Battery life

Our yeti is 7 y/o. it has the original battery

last Saturday I was waiting in the car during the kids gym class and I had the ignition switched to on so my phone could charge up.

But I also had the lights on and didn’t notice. I was probably sat like that for 30 mins. So the car wouldn’t start and I ended up getting help from someone with jump leads.

the car has been fine since.

so my question is:

is the battery Likely to need a replacement Now / soon

or is it a good idea to charge up the battery to boost its charge for 10hs approx.

they vary. Charge yours fully, and see if you get another flat event.

Sitting with the lights on will soon flatten even a good battery.

With a Silver Varta I got ten years good life, but then it wouldn't hold a charge sitting parked for a month in winter. It had a 5 year warranty.

A black Varta in a different car gave me 9 years.



i think both are very fair lives.

i got DP a blue Varta but she kept parking it with the interior light on and it didn't last so well.

i leave a trickle charger in the boot and put the batts on if they have been standing more more than a few weeks. If you have an ammeter on it you will see that charging rate soon drops so it will take quite a while to charge fully.

Looking at the dates I see all batts were bought in winter, when loads are highest and batts more likely to let you down.

Also have jump leads in each car so unlikely to ever be in real trouble.

I haven't bought a smart charger for the cars but I have a tiny one for the bike batt.

I would use a cheap smart charger and charge for as long as you can. The problem with any lead acid battery is it will not charge fast, and longer it has been discharged for the longer it takes to charge, so with an abandoned battery, I have seen it do nothing for 10 days, then fully charge. Yours will not be that bad, but 24 hours on a smart charger can only help.

With other chargers depends on the battery, there are three common types, flooded with and without ability to top up, and absorbed glass mat also called valve regulated lead acid. The latter need to be very careful not to over charge, the maintenance free not quite so bad but again needs to be low charge rate, and flooded with top up plugs no problem.

Change it! What’s it going to cost you - with winter coming up and a 7 year old battery, how many more winters do you expect to get out of it? One? Two? What does that work out at, fifteen quids worth of battery if it’s changed prematurely? Could you really be arsed chancing it and all the aggro associated with it for fifteen quid?

And how deep would the regret run when it finally fails one cold winters evening stuck in a car park or something.

JohnD said:

With a Silver Varta I got ten years good life, but then it wouldn't hold a charge sitting parked for a month in winter. It had a 5 year warranty.

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It's not reasonable to expect a modern car to sit unused for that long, regularly, because of the constant discharge on the battery due to the electronics. Each car varies, but 20 to 70mA of discharge is typical whilst parked, due to the electronics. The constant cycle of deep discharge and recharge will soon wreck a car battery.

Yep I was lucky, my old battery failed in Tesco car park within walking distance carrying a battery from a motor factors, one is not often that lucky, but battery was causing problems when my dad died and we got the car, and charging it every couple of months had kept it going, so that was 7 years ago.

Batteries gradually lose capacity as they get older but will still start the car because the large plate area can provide a high enough current for just a few seconds but the reserve can be very small.

Peter

Harry Bloomfield said:

It's not reasonable to expect a modern car to sit unused for that long, regularly, because of the constant discharge on the battery due to the electronics. Each car varies, but 20 to 70mA of discharge is typical whilst parked, due to the electronics. The constant cycle of deep discharge and recharge will soon wreck a car battery.

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how long do you think a 100AH battery can safely be left, then?

JohnD said:

how long do you think a 100AH battery can safely be left, then?

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It is always a trade off between wear and tear on the battery and extending its working life to the maximum. I would want a parked car's battery given a charge at least once per week. My present regime puts my car's new battery on charge once per day for a 20 minute boost, using a Smart Plug. It has a 20mA discharge to maintain its systems when parked and I might not use the car for weeks at a time.

If you mean how long can it be parked without any charge, yet be expected to still be able to start the vehicle, assuming a 50mA discharge, then between 3 and 6 weeks, depending on the weather, plus how easily it starts.

The Jaguar I have left for two months between charges, the Kia much longer, but used a little more, the Honda which had the battery fail early this month was needing charging every three weeks, but the problem is lead acid batteries take time to charge, it's not down to how far you travel but how long the engine is running for.

I was surprised, I had some 7 Ah VRLA batteries which were changed in an emergency when my father-in-law had unplugged his stair lift and it had gone flat half way up the stairs blocking the stairs as a result, then old ones lost for 6 months until he died and house cleared out.

The batteries would not take a charge, not unexpected, so put one in parallel with another 12 volt battery which was being charged, using a Lidi smart 3.8 amp battery charger plugged into an energy monitor and the pair of batteries sat at a 0.1 amp charge rate for around 10 days, then I saw on the energy monitor graph charge rate moved to 0.8 amp which is highest rate that charger will auto return to. And it sat there for 8 hours approx. i.e. 7 Ah of charge. Then using the now charged 7 Ah put second on of pair in parallel, this time at 0-12 Ah setting, so battery charger switched to zero output very quickly, and again after around 10 day the battery as if a switch was clicked charged up fully.

So I have now repeated this a few times, the caravan battery 75 Ah left nearly 9 months due to lock down, and again recovery was as if some one flicked a switch, after 4 days.

So with a battery which is never fully charged on a car, it will over time gradually sulphate more and more, and to bring back to full capacity we are likely looking at a week or more at a 0.1 amp charge rate, does not matter if charger can give 100 amp, the battery can't accept the charge that fast, the smart chargers vary how they work, but with the Lidi at lowest charge rate of 0.1 amp on a 90 Ah AGM battery in fullness of time voltage shown is 13.4 volt, the 75 Ah flooded caravan battery reaches 13.6 volt, the Jag battery charged in car hit just 12.9 volt, although this is likely due to way charger works, at 12.8 volt it jumps from 0.1 amp charge rate to 0.8 amp, and at 14.4 volt drops to 0.1 amp again, so it switches to 0.8 amp and a few minutes latter hits 14.4 volt so drops to 0.1 amp again, so catching it during the pulse is rare, however even though charger shows fully charged, it needs leaving on charge for a few days to fully charge.

We have noticed if left on charge for a few days, the Jag stop start works A1, but after sitting in drive for a month stop start does not work, as car computer realises the battery not fully charged. We have three cars, one for me, old Honda Jazz, one for caravan towing old Kia Sorento, and one for wife a reasonable newish Jaguar XE, during lock down they are hardly used, and it has been a case of moving smart battery charger around the batteries, which also includes two caravan and a jump start pack, a pair of mobility scooter batteries, and some old 7 Ah now used to power a radio, so the charger simply alternates between the batteries 5 days on each, then back to first, unless we have used a car then it can miss a turn. So works out at around every 2 months we charge batteries on unused cars. I would be more often but daughter tidied up for us, and one smart charger has gone missing.

ericmark said:

I was surprised, I had some 7 Ah VRLA batteries which were changed in an emergency when my father-in-law had unplugged his stair lift and it had gone flat half way up the stairs blocking the stairs as a result, then old ones lost for 6 months until he died and house cleared out.

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Unplugging them, even switching them off at the chair, does not isolate the batteries - the batteries. The batteries will continue to power the brake until the batteries are completely exhausted. The only way to safely leave a stair lift unplugged, is to either disconnect the batteries, or add a separate heavy duty switch to isolate the batteries.

Two stair lifts, one for mother other for father-in-law, two different makes, both spring brake, i.e. no battery or power and brake is on, the better quality Stenner had a brake de-activating switch so you could energise brake release and manually wind the chair to a convenient point. Father-in-laws had no brake release function, so had to buy new batteries to move it, or remove mills pins and take off whole chair and rack sections.

The power to motor is not that much, seem to remember 15 amp fuse was in the link between the two batteries, the Stenner would over charge the batteries, so unused batteries would last no more than 2 years, but in daily use would last 4 or more years, why not fitted with a stage charger don't know, the Lidi one only cost around £14 so would not have added much to chair cost. The other cheaper one did have some form of regulation charging the battery.

I was surprised at Stenner thought they were well made, but fitted by Stenner and made special for U shaped stair case, the U resulted in no view of bottom of stairs from top, and at the bottom there was an extending arm that went into hall way for last meter of travel, the chair would not move until arm down, and the arm was strong enough to crush a cardboard box, and would clearly injure a child or animal if it went down on them. But no safety stop, or even a mirror to see if clear before lowering the arm, or way to know if arm was up once at top of stairs. I was not impressed, had I been the council inspector when fitted I would have never passed it. Had you been able to go half way down before lowering then it would have been OK. All sorts of safety on the chair, but the arm nothing.

Our Superb battery is about 6.5 years old and working fine. It lasted through Corona wave 1 o.k without charging.
I managed to flatten the battery when the car was still fairly new doing what you did - ignition on, radio, and whatever else. You have 2 x 55W bulbs in the headlight, sidelights, 2 x 5W rear cluster, your radio is upwards from 25W,, several controllers talking to each other and maybe your cabin lighting on.
Even when you have a faulty door or boot light switch and only a tiny cabin or boot light stays on over night, you could be very unlucky the next morning.

Mottie said:

Change it! What’s it going to cost you - with winter coming up and a 7 year old battery, how many more winters do you expect to get out of it? One? Two? What does that work out at, fifteen quids worth of battery if it’s changed prematurely? Could you really be arsed chancing it and all the aggro associated with it for fifteen quid?

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My view exactly. My Insignia has been a bit sluggish starting over past few weeks and when I went to start it on Saturday AM it was flat... I've charged it and it seems fine, but as it's 6 years old and on original battery its getting changed this week.