Battery Drain - 240 V Central Heating pump

[Geo]

sirweste, Wondering how things are going

 

ETA I am wondering whether something like a Victron 375W or even 120W or there abouts pure sine inverter might be the answer to the inverter overhead problem. Just a thought.

 

I fitted one to a friend's boat along side an MV 2K because 99% of the time the inverter load was under 30 watts or so, but the overhead on the inverter amounted to 50% of the load.

 

If I say the boat had a hairdryer and a 4kW generator, you will appreciate 230V AC was an important part of life aboard. Anyway it solved the battery drain problem, battery charging went from daily to every 2nd or 3rd day.

Edited December 7, 2016 by Geo

[sirweste]

No progress I'm afraid team. Work has been mental, the lass has got norovirus and the 1.5 hours I was at the boat I spent driving/sailing/cruising/navigating/steering flat out into MK.

 

Hopefully sicknote will cheer up and I'll get to spend some time at my house this weekend. Not even ordered the part for the genny yet!!

That is very good.

Mine is a 2kW continuous and is 1.2W asleep and 16W running with zero load.

 

Mine is supposed to be 0.5 W when asleep, if it's as much as 15 - 20 W with no load when awake. I'll be spending > £200 squids on a fancy 12 V one.

[sirweste]

OK, Matervolt Combi is now fully set-up to charge at 14.82 V on bulk, abs and float! And obviously as because there was an Engineer round the inverter side of things was workign perfectly.

 

Sat happily in 40 VA idle mode, causing the 5 W phone charger to blip on and off. The CH pump was enough to pull it out of idle / sleep though, suggestign that the threshold is somewhere around 7 W.

 

Anyhow, putting a 12 V pump on order this week I think. I'd also like to convert the water boiler to 12 V somehow.

 

I'm at home tonight so plan to take the final readings from the inverter to see what it's drawing for sure. And I hope to finally make a decision on what bits to order for the Honda genny.

[Chewbacka]

Good that it is all becoming clear for you, and as always just a bit more money needed to spend on the boat..................

[WotEver]

Bring

Out

Another

Thousand

[Geo]

No progress I'm afraid team. Work has been mental, the lass has got norovirus and the 1.5 hours I was at the boat I spent driving/sailing/cruising/navigating/steering flat out into MK.

 

Hopefully sicknote will cheer up and I'll get to spend some time at my house this weekend. Not even ordered the part for the genny yet!!

 

Mine is supposed to be 0.5 W when asleep, if it's as much as 15 - 20 W with no load when awake. I'll be spending > £200 squids on a fancy 12 V one.

 

Hope lass makes a good recovery from Norovirus and that it bypasses you. Or is the sicknote for you I hope not.

 

Be well

Edited December 12, 2016 by Geo

[Geo]

sirweste, who is the manufacturer of your water heater and which model is it?

[nicknorman]

Can I suggest you have a look at these pumps:

 

http://shop.solarproject.co.uk/catalog/product_info.php?cPath=2&products_id=10

 

I've used one to run our radiator circuit through an engine heat exchanger for the past 4 years. Although we are not live aboard, we do a lot of winter cruising and so it's had a fair bit of use. Obviously it's fairly cheap and cheerful, but so far quiet and reliable and being so cheap, you could get 2!

[cereal tiller]

Can I suggest you have a look at these pumps:

 

http://shop.solarproject.co.uk/catalog/product_info.php?cPath=2&products_id=10

 

I've used one to run our radiator circuit through an engine heat exchanger for the past 4 years. Although we are not live aboard, we do a lot of winter cruising and so it's had a fair bit of use. Obviously it's fairly cheap and cheerful, but so far quiet and reliable and being so cheap, you could get 2!

I mentioned that Pump early on in this Thread,they work well and have been using one for a couple of years for the same purpose as you

 

Installed one on a Friends Boat recently,the Pump running time is decided by a Digital controller that has a Temperature probe attached to the Hot outlet Pipe from the Stove.

 

Pump runs for 20 seconds then idles for 8 Minutes.

 

A.H. consumption is only 2 as opposed to the previous 48,the Pump does not need to run continuously

 

CT

[sirweste]

Just to add a small update.

 

With regards the confusing state of the Mastervolt Combi (MVC) not dropping into its 40 W idle mode (I.e. Where it searches for a power demand of > 40 W every couple of seconds, if it doesn't find this demand it remains "asleep"). 

It turns out that this was caused by the bloody washing machine! Something I miser when checking that all 240 V consumers were switched off, idiot. So sometimes the washer would allow the MVC to go into "sleep" mode. But most of the time it would hold it out of it, thus causing a battery drain.

For some reason the washer being switched on at the plug top meant that the 240 V central heating pump would always (confusingly) operate. With the washer switched off the MVC functions correctly in idle mode and the central heating pump is not enough to wake it and thus the pump doesn't operate. 

 

I've still not been on shoreline or fixed the Honda genny to enable me to do half a dozen equalise charges on the poorly T105s.

I did take a SG reading though, with a very basic floating disc tool, it guessed that they were all equally shagged at around 75% - when the smart gauge was declaring > 95%. 

 

 

[WotEver]

3 minutes ago, sirweste said:

it guessed that they were all equally shagged at around 75% - when the smart gauge was declaring > 95%. 

Yup. SmartGauge is telling you that they're charged to 95% of their present capacity. The present capacity will be way down until you can equalise them. 

[sirweste]

Yep this is understood.

 

Present usage is indicated to be from 100% to between 87% and 82% each night.

So get home post work, then lighting and MVC on to supply the (still) 240 V central heating circulation pump overnight for the fire and for TV / music.

This usage at the moment is all replenished while I'm at work by the 200 W solar install. So for now I'm coping, but today is the first day I've put the 240 V fridge freezer on (with the MVC in 40 W idle mode) so will see how the solar has kept up.

[WotEver]

Solar should be pretty good now right through to November. 200W might be a bit on the low side for you. 

[rusty69]

Our freezer is running from solar at the moment, but 1000W of panels. You maybe pushing your luck with 200W unless its a very efficient freezer. 

[sirweste]

Yer the audit I did suggests that I need ~ 600 W I think. But I'm curious to see how it's performed today. Been a ok to good day for sun. 

Plan is more solar. But I barely have the time to think about it let alone buy and install it!

[sirweste]

Some anecdotal solar power info for folks:

2 (old) 100 W panels connected to a MPPT (with the MT50 toy) charging 6 poorly T-105 batteries, produced enough power to run the Mastervolt Combi in it's 40 W idle mode with a under counter slimline LG fridge freezer as the only demand.

Battery charge remained the same throughout the 13 hour period I was at work. From 82% 8:00am to 85% 9:00pm.

[WotEver]

But it was sunny yesterday

[rusty69]

6 minutes ago, WotEver said:

But it was sunny yesterday

It's alway sunny somewhere

Was looking at Googles project sunroof earlier. Hope they extend it to boats in the uk. 

Edited April 4, 2017 by rusty69

[Alan Saunders]

On 11/30/2016 at 21:24, Geo said:

I wonder if the decimal point has been misread and it is a 75 watt.

My apologies for commenting without reading the whole thread!

With a totally 22mm single pipe system (pipes and fin radiators) in my 33' nb the round-trip CH circuit was ~54' (2x10' cabins + 4' centre cockpit and 3' each end) plus very short, parallel, 15mm pipes to the calorifier adjacent to the 6KW Alde gas boiler. ~1.2A at 12V (15W) was adequate to circulate the water. The 12V circulator pump was capable of more if the resistance were greater. N.B. A motor only has to overcome resistance! e.g. Your boat may have a 50hp engine but, at 3kts it is only producing (inefficiently) 4hp.

If I had a 15mm 54' circuit I would need ~20²/13² (2.37x) watts more power = 35W. I had the room thermostat set to 22C during the day and 15C overnight. With only 1" of polystyrene insulation the circulation pump ran, in an average winter, for 50% of the time and maybe 80% when it was below freezing during the day. i.e. The radiator area and boiler capacity was reasonably balanced to expected air temperatures,  ~0C in southern UK.

I guess that a typical 50' nb (40' cabin) could need ~25W for a 22mm circuit and ~60W for a 15mm circuit at 12V with a similar installation.

Worst case is your inverter is (say) specified as 90% (or 85%) efficient at maximum output. It may only be 50% efficient at low power due to the 1A @ 12V standby current. Inverters with a low power (<0.5A@12V) standby function typically need a load of ~1A @ 230V (230W) before they switch on. Typically, if you intend to leave your inverter switched on 24/7 you need to allow for a 24A/h drain per day in addition to the consumption of 230V appliances, 'fridge, TV etc.

A gravity central heating system (32mm+ pipe?) is the most efficient (>2x better than 22mm), preferably with an injector tee to allow a pump to to initiate the flow. Generally, I find that 12/24V DC devices, despite their initial cost, are the best solution for off-grid living.

I despair when I hear of people using a 3,000W inverter (or even running the engine) to plug in their 2A, 5V (10W) 'phone charger when 12V to 5V USB converters are cheap and a better option even if only 80% efficient. Similarly, it is more efficient to power your laptop from a 12V to 18V converter. Do not disconnect it when the internal battery is charged!

If you have Apple iPhone, iPad, iRon etc. devices the above advice is not for you, just do whatever you want. You already have much more money than sense - before you have worn out the Li-Ion cell @£100 you will be queuing up for the next iPhone at £800 when an unlocked Android 'phone for £150 would serve you better for five years (replacement battery ~ £20)!

Apologies if my arithmetic is wrong but, hopefully, I have conveyed the general message about pipe x-section (less wall-effect) and length and the proper interpretation of the efficiency figures for electronic devices. I am certain that several members will correct me.

HTH, apologies for the rant, Alan

[sirweste]

Congratulations for not letting the fact that you'd not read the thread get in the way of making assumptions and throwing out some insults for good measure.

Though the first section of the post seems to be with good intentions. However I'm not really sure on your theory. From my understanding of the physics involved in my system, if I were to increase the pipe cross section (which I'm definitely not about to do) the required work done to circulate one full volume of water would increase. I'm assuming that the pressure difference due to diameter difference is negligible.

Project sunroof is pretty cool, not heard of it before now!

Currently surviving (just) with the 200 W of solar on the roof, but it requires me to be away a the weekends for it to go a catchup full charge!