To leave battery on charge on not

[Cerebus]

I have just realised I have a boat (better to call it a project) that I have not been near for just over 2 years. It is stored a LONG way away from me.

I have left a large (in size, cannot remember capacity) battery (open lead acid) on a solar panel all that time via a controller (told it was MTTP) but suspect it is not and is a cheap old thing.

Have read a post where Vyv-Cox left a battery without charging for 3 years and it was ok.

Have I done wrong?

Should I visit or try to find someone to disconnect the solar panel and check the distilled water levels are ok?

Or is it too late (such batteries are comparatively cheap) and just save a lot of petrol and hassle and leave the thing?

 

[Irish Rover]

I've forgotten to bring the boat keys a few times when going to the marina, and I forgot to bring milk for my coffee on Monday, but forgetting you have a boat seems a bit extreme.
As regards the battery, if the controller is doing its job, it should be OK. If not the danger is overcharging and a burst battery.

 

[Cerebus]

I've forgotten to bring the boat keys a few times when going to the marina, and I forgot to bring milk for my coffee on Monday, but forgetting you have a boat seems a bit extreme.
As regards the battery, if the controller is doing its job, it should be OK. If not the danger is overcharging and a burst battery.

Understand.

Boat is 400 miles away; project and low priority.

I would have thought worst case was dry cells? Or low electrolyte?

I am not up to date with electronics.

 

[Cerebus]

I've forgotten to bring the boat keys a few times when going to the marina, and I forgot to bring milk for my coffee on Monday, but forgetting you have a boat seems a bit extreme.
As regards the battery, if the controller is doing its job, it should be OK. If not the danger is overcharging and a burst battery.

Leaving a battery on charge at say 13.4v everyday instead of leaving it with no charge for a couple of years is the question.

Could 13.4v or whatever the controller puts out allow it to ‘boil’ off the hydrogen and deplete the electrolyte is my question and knacker it as opposed to leaving it at 12.8v and slowly discharge to who knows what?

 

[Irish Rover]

I'm not an expert but the reality is that even well maintained batteries die at some stage, and that can involve overheating and even bursting if they're on charge. So, if it was my choice, I'd get someone to completely disconnect the battery. That way your biggest potential loss is a battery.

 

[Cerebus]

I'm not an expert but the reality is that even well maintained batteries die at some stage, and that can involve overheating and even bursting if they're on charge. So, if it was my choice, I'd get someone to completely disconnect the battery. That way your biggest potential loss is a battery.

I agree, thank you.

Would appreciate verification from others seeing as logistical matters arise in having the solar controller disconnected.

 

[rafiki_]

I leave mine on charge. Smart charger, so only top up when needed.

 

[Irish Rover]

I leave mine on charge. Smart charger, so only top up when needed.

But not for 2+ years unseen and unattended?

 

[ylop]

Could 13.4v or whatever the controller puts out allow it to ‘boil’ off the hydrogen and deplete the electrolyte is my question and knacker it as opposed to leaving it at 12.8v and slowly discharge to who knows what?

Depends what “whatever the controller puts out” actually means. Is 13.4V just a number you plucked out thin air?

How big is the panel? If it’s going through some sort of controller it is probably not going to burst your batteries.

 

[johnalison]

My last lot of ‘heavy duty’ service batteries lasted for nine years and the start one for ten. They were kept on the boat and the charger left on all year round. This seemed an adequate solution for my needs, but I suppose that the situation may vary with battery type.

 

[Momac]

Sounds like any attempt to restore the boat is many years away so would it not be best to remove the battery and scrap it now ?

There is such a boat moored near my boat so it that's yours please do come to clean it as it is in a disgraceful state .

 

[WoodyP]

You have to be realistic. At 400 miles from home you are never going to sort it out.
I don't understand why batteries are left on charge if there is nothing to drain them.

 

[Cerebus]

Sounds like any attempt to restore the boat is many years away so would it not be best to remove the battery and scrap it now ?

There is such a boat moored near my boat so it that's yours please do come to clean it as it is in a disgraceful state .

Boat stored on land.

 

[Cerebus]

You have to be realistic. At 400 miles from home you are never going to sort it out.
I don't understand why batteries are left on charge if there is nothing to drain them.

Point taken, hence reference to Vyv-Cox’s experience, where he left batteries for three years with no drain and no charge and they remained ok.

Previously I thought batteries left even with no drain would diminish over time.

 

[Cerebus]

Depends what “whatever the controller puts out” actually means. Is 13.4V just a number you plucked out thin air?

How big is the panel? If it’s going through some sort of controller it is probably not going to burst your batteries.

I would imagine (given the number of multimeters I own and ammeters that I would have measured the voltage (if not kept a diary), but time goes by and I forget things.

Solar panel is large ish; cannot remember wattage but it must be about 3 foot long by 1 foot wide (very approx from memory).

The battery is very large and extremely heavy but again I forget specifics and being open and lead acid I am worried about electrolyte levels not having been looked at for 2 and a half years.

Rest of boat should be ok in a barn.

 

[WoodyP]

My biggest and most expensive mistake was not getting my boat near home before carrying out necessary work.

 

[Mistroma]

A lot of "it depends" here.

I left my boat for about 20 months on charge with a single 100W panel in Greece. Excessively more sunshine than needed and the batteries were OK.

I'm usually very careful and assume my return might be delayed but COVID came along.

They were OK because I overfilled them before leaving. Adjusted the MPPT carefully to just keep to correct float voltage. It was also set to go to a higher voltage one a month for a short time. The controller has 16 parameters.

The electrolyte was at the top of the plates when I returned. 24 months would have been too long, even with all that care.

Engine and bowthruster batteries were fine. The T205s have a very high self-discharge the others are the complete opposite.

It depends on battery chemistry, condition, charger settings and many other factors.

An indication of battery make and chemistry would help but you still won't get a reliable answer.

 

[wonkywinch]

Smaller sealed lead acid batteries sit on trickle charge 24/7 in burglar and fire alarms for years. The Yuasa 7A/Hr ones I use seem to last 6-7 years at least before the alarm panel warns of failing battery.

 

[Bouba]

A lot of "it depends" here.

I left my boat for about 20 months on charge with a single 100W panel in Greece. Excessively more sunshine than needed and the batteries were OK.

I'm usually very careful and assume my return might be delayed but COVID came along.

They were OK because I overfilled them before leaving. Adjusted the MPPT carefully to just keep to correct float voltage. It was also set to go to a higher voltage one a month for a short time. The controller has 16 parameters.

The electrolyte was at the top of the plates when I returned. 24 months would have been too long, even with all that care.

Engine and bowthruster batteries were fine. The T205s have a very high self-discharge the others are the complete opposite.

It depends on battery chemistry, condition, charger settings and many other factors.

An indication of battery make and chemistry would help but you still won't get a reliable answer.

That covid was a pain....I left my battery charger on the boat ....but the car on my drive got a flat battery.....it was a 2.3 liter diesel....but I started each time from my drill battery....the car battery I replaced after covid....but I still use the drill battery

 

[Mistroma]

Smaller sealed lead acid batteries sit on trickle charge 24/7 in burglar and fire alarms for years. The Yuasa 7A/Hr ones I use seem to last 6-7 years at least before the alarm panel warns of failing battery.

Yes, my bowthruster battery is a sealed high spec. AGM and was fine. Ditto with low maint. engine battery chosen because it handles a high charging current.

Problem is the OP didn't specify his batteries. He mentioned a cheap regulator so good chance the domestic batteries are just cheap "leisure" batteries.