Battery problems

[Guest]

Yet again the car battery installed for nav , interior cabin lights & radio has expired on a recent overnight cruise. Should I invest in an expensive deep cycle model (3 times the price of a car battery replacement) or get a new battery with a solar panel to keep it topped up and fully charged. The battery gets little use especially over the winter period. Any Ideas?

 

[vyv_cox]

I think this is two questions in one. A car battery is perfectly adequate for boat use IF its voltage is kept above about 12.2 V at all times. In practice this is not easy to do. A deep cycle battery will allow voltage to fall below this figure more frequently, although doing so will shorten its life.

To avoid your problem you need to ensure that voltage is kept up, by running the engine periodically or by measuring your consumption and ensuring that the battery has sufficient capacity before setting off. A solar panel is well worth having, especially in winter if you don't visit the boat. However, it is quite an expensive investment that may be unnecessary with proper battery maintenance.

I have a solar panel and an installed charger and I do as much as possible to ensure that voltages remain high. My engine start battery was bought in 1995 and my service batteries in 1999. All appear to be in excellent condition.

 

[Boathook]

I would invest in deep cycle batteries as the expense is better than the agro and that is speaking from experience!. My existing batteries are 105 amp voyager and they are starting to play up at 8 years old but still work. Another area to check is that the battery size is suitable and capable of supplying the power you require.

 

[boatone]

Have you actually done a power calculation to assess just how much drain you're placing on the battery? What is the capacity of the battery, how do you charge it and how well is it charged etc etc . These are all critical to satisfactory battery perfomance. Just buying a deep cycle battery without regard to these issues is unlikely to solve the problem.

boatone@boatsonthethames.co.uk

 

[RobertMartin]

If your going to use a car battery for you houseload ( not a great idea ) the you need to keep the charge up and not let it drop to low. Using the engine all the time during the day to top it up defeats the poin of sailing. A solar panel is ok, but how much sun do you really get in the UK?? Not much. Get small wind generator, maybe a Rutland 503, 913 . this will keep your car battery topped up all winter, when sailing, stopping for lunch etc. lots of wind when sailing. And when theres no wind you will probably be motoring anyway. so you will be charging you batteryat the same time. It may cost a bit at first to get the generator, but your battery will last for many seasons, as long as you check it every month...

Bobby aka Seawolf..
Sail as if your free

 

[brianhumber]

As others have said, auto batteries must not be run down, it is instant death, having said that I use 648 auto batteries. Yacht is on a swinging mooring, with only alternator charge except when I vist French marinas. Replaced my Domestic this year after 6 years, found the price had gone down to £69 from £70 in 1994 with 2 year warranty. Others may fit deep cycle but I still maintain they are a complete rip off and waste of money.

 

[oldharry]

Car batteries are designed for one use, and one use only - to start car engines. They are specifically designed to push several 100 amps to start an engine, then to go onto a standby charge cycle. They will not maintain a low load current drain over extended periods and lose voltage very rapidly, resulting in slight but cumulative damage to the plates - every time they are allowed to remain much below around 85% charge without being 'topped up'

A very viable alternative for domestic electrics - and much cheaper than true 'deep cycle' batteries is the 'Leisure battery' supplied for caravan use - our local caravan centre sells them in an 80 ah version for £35.00 - cheaper than most car batteries.

They do not tolerate deep cycle discharge quite as well as the true deep cycle battery, but can safely be run down to around 60% charge before voltage starts to drop to a critical level, and they will start small single or twin cylinder engines. You will also notice your lights stay noticeably brighter for longer - important when using Nav lights where a 1 volt drop in supply can reduce light output by as much as 40%

Alternatively try your local agricultural suplier for 'Traction batteries' - a little more expensive, but able to start larger engines and maintain a safe working voltage down to around 60% charge.

But ordinary car batteries? No thanks!

 

[Guest]

Try Halfords for Leisure Batterys. i get my Lucas ones from there and they work fine for me.
But i don't have a diesel to start either...?

 

[Guest]

Agree that Halfords leisure batteries are good... mine's giving great service. Have just installed a "windgen" wind generator (www.windgen.org). They are brilliant. I have never dealt with a more helpful company. They made a bracket to my design for simple wheelhouse mounting, kept me informed by e-mail of progress of the unit through their new factory (they were in the middle of moving when I placed my order) and were most importantly fairly cheap ( less than £200 all in). They're also finger friendly!!!!