Wednesday, 30 December 2009

Recharge ... its the only way to operate

Having recently posted about my batteries (electricity is the next most popular topic after toilets for boaters) I reflected once again on living aboard. Seems to me recharging has massive advantages for boaters - in fact a good proportion of boaters live and freeze by their batteries. There are some that hook up with all the issues of galvanic isolation but in the main and through the year we rely on recharging our batteries. We do this with the help of our engine, mines a Beta Marine and therein lies the benefit. When cruising I will be recharging like mad....
  • Laptop
  • Torch
  • Radio
  • Boat batteries
  • Two way radios
  • Phones
I have just brought a 1 million candle power (?) rechargeable torch from Halfords for £9.99 that comes with a 12v charger as well as a 240v wall wart. Plus my lads got me a nice portable DAB rechargeable radio for Christmas.

I have been thinking of getting a new telly for the boat but the ability to use my 17" laptop on batteries for TV and DVD's stopped the purchase - just another use of the free power whilst cruising......

One thing though I never have understood how extra load on the alternator increases the fuel consumption - is that a fact on a boat as well? The benefit must outweigh the small cost, but I'd still like to understand the impact.

So recharge, recharge I say and buy a Smartgauge so you know what the heck is happening with your batteries without the need for scrabbling under the deck boards with a multimeter.



Bruce in Sanity said...


If your engine is at Beta Marine, and the boat's at Fradley, how do you use it to charge your batteries?


Normally, the extra load on the engine from the alternator slows it down, so you have to open the throttle a bit to maintain revs, but a boat engine is working so little, even when pushing a lot of watts into the battery, that in practice we don't see much change.

Charley Johnston on Felonious Mongoose says he sees little change in fuel consumption when using the engine to recharge his huge battery bank for the hybrid engine.

Have a good New Year


Nev Wells said...


Thanks for the info and the correction.

Still not sure how the alternator adds load - I thought it is driven all the time ?

I also wish to a Happy New Year and an exciting one with your new boat,

Take care


Bruce in Sanity said...

The alternator is harder to turn when it has a load across it. The rotating coil that has the generated current in it presents a magnetic field opposed to the one in the stator

On Sanity, you can always tell when the fridge freezer has started by the way the engine note drops if it's running.



Captain Ahab said...

The alternator may spin all the time but it isnt under load all the time. I also have a beta (38)and I can hear the alternator chirruping as it goes on and off load, and how it makes quite a noise 1st thing when it is charing like billy oh. Yours probably does the same.

Nev Wells said...

Bruce & Andy,

Thanks for the explanation - I now realise how it can and does impact on engine load..... my learning point today.

I'll certainly listen and watch more to get a better understanding of how it is working - epecially with the adverc,

Thanks again,


BigJohn said...

Since I would think you use your two way radios when under way, how do you recharge them?

Nev Wells said...


We use the two way radios infrequently, mainly on flights so they are in the main charged when we want to use them as we leave them on charge while we cruise,