Need a new leisure battery........

[wandering photographer]

Hi,
My battery has packed in and need some advice on a new one. The van is a self build and the battery charges direct from the main battery by way of a cut-off switch. There is no zig unit etc. This was installed by the previous owner and wondered if there was a certain type of battery I should use ie. is it necessary to buy a specific leisure battery? and if so do I just go for the most powerful I can afford? We have a 12v fridge and interior lights.
Thanks in advance.
Chris

 

[Firefox]

My self build works the same way. You'll hear some people speak of split charge relays and zigs as though they do something really clever like managing the engine charging. In fact, all they do is connect the two batteries exactly the same as a switch, albeit automatically when the alternator is running.

So you don't need any special batteries. I tried some Elecsol batteries recently but they only lasted 2.5 years. Some people swear by certain brands, but probably the best thing is get the largest cheapest ordinary lead acid battery that will fit. You can go for a special "leisure" battery but the ones in the £60 to £100 price range are basically starter batteries with a different label on.

The main point of battery care is don't deep discharge your battery even if it says "deep cycle" on it. Only discharge 40-50% max and charge immediately. Your battery will last a lot longer.

 

[wandering photographer]

Thanks Firefox,
A friend turned up last night in his Mercedes Esterel motorhome and he has ended up giving me one of his old batteries which he has just upgraded. He thought they had packed in so replaced them but it turned out he had a wiring fault so all being well it should work fine. Does it hurt the battery to charge them everytime you drive and is there an easy to fit "gauge" available that shows you how much charge there is left in the battery?
Chris

 

[Bigpeetee]

No problem at all.

A cheap digital voltmeter used across the battery will tell you the voltage (after a period of rest) I don't have details as to the battery capacity v voltage but a quick search of 'tinternet will. Obviously your leisure battery, is used so what it says in the way of AH on the outside probably bears no resemblance to what's going on inside!!

A lot of suck it and see, but as stated, don't let it go too low as it will take ages to recharge and doesn't do it any good at all.

Digital voltmeters can be had for about 5 quid, so you might as well buy one and virtually have it in circuit all the time.

Get rid of current sucking lamps and replace with LED

 

[Firefox]

The state of charge depends on battery type and temperature but as a rough rule something like 12.8-13.0 V on your DC multimeter is fully charged and around 12V is 50% charged.

10-10.5V is actually fully discharged, it should never get this low - try to keep it above 12V so as not to discharge too deeply.

 

[ivecotrucker]

Very good advice from Firefox in my opinion. Buy the cheapest largest wet acid lead battery but just make sure it has removable filler caps so you can top up the electrolyte -- do not buy a low or no maintenance battery. Split relay systems actually loose a volt or so (depending on their quality/price) from the alternator to the leisure battery, so avoid relays & Zigs by fitting a heavy duty switch or relay. make sure it will handle at least 100A though. We have a 1000A industrial solenoid relay that simèply connects everything together. Auguri da Napoli.

 

[wandering photographer]

That's brilliant guys. Thanks for your clear and easy to understand answers.

Much appreciated

C