Battery charge (non boaty)

Leighb

Leighb

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I have been keeping an eye on the car batteries, one is probably getting on a bit, been a bit reluctant in cold weather after standing for a day or two, the other OK AFAIK, it started fine after sitting at Stansted for 2 weeks back in February. I put both of them on charge about 2 weeks ago as they were down to around 12.3 volts. After charging they were up to 12.75. Today they are both at 12.17. Both cars have alarms fitted, but as they are parked in the drive I don’t want to disconnect the batteries.
Should I just keep giving them a boost every couple of weeks, or is it likely they might both need replacing?
 
I would charge them every couple of weeks while lockdown is stopping you using the cars.
Some cars are much worse than others for draining the battery.

They may need replacing, but what's the point of doing it now, when you would end up abusing the new battery?
 
It seems a bit strange to me that two different batteries in two different cars should both coincidentally have dropped to exactly the same voltage! Were they showing 12.75 just after you disconncted them from the charger or were they sat a while before you checked the voltage? Even if the latter one or both could still need replacing but as above there's not much point doing much at the moment...
 
I have a smart battery chargers that I use on my classic cars to keep the batteries in a charged condition.

I keep my chargers on all the time and they cut out when the battery voltage gets up to a set point without over charging.

When we go away I also use the same type of charger on my wifes car so when we come back

Like this

Amazon.com: BMK 12V 5A Smart Battery Charger Portable Battery Maintainer with Detachable Alligator Rings Clips Fast Charging Waterproof Trickle Charger for Car Boat Lawn Mower Marine Sealed Lead Acid Battery: Automotive
 
Some cars have electrics connected via the interior light. Honest John suggests turning the interior light fully off, as well as removing the boot bulb. I do the first but not the second.

I am using a solar panel on my car.
 
V1701 said:
It seems a bit strange to me that two different batteries in two different cars should both coincidentally have dropped to exactly the same voltage! Were they showing 12.75 just after you disconncted them from the charger or were they sat a while before you checked the voltage? Even if the latter one or both could still need replacing but as above there's not much point doing much at the moment...
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They weren’t exactly the same but very similar, and a day or so different since previous charge. It was the general principal that I was illustrating. The 12.75 was the following day after charge.
 
If it was me ... I would have plain charger of 4A or so ... and a mains plug in timer.

This is how I mantain my boats batterys ..... the 4A charger is a plain cheap non smart job. It is powered from mains via a timer which is set for a couple of hours each day 5 days out of 7. The charger feeds to a Maplins solid state splitter that detects low battery to charge ... stops when full charged ..... and just monitors to top up as necessary when timer kicks in.

It might sound a bit much - but its simple and works. One charger doing two decent sized batterys.
 
Biggles Wader said:
I charge mine up for a few hours every couple of weeks at the moment. Prevention is better than cure I think.
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Similar here.
I have Ctek smart chargers which I normally leave looking after my motorbikes in the winter.
I put it on my car now and then.
 
Leighb said:
I have been keeping an eye on the car batteries, one is probably getting on a bit, been a bit reluctant in cold weather after standing for a day or two, the other OK AFAIK, it started fine after sitting at Stansted for 2 weeks back in February. I put both of them on charge about 2 weeks ago as they were down to around 12.3 volts. After charging they were up to 12.75. Today they are both at 12.17. Both cars have alarms fitted, but as they are parked in the drive I don’t want to disconnect the batteries.
Should I just keep giving them a boost every couple of weeks, or is it likely they might both need replacing?
Click to expand...
I would suggest that much depends on the age of the batteries. If you get 5 years out of a car battery you are doing well. If a new battery costs 100 squid then that is 20 squid per year. If you squeeze another 6 months out of the batteries then you have saved 10 squid. However in doing so you may end up getting stuck at some stage with car looking for help. I reckon the savings eking out a longer life from a car battery might not be worth the risk. (especially wife's car). So if it seems a bit sluggish to start may be time for new battery. ol'will
 
William_H said:
I would suggest that much depends on the age of the batteries. If you get 5 years out of a car battery you are doing well. If a new battery costs 100 squid then that is 20 squid per year. If you squeeze another 6 months out of the batteries then you have saved 10 squid. However in doing so you may end up getting stuck at some stage with car looking for help. I reckon the savings eking out a longer life from a car battery might not be worth the risk. (especially wife's car). So if it seems a bit sluggish to start may be time for new battery. ol'will
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5 years? In my experience, I get 8 years from my boat batteries (normal car starter type) and more in a car. Current car battery is 12 years old and still good.

Www.solocoastalsailing.co.uk
 
We both drive Audi’s with stop-start function so they are fitted with AGM batteries. My wife’s TT hasn’t moved since we were put under house arrest but my car gets a 3 miles return trip to Tesco once a week. Much longer than 4 weeks without charge is pushing your luck, I reckon.

Next on the list is to make sure that tyres are inflated correctly. May even consider rotating them to avoid flat spots. Fortunately, it's been very dry. Cars left outside, especially in wet weather, often suffer brake issues.

It's not only boats that benefit from being used :)
 
William_H said:
I would suggest that much depends on the age of the batteries. If you get 5 years out of a car battery you are doing well. If a new battery costs 100 squid then that is 20 squid per year. If you squeeze another 6 months out of the batteries then you have saved 10 squid. However in doing so you may end up getting stuck at some stage with car looking for help. I reckon the savings eking out a longer life from a car battery might not be worth the risk. (especially wife's car). So if it seems a bit sluggish to start may be time for new battery. ol'will
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True but depends on cars use.

I get a lot more than 5 years out of car batterys - but that's because of long drives regularly. I just changed the battery in my Volvo XC70 and that was near 10yrs ....
My Renault Master gets used less but still usually long drives of at least 1hr at least once a week ... 6yrs.

But if I was to only use either as motorised shopping trolleys doing short stuff shops and back like the typical Wife / secoind car ... then battery has a hard life of short charge ... lots of starts etc. That will have a short life.
 
I was going to make my fortune at the end of lockdown by cornering the market in battery chargers. I see you all have one already, have to think again.
 
Skylark said:
May even consider rotating them to avoid flat spots.
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Found this on Halfords website...

If you feel some vibration or juddering, it could be because the flattened shape of the tyre means it is not a smooth circle. However, this should naturally recover as the tyre warms up and regains more of its natural flexibility.

:) ?
 
We use a combination of:

solar panel permanently connected through cigarette lighter (where non ignition dependent),
solar panel permanently connected through ODB2 port (where ignition dependent),
solar panel permanently connected using crocodile clips direct to battery, (where no cigarette lighter or OBD2 port),
battery permanently connected to smart charger,
battery permanently connected to trickle charger,
battery connected to bulk charger but through mains timer,
battery connected intermittently every week or so using one of the above for top up.

It's a full time job keeping on top of that lot. :(

Richard
 
Skylark said:
We both drive Audi’s with stop-start function so they are fitted with AGM batteries. My wife’s TT hasn’t moved since we were put under house arrest but my car gets a 3 miles return trip to Tesco once a week. Much longer than 4 weeks without charge is pushing your luck, I reckon.

Next on the list is to make sure that tyres are inflated correctly. May even consider rotating them to avoid flat spots. Fortunately, it's been very dry. Cars left outside, especially in wet weather, often suffer brake issues.

It's not only boats that benefit from being used :)
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Rotating tyres is fine on 2WD .... real 4WD ... but not on AWD or Part-Time 4WD .... if not careful you can do serious damage to AWD as I found out to my cost ...
 
duncan99210 said:
In normal times, my car spends the summer parked in the yard in Greece for 3-4 months. It starts ok when we come back after this benevolent neglect. No idea how old the battery is, I suspect that it’s the original one on an 8 years old car.
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Do you disconnect the battery?

Worst vehicle I had for self-flattening the battery was a BMW K1100 motorbike. A week and it would be flashing error lights when it started, 3 weeks and it wouldn't start. The battery had pretty good capacity when I measured it , but it was basically a poor era of car type ecu and a bike-sized battery.
 
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