Charging Gel mobility scooter batteries

50Twuncle

I have a mobility scooter - a simple 4mph pavemement job - which I use regularly
The batteries are sealed 24v lead acid gel based.
I charge them after every time that I use them - perhaps 2 times weekly - they generally fully recharge in about 4 hours (the indicator light on the charger goes green to indicate fully charged)
The instructions that came with the scooter tell me to give the battery a 48 hour charge, once a month - which I am unable to do (my wife has a fire phobia - so can't leave it charging overnight anyway!
My question is Why should a lead acid battery benefit from being fully charged and then left with the charger connected for so long ?
I have an engineering background but nothing in my memory tells me that this is a good thing for the battery life ..
In fact overcharging a lead acid battery can reduce its useable lifespan !!
Any comments welcome.

hans_2

The long charge is so the battery can reach full saturation and prevent Sulfation which will reduce battery life.

Do you pay for battery replacement? If not don't worry about it too much.

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

shaun_from_Africa

One of the problems with gelled electrolyte batteries is that if they are charged too fast, the gas that is formed can't be vented quickly enough (or in the case of a totally sealed battery, the gas can't be recombined quickly enough).
If this happens, pockets of gas can form in the gel electrolyte and as this means that as there is now less electrolyte in contact with the plates, the capacity of the battery will be lower than it should.

A long slow charge can help recondition the battery by allowing any gas trapped in the gel to either be released or to be recombined inside the case and if there are any voids in the gel, these should also fill up.
That's the theory I was taught. Whether it works in practice is another matter.

50Twuncle

hans_2 wrote: »

The long charge is so the battery can reach full saturation and prevent Sulfation which will reduce battery life.

Do you pay for battery replacement? If not don't worry about it too much.

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

Yes I do pay - the scooter was self funded

50Twuncle

shaun_from_Africa wrote: »

One of the problems with gelled electrolyte batteries is that if they are charged too fast, the gas that is formed can't be vented quickly enough (or in the case of a totally sealed battery, the gas can't be recombined quickly enough).
If this happens, pockets of gas can form in the gel electrolyte and as this means that as there is now less electrolyte in contact with the plates, the capacity of the battery will be lower than it should.

A long slow charge can help recondition the battery by allowing any gas trapped in the gel to either be released or to be recombined inside the case and if there are any voids in the gel, these should also fill up.
That's the theory I was taught. Whether it works in practice is another matter.

The charger is designed for a slow trickle charge - but my question was whether the batteries benefit from an "over charge" no matter how low a current it is.....
ie The battery is fully charged when the indicator led lights - but you don't disconnect for another 36 hours !

forgotmyname

Its not an overcharge, its a maintenance charge to prolong the batteries life.

At the end of the day you either do it or you dont. Your choice. But if the batteries dont last as long as expected you know why.

DavidP24

You can get fireproof bags to put batteries in, I know will be a pain in the A but if she will not let you

50Twuncle

DavidP24 wrote: »

You can get fireproof bags to put batteries in, I know will be a pain in the A but if she will not let you

Thanks but no help - she thinks that bags will burn !!!

forgotmyname

Do you turn the power to everything off when you goto bed? Do you have smoke alarms in every room and cupboard?

Fireproof bags do not burn.

You oven or boiler are more likely to have a fire risk over a lead acid battery.

I leave my leisure batteries on charge for a week at a time and you can leave then on charge 24/7 x 365.

50Twuncle

forgotmyname wrote: »

Do you turn the power to everything off when you goto bed? Do you have smoke alarms in every room and cupboard?

Fireproof bags do not burn.

You oven or boiler are more likely to have a fire risk over a lead acid battery.

I leave my leisure batteries on charge for a week at a time and you can leave then on charge 24/7 x 365.

Do you have any idea what it is like to have a genuine fear of fire ?

iammumtoone

sounds like you either need to accept that your battery may not last as long as it should, meaning you may have to buy another one early or find a solution that doesn't upset your wife.

Do you have a neighbour/family nearby you could plug it in overnight or a garage/shed with an electrical supply?

How much are the batteries (no need to answer publicly) in situations like this sometimes it is better to accept its going to cost you more rather than cause your wife distress.