Seem to be using more power than I thought

[Bewildered]

Been living aboard for about 5 months now and still trying to get to grips with power management.

Had to replace the leisure batteries a couple of months ago as they were slowly dying, to the point they would not last the night.

 

I replaced them with 3 x Varta 230ah, so I have a nice hefty 690ah or rather 345ah to keep them above 50% charged. I also fitted a smartguage so I could keep an eye on this expensive purchase.

 

However I have not yet gotten around to buying a 12v tv so we are still using the 230v tv through the inverter. Having just read through one of the post on here regarding 230v tv's, I read that a modern tv is going to use about 9amps so for 4 hours around 36ah

My tv is rated at 1.2 amps 63w; after charging my batteries to 100% (according to the smartguage) and then leaving it on float charge for a good couple of hours we sat down to watch tv for about 4 hours after which the smart guage read 77% pretty much a 1/4 of the total capacity around 170 ah

 

The inverter is a 600w sterling unit. This is 16 year old boat and it was fitted when I bought the boat.

I suspect the inverter may be faulty. Rather than an isolator switch to route the 240v this boat has 3 mains sockets mounted in the electrical cupboard. The first is for power from the sterling generator built onto the engine, the second is for shore power and the third is for the inverter. To select a power source a 13amp plugtop that feeds the boats sockets is plugged into one of these 3 choices.

The inverter socket is labelled "disconnect battery charger first" however it is easy to make a mistake and leave it in, which is why I suspect it may have a problem even though it still produces 230v

 

On the odd occasion we have watched a couple of dvd's (the DVD player also being 230v) say 4-5 hours worth and had the smartguage reading drop from full to around 60%

This all seems to me to be far to much power

The only other things being powered during this time are the 12v fridge the 12v freezer as we tend to watch tv in the dark.

 

Hopefully I have given all the necessary info for you to make valid suggestions

 

Note: overnight we tend to turn the freezer off but leave the fridge on, very little power if any is registered as lost on the smartguage

[mickp]

Are you charging from shore or generator power as you mention float charging?i think it may be best to isolate the charger and maybe imersion heater circuits from the inverter circuit to stop mistakes .fridge is my biggest user of power.do you run any tv boxes ie freesat etc?.ur usage sounds does high

Maybe get a voltage reading to backup sg reading

[Bewildered]

When I had it float charging yesterday it was with petrol genny powering sterling 3 stage charger.

We have a digital recorder but it is running on 12v

 

The smartguage measures voltage and this tallies pretty much with the voltage reading on the solar controller, within 1/2 a volt usually

Edited August 28, 2016 by Bewildered

[Bod]

My Take on how to read a Smart Gauge.
Battery takes a long time to run down-- takes a long time to charge = all good.
Battery takes a short time to run down-- takes a long time to charge = heavy drain on battery. (using to much power)
Battery takes a short time to run down -- takes a short time to charge = battery has reduced capacity. (battery at end of life, needs replacing)
Smart Gauges tell it as it is, you may not like what they say, but are almost unknown to be wrong.
It won't tell you if, only 1 battery in a bank is duff, only that the bank has a problem.
A hydrometer is the only way of checking each cell in each battery. (assuming Wet Lead Acid battery)

 

Bod

[WotEver]

SG takes a few cycles to sync with a new bank and can also be up to 10% out when charging. So...

 

1. How many charge/discharge cycles have you been through?

 

2. After you start watching TV with SG showing 100%, what does it show after 10 minutes?

 

Tony

[nicknorman]

There is nothing wrong with the 3 socket arrangement you mention to select the power source, however from the sound of it you need to be careful to ensure you have the battery charger switched off before you connect to the inverter. Otherwise the inverter will supply the battery charger which will supply the batteries which supply the inverter. But with quite big losses around that loop.

 

Can you confirm the battery charger is off when you are running on inverter power, and ditto for any immersion heater?

 

Anyway, the best thing is to have means to measure the current in and out of the batteries. You get get a "proper" shunt based monitor such as a NASA or Victron BMV for a little over £100. Alternatively if you want something cheap and cheerful you could get a DC clamp meter such as a UNI-T UT203 for around £30. Either of these devices will allow you to monitor the instantaneous current coming out of the batteries, and also the charging current. The Smartgauge is not particularly good at knowing when 100% SoC is reached, and anyway there is no precise definition of that. Rather, it is best to monitor the charge current into the batteries and stop charging when it has fallen to just a few amps, 10A or less in your case.

 

There can be an issue with multistage chargers whereby they go into float prematurely. If your problem is gradually getting worse chances are it is due to undercharging. If your problem has been there ever since you fitted the new batteries it's probably because you are taking more current out of the batteries than you think.

Edited August 28, 2016 by nicknorman

[Alan de Enfield]

My tv is rated at 1.2 amps 63w; after charging my batteries to 100% (according to the smartguage) and then leaving it on float charge for a good couple of hours we sat down to watch tv for about 4 hours after which the smart guage read 77% pretty much a 1/4 of the total capacity around 170 ah

 

 

 

 

If the TV really is 1.2 amps, and is a 'mains' TV, then that would be 275 watts, this would equate to about 27.5 amps ( or 110 Ah over 4 hours) taken from the battery via the inverter.

 

Are you sure it is a 230v TV ?

 

Is the 'watts' & 'amps' stated on a small black box in line between the mains plug an the TV ?

Many / Most / All TVs these days are actually 12v and have a step down transformer (the 'in-line' black box).

If you have such a TV / Black box then you are being incredibly inefficient by taking your 12v from the battery, inverting it up to 230v, then reducing it back to 12v for the TV.

 

If you do have such a 'black box' have a close look at the printing on it - look for input voltage and output voltage.

 

A usage of 170Ah is not possible with just a TV - there is something else, somewhere, sucking your life blood.

Edited August 28, 2016 by Alan de Enfield

[Sea Dog]

1. I also fitted a smartguage so I could keep an eye on this expensive purchase.

 

2. I read that a modern tv is going to use about 9amps so for 4 hours around 36ah

My tv is rated at 1.2 amps 63w;

 

3. after charging my batteries to 100% (according to the smartguage) and then leaving it on float charge for a good couple of hours

 

4. The inverter socket is labelled "disconnect battery charger first" however it is easy to make a mistake and leave it in, which is why I suspect it may have a problem even though it still produces 230v

 

5. Note: overnight we tend to turn the freezer off but leave the fridge on, very little power if any is registered as lost on the smartguage

1. Good idea. Someone who knows xxresearchxx Smartguage well will be along shortly to confirm you've set it up ok.

 

2. If your TV is rated at 63W at 230V, it's drawing over 5 amps from your 12V batteries plus the internal losses of the inverter.

 

3. Smartguage has a good reputation for getting the State of Charge (SOC) about right from voltage measurements. It is an actual "Smartgauge" isn't it, only other types that can measure current draw (a plus) are notoriously deceptive when reporting SOC. I ask that because it will be important to know that you really are charging to 100%.

 

4. An old plug in inverter isn't gonna be the most efficient in terms of internal losses so you need to stop making the mistake of leaving it plugged in when not required.

 

5. On the face of it, that's encouraging. However, a fridge is usually one of the more power hungry devices onboard and I'd expect this to show more than "if any" on your Smartguage. Which takes us back to my point #1.

 

Your later post says you have a recorder running, but it's 12V. This does still count!

 

For me, the first thing to be sure of is that you are 100% charged when you think you are and that your battery capacity is what you think it is - which it won't be if you've been under-charging for a while. You can look at the Sterling in parallel, of course.

 

OK, there's a few points and queries to get us started. Others, many of who are really good at this stuff, will have a few more shortly I don't doubt. Good luck!

 

 

Edited to change research back to Smartguage (bloomin autocorrect!)

Edited August 28, 2016 by Sea Dog

[MtB]

Been living aboard for about 5 months now and still trying to get to grips with power management.

Had to replace the leisure batteries a couple of months ago as they were slowly dying, to the point they would not last the night.

 

 

Given that you've now found a massive 690AH of new battery can't cope either, and you've only been living aboard 5 months, it seems likely your old batteries were killed by the same fault. I'd say you need to get a grip on this quick or your new batteries will suffer the same fate just as rapidly.

 

As Nick says, one way or another you are probably not fully charging them AND there is a hidden power drain you haven't spotted. The SG is nototiously poor at knowing when the batts are 'fully charged' when a charger is connected to them. I also suspect solar panels can confuse the SG similarly.

 

I also suggest doing some research on what 'fully charged' means to you and how to measure it (other than with the SG!) so you can get to know how accurate the SG really is when it gives you that reassuring 100% on the display!

Edited August 28, 2016 by Mike the Boilerman

[OldGoat]

Modern LED TVs are only around 30 - 40 watts - that's (say) 4 amps at the 12v end with a reasonable inverter.

MSW inverters are very inefficient - especially Sterling ones, at least that's what is stated on his website.

A good quality PSW inverter can be very efficient - and if you watch a lot of TV, then it might be worth buying a small (say 300W) unit just to power the tv.

I have such a unit and it powers a LED TV, up to two Freesat boxes and a small soundbar all together.

If I want to run a vacuum cleaner, then I switch on my aged Sterling MSW unit...

[The Lockie]

You have a fridge And a freezer? Look at the rating plates on them to see how much they draw you know what the tv draws so with the data from all three rating plates you can then check that against what the smartguage is saying

[Bewildered]

Ok this is going to take some writing out, please bear with me.

The boat has a sterling power pro plus 600w inverter, a sterling 5kva 230v alternator/generator (this is essentially a generator the runs off the main engine via a bloody big alternator) and it originally had two sterling 40amp 3 stage battery chargers. It also has two solar panels 1x140w &1x80w that were until I changed it running through a little pwm controller, the controller is now a 40am tracer Mppt with an mt50 meter.

 

When I bought the boat I moved it from Whilton to harefield Marina over xmas week, running all day no charging problems but wasn't using much power anyway. The boat then stayed at harefield for 3 months on shore power; no problems there.

 

We set off in early April, 2nd day out I noticed that the Rev counter had stopped working, realised the cause of this was an alternator failure. No problem I just fired up the sterling AC genny and switched on a battery charger to keep the batteries charged til I could get the engine alternator sorted out. Was ok for a couple of days, then at the end of a day's cruising we were just locking up the boat to go to the pub when I noticed smoke billowing out of the electrical cupboard, quickly jumped down the steps and unplugged everything. Smoke cleared to find that the mains leads on one of the battery chargers had burnt out.

Because I panicked and pulled all the plugs I can't be sure what was plugged in where but I suspect that I had the charger and the inverter both plugged in. So now down to one battery charger with no engine alternator.

 

Eventually got to a boat yard, they couldn't do the job and gave me some numbers of mobile mechanics. Got a new alternator fitted and we're off again. Well we were off for two days until the engine overheated due to a knackered water pump. Called the mechanic to be told it would be a week for parts. Now this was still early April and it was very cold. The squirrel has a back boiler with 4 rads and a colorifier in line, I had already had problems with the 12v pump and eventually had it changed out for a 230v pump. No power, no pump, no heat. I'm considering re plumbing to thermosyphon, but that's a whole different thread.

Had no alternative but to buy a petrol suitcase genny to charge batteries. Had during this time let them go very flat

 

After having the pump fitted were OK for about 3 weeks then the batteries started to loose power, charge up for a good few hours using the engine alternator and the battery charger via the sterling 230v alternator and started getting less and less life out of them until eventually after a full days charge the low power alarm on the inverter would go off after watching less than an hour af tv in the evening.

So sod it, time to fork out for new batteries.

Originally the boat had 2 x 230ah and 2 x 110ah. I decided to changed them for 3 x 230ah. The day they were fitted I also bought the smartguage and fitted it the next day. That was about 3 months ago so the smart guage has had plenty of time to calibrate itself.

 

With the guage saying 100% most evenings we have the shoreline fridge and freezer running, the 12v dvr the inverter powering the tv and possibly the DVD player, the 12v tv signal booster and the wifi unit. At most we watch 2-3 hours tv on the odd occasion 4 hours by the time we go to bed the guage is usually reading 55-60% the voltage reading on the smartguage and solar guage read the same.

 

My concern is that the inverter, though it is working may actually be faulty and is pulling to much current. When I removed the fire damaged charger I took it apart, the earth wire in the lead and all the earth wires inside the unit were fried. I think that when we had the fire the inverter and charger created an earth short. Is it possible for the inverter to appear to be working properly for 4 months but still have a fault. Is there any way to test this?

Tonight I plan to charge up fully, nearly at 100% now and the petrol genny has a full tank. I'm going to leave it charging until is runs out.

I'm then going to turn off everything, fridge freezer, the lot, and only have the tv and inverter on and check the guage every 1/2 hour.

 

Of course it could just be that I'm using too much juice.

Oh buy the way the tv has a sticker on the back that says it is 110-230v 1.2a 63w and it is 230 only, there is no inline transformer

Phew!

Edited August 28, 2016 by Bewildered

[Bewildered]

You have a fridge And a freezer? Look at the rating plates on them to see how much they draw you know what the tv draws so with the data from all three rating plates you can then check that against what the smartguage is saying

Both units are shoreline, I have the instruction books for them but can't find the power consumption in them. The fridge is a real pig to move so I can't get to the back. It's a standard under counter 12v unit.

I looked for a plate when I fitted the freezer but couldn't see it? It is half the size of the fridge and gets turned off over night.

I will try to find the info on shorelines web site.

[MtB]

Good thorough history, thanks.

 

The next step is to start measuring currents. You NEED to buy a DC a clamp meter.

On the shelf at Maplins for £40 IIRC, on buy on ebay for £30-ish for a uk supplier, and £20-ish for one from China. I'd go to Maplins today if I were you.

[nicknorman]

As I said in my earlier post, you need a way to measure current going in and out of the batteries. Electricity is invisible and the only way to properly know what is going on is to have measuring equipment. As I said, this can cost as little as £30 and will be well worth it if the alternative is trashing your expensive new batteries.

[Tony Brooks]

Absolutely. I think every boat should carry a multimeter that can measure DC amps. Even if the boater can not use it they may know someone else who can. We have another topic running where such a meter woudl have been useful.

[Bewildered]

It's rediculous, I spent the last twenty years installing, fault finding and repairing low voltage electronic equipment. Never in that time was I particularly concerned with current. Regulated power supplies with the correct fuse fitted, all I needed to do was make sure I ran the right size cable and made sure the equipment on the end of it was under the rated PSU output. Only ever measured volts and ohms, can't remember the last time I had to measure amps. My biggest concern was Volts drop, if something drew to much current and blew a fuse or too little and didn't run I just changed it out.

I even passed O level electronics (ok that was 32 years ago) now my head is swimming around this hole in the water I poor money into

[MtB]

 

Absolutely. I think every boat should carry a multimeter that can measure DC amps. Even if the boater can not use it they may know someone else who can. We have another topic running where such a meter woudl have been useful.

 

 

I think we should draw a distinction between a DC multimeter and a DC clamp meter. The latter is of FAR more use as breaking the conductor is not necessary.

[Bewildered]

Good thorough history, thanks.

 

The next step is to start measuring currents. You NEED to buy a DC a clamp meter.

On the shelf at Maplins for £40 IIRC, on buy on ebay for £30-ish for a uk supplier, and £20-ish for one from China. I'd go to Maplins today if I were you.

Easier said than done, I'm CCing. Only transport boat or bike. Currently on the Shropshire Union heading south at Gnosall, will have to google the next nearest Maplins

[MtB]

It's rediculous, I spent the last twenty years installing, fault finding and repairing low voltage electronic equipment. Never in that time was I particularly concerned with current. Regulated power supplies with the correct fuse fitted, all I needed to do was make sure I ran the right size cable and made sure the equipment on the end of it was under the rated PSU output. Only ever measured volts and ohms, can't remember the last time I had to measure amps. My biggest concern was Volts drop, if something drew to much current and blew a fuse or too little and didn't run I just changed it out.

I even passed O level electronics (ok that was 32 years ago) now my head is swimming around this hole in the water I poor money into

 

 

BUT....

 

In this case the thing that's troubling you is Amps. Or more accurately, AmpHours. You can fiddle about with the derivatives like Volts and Ohms but its far better to measure the current in various conductors with a clamp meter. That way you'll diagnose this in minutes.

[MtB]

With the electronics you were never concerned wirth energy consumption as you had a (virtually) unlimited power supply.

 

Now you're running off a battery and concerned about battery life so you need to be measuring current too. A clamp meter is an indispensible piece of boating kit. I have four!

[Arthur Brown]

first do a good power audit. what are you generating, and what are you using. plan to generate 10% more than you use to cope with charging inefficiencies.

 

second make sure that it's not possible to use the inverter to power the charger.

[Bewildered]

Just took a look at Maplins web site, I can't see a clamp meter for less than £100 that measures DC current.

Thought I would take a look at halfords site they sell one for £60 but it only does AC. Hmmm I thought they were a car spares specialist?

[nicknorman]

Just took a look at Maplins web site, I can't see a clamp meter for less than £100 that measures DC current.

Thought I would take a look at halfords site they sell one for £60 but it only does AC. Hmmm I thought they were a car spares specialist?

Oh dear looks like Maplin have stopped doing them. Do you know someone that you could have one delivered to from eBay? Eg

 

http://www.ebay.co.uk/itm/New-UNI-T-UT203-Digital-Handheld-Clamp-Multimeter-CE-DC-AC-Volt-Amp-Meter-Tester-/141806606167?hash=item2104551757:g:8dIAAOSwhcJWJg0n

[MtB]

Oh dear looks like Maplin have stopped doing them. Do you know someone that you could have one delivered to from eBay? Eg

 

http://www.ebay.co.uk/itm/New-UNI-T-UT203-Digital-Handheld-Clamp-Multimeter-CE-DC-AC-Volt-Amp-Meter-Tester-/141806606167?hash=item2104551757:g:8dIAAOSwhcJWJg0n

 

 

Actually I think this is right. When I lost my clamp meter number 3 I went to Maplins to buy a replacement and there were non on the shelf. So I bought on ebay as I was in no particular hurry.