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captain flint

Travel power quick question

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Hi all 

 

I've seen this thread and it was very helpful. I most of what I am curious about it pretty much covered in there, but I just wanted to double check.

 

I have the dometic 3.5 kw travel power but I don't have any amp metre, or any way of checking my batteries health/charge (when I can get something, I will, but for now I'm living with that) - so I wanted to be sure to avoid flattening them by doing something stupid. Or, at least, try to avoid it! 

 

My 3 leisure batteries are all new, and I've been keeping them charged (I have no solar, so I stick the engine on for a while). Oh, and the lighting in the boat is all LED

Two mean questions:

1. Am I right in thinking that running low wattage items, such as a bedside lamp (LED bulb), mobile and laptop charger, etc., should generally be OK with the engine off? (As long as I'm running it now and then to keep the batteries charged)

2. There is an erbespacher central heating unit fitted. Currently I tend to use it with the engine on, or stick it on for just an hour or so and make sure I run the engine the next day - I have read on here somewhere that they can chew through batteries. But I'm wondering just how fast? The main action of heating the water is performed by diesel not electricity, of course, but that's not to say they aren't fairly power hungry. 

I am sure proper answers will involve asking more questions, details, and, basically, numbers. But I'm hoping someone might be prepared to stick their neck out and give me a rough guess for a kind of rule of thumb. I'm new to boat owning and enjoying the steep learning curve, but learning about the ins and outs of electrics is a bit outside my comfort zone, and I feel I have more pressing boat issues to deal with for now - the electrics are professionally installed and I figure with the TP I have more than I generally need. If anything, I'm probably being over cautious about charging the batteries... But I have no idea if leaving the heating on for prolonged periods is doable or not.

 

Oh, I'm sure it's stating the bleeding obvious, but I CC....!

Thanks!

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3 minutes ago, captain flint said:

I don't have any amp metre, or any way of checking my batteries health/charge 

If you get one sooner as opposed to later then not only will all of your questions be answered but you’ll also likely save your batteries which, from your post, you are likely to be chronically under-charging at present. 

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You really, really need to monitor your batteries' state of charge so you don't ruin them by undercharging. The most reliable indicator of state of charge is the current the batteries are taking. You will need an ammeter to measure this. A panel meter with a shunt in the negative battery cable is probably the best arrangement.

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2 minutes ago, WotEver said:

If you get one sooner as opposed to later then not only will all of your questions be answered but you’ll also likely save your batteries which, from your post, you are likely to be chronically under-charging at present. 

What makes you say that? Most days the engine is running for an hour or so with the travel plus on and the fast charge light lit. I should have thought my batteries are doing excellently, what am I missing?

I will get one, as I said, but can't right now

1 minute ago, aread2 said:

You really, really need to monitor your batteries' state of charge so you don't ruin them by undercharging. The most reliable indicator of state of charge is the current the batteries are taking. You will need an ammeter to measure this. A panel meter with a shunt in the negative battery cable is probably the best arrangement.

yes, it's on my list of things to do, but it's a long list and I can't do it right now. Hence my question re low power items, and the separte one re the erbespacher. My hunch is that when it comes to question 1, I can, basically, relax, but when it comes to 2, I should be a bit cautious.

 

Well, I say hunch, I am regurgitating things I have read on here from folks who posted fairly detailed comments on these subjects.

I am erring on the side of caution, I believe - having 3.5 TP on fast charge for at least an hour a day surely should keep me on the right side of the amps, no?

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Is your Travel Power in addition to a normal 12V (OK 14+V if we are being accurate) alternator or is it the only thing that charges the batteries? Does it do this via a battery charger? 

It would help if you could tell us the output of the alternator(s) you have and / or what battery charger you have.

What other electrical equipment are you using in addition to the lights? Do you have a fridge? 12v or mains via invertor?  These are the major power consumers. How about heating? How do you do that?

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3 minutes ago, philjw said:

Is your Travel Power in addition to a normal 12V (OK 14+V if we are being accurate) alternator or is it the only thing that charges the batteries? Does it do this via a battery charger? 

It would help if you could tell us the output of the alternator(s) you have and / or what battery charger you have.

What other electrical equipment are you using in addition to the lights? Do you have a fridge? 12v or mains via invertor?  These are the major power consumers. How about heating? How do you do that?

I have 3 alternators, not sure if the numbers right now. I think the charging is controlled by the sterling power pro combi s that is also the inverter. Does that sound right? 

 

No fridge right now. Well, there is one, a 12v, but it's not wired in, and doing that is on hold for now. 

 

Generally I'm using the mf stove for heating, but I'd love to know whether the erbespacher is suitable for life on the cut with the engine off, or best for just when on shore power/engine on... 

 

I'll dig up some figures at some point but I've got my hands full right now and am up against it for time, with various things... 

 

 

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22 minutes ago, captain flint said:

What makes you say that? Most days the engine is running for an hour or so...

Because an hour or so is usually insufficient to fully charge a bank unless it’s only been very lightly discharged. Any answers to your OP are guesses without some voltage and/or current readings from your batteries. 

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8 minutes ago, WotEver said:

Because an hour or so is usually insufficient to fully charge a bank unless it’s only been very lightly discharged. Any answers to your OP are guesses without some voltage and/or current readings from your batteries. 

Fair dos. I'll try to provide more detail but it will probably have to wait a coupe of days. Currently (no pun intended) I'm using power tools on board, so right now the engine, TP and fast charging are on for serveral hours at a time :)

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7 minutes ago, captain flint said:

I have 3 alternators, not sure if the numbers right now. I think the charging is controlled by the sterling power pro combi s that is also the inverter. Does that sound right? 

 

No fridge right now. Well, there is one, a 12v, but it's not wired in, and doing that is on hold for now. 

 

Generally I'm using the mf stove for heating, but I'd love to know whether the erbespacher is suitable for life on the cut with the engine off, or best for just when on shore power/engine on... 

 

I'll dig up some figures at some point but I've got my hands full right now and am up against it for time, with various things... 

 

 

Most peoples biggest power draw is the fridge with a normal 12v one using around 40AH from the battery bank per day, if yours is one of the older 3-way fridges (12v 240v and gas) its usage will be a lot higher (to the point that most people will advise not to use it unless it's on gas)

 

your biggest power user will be the inverter, some makes of inverter will use a significant amount of power while doing nothing, with that in mind if you aren't using mains power from it turn it off.

if you can get them it is better to get 12v chargers for items like phones tablets and laptops, it cuts down on losses only having to convert voltage once rather than converting from 12v up to mains and then back down to whatever the item needs (5v for phones)

 

your 2nd biggest user will be the eberspacher, I don't have one but have seen figures of around 10A banded around as their draw when in use, while this sounds a lot it isn't too severe since they only tend to be used for an hour here and there.

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Youve had plenty of good advice. Its not possible to give you a definitive answer though but I doubt one hour a day is anywhere near looking after your batteries. You realy MUST install a battery monitoring system such as a BM2 or similar for about £100 and a doddle to self install it will save you hundreds in batteries alone quite quickly.

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Thanks, Jess. 

 

It is a dedicated 12v fridge I think, but like I said, not connected at the moment so it's drawing nothing. 

 

Until I read the comments on the thread I linked to at the top, and the manual for the inverter, I was only using it with the engine on, to be in the safe side! I certainly only have it on when it's in use, and don't use it for long periods... :)

3 minutes ago, mrsmelly said:

Youve had plenty of good advice. Its not possible to give you a definitive answer though but I doubt one hour a day is anywhere near looking after your batteries. You realy MUST install a battery monitoring system such as a BM2 or similar for about £100 and a doddle to self install it will save you hundreds in batteries alone quite quickly.

Thanks, mr smelly

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57 minutes ago, mrsmelly said:

Youve had plenty of good advice. Its not possible to give you a definitive answer though but I doubt one hour a day is anywhere near looking after your batteries. You realy MUST install a battery monitoring system such as a BM2 or similar for about £100 and a doddle to self install it will save you hundreds in batteries alone quite quickly.

Thanks, mr smelly

I think my usage is pretty low tbh, just LED lights and occasionally a phone and occasionally a laptop charging off the inverter, which is kept off when not in use. Nothing else at all right now... 

 

But I will get some figures up at some point

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8 hours ago, captain flint said:

I think my usage is pretty low tbh, just LED lights and occasionally a phone and occasionally a laptop charging off the inverter

It doesn't make a huge difference, but given your power usage it might be significant - as suggested above get 12V chargers or adapters so you don't have to use the inverter. I'm on shore power now, but have only turned the inverter on once in the two weeks I wasn't, in order to charge up my bike light I only have a 240V charger for (strictly speaking I do have a couple of suitable 12V chargers, but not with the right connectors and it's something I use occasionally enough not to be a big issue). I use 12V chargers for my phone and laptop when running on battery power - they're readily available and cheap, I picked up a 12V charger for my laptop when I got the boat for about £10. You'll need a cigarette lighter socket if you don't want to be messing around rewiring things - my boat has one in the engine compartment though I don't know how standard that is, but I've also made an cigarette lighter adapter which plugs into the other round pin 12V sockets.

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11 hours ago, captain flint said:

Hi all 

 

I've seen this thread and it was very helpful. I most of what I am curious about it pretty much covered in there, but I just wanted to double check.

 

I have the dometic 3.5 kw travel power but I don't have any amp metre, or any way of checking my batteries health/charge (when I can get something, I will, but for now I'm living with that) - so I wanted to be sure to avoid flattening them by doing something stupid. Or, at least, try to avoid it! 

 

My 3 leisure batteries are all new, and I've been keeping them charged (I have no solar, so I stick the engine on for a while). Oh, and the lighting in the boat is all LED

Two mean questions:

1. Am I right in thinking that running low wattage items, such as a bedside lamp (LED bulb), mobile and laptop charger, etc., should generally be OK with the engine off? (As long as I'm running it now and then to keep the batteries charged)

2. There is an erbespacher central heating unit fitted. Currently I tend to use it with the engine on, or stick it on for just an hour or so and make sure I run the engine the next day - I have read on here somewhere that they can chew through batteries. But I'm wondering just how fast? The main action of heating the water is performed by diesel not electricity, of course, but that's not to say they aren't fairly power hungry. 

I am sure proper answers will involve asking more questions, details, and, basically, numbers. But I'm hoping someone might be prepared to stick their neck out and give me a rough guess for a kind of rule of thumb. I'm new to boat owning and enjoying the steep learning curve, but learning about the ins and outs of electrics is a bit outside my comfort zone, and I feel I have more pressing boat issues to deal with for now - the electrics are professionally installed and I figure with the TP I have more than I generally need. If anything, I'm probably being over cautious about charging the batteries... But I have no idea if leaving the heating on for prolonged periods is doable or not.

 

Oh, I'm sure it's stating the bleeding obvious, but I CC....!

Thanks!

 

Blimey if that's your idea of a quick question, I'm not looking forward to a complex question from yer good self!!

:giggles:

 

 

 

Edited by Mike the Boilerman
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The problem with charging batteries is that it doesn’t matter how big the alternator, how massive the charger powered by the travelpower is, they don’t and won’t take much charging current towards the end of the charge. And so it is an intrinsic feature of lead acid batteries that they take many hours to fully charge, regardless of how they are charged. And if you don’t fully charge them regularly, they accumulate damage.

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Absolutely and charging for an hour now and again is nowhere near long enough. Try at last 8 hours once a week until you get some monitoring equipment plus an hour now and again.

 

I bet if there was a way of measuring your battery capacity you would now find it will be rather less than what the labels say it should be. That is due to sulphation which is the accumulated damage Nick mentioned.

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16 hours ago, aracer said:

It doesn't make a huge difference, but given your power usage it might be significant - as suggested above get 12V chargers or adapters so you don't have to use the inverter. I'm on shore power now, but have only turned the inverter on once in the two weeks I wasn't, in order to charge up my bike light I only have a 240V charger for (strictly speaking I do have a couple of suitable 12V chargers, but not with the right connectors and it's something I use occasionally enough not to be a big issue). I use 12V chargers for my phone and laptop when running on battery power - they're readily available and cheap, I picked up a 12V charger for my laptop when I got the boat for about £10. You'll need a cigarette lighter socket if you don't want to be messing around rewiring things - my boat has one in the engine compartment though I don't know how standard that is, but I've also made an cigarette lighter adapter which plugs into the other round pin 12V sockets.

This is the thing, although my boat is pretty well set up for life on the cut in many ways, it has no cigarette lighter sockets not round pin 12v sockets! Obviously, getting some in is on my list of things to do, but it's quite a long list... 

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Reducing current draw doesn’t seem to be your priority as you are able to put the first bit of charge back into the batteries quite quickly, where I think you are having problems is in not recharging enough.  Those last few percent can take hours to push back in which is why you are being told to charge for 8 hours in one session.  If you don’t then you quite quickly loose that bit of capacity, then your battery only has say 95Ahrs rather than the the 100Ahrs you thought you had,  carry on undercharging and you loose another few percent quite quickly, and again etc.  By the end of winter you could have lost 25% or more, and you can’t get it back.

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1 hour ago, Chewbacka said:

Reducing current draw doesn’t seem to be your priority as you are able to put the first bit of charge back into the batteries quite quickly, where I think you are having problems is in not recharging enough.  Those last few percent can take hours to push back in which is why you are being told to charge for 8 hours in one session.  If you don’t then you quite quickly loose that bit of capacity, then your battery only has say 95Ahrs rather than the the 100Ahrs you thought you had,  carry on undercharging and you loose another few percent quite quickly, and again etc.  By the end of winter you could have lost 25% or more, and you can’t get it back.

Got it! Thanks. I'll do as suggested. The last few days it's had 5 or six hours a day so that's a positive... 

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7 hours ago, WotEver said:

£6.79 for a 100A voltmeter/ammeter complete with shunt, Free p&p. 

https://www.ebay.co.uk/itm/DC0-100V-50A-100A-LED-Dual-Digital-Voltmeter-Ammeter-Gauge-with-Current-Shunt/123231746251?hash=item1cb12f38cb:m:maYMyXwyZtuOSvgpR3n-p4A

 

No reason not to have one really. 

True! Thanks for the link

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12 hours ago, WotEver said:

£6.79 for a 100A voltmeter/ammeter complete with shunt, Free p&p. 

https://www.ebay.co.uk/itm/DC0-100V-50A-100A-LED-Dual-Digital-Voltmeter-Ammeter-Gauge-with-Current-Shunt/123231746251?hash=item1cb12f38cb:m:maYMyXwyZtuOSvgpR3n-p4A

 

No reason not to have one really. 

I bought 2 of these. They lasted around 1 month before packing up. Don’t waste your money. Buy a better one. 

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1 minute ago, MHS said:

Maybe I was just unlucky. Very happy now with my Victron 

I liked my victron on a previous boat and a bem on one before that but I will always go first choice for the nasa bm2 cos the readout is bloomin OOOOGE so ya dont need ya specs on ?

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