Cost of keeping batteries charged?

[Quattrodave]

6 hours ago, Ex Brummie said:

Getting back to the original post, it has been shown that the cost of maintaining charge is next to minimal especially when it is factored into the battery life/cost equation, plus the advantage of fully charged batteries when you want to use the boat as consumption is likely to be high for the first few hours.

100% agree. In short, what's the cost of keeping batteries full charged? Peanuts, in comparison to replacing nackered batteries.

[Alan de Enfield]

16 minutes ago, Quattrodave said:

100% agree. In short, what's the cost of keeping batteries full charged? Peanuts, in comparison to replacing nackered batteries.

 

But what cost of leaving your boat batteries on charge for months on end with no weekly visit to check water levels, battery temperature or signs of swelling or an internal short ?

 

When the battery explodes spraying the engine room with acid, the cost of replacements and refurbishment of the engine and ancilliaries far outweighs the cost of a new set of batteries.

 

We were seconds away from such a battery explosion when the CO alarm went off in the middle of the night - fortunately we were on board. The battery was too hot to touch, I was choking on the fumes but managed to get a spanner onto the terminals and disconnect the battery, The battery was still too hot to touch 12 hours later.

[Rebotco]

11 minutes ago, Quattrodave said:

100% agree. In short, what's the cost of keeping batteries full charged? Peanuts, in comparison to replacing nackered batteries.

 

That rather depends.

The reason I asked the original question was because it will cost me £1 per day to have shore power.

I have no other use for it than keeping the batteries charged up.

So £365 per yr is not exactly peanuts!

[Alan de Enfield]

24 minutes ago, Rebotco said:

 

That rather depends.

The reason I asked the original question was because it will cost me £1 per day to have shore power.

I have no other use for it than keeping the batteries charged up.

So £365 per yr is not exactly peanuts!

 

Is that £1 irrespective of usage ?

 

If so you could leave engine room heaters on all Winter saves draining down and makes the boat quickly usable if you decide to have a day-out

 

I have 2 engine room 375w heaters and it works out at £1 per day.

[George and Dragon]

On 26/05/2021 at 21:05, Rebotco said:

 

That is very helpful, thank you.

The real world cost is exactly what I was looking for, rather than mathematical theorising!

You're welcome. It's a useful number for me to know too.

[George and Dragon]

At £365 pa you can probably replace the batteries annually (I've forgotten how many you have, mine were £95 each). 

 

Investigate solar - the initial cost may rule it out but it pains me to destroy perfectly good equipment.

[ditchcrawler]

12 hours ago, George and Dragon said:

 

 

Investigate solar - the initial cost may rule it out but it pains me to destroy perfectly good equipment.

Agree, something like 40 watts would do it, so not that much money to lay out.

[Laurie Booth]

On 10/05/2021 at 21:08, Rebotco said:

Bit of advice appreciated.

Can I work out the cost of shore power to run a smart charger at say 14p/KWhr?

That's for a "Genius" 7.2 amp charger connected to 2 x 110 Ahr batteries.

Generally batteries are well charged after cruising for a few days, so I guess its probably only a maintenance charge to consider.

However it would be on 24hr/day when boat is left unattended in marina, which is about 75% of the time!

Thanks in advance.

I use this charger.

 

https://www.7dayshop.com/products/aa-car-essentials-12v-solar-powered-car-battery-charger-solar-panel-5060114614185

[Rebotco]

13 hours ago, George and Dragon said:

At £365 pa you can probably replace the batteries annually (I've forgotten how many you have, mine were £95 each). 

 

Investigate solar - the initial cost may rule it out but it pains me to destroy perfectly good equipment.

 

I have been relying on a flexible 100 watt solar/mppt for several years.

It worked well for a couple of years, but seems to have deteriorated since.

Presumably the batteries have started to sulphate during the winter, with no engine running and precious little sun either.

[ditchcrawler]

10 minutes ago, Laurie Booth I.S.M. said:

I use this charger.

 

https://www.7dayshop.com/products/aa-car-essentials-12v-solar-powered-car-battery-charger-solar-panel-5060114614185

I would say that that charger may just maintain a bank of 4 110Ah batteries in the summer months, I doubt it would keep up in the winter.

[Laurie Booth]

Just now, ditchcrawler said:

I would say that that charger may just maintain a bank of 4 110Ah batteries in the summer months, I doubt it would keep up in the winter.

I use it to charge the starter battery.

[ditchcrawler]

1 hour ago, Laurie Booth I.S.M. said:

I use it to charge the starter battery.

Which is what they are designed for. But it doesn't prevent your domestics degrading

[Laurie Booth]

On 28/05/2021 at 13:30, ditchcrawler said:

Which is what they are designed for. But it doesn't prevent your domestics degrading

Just connect one to each battery