Look after your motorhome’s leisure battery

Winter can be a trying time for your motorhome’s leisure battery (or batteries).

Here’s how to cope…

If you’re planning a bit of a rest from your motorhome this winter and you want to go back to a healthy leisure battery, it’s time to start looking after it. Right now!

One of the key factors is making sure your battery doesn’t get too cold, because that’s when performance really can deteriorate. Location can be key – most professionally converted motorhomes have in-board locations for their leisure batteries, where it’s hardest for the extremes of cold to get at them – it’s those with external access battery boxes than can be most vulnerable.

That’s just one reason why best advice for anyone not using their motorhome in the winter is to disconnect the leisure battery and store it somewhere dry indoors (note, also, it’s a myth that you shouldn’t keep a leisure battery on a concrete floor – there is nothing to prove such a location speeds up the rate of discharge).

Only do this however, if removing the battery doesn’t affect the performance of any key security fittings, such as tracking devices or alarm systems. That depends if these devices power from the leisure battery or not.

Get an intelligent charge

One consideration is to fit an intelligent charger. Such a fitting works effectively all year round, of course.

Through winter, you can keep your leisure battery connected and, because intelligent chargers are constantly monitoring, it means there’s no chance of over-charging. For many, this is the ideal scenario. Key names to look for include Automate, CTEK, NDF and Sterling.

Leisure batteries by type

To be clear, leisure batteries operate very differently to the similar-looking battery that is used to start your motorhome’s engine, which needs to supply power in an instant burst. Deep-cycle leisure batteries provide their power over long periods, so the cycle of discharging/charging is longer, too.

A typical leisure battery is the lead-acid type and, as such, will self-discharge, to a greater or lesser extent depending on make, age etc. You need to be able to keep any eye on electrolyte levels, and top up as necessary.

When a battery is discharged, it will start to deteriorate. So, it should always be kept warm, comfortable and well fed… with electricity.

Other types include AGM (for Absorbent Glass Mat, a form of matting between the plates that filters the sulphuric acid inside a battery, making it more resilient in use) or Gel – a format that means no free-flowing liquid and less gassing.

Most recently, lithium batteries have come to the fore. Ideally suited to owners who use their vehicles “off-grid” (i.e. away from a campsites and other sources of mains charging), these don’t self-discharge, are truly maintenance-free, and work particularly well in conjunction with an inverter.

The capacity of a leisure battery is measured in amp hours (Ah). Any quoted figure will be at an ambient temperature of 25degC. As a guide, for every one degree below this, the battery’s Ah will fall by one per cent.

Get the right leisure battery

In response to concerns that too many suppliers were suggesting their batteries were suitable for leisure vehicle use, trade body the National Caravan Council introduced a Verified Leisure Battery Scheme.

It categorises leisure batteries as: A, for frequent use away from a mains charging source; B, for frequent users, who also have access to mains hook-ups; or C, lower-capacity batteries whose main use is for short periods.

You can find out more here: http://www.thencc.org.uk/our_schemes/ncc_verified_leisure_battery_scheme.aspx.

Also, the following download lists batteries it deems acceptable:  http://www.thencc.org.uk/downloads/Verified_Battery_Register_October_2017.pdf

Do’s

• Make sure your batteries are wired and installed in the correct manner
• Charge your battery after purchase and before each use
• Keep the terminals and posts free from corrosion. Lightly coat with petroleum jelly
• Always keep your battery fully charged, even when not in use. When not in use, store in a cool environment connected to an appropriate charger.
• Always keep the battery upright and adequately secured
• If you’re laying up your vehicle for the winter, charge the battery at the end of the season and remove it from the motorhome, or use a permanently connected intelligent charger
• Check your motorhome for appliances that draw a constant charge from the leisure battery, e.g. a tracking system or alarm, as you will need to counter this draw with a constant re-charge to maintain the battery and you won’t be able to remove your leisure battery.

Don’ts

• Never over-charge your battery. Once disconnected from the charger and, after 24 hours, a fully charged 12V battery should have a voltage of 12.7V. This can be checked with a multimeter
• Never over-discharge your battery. A battery is fully discharged when the load voltage is 11.70V – this means charge immediately!
• Never leave your battery in a discharged state for a prolonged period of time
• Never reverse the polarity on your battery charging leads as this may damage the battery and charger
• Never rely on an automotive alternator only – it may reduce battery life. Worth knowing, also, is these days some base vehicles have “smart” alternators, which may not fully charge a leisure battery.

Leisure battery top tips summary

• As long as it has access to daylight through the winter, a solar panel can keep your leisure battery charged. Beware of over-charging, however, particularly if your panel has a cheap regulator.
• Overcharging can be just as bad for your leisure battery as undercharging.
• As a general rule, never allow your leisure battery to discharge below 50 per cent of its capacity.
• Performance will deteriorate with age. A typical leisure battery can last as little as five years. Winter is often the time when you find out how good your leisure battery actually is.
• Ideally, use a leisure battery charger rather than a standard vehicle unit.
• Save your pennies. If you rely almost solely on mains hook-up whilst you’re touring, you don’t actually need a top quality leisure battery.

Key leisure battery contacts

Regular servicing of the habitational aspects of your motorhome will include assessments of the leisure battery (or batteries, if you have more than one).

Independent suppliers who can recommend which leisure batteries and related accessories are best for you include:

Manbat (www.manbat.co.uk)

RoadPro (www.roadpro.co.uk)

Tayna Batteries (www.tayna.co.uk)

Over to you…

Got any advice on looking after your leisure battery this winter to pass on to others? Feel free to add your comments below.

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