What Batteries

[Mr Pugs]

Evening All

 

4 x 105 Trogan batteries complete with a single point filling system installed

The batteries are monitored by a smartgauge system

 

 

Power system now:

 

1KW of Solar panels, Outback flexpack 80 controller, 4 x 105 Trogan batteries (with smartgauge monitor), 3kw inverter

 

The system is up and running for about three weeks or so

The Outback controller has been setup for the Trogan Batteries

 

Batteries discharge to about 60% overnight

Recharge to 90% by about lunch time each day

The Outback controller goes into float charge mode when the smartgauge unit is reading around 90% charge

 

 

Questions:

 

1 is it ok to discharge the trogan batteries to 60% daily

2 Should the outback controller be charging the batteries to a level that will read 100% on the Smartgauge monitor

[Kae]

Yes it should be, and it's been shown on here a few times that the Smartgauge knows better than battery charger indicators.

I can't help any further than that though as I don't know anything about the Outback.

[nicknorman]

The Smartgauge in charge mode is not particularly accurate, however it is likely that the outback is going into float prematurely. The real test is to determine the charge current just before the outback goes into float. Best way to do that is to get a clamp meter -the ubiquitous UNI-T UT203, around £30 from ebay. Personally I would want the charge current to be less than 1% of the AH capacity - ie 4.5A in your case - to be confident the batteries were fully charged. I'm not familiar with the Outback but you may be able to switch it off and on again to get it back into absorption after it has gone into float, then check the current.

 

Taking the Trojans down to 60% each night is not exactly a problem, but it does seem you are using a lot of juice over night. We have the same type and number of batteries as you but no solar, and last night we tied up at around 16:00. We then boiled the electric kettle for tea. We then had a lot of LED lights on, the recording satellite box and tv on for much of the evening, the fridge on 24/7. We used the gas fan oven (mains fan and light) to cook dinner. After dinner the electric kettle was boiled again and the new electric nespresso machine was used to make 3 x coffees. We went to bed at 23:00 with bother Smartgauge and another AH counting gauge reading 80%. Awoke at around 08:30 with gauges reading 76%. Used electric kettle for tea, electric toaster on twice, and by the time we were ready to start the engine at about 09:30 the gauges were on 70%.

 

I consider that we are fairly heavy power users, but unless you are worse than us your terminal SoC of 60% suggests to me you are not starting out at 100% when the sun goes down.

Edited August 17, 2014 by nicknorman

[bottle]

SOC.. 95% at 20:00 hrs

 

Two hours of TV + satellite box. Fridge and Freezer (240v) ON

 

SOC.. 78% at 22:00 hrs

 

Fridge and Freezer ON overnight.

 

SOC.. 58% at 07:00 hrs. Note> This can vary by a few percent if the fridge and freezer happen to running at the same time.

 

Battery bank. 330 amp.hr @24v, deep cycle AGM

 

 

When I had 'leisure batteries', (sealed, wet, lead acid) same bank size, for approximately the same usage they would be down to 55% SOC before bed time so fridge and freezer were turned OFF overnight.

[nicknorman]

SOC.. 95% at 20:00 hrs

 

Two hours of TV + satellite box. Fridge and Freezer (240v) ON

 

SOC.. 78% at 22:00 hrs

 

Fridge and Freezer ON overnight.

 

SOC.. 58% at 07:00 hrs. Note> This can vary by a few percent if the fridge and freezer happen to running at the same time.

 

Battery bank. 330 amp.hr @24v, deep cycle AGM

 

 

When I had 'leisure batteries', (sealed, wet, lead acid) same bank size, for approximately the same usage they would be down to 55% SOC before bed time so fridge and freezer were turned OFF overnight.

Wow! Considering you have effectively 660AH that seems a rapid drop overnight. Either the fridge or more probably the freezer is very thirsty, or you actual battery capacity is way down. You use about 20% overnight whereas our fridge uses about 3 - 4% of a smaller (450AH) bank overnight.

[Grace and Favour]

We have a 240v fridge, and a 240v freezer, and our (new) 12v 900Ah battery bank will drop about 5 - 6% overnight - - which ties in with Nick's figures.

[Robbo]

Evening All

 

4 x 105 Trogan batteries complete with a single point filling system installed

The batteries are monitored by a smartgauge system

 

 

Power system now:

 

1KW of Solar panels, Outback flexpack 80 controller, 4 x 105 Trogan batteries (with smartgauge monitor), 3kw inverter

 

The system is up and running for about three weeks or so

The Outback controller has been setup for the Trogan Batteries

 

Batteries discharge to about 60% overnight

Recharge to 90% by about lunch time each day

The Outback controller goes into float charge mode when the smartgauge unit is reading around 90% charge

 

 

Questions:

 

1 is it ok to discharge the trogan batteries to 60% daily

2 Should the outback controller be charging the batteries to a level that will read 100% on the Smartgauge monitor

 

What you could do is add more batteries, this will reduce the daily discharge % and you'll be able to make more use of your solar.

[nicknorman]

We have a 240v fridge, and a 240v freezer, and our (new) 12v 900Ah battery bank will drop about 5 - 6% overnight - - which ties in with Nick's figures.

Well not really, since your battery bank is twice the size of ours. So your 5 - 6% would be 10 - 12% for us, approaching 3 times the amount. Maybe these freezers are just really thirsty for power?

[Grace and Favour]

Well not really, since your battery bank is twice the size of ours. So your 5 - 6% would be 10 - 12% for us, approaching 3 times the amount. Maybe these freezers are just really thirsty for power?

Aye - that was the point I was making, (badly I guess), the true cost of having fresh lime and ice available for the early evening Bombay Sapphire is somewhat higher than first thought!

[nicknorman]

Aye - that was the point I was making, (badly I guess), the true cost of having fresh lime and ice available for the early evening Bombay Sapphire is somewhat higher than first thought!

When we were commissioning Telemachus I wanted a freezer. Jeff said no and as usual he was right. We have a Shoreline fridge with icebox that is totally competent at keeping bags of ice in tip top condition for the evening's TANQUERAY and LEMON. As well as icecream, frozen peas, and emergency cooling of Cava etc.

 

Of course it doesn't allow for long term storage of frozen food, and space is limited, but it seems a good compromise for a narrowboat.

[bottle]

According to specification sheet freezer uses 189 Kwh per annum and is A+ rated.

 

Frost free, integrated.

 

As live aboard, CCers we believe it necessary, we did manage to live without one for a month when the last one went wrong but it was a hassle.

 

My post was just to show that you are not a heavy user.

 

edit: and to also show the difference that different type of batteries made.

Edited August 18, 2014 by bottle

[nicknorman]

According to specification sheet freezer uses 189 Kwh per annum and is A+ rated.

 

Frost free, integrated.

 

As live aboard, CCers we believe it necessary, we did manage to live without one for a month when the last one went wrong but it was a hassle.

 

My post was just to show that you are not a heavy user.

 

edit: and to also show the difference that different type of batteries made.

However something doesn't seem quite right there. You are using 20% of let's say 660AH at 12v in 9 hrs overnight when, presumably, the only significant loads are the fridge, freezer and inverter. That is 132AH at 12v which is 1.58kwh. So over 24 hrs it would be 4.21 kwh. Annually that would be 1,536kwh which seems a long way from your reported 189kwh for the freezer, even if you add the same again for the fridge.

 

Methinks your actual battery capacity is way down.

[Robbo]

If you have a DC clamp meter you will find this very handy too see where the amps are been used. IMHO a "a amp counter" battery monitor is a lot better than the standard smartguage.

[nicknorman]

IMHO a "a amp counter" battery monitor is a lot better than the standard smartguage.

They serve different purposes. An amp-counter lets you know how much current is going in and out, what energy different devices use etc (though of course, a clamp meter is also a good if slightly less convenient way of knowing that). The SG tells you what the actual state of charge is, rather than the state of charge you would like to think your batteries are at.

 

In Bottle's case for example, if he had an AH counter instead, he would think his fridge and freezer only took perhaps 7% charge overnight. He might run his batteries down to near 50% on the gauge, at which point the lights would go out.

 

I am lucky enough to have both types of gauge, but if I could only have one it would be the SG, plus of course the clamp-meter.

Edited August 18, 2014 by nicknorman

[bottle]

Clamp meter reading (amps) into the inverter, just read at 2.75 amps for freezer.

 

Edit:

 

fridge just kicked in reading now 4.8 (both running)

 

Battery voltage 27.1

 

Smartgauge 97 %

 

Solar output 5amp

Edited August 18, 2014 by bottle

[Robbo]

They serve different purposes. An amp-counter lets you know how much current is going in and out, what energy different devices use etc (though of course, a clamp meter is also a good if slightly less convenient way of knowing that). The SG tells you what the actual state of charge is, rather than the state of charge you would like to think your batteries are at.

 

Not really, my amp-counter has a percentage guage just like the smartguage. The calculations on the smartguage may be more accurate or as reported on this site can be quite inaccurate, but as both have a volt meter you can get the state of charge from this if you so wish.

[Robbo]

In Bottle's case for example, if he had an AH counter instead, he would think his fridge and freezer only took perhaps 7% charge overnight. He might run his batteries down to near 50% on the gauge, at which point the lights would go out.

 

But as the smarthuage is smart, you are not aware that something is wrong. with a amp-counter you can tell when your consumption is higher than normal. Lights don't go out at 50%, you can run down batteries to 10% if you wish but it's not recommended for their longevity - 30% is the lowest recommended I've seen on traction type batteries.

[nicknorman]

Not really, my amp-counter has a percentage guage just like the smartguage. The calculations on the smartguage may be more accurate or as reported on this site can be quite inaccurate, but as both have a volt meter you can get the state of charge from this if you so wish.

They both have percentage gauges, but it is the percentage of what that is totally different so "not really"? - Yes really!

 

If the batteries are in as-new condition then both gauges will show the same thing on discharge, and the AH gauge will be more accurate on charge. However a lot of people's batteries are not in as-new condition, and some (most?) are seriously down on capacity. In those circumstance if you remove say 50% of the as-new charge, your AH gauge will of course show 50% SoC, but maybe before you even get there, the lights will go out because the actual SoC might be down to zero.

 

Friends of ours who have an AH gauge couldn't understand why their lights had gone out with the gauge showing 85%. It took me some time to explain the deceptive nature of AH gauges.

 

Had they had a SG, its reading would have reflected the actual state of charge not the imaginary one, and they would have realised long before that their batteries were goosed.

[nicknorman]

But as the smarthuage is smart, you are not aware that something is wrong. with a amp-counter you can tell when your consumption is higher than normal. Lights don't go out at 50%, you can run down batteries to 10% if you wish but it's not recommended for their longevity - 30% is the lowest recommended I've seen on traction type batteries.

 

No that is wrong for the reasons I just posted. The lights do go out at 50% on your AH gauge if the actual capacity is down to 50% of what it was when you set the gauge up with new batteries.

 

You are right that an AH counter can tell you when your consumption is higher than normal, but after a short time you should have a pretty good idea of your consumption and it seems relatively unlikely that it will change unexpectedly. By contrast most people with leisure batteries more than a few months old seem to have banks that are well down on their stated capacity. This forum is full of them. The SG lets you know that your batteries are deteriorating by showing a lower reading for the same usage. In particular it is useful to ensure that you don't over-discharge your batteries. Deteriorating batteries is a much more likely scenario than unexplained increase in consumption.

 

So as I said, they show different things. The AH counter shows your SoC as a percentage of the original capacity - which is in effect an imaginary figure once the batteries have aged at all. The SG shows the SoC as a percentage of the actual capacity that the batteries have right now. I suppose you can argue that you would rather have an imaginary figure that shows a higher reading - ignorance is bliss etc - but personally I would prefer to know the real SoC.

Edited August 19, 2014 by nicknorman

[Robbo]

So as I said, they show different things. The AH counter shows your SoC as a percentage of the original capacity - which is in effect an imaginary figure once the batteries have aged at all. The SG shows the SoC as a percentage of the actual capacity that the batteries have right now. I suppose you can argue that you would rather have an imaginary figure that shows a higher reading - ignorance is bliss etc - but personally I would prefer to know the real SoC.

 

Which a simple volt-meter can tell you!

[nicknorman]

Which a simple volt-meter can tell you!

Yes it can do, if you haven't charged recently and if you turn off all loads and leave things to settle for a while. But most people find that a bit of a pain to have to routinely do, hence the SG which does it seamlessly. Your argument equally applies to the need for an AH counting gauge - you can just use an ammeter to get a good idea of usage and to indicate when the batteries are fully charged. Again, these fancy gauges merely add convenience.

[Robbo]

Yes it can do, if you haven't charged recently and if you turn off all loads and leave things to settle for a while. But most people find that a bit of a pain to have to routinely do, hence the SG which does it seamlessly. Your argument equally applies to the need for an AH counting gauge - you can just use an ammeter to get a good idea of usage and to indicate when the batteries are fully charged. Again, these fancy gauges merely add convenience.

 

For troubleshooting I would rather have the amp-hour meter with it's ammeter, it tells me a lot more than the basic smartguage, which is just percentage and volts. And for getting the percentage from the volts it's only really high loads that need to be not running, and leaving things to settle is only when you want a very accurate reading.

[nicknorman]

For troubleshooting I would rather have the amp-hour meter with it's ammeter, it tells me a lot more than the basic smartguage, which is just percentage and volts. And for getting the percentage from the volts it's only really high loads that need to be not running, and leaving things to settle is only when you want a very accurate reading.

Your choice of course, and there are a few others who agree with you, but personally I disagree and whilst as I said, I am lucky enough to have both (and so am in a ready position to compare the merits of each), if I could only have one it would definitely be the SG (and a clamp meter).

 

Ed - I realise I am not going to convince you, but since others may be reading this I will compare with a car fuel gauge.

 

A car fuel gauge is typically calibrated in relative terms ie it has 1/4, 1/2, 3/4 etc. It is not calibrated in litres or gallons. 1/2 full on one car is a different amount of petrol than 1/2 full on another make of car. So what it gives you is an indication of how you are doing compared to full, empty etc. If you had a gauge that, after a while, showed 1/2 full just as you ran out of petrol, you would not be best pleased and would consider that gauge to be rubbish.

 

So for most people, that is the primary purpose of having an SoC gauge - they want to know how they are doing compared to how much energy they have remaining, and probably to avoid going below the "magic" 50% (which is not of course a magic figure, but never mind!).

 

The SoC reading on an AH counting gauge is a completely meaningless figure, like the car gauge that might decide to show 1/2 full just as you run out of petrol. That leaves 1/ an instantaneous current reading - but that is not a particularly useful figure that you need to refer to frequently, since you soon get a handle on which appliances use what. So for the odd occasion you do want to know the instantaneous current is, you can put a clamp meter on.

 

It also leaves 2/ the AH extracted from the batteries since they were last fully charged. I suppose this figure might have some use but it is not very helpful unless the actual capacity of the bank is known - which it isn't easily. This figure is certainly not as useful day-to-day as the percentage of charge used and remaining - ie the SoC reading on the SG, just like your car fuel gauge.

Edited August 19, 2014 by nicknorman

[smileypete]

Reckon it's well worth having a passing knowledge of what volt and amp readings mean, BEFORE moving onto the batt monitoring method of choice.

 

Passing knowledge being spending just a little time looking at batt charging and 'tail current', then batt discharging and 'resting voltage'. Don't see why it's made out to be so complicated.

 

Yeah I know resting voltage isn't ideal, but that in itself does not cause real problems. The odd deeper discharge won't kill a batt, what does kill them is persistent undercharge.

 

cheers, Pete.

~smpt~

[ditchcrawler]

Reckon it's well worth having a passing knowledge of what volt and amp readings mean, BEFORE moving onto the batt monitoring method of choice.

 

Passing knowledge being spending just a little time looking at batt charging and 'tail current', then batt discharging and 'resting voltage'. Don't see why it's made out to be so complicated.

 

Yeah I know resting voltage isn't ideal, but that in itself does not cause real problems. The odd deeper discharge won't kill a batt, what does kill them is persistent undercharge.

 

cheers, Pete.

~smpt~

Because there are a number of boaters out there who don't have a clue what a volt is or even what voltage there power supply is, as long as the light comes on when they flick the switch they are happy, O and the fridge keeps running.