

Now for the batteries, Calcium batteries degrade fast in hot temperatures 50C+ and they are poor at cycling, takes a long time to charge, if you have ever run them flat they have a "memory effect" so they need to be overcharged for up to 3 day's with 15+ volt, or they will loose capacity each time it goes flat.

So they are not an good option unless you have a landline or charge them for hour on end and use them rarely.

 

Then again the alternative is high maintance

Edited January 9, 2015 by forsberg

[luggsy]

Just a quick up date victron has been fitted looks a nice bit of kit and easy to use , battery's have been on shore line for 8 days now so both the victron and smart gauge are showing 100% soc victron is showing 13.49 v smart gauge showing 13.50 v, I have now got a clamp meter ( haven't got a clue how to use it instructions are in Chinese ) also a digital meter ( same again instructions in Chinese ) so I will be off again this weekend and see how I get on , I also brought a plug in power meter to see what's using what, will keep you up dated thanks for all your answers suggestions and input

[forsberg]

DC- clamps are prone to missreadings, especially when close to other magnetic fields or when measuring low current.

So measures close to the alternator may be erratic.

 

Equipment --------------O--------------------- Alternator
l
l <- measure here
l
----------
Battery Bank

 

But your system may not be Wired in this way.
Making things a bit more complicated.

It may be wired like this:

 

Equipment ------------ --------------------- Alternator
l l
l l
l l
----------
Battery Bank

 

In which case you can not measure whats going into the bank whithout turning off
all equipment. Or mesure both cables and do a little math.

[luggsy]

Quick up date still in marina on shore power due to Harecastle tunnel being closed ,so to test the victron I disconnect from shore line at 9 pm 1st night smart gauge showing 99% 12.65v victron showing 97.1% & 12.62 at 11.45 pm , at 8.30am smart gauge showing 71% & 12.24 v victron showing 91.8% & 12.23v so a big difference on s o g need to get out cruising to test proper , will up date once out cruising , just to add 240v fridge 240v freezer and 240v central heating pump on all night