Unattended Battery Smart Charger

[Harry Brown]

I am putting this out there to get some views on leaving a Battery Smart Charger (like these www.ctek.com) ALWAYS plugged into the mains shore power, and maintain the battery safely whist away from the boat for weeks or months at a time.

Ideally a Galvanic Isolator should be use if plugged into shore power for any length of time, but that’s another post!
I also understand you could charge by other means (solar / wind) but would like to discuss this possible battery charger solution.

Now to me leaving any mains electrical item unattended for any length of time just feels bad.

However, battery banks are not cheap and these chargers are very good indeed. I have several of these hooked up to different vehicles in a garage and do leave these unattended for weeks at a time, if I have a fire in this particular garage it’s not a problem as there is nothing around to catch fire, just the charger its self and a scorched floor!

I have thought about putting a charger in a fire proof box, in the sink, with the lid open, like in the picture below.

What I am concerned about is the charger overheating inside the box, in the very hot cabin, due to the ambient summer temperatures, and then catching fire. If the charger being in a box would overheat, what about just placing the charger in the sink on its own, (water turned off!)

Has any anyone done anything like this? Look forward to you thoughts.

 

[Deleted member 36384]

This is my thoughts based on experience of a Sterling Pro Charge Ultra. I used to leave it on all the time (wet cell, lead acid batteries, not sealed) and I was very impressed with the the fact that I had fully charged batteries when I went down to the boat. What I failed to appreciate was that the water level in the batteries dropped faster than I had been used to. The end result was that I ruined the batteries. Of course if I was frequently down at the yacht, then I could have topped the batteries up more often had I been aware. I work away from home month on month off, so the charger was left on for at least 6 weeks between visits.

What I understand now is that smart chargers are very good at rapidly charging the battery, compared to non smart and basic engine driven alternators / regulators. It is therefore easier to have batteries in a good state of charge which allows them to be left for a period of weeks without any charger being left switched on.

It could be that my issue is entirely down to infrequent monitoring of cell levels and that had I kept them topped up and left the charger on all the time, then there would have been no issue. I never experienced any overheating problems and the summers do get reasonably warm, the yacht side was facing southwards and the locker where the charger was mounted did get warm. My charger had a fan in it.

For next season I am replacing all my batteries and my plan is to charge them fully, use the boat, then charge them fully back at the marina and then switch of the charger between visits.

 

[prof pat pending]

Most of the Ctek chargers have a temperature sensor, so that won't be a problem.
I leave mine plugged in all winter and have had no issues....so far

 

[prv]

Now to me leaving any mains electrical item unattended for any length of time just feels bad.

You don't own a fridge or freezer, then? No timer on your central heating?

Maybe you do turn the telly off at the wall every night, my grandparents used to do that. But hardly anybody else does.

The majority of boats in full-service marinas with shore power will have their battery chargers connected. It's perfectly normal, and ideas like fireproof boxes in the sink come under the heading of "eccentric".

Pete

 

[Sailingsaves]

I know someone with a Ctek charger and they leave it charging their classic car almost 24/7, 365 days (except the rare occasions in Summer when they drive it).

Charger is a few years old now and all is well.

 

[Harry Brown]

You don't own a fridge or freezer, then? No timer on your central heating?

Maybe you do turn the telly off at the wall every night, my grandparents used to do that. But hardly anybody else does.

The majority of boats in full-service marinas with shore power will have their battery chargers connected. It's perfectly normal, and ideas like fireproof boxes in the sink come under the heading of "eccentric".

Pete

Yup, I'm eccentric! This was caused by an "eccentric" person leaving a battery charger unattended! I have no concerns about leaving my house appliances on! I was asking about leaving a charger connected for weeks / months at a time, unattended, as this one was!

 

[Sailingsaves]

Eccentric is ok - a poor battery charger is not.

Ctek are ok. Google all the info you can about them to convince yourself.

Sorry to see your poor previous experience. What charger was it? Did it overheat, or cables, or what?

Looks like you were able to save boat? How did you manage that?

 

[RichardS]

I know someone with a Ctek charger and they leave it charging their classic car almost 24/7, 365 days (except the rare occasions in Summer when they drive it).

Charger is a few years old now and all is well.

My convertible Jag battery has been on permanent charge for 16 years now. Currently on the second battery and the second charger - first a Halfords smart charger which stopped working after a few years and now a CTek which seems to be working well and, helpfully, resumes charging after a power-out.

The car often goes several months at a time in winter without any human intervention.

Richard

 

[rob2]

Maybe you do turn the telly off at the wall every night, my grandparents used to do that. But hardly anybody else does.

I do - that's economics not safety, the TV on "standby" consumes something like 80% of what it does when you're watching. And how come, if this is standby, does it take just as long to start as if switched on from cold?

There is a large degree of fatalism involved in house ownership and each has his own risk assessment. I have a friend who will not leave the house with the washing machine running in case it floods... One hopes that neighbours or passers-by will alert someone to a fire or flood and the fire brigade will save the day.

I guess with a boat it is likely to be longer before a fault is noticed and the brigade may well decide to let it burn if no-one else is threatened, after all they don't know what fuels and pyrotechnics are onboard and they can't so easily run their pumps and hoses down half a mile of pontoon. I would be very careful that the fuse for permanently connected mains item is correct and still be a little uncertain - I still remember how many boats were lost to fires caused by faults in dehumidifiers - how come the fuses didn't save them?

Rob.

 

[Harry Brown]

Eccentric is ok - a poor battery charger is not.

Ctek are ok. Google all the info you can about them to convince yourself.

Sorry to see your poor previous experience. What charger was it? Did it overheat, or cables, or what?

Looks like you were able to save boat? How did you manage that?

I don't know the story about it unfortunately. Those pictures we a result of my research into this subject.

I just want to clarify the reason for my post as I'm sure some people are saying "What on earth is this guy worried about"

The way I see it is, most of us do not have a battery bank and high amperage chargers in our homes, we do however in our boats, and I'm sure that it is very very very small number that ever go wrong, but if they do, well the pictures tell the story.
To me, a battery charger is a risk, however small and leaving that risk unattended for months concerns me, because if it does go wrong, the chances of loosing the boat are high. Hence putting the thing in a box in the sink whilst not there, however crazy, will probably save the boat! And your neighbours come to think of it!

 

[prv]

This was caused by an "eccentric" person leaving a battery charger unattended!

They may have been unlucky, they may even have been foolish (though I don't think that) - but doing what the majority of marina bertholders do is not eccentric, pretty much by definition.

Pete

 

[prv]

I do - that's economics not safety, the TV on "standby" consumes something like 80% of what it does when you're watching.

I don't believe that. It may once have been true, but it's now become a standard piece of greenwash mantra whose veracity nobody actually questions. Such a telly would, as I understand it, be illegal in Germany and various other places, and since the manufacturers want to sell the same product worldwide, they ensure that their standby meets the low-energy requirements on all models.

Pete

 

[NormanS]

Getting back to batteries, why would you want to have the battery on charge all the time? The whole idea of a battery is that it's a store of electricity, so that you DON'T have to be connected all the time. What is left switched on that is draining the battery? If it's just to counteract the very slight and gradual loss, suffered by all batteries, you might be better with a small solar panel. That way, you wouldn't have to leave power on, which is worrying you.

 

[blackbeard]

......Maybe you do turn the telly off at the wall every night, my grandparents used to do that. But hardly anybody else does. .....
Pete

Back in the distant past of the last century, it was not all that uncommon for television sets to catch fire, often with a resulting house fire. Design and manufacture of tellys has improved since then.

"Smart chargers" - these vary, depending on what you want. Some are designed to give enough volts to give some gassing and are intended for use with top-up-able cells, others are designed for use with sealed batteries and will not give more than 14pointsomething volts. Mine (Ring) which I think is designed with car batteries in mind will give 14.2 volts until it thinks that the battery is full and then will give 13pointsomething volts as a float charge. In theory it should be possible to leave the charger on permanently without doing anything dire to the batteries, though I haven't tried this.

There was, on this very forum I think, a report of an instance where a battery had been left charging unattended. The batteries gassed which produced hydrogen and oxygen, forming an explosive mixture, there was then, apparently, a spark ... fortunately no-one near at the time, but the boat was a write-off.

 

[Alex_Blackwood]

[QUOTE=



I have thought about putting a charger in a fire proof box, in the sink, with the lid open, like in the picture below.
If the lid is open it is not Fire Proof!

 

[Harry Brown]

No, but it is not going to set fire to the surface it is on, be somewhat contained until it trips and burns out, and can still ventilate.

 

[Scotty_Tradewind]

I have a built-in Sterling charger on board.

This year in Spain the small family yard, would not leave the shore power connected 24/7 and would not allow a dehumidifier aboard at all. I am used to doing both back in the U.K.
(if you use a dehumidifier ensure that you can prove required regular maintenance has been done to it, otherwise you could find yourself uninsured in the event of a fire. My insurers have sent me a letter to that effect.)

They would however connected up the shore power in the day time only, as often as I thought fit to bring batteries up to full charge.

I do have wind and solar so to boost the batteries only occasionally is probably satisfactory.

I do have an automatic fire extinguisher in the engine compartment where the battery charger is, but I would have hoped that the circuit protection on the batteries and charger/regulator were such that overcharging was not an issue.
I'll check with my excellent electrician ( Bob, Solent/Portsmouth area 07725854532 ) although he has recently upgraded my boat.

Harry Brown..... very sad pictures that of fire on board.
A similar thing happened in my yard a few years back and the fire burnt itself out, (probably due to the boat being sealed and lack of oxygen etc. ) and was not evident from the outside although the boat was a write-off.

S.

 

[lw395]

I do - that's economics not safety, the TV on "standby" consumes something like 80% of what it does when you're watching. .......

Rob.

Really?
Mine, together with the hard disk recorder, consumes well under a watt. vs over 50w when its all busy. That's quite an old Sony, modern ones are better.

 

[mlines]

Getting back to batteries, why would you want to have the battery on charge all the time? The whole idea of a battery is that it's a store of electricity, so that you DON'T have to be connected all the time. What is left switched on that is draining the battery? If it's just to counteract the very slight and gradual loss, suffered by all batteries, you might be better with a small solar panel. That way, you wouldn't have to leave power on, which is worrying you.

Smart chargers are not on all the time. At the bottom of this picture you can see my CTEK pulsing on and off (which is apparently what they are supposed to do)

 

[coaster63]

I had a built-in Sterling charger on board & luckily only used it when on board as it decided to destroy itself filling the the saloon with pungent thick smoke as the cooling fan pumped it out of the charger before quickly unplugging shore power here's a pic of two large capacitors that were responsible for smoke who knows what would have happened left to continue plugged in adjacent relay which failed probably caused popping of capacitors .these built in chargers being priced as they are I will probably go down your choice of portable charger