12 Volt battery charger

[bm]

I am looking for a reasonably priced 12 Volt battery charger and was shocked to see Halfords selling them about £60 Where can I buy a more reasonable one Blair

[Palindrome]

Basic but work well - I have a couple (they parallel nicely for higher output current)

-- Sue

[cerberus]

Argos, from £30, see;

Don.

[bm]

Thanks Sue for your help.The cost is very reasonable (with delivery £14) I noticed it was 4 watt and I assume that is adequate for a lawnmower which I have. Blair

[bm]

Thanks Don for your help.When I went on to the Argos site I noticed that there was a cheaper version for £19.99. This was a 6 amp model I'm not really sure what amperage I require for a small engine lawnmower. The one you recommended certainly was a more sophisticated model Blair

[Kevin]

or use something like this

just leave it connected and no danger of over charging the battery,but it wont charge it in a couple of hours

[Palindrome]

I ordered them on line for collection at the "local" store.

It is rated at 4 AMPS, (more like 50Watts than 4watts)

I am assuming that this is an electric powered mower? And not an electric start petrol mower?

The battery in the lawnmower will have a rating in AH. A very rough approximation as to how long it will take to fully charge from flat is to take that figure and divide it by half the amp rating of the charger. eg a 12AH battery will take around 6 hours to recharge. If you want quicker charging, get two chargers and connect them in parallel.

(This is very approximate - and allows for things like the battery won't be completely discharged, the charger won't charge at its full rated output for the whole time, etc)

Always, always, always, always charge the battery after use - never leave it flat and uncharged. A battery will discharge itself in a few months (less time as it gets older) - so, pop it on charge for a couple of hours every month, if you aren't using it.

If the battery is allowed to get and to remain totally discharged - it will die. Howwibly. In a very short time. Hence the need to always store it charged. So, never put off charging it until "another day".

-- Sue

[Andy Champ]

Your battery is probably something like 60 amp hours (AH) this will be on the side, divide by the amps and you'll get a *very rough* idea of how long it'll take to charge. (It'll be longer than that - those amp hours are for discharging and you need more to recharge).

I assume you can leave it for a week between mowing so almost anything will do the job. 4 amps for 7days x 24hours = 672 amp hours.

A cheap one wants disconnecting once the battery starts "gassing" (fizzing) whereas a better one ou can just leave connected.

Andy

[bm]

Thanks again Sue. I should have pointed out that it is a petrol machine I have. What difference does that make? Blair

[Palindrome]

Electric start petrol lawnmower? I *am* envious. I get so annoyed trying to start mine that I have to have an extra large swear box in the shed.

The battery is going to be a lot smaller than that needed in an electric mower. So it won't take as long to charge and a small charger will be fine.

However, the same rule applies to topping the battery up every month or so. If the mower isn't used for several months, then the battery (especially an old battery) can become totally flat and will die soon after.

-- Sue

[bm]

Thanks again Blair

[Andrew Gabriel]

ALDI had some very nice small switched-mode microprocessor ones for £13 some weeks back. Would be worth checking if your local store still has any left. They are switchable

0.8A or 3.8A charging, with auto fallback to float charging when fully charged. They also do 6V batteries and a mode for very cold batteries. Short circuit and reverse polarity protected.

[Andrew Gabriel]

For a sealed lead acid battery, the guideline max charging current is 1/7th of the battery capacity in AHrs, although a leasure rated battery might cope with more. For car batteries, they can cope with much higher changing rates -- a car alternator can easily supply a drained battery with 40A, although that will quickly reduce as it charges.

[bm]

Thanks for your help Blair