Ric
Well-Known Member
Is it safe and advisable to leave a boat plugged into shore power with the battery charger switched on for long periods? Any examples of chargers going wrong and frying the batteries or worse starting a fire?
Battery charger - to leave on permanently?
- Thread starter Ric
- Start date
Talbot
Well-Known Member
If you have a proper marine charger that has a float charge stage, then should be OK, but remember that most of these have a fan for cooling so if you leave on all the time rather than for the odd week, it will probably fail.
Get a small solar panel instead.
Get a small solar panel instead.
Phoenix of Hamble
Well-Known Member
Worth checking, as mine has a float charge, and a fan, but the fan only runs when boost charging, not on float.....
jerryat
Well-Known Member
Re: Battery charger - to leave on permanently?
Yes, mine has what is presumably a temperature-controlled fan. It only operates when/if the batteries are down and a relatively sustained period of bulk charging is required. The fan is therefore off for the vast majority of the time.
Yes, mine has what is presumably a temperature-controlled fan. It only operates when/if the batteries are down and a relatively sustained period of bulk charging is required. The fan is therefore off for the vast majority of the time.
seaesta
Well-Known Member
Re: Battery charger - to leave on permanently?
I have a very low powre one form Halfords. It is about the sizeand shape of a mobile phone charger. I leave this on my batteries for about a month at the start of the winter lay up and it seems to give a good charge with no problem. If you are just holding charge it may be worth getting one and using it.
Martin
I have a very low powre one form Halfords. It is about the sizeand shape of a mobile phone charger. I leave this on my batteries for about a month at the start of the winter lay up and it seems to give a good charge with no problem. If you are just holding charge it may be worth getting one and using it.
Martin
Norman_E
Well-Known Member
Has anyone considered the pros and cons of fitting a time switch to run the charger for an hour or two each day? this should keep the batteries topped up (assuming use of a proper boat charger) yet avoid the fan failure risk.
pcatterall
Well-Known Member
Re: Battery charger - to leave on permanently?
Wasn't there an issue even with 'low power' charging when batteries developed a fault like a bad cell and the charger was still forcing in 13 volts?
Wasn't there an issue even with 'low power' charging when batteries developed a fault like a bad cell and the charger was still forcing in 13 volts?
andyball
Well-Known Member
Any electrical item could develop a fault & cause problems - albeit fairly unlikely if a quality item.
For most people though - I do question the real need to leave it constantly floating. I suppose if you can't get to the boat for months at a time & have the risk of extremely cold weather - or may need to arrive at the boat & be sure of maximum capacity available ; but don't think that's most people.
I wouldn't think twice about parking my car at an airport say - for a month.... don't think I'd worry the whole time 'cos the battery wasn't on a float charge.
Of course, over time you'll lose charge - but I prefer to leave them to it (within reason - not suggesting letting them go flat) & then charge when visiting/returning to the boat.
Don't think there's any significant disadvantage to leaving them floating - assuming a decent charger that doesn't go wrong. But probably a slight benefit in life by leaving them alone, then charging when needed.
For most people though - I do question the real need to leave it constantly floating. I suppose if you can't get to the boat for months at a time & have the risk of extremely cold weather - or may need to arrive at the boat & be sure of maximum capacity available ; but don't think that's most people.
I wouldn't think twice about parking my car at an airport say - for a month.... don't think I'd worry the whole time 'cos the battery wasn't on a float charge.
Of course, over time you'll lose charge - but I prefer to leave them to it (within reason - not suggesting letting them go flat) & then charge when visiting/returning to the boat.
Don't think there's any significant disadvantage to leaving them floating - assuming a decent charger that doesn't go wrong. But probably a slight benefit in life by leaving them alone, then charging when needed.
William_H
Well-Known Member
Yes solar is good to leave on permanently. However you could use a small power pack that develops about 13 volts and using a multimeter check the actual current into your charged batteries. anything around the 50 milliamps or so would help your batteries on a permanent basis. If the current is too much you could fit a high (5) watt resitor in series try 5 ohms for starters. Make sure the ratings of the power unit are more than that by a factor of 2 or 3. Fit a small fuse near the battery. The charger could be a plug type actually on the shore or if it is a transformer type you may be able to put into a sealed box on the jetty and run the low voltage to the batteries. If it is actually in the boat you could do well to sit it on a ceramic tile on a SS sink or similar area where fire is not likely to develop if the transformer does overheat and smoulder. Eventually it will disconnect if it does burn. olewill
davehu
Well-Known Member
why do you want to keep the batterries on constant float charge,if you have the battery switched off and fully charged a good battery will last 3 months with no significant loss of charge
G
Guest
Guest
Having bought a Halfords 50 quid job with switch for different battery types and also fitted with auto sense for main or float charge ......... I left it connected for about 3 month ..... Returned to boat and all was very nice thank-you. Spoke to a few people - some knowledgable, some just boaters like me and a lot of you .... General consensus was the length I leave the boat - namely months is not good to trust the system. BUT if I was visiting boat at weekends or at least more often - then would likely more safe.
So IMHO - if I was visiting boat at least once or twice a month - float charge OK. Seeing as I only see the boat 2 - 3x a year ......... I prefer to leave boat as charged as possible when I depart ....... stick it back on charge as quick as possible aftyer arrive in UK .... normally enough as I have 1 - 2 days often before using boat .....
Float charge is fine - but you are trusting various things IMHO :
a) Battery does not dry-out
b) Charger doesn't develop fault
c) Wires don't short etc.
d) Mains power to boat doesn't develop fault
e) Leaving power onto boat without supervision.
........ ????????
So IMHO - if I was visiting boat at least once or twice a month - float charge OK. Seeing as I only see the boat 2 - 3x a year ......... I prefer to leave boat as charged as possible when I depart ....... stick it back on charge as quick as possible aftyer arrive in UK .... normally enough as I have 1 - 2 days often before using boat .....
Float charge is fine - but you are trusting various things IMHO :
a) Battery does not dry-out
b) Charger doesn't develop fault
c) Wires don't short etc.
d) Mains power to boat doesn't develop fault
e) Leaving power onto boat without supervision.
........ ????????
Elza_Skip
Well-Known Member
I was advised by my dealer not to leave on charge all the time as this is bad for the batteries.
Ships_Cat
Well-Known Member
I too would never contemplate leaving a battery charger running on board - the larger ones can produce very high currents if a fault and they are connected to the batteries being a very high current source in fault. I don't even do it between weekly visits to the boat. We do have solar to keep them topped up though when unattended but virtually impossible for anything to go seriously wrong with that as long as capacity is limited.
I also leave the charger isolated from the batteries (we have a built in charger) when the boat is not attended. Friends of ours had their charger burst into flames in the middle of the Pacific and they got a hell of a fright. Obviously they were not even connected to shore power. The boat came from one of the best regarded USA yards, so was well equipped, but the charger developed a fault.
John
I also leave the charger isolated from the batteries (we have a built in charger) when the boat is not attended. Friends of ours had their charger burst into flames in the middle of the Pacific and they got a hell of a fright. Obviously they were not even connected to shore power. The boat came from one of the best regarded USA yards, so was well equipped, but the charger developed a fault.
John
andy_wilson
Well-Known Member
It will probably be fine until a battery goes wrong, either due to falling acid level, or simple cell failure (which is what happens to most batteries eventually).
Once a cell goes low, the charger will ramp up to 'charge' it, thus boiling the lot dry. Ruining a battery with a dud cell is no problem, it's knackered anyway, tw problems may follow however.
If the dud battery is part of a bank, the entire bank will be exposed to over-charge.
A good charger may detect a fault and switch off, at which point the good battery will discharge into the bad one, and if left for any time at all, the entire bank is stuffed.
Far better to use a timer for an hour or two per day.
Once a cell goes low, the charger will ramp up to 'charge' it, thus boiling the lot dry. Ruining a battery with a dud cell is no problem, it's knackered anyway, tw problems may follow however.
If the dud battery is part of a bank, the entire bank will be exposed to over-charge.
A good charger may detect a fault and switch off, at which point the good battery will discharge into the bad one, and if left for any time at all, the entire bank is stuffed.
Far better to use a timer for an hour or two per day.
andy_wilson
Well-Known Member
In three months they may still start the engine or light the lights, but the discharge will be significant.
The significance is the the length of time the battery has been less than fully charged, not the percentage.
Unless they are Gel batteries of course which don't seem to suffer long periods of non-use, and self-discharge is minimal.
The significance is the the length of time the battery has been less than fully charged, not the percentage.
Unless they are Gel batteries of course which don't seem to suffer long periods of non-use, and self-discharge is minimal.
G
Guest
Guest
Loss of charge ? and Timer .... + extra questions ....
I do question the 3 months no-losses claim .... maybe if battery is totally isolated and disconnected.
My experience has been that at that length of time - if engine doesn't start quickly - then battery is flat in short time and I'm stuffed !
Leaving a cahrger on a timer .... I've considered this and even have the timer .... simple rotary dial type with press in on/off tags ... but decided against it ..... Can't really say why - just a gut feeling it was wrong.
Question I have is .... if you leave a charger connected but not charging .... does the charger being connected allow battery to back-drain slowly ? Reason for question ... Say you connect via a time switch, and you charge for 2 hrs in every 24 ..... the remaining 22 hrs - is there any leakage out ?
If I was to do a timer system .... is there any way a system could be created to alternate between 2 batterys on a single charger ? automatically ??????
Another question .... on my Truck and I know that various MOBO's have similar .... I have two 12v battery's in series to produce the 24v required for starting / general systems etc. After approx 1 week because of tacho / other internal systems on standby - the batterys are drained significantly (yes I have reduced capacity batterys on there at moment temporarily ..... with correct I should have 2 weeks standing). Now question is ......... can a 12v charger be connected to one battery EVEN though system is still connected ...... say one battery for one day ... then connect to other for another day .... (It's a real pain to get under the cargo body playing about with leads etc. !!)
I do question the 3 months no-losses claim .... maybe if battery is totally isolated and disconnected.
My experience has been that at that length of time - if engine doesn't start quickly - then battery is flat in short time and I'm stuffed !
Leaving a cahrger on a timer .... I've considered this and even have the timer .... simple rotary dial type with press in on/off tags ... but decided against it ..... Can't really say why - just a gut feeling it was wrong.
Question I have is .... if you leave a charger connected but not charging .... does the charger being connected allow battery to back-drain slowly ? Reason for question ... Say you connect via a time switch, and you charge for 2 hrs in every 24 ..... the remaining 22 hrs - is there any leakage out ?
If I was to do a timer system .... is there any way a system could be created to alternate between 2 batterys on a single charger ? automatically ??????
Another question .... on my Truck and I know that various MOBO's have similar .... I have two 12v battery's in series to produce the 24v required for starting / general systems etc. After approx 1 week because of tacho / other internal systems on standby - the batterys are drained significantly (yes I have reduced capacity batterys on there at moment temporarily ..... with correct I should have 2 weeks standing). Now question is ......... can a 12v charger be connected to one battery EVEN though system is still connected ...... say one battery for one day ... then connect to other for another day .... (It's a real pain to get under the cargo body playing about with leads etc. !!)
G
Guest
Guest
Split the bank .... maybe this helps ??
Maplins Charge Splitter
I know I shall be seriously looking at this ... even maybe combining a meter and this to provide solution to my charge regime ......
My set-up at present is :
Halfords Charger
and connect to whichever battery I want to charge. I have in past connected charger through the Battery 1-2-off switch - but wasn't too happy with that ...
So now my thoughts are to couple the charger with the maplin unit .......
Maplins Charge Splitter
I know I shall be seriously looking at this ... even maybe combining a meter and this to provide solution to my charge regime ......
My set-up at present is :
Halfords Charger
and connect to whichever battery I want to charge. I have in past connected charger through the Battery 1-2-off switch - but wasn't too happy with that ...
So now my thoughts are to couple the charger with the maplin unit .......
damo
Well-Known Member
Re: Battery charger - to leave on permanently?
My Sterling charger was fitted 2 1/2 years ago and is permanently on while the shore-power is connected. (As I liveaboard this means all the time I am not sailing). All the boat electrics are off the batteries so this seemed the best compromise when I installed the electrics. The fan only cuts in when the batts are down after sailing and I haven't recharged with the engine.
Don't know the life of the charger and batts with this set-up but it has been very convenient so far
My Sterling charger was fitted 2 1/2 years ago and is permanently on while the shore-power is connected. (As I liveaboard this means all the time I am not sailing). All the boat electrics are off the batteries so this seemed the best compromise when I installed the electrics. The fan only cuts in when the batts are down after sailing and I haven't recharged with the engine.
Don't know the life of the charger and batts with this set-up but it has been very convenient so far
gandy
Well-Known Member
Re: Battery charger - to leave on permanently?
Let us know how you get on with the Maplin relay, will you, Nigel?
How many amps does that charger put out? I need a better charger, but it doesn't justify a Sterling or similar expensive unit.
For ease of ad-hoc charging, maybe the relay could be permenantly fitted with strategically placed 20amp fuses in the lines, giving a single pair of + and - to connect the battery charger.
Tony S
Let us know how you get on with the Maplin relay, will you, Nigel?
How many amps does that charger put out? I need a better charger, but it doesn't justify a Sterling or similar expensive unit.
For ease of ad-hoc charging, maybe the relay could be permenantly fitted with strategically placed 20amp fuses in the lines, giving a single pair of + and - to connect the battery charger.
Tony S
A
Anonymous
Guest
Don't forget the issue of galvanic isolation if you leave shore power connected all the time. Without a galvanic isolator, shore power can cause terrible electrolysis problems resulting in ruined props and sea cocks.
As for the other issues already discussed, yes all good points already made. I have always left my chargers on but on balance I think that an appropriately-sized solar panel is the most advisable, and is a useful piece of kit year round.
As for the other issues already discussed, yes all good points already made. I have always left my chargers on but on balance I think that an appropriately-sized solar panel is the most advisable, and is a useful piece of kit year round.
