Batteries...

DukeII

DukeII

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We need a bit more help/advice please (sorry!)

We are sadly lacking in leisure battery oooomph to run the beer fridge, radio, lights and such on the old Seamaster...

If we want to add another leisure battery is it simply a case of wiring it in parallel, or do we need switches/gizmo's in addition to this to ensure proper charging / safety ?

Any advice would be most welcome (it's only 12v, we don't have an inverter-thingy or anything!!)

Thanks,

Emma
 
KISS, you only need to connect the second battery to the existing one, no extra bits other than cable required, but do make the second battery the same capacity as the existing one to avoid complications.
 
agreed, that's the simplest way to add storage capacity, but if you are running lots of consumer units, then you need to do some simple maths to check the AHrs needed, and then look at whether your present alternator can cope, or whether you need additional sources of power such as solar panels.
 
A second, third or even more batteries can be connected directly in parallel with the existing and they will all act as if they are one big capacity battery e.g. 2 x 110Ah will act like 1 x 220Ah.

However, it is generally accepted that you should only parallel batteries of a similar type and age - i.e. not good to connect a 110Ah new to a 80Ah well used already as the older battery will tend to drag down the new one. I have always replaced my 4 x 110Ah units as a complete set.

Also, many people fail to recognise that 110Ah doesn't mean that is what you get! In fact, in a well managed battery setup you should only assume useable power of about 1/3rd actual stated capacity so my 4 x 110Ah = 440Ah actually gives me about 150Ah 'sweet' battery power without pushing the batteries too far. Reason for this is that even in a well managed charging routine pushing the charged level up above 85% is difficult and letting them discharge below 50% is best avoided on a regular basis so we get to use 35% (85-50) with confidence.

On our boat this 150Ah is enough to stay somewhere for up to 3 days without need to run engines, generators or shore power and we run an electric fridge 24/7 as well as computer/TV/cabin lights/hifi etc etc. I can even run a complete music setup with 300watt+ PA system for several hours using the boat 12v supply thru a 240v inverter.

My alternator is not huge - about 50A I think - but it copes quite happily You do need to make sure the charge cable from alternator to battery is man enough for the job. If it is too small it will offer high resistance and severely restrict charging.

The only 'battery' management I employ is this simple approach to battery capacity. I worked out that I needed 50Ah per 24 hours to run all electrics generally in use and then installed the 4 x 110Ah's to make sure I got it.

Incidentally, I never use shore electricity, not even in the marina. The only charging my batteries get is when the engine is running. That saves me around £150 a year which over 5 years pays for a new set of batteries and leaves me around £400 up on the deal !
 
That's brilliant - thanks for the information!

Looks like we'll be buying a couple of new, similarly Ah'ed batteries this weekend then - just to be on the safe side.... I don't know for sure how old the one in there is so best not to risk it by the sounds of it.

Thanks again!

Emma
 
BTW, if you are buying new batteries, it will make life easier for the charger if they are identical in type as well as capacity. Don't mix gel and lead acid or others as the charge and discharge patterns are different.

grandmother eggs, suck, sorry, if.
 
No worries...will do.

We've got a trade account at work with a major battery supplier, so I'll probably get a pair of identical Varta's or something.

Cheers,


Emma
 
Do make sure you get Leisure Batteries - also sometimes referred to as deep cycle.

They are different to crank power needed for engine starting.

I have had good service and good prices - including delivery to my home address from CPC in Twickenham http://www.cpcbatteries.co.uk/

Also, if they need to go into a confined space check which away round the terminals are especially if the leads are short ! CPC also made up new leads for me including the short jumpers to connect the batteries together.
 
boatone said:
Do make sure you get Leisure Batteries - also sometimes referred to as deep cycle.

They are different to crank power needed for engine starting.

I have had good service and good prices - including delivery to my home address from CPC in Twickenham http://www.cpcbatteries.co.uk/

Also, if they need to go into a confined space check which away round the terminals are especially if the leads are short ! CPC also made up new leads for me including the short jumpers to connect the batteries together.
Click to expand...

From personal experience respectfully beg to differ here, leisure batts are expensive and while possibly able to deliver over a long period when they do go down are the absolute devil to charge up. In the caravan I bought a leisure battery, even carting around in the 4 x 4 charging while driving it never gets up fully. By contrast, the 110 AH truck batteries on the boat, (£95 each including vat and doorstep delivery from Advanced Battery Supplies) which are re-badged Exides never let me down and charge up pretty quickly.

I rest me case me'lud!
 
Tony has it here, cranking batteries are for cranking an engine, deep cycle/leisure batteries are for delivering power for lighting music and other leisure activities.

A cranking battery will deliver a whopping great clump of power to turn an engine, but it should be recharged immediately if it is to last any time. Deep cycle batteries can be discharged by up to 50% time and time again.

There's a clue in the name...

The leisure battery will need a proper charging method, it is possible that the alternator on a 4x4 is not man enough to charge the leisure batteries, but if you want a system to last, use the right components.

R
 
Deep discharge batteries are expensive. However if you take a sample battery to a your local privately owned battery/tyre place, you can strike a deal. They are not something he would normally stock but can get them overnight. I had a great deal when I replaced six of them. He ordered them up for me and added 10% to the cost price for his troubles. The net result was I had bought my batteries at about half the price that a Chandler wanted to charge.
 
Just as a price guide, the last set I bought from CPC ( 4 x 110Ah) cost me about £60 each I think and that included free delivery to my home address in Surrey.

AMongst others, they supply our local disabled vehicle suppliers who, as you would imagine, are quite choosy about reliable batteries !
 
It's actually CPC in Twickenham that we have the trade account with (they delivery motorcycle batteries to where I work).

I did specifically ask for Leisure/Caravan batteries and they quoted me around 80 for the 110ah Varta's and 60 quid for their own brand version from memory.

Emma
 
DukeII said:
It's actually CPC in Twickenham that we have the trade account with (they delivery motorcycle batteries to where I work).

I did specifically ask for Leisure/Caravan batteries and they quoted me around 80 for the 110ah Varta's and 60 quid for their own brand version from memory.

Emma
Click to expand...

Well, there you go, then :D

I've been using their own brand and they seem to be fine.
 
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