Battery Charging over the Winter

[Ian_Rob]

As the boat was connected to the shorepower last winter to run a de-humidifer, I left the charging circuit on for say 60-75% of the time to keep the batteries charged. This year the boatyard where I keep boat has offered to remove them and trickle charge them over the winter for £25+VAT/battery.

Is there a difference between trickle charging them and charging them via the boats in-built battery charger?

 

[VicS]

As the boat was connected to the shorepower last winter to run a de-humidifer, I left the charging circuit on for say 60-75% of the time to keep the batteries charged. This year the boatyard where I keep boat has offered to remove them and trickle charge them over the winter for £25+VAT/battery.

Is there a difference between trickle charging them and charging them via the boats in-built battery charger?

We would have to know the specifications of the chargers involved to answer that.

£25 would buy you a couple of small solar panels

 

[KenMcCulloch]

Unless your batteries are coming to the end of their life they should hold their charge for a number of weeks without needing charging. Last winter I put the boat ashore about mid November, charged the batteries for a day or so then put them out of my mind until January. In January they still showed a good charge (12.6V or so) so I charged them again for a couple of days and then again shortly before launching in April. Keep your money in your pocket.

 

[Quandary]

Similar question

When my shore power is connected, (all winter usually), the Navix unit automatically tops up the batteries, it show amber on the display at the chart table for an short while after connecting which I presume means it is charging, then goes to green and stays like that unless I disconnect the lead.
The batteries seem good after 4 years but should I be disconnecting the batteries after a day or two or is it Ok to leave the automatic charger to take care of them as I have been doing?

 

[Leighb]

I have left mine connceted to shore power for the last 4 years, the on-board charger keeps them nicely topped up and they give no trouble during the summer.

The first season I left them disconnected from shore power, and the domestic battery was flat in the Spring.

Although everything was "Off" and there should have been no electrical drain it turned out that the switch for the cabin heater even when off drew about 0.3A. In spite of this I recharged the battery and it has been OK for 4 years since.

I removed the heating system later anyway, as we only used it twice in 2 years and it took up valuable space in the cockpit locker.

 

[Deleted member 36384]

...... is it Ok to leave the automatic charger to take care of them as I have been doing?

Quandary my modern so called smart battery charger, with low activity standby mode, can be left on indefinitely. The unit is a Sterling Pro Charge Ultra and I asked this question to Sterling's technical help line as it was not clear from the instructions.

I have no idea whether the low activity standby mode is different from a float mode but I have read on here that long term float mode can reduce battery life (IIRC not by a significant amount, but noticeable).

 

[Plevier]

Float is a pretty vague term that to different people can mean anything from about 13.5V to 14.2V (for a 12V battery) to different people.
13.5 will just maintain charge but won't recharge so the battery needs too be fully charged first. OK to leave on continuously, not enough intermittently.
13.8 will slowly recharge and can be left on continuously, it's just about enough to use intermittently.
Above 13.8 up to about 14.2 will recharge quicker and is fine for intermittent use but not left on indefinitely.
Above 14.2 is definitely more than float-recharge, should not be used too often if the battery isn't being discharged. An hour a month should keep a good battery topped up without losing significant water.
I think the real danger of leaving a charger on constantly is if you have a power cut and on resumption it goes automatically onto several hours boost. Do that a few times and the battery won't like it. Turn off the auto boost if you're leaving it all connected up!
Definitely not worth paying the boatyard provided you can give your battery a bit of a charge every 3 months or so. 6 months should be OK but charge up before using.

Above figures relate to lead antimony batteries. Lead calcium - less common in Europe, more common in USA - probably want a minimum of 13.8. Figures do vary a bit for different batteries.

 

[ghostlymoron]

Word of warning. I left my batteries on charge all winter using a Halfords so-called automatic charger and at the end of it I found they had been fried so had to be replaced. I suspect I had the selected the setting for the wrong type of battery so it may have been my own fault.
Its important not to let the batteries become fully discharged but also not to overcharge and boil the electrolyte. Probably a pukka marine auto charger is the best bet.

 

[jontifosi]

Save all the hassle buy a new battery next yerar

 

[Ian_Rob]

As always THANKS to all for sharing their expertise and saving me some dosh.

 

[bedouin]

Save all the hassle buy a new battery next yerar

Yes - it would have to be a very expensive battery for £25 to be money well spent.

Make sure it is full charged and it should last fine over winter