Car flooded Lead acid Batteries - Question for Lead Acid expert (in search of lost wisdom)

Don't use my subary impreza much these days. On september 1st 2019, did a 1000 miles round trip and by then my ammeter showed close to 0 amps (battery fully charged, no current going in). Since then, I only started my car once every one or two week and went for a 15-20 minute ride so the alternator would recharge the battery a bit (at least a surface charge).

I've been lazy for the last two weeks or so and didn't start the car. Last thursday, temps went below -18 C...And friday back to 0°C. But my car would not start. No lights come on the dash. Battery completely dead :?

So took my battery in the house. Checked voltage : 4.86V. I hope it hasn't dipped that low a voltage for more than 2-3 days... and in the cold weather. Thought I'd need to buy a new battery for my dinausor juice fueled car...

I though, why not give the Imax B6 RC charger a shot at it before I buy a new battery... And so I brought it back to minimum voltage of 10.5 V by trying different charge programs at first (LiPo 2S... LiOn...Pb 4S... etc). Then I was able to have minimum voltage to start a PB charge 6S (12V) program... charging slow at first at 2A, then when I reached 12.4V opened circuit voltages (after injecting 8Ah) then charging faster at 4A.

So the Imax B6 says I injected in total 54.5 Ah into the dead battery. This is an Exide Global Extreme 35X 12 V flooded lead acid battery, rated for 700 CA and 585 CCA rated 100 reserve minutes (full, it should run a 25A load for 100 min at 26.7°C until reaching 10.5V, which is about 43 Ah). And at C/20 (2.7A), discharge capacity should be 58Ah...

This battery is manufactured Dec 2016 (3 years old). Now that it reached 13.4V opened circuit voltaged, I put it on a float charger for a few day (Noco Genious G750 charger). Electrolyte levels all look topped off.

Do you think my battery is just worth trowing into recycling, or is there any chances it is still recoverable to put back in my car for another year (or two) ??

Is 4.86V for 2-3 days too far gone ? Has irreversible hard sulfation taken place or just soft charge-reversible sulfation ? What is you experience with this ?

Two years prior I had to buy this battery new because the previous one was also shot, leaving my car in a parking for two month in the suburbs while I was living in Manhattan.

BTW, this is the first time I ever use my SKYRC Imax B6AC v2 charger in Pb mode.
I'll let the Noco Genious G750 intelligent charger finish the maintenance charge and then give the battery a try in a few days to try and crank the car.

Any input appreciated :wink:

Matador

Load test will tell.

Fully charge, then feed a light or inverter at 0.05C or so.

If it gets to 10.5V in less than 15-16 hours, scrap it.

Thanks for the input!
Also tried the Battery resistance function of the Imax B6 charger... Said battery was 20 millioms.

depleting battery once or twice wont kill it. That you were able to put 58 amp back into it is a good sign. A bad battery wouldn't take too many amps due to loss of capacity. As long as it cranks your car over I would keep using it and just keep an eye on it, I have a led voltmeter on my dash just so I know condition of battery every day.

If you bought a new battery you will run into the same thing, lead acid have to be charge everyday to last a long time.

> lead acid have to be charged to 100% Full everyday most cycles to last a long time.

FTFY

Till you kill it, as you did. Can you still use it? sure, just put it on a charger the night before each time. Its got half its capacity left, and less when its really cold. So you need it full, and perhaps warmed to use it now.

Really if you want it to start, especially in the cold, its new battery time. Its always money you don't want to spend, but you really need it to not leave you someplace bad, in that much cold.

And, something perhaps trickles that thing dead while you park it a long time, so even with a new battery you might want to put that float charger on it while it sits. You could use a disconnect, but that messes with modern cars computers each time you disconnect. It goes to a default mode for a few miles, and will run shitty for a mile or two.

Whilst we are talking lead...
Lawn tractor 28ah battery a few years old, but working fine until one day ..nothing..not even a solenoid click ?
Battery reads 10.4 volts, but wont take a charge 0.0 amps when connected to pb charger ? ( charger is good)
Any clues , or is this just typical pb death ?

Some chargers will not output into too low a voltage

OK, sorry, to add to the detail...
When connected to the charger (Turnigy Reaktor) , at either 12v (6s pb), or 10v (5s pb), the charger checks ok and attempts to charge for 10 secs or so. But no amps flow and the charger builds the voltage up to 13.8v before shutting off on. “Full charge”.
Also, when doing a sophisticated discharge test proceedure ( 10g wire direct across the terminals ).. nothing happens,..no spark, no smoke, no fun at all !
Battery still reads 10.4 volts and holding !!?
How can it read 10.4 volts but appear to be open circuit. ??

I’d guess one of the internal jumpers or terminals cracked. The crack will pass enough current for your voltmeter to read but not more than that. I’ve had several die like this before.

Yes, i figured something like that..
But even with a cracked (series ?) link, should’nt it read 12v or zero ??
Just ticked off that its $150 for a replacement , just to mow !
Im tempted to cut it open to investigate !

PS..update.. just found that one of my 4s , 16ah Multistar packs will easily start the tractor ( drawing 95A).
Just a shame i cannot leave it on permanently !

Thank you all for all the inputs.
Will try to crank my car this week end and give you an update then.
Right now battery seems pretty good.
Left it rest for 12 hours unplugged and still reading 13.22V (there is hope).
Putting it back onto the maintainer charger until this week-end and we'll see how it goes

Matador

Hillhater said:

OK, sorry, to add to the detail...
When connected to the charger (Turnigy Reaktor) , at either 12v (6s pb), or 10v (5s pb), the charger checks ok and attempts to charge for 10 secs or so. But no amps flow and the charger builds the voltage up to 13.8v before shutting off on. “Full charge”.
Also, when doing a sophisticated discharge test proceedure ( 10g wire direct across the terminals ).. nothing happens,..no spark, no smoke, no fun at all !
Battery still reads 10.4 volts and holding !!?
How can it read 10.4 volts but appear to be open circuit. ??

Click to expand...

Topping off the electrolyte well with distilled water might also help, especially if a well has fluid below the Pb plates.

Leaving the battery on the charger for an extended period of time will help reverse any suphation on the plates. Float at 14v or so. In really cold weather it can take a slightly higher voltage.

charge it to full and keep the negative battery terminal disconnected until you want to use the car.

Self-discharge rate depends on the chemistry, but lead is much worse than any LI that way.

Ideally kept right up at fully charged all the time.

But keeping hooked up to a maintenance charger 24x7 brings its own risks.

So my reco is keep completely isolated, but do top up every few weeks or so.

sure, you can disconnect it, and keep it on the maintainer. But then the car computer resets every time, and it runs shitty for a few miles each drive. Just what you need in really cold weather.

Yeah, this will work, till it leaves you stranded someplace, and its below zero. I get it that a new one is costly, and I get it that the car is not used daily. So its hard to pay the money. But one thing I learned when I skied a lot, was get a new battery every two years or so, at the start of winter. Needing a jump in the ski area parking lot was not that bad, but it was a hassle to have to, when you were tired and hungry, and it was cold as hell.

At the very least, carry jumper cables. One idea here though, lots of people have jumped a car with a 3s lithium pack. that fairly cheap, and you could carry one.

Starting your car just to maintain your battery seems unwise, expecially if the car doesn't get fully warmed up. Modern cars' computers draw enough current to justify a maintainer charger if you aren't using the car daily. If you can't plug in, attach a 'booster' battery that you can easily bring inside to recharge periodically.

dogman dan said:

sure, you can disconnect it, and keep it on the maintainer. But then the car computer resets every time, and it runs shitty for a few miles each drive. Just what you need in really cold weather.

Yeah, this will work, till it leaves you stranded someplace, and its below zero. I get it that a new one is costly, and I get it that the car is not used daily. So its hard to pay the money. But one thing I learned when I skied a lot, was get a new battery every two years or so, at the start of winter. Needing a jump in the ski area parking lot was not that bad, but it was a hassle to have to, when you were tired and hungry, and it was cold as hell.

At the very least, carry jumper cables. One idea here though, lots of people have jumped a car with a 3s lithium pack. that fairly cheap, and you could carry one.

Click to expand...

Right. The thing is, untill next august, I work 800 meters from where I work. So I don't really need my car till then... I plan to buy a new battery then. But untill then, if I get a new batt, it might still discharge until it becomes a new dead batt if I'm not carefull. I think I got lucky this time. Battery still seems I good condition (I yet hat to try it on the car), but I seems to hold a charge, and with the maintained on it, I estimate I injected 65-70 Ah in to recharge this 58 Ah battery. Battery did not even get hot (but did see some hydrogen bubble past 14.0V). Unplugged for few hours it hold at 13.2V. Crude DCIR resistance (ImaxB6) in the order of 20 millioms...

It's just that I would only start it maybe 6-7 times in 3 months and then left it for 2 weeks in the cold... But I think the battery will still be strong enough for another winter if I start every week or so instead of every two weeks. 2008 Impreza seems to pull quite a few milliamps quiescent load...

gogo said:

Starting your car just to maintain your battery seems unwise, expecially if the car doesn't get fully warmed up. Modern cars' computers draw enough current to justify a maintainer charger if you aren't using the car daily. If you can't plug in, attach a 'booster' battery that you can easily bring inside to recharge periodically.

Click to expand...

I always let it warm up till the water temp gauge I installed reaches 180-190°F and the amp meter reads less than +10A (installed a externally shunted ammeter on my car (this one: http://www.partdeal.com/vdo-2-1-16-in-vision-black-150a-ammeter-12v-requires-external-shunt-391-007-190-151.html)). But the 90A alternator only give shallow charge every time... I think the Imax B6 does a better job, especially for the absorption phase of the charge than the alternator.

Two weeks ago or so, when the car did tart on his own. A second or sow after starting, the ammeter read +45A ... So that tells me the battery was discharged a lot as it would take a lot of amps. Usually read +20A at most just after I start. The way I intalled the shunt of the ammeter, I only read net current (what the alternator produces - car load + battery recharging load)

it not a fair comparison between the alternator and the charger, both do the same thing but you cant beat the SLA chemistry and it simply takes many hours to charge it, just running the car a few minutes does nothing for actual float charge and storing energy in the part of the battery that holds the most grunt (the top 90%), you would need to keep it running for half a day to top it off properly.

once you get below 85% SoC you will start seeing low cranking speeds and voltage dips during cranking below 10.5V.

Update: Battery rescue mission is a success:

[youtube]eGWQqUe0IxU[/youtube]

DESCRIPTION OF YOUTUBE VIDEO
Car: 2008 Subary Impreza 2.5i 5Dr
Battery: Exide Global Extreme 35X (100RH, 58 Ah@0.01C discharge, 42Ah@25A discharge, 585CCA, 700CA, Manufacture date Nov 2016)
This test: Dec 25 2019.
Battery had slowly discharged from leaving car for two three weeks. Had'nt used it much in the las three months. Car was dead with battery voltage sitting at 4.85V. Rescued battery by rechaging it with Imax B6AC V2.0 RC charger... injecting 57 Ah into the battery by charging at 4A rate. Then left the battery on maintainer charger for a week (Noco Genious G750).
Battery resting voltage between 13.05 and 13.20 V.

Installed battery on car. Outside temp was -7°C. Cranking car, battery dips from 12.76V (electronics on) to 11.01V lowest during cranking... So for a 3 years old 585 CCA battery... I think this battery rescue mission was a success. Now time will tell in the long run.

Voltage prior to cranking (12.76V, accessories ON).
Lowest voltage during cranking starter (11.01V).
Ammeter reading just after engine ignition: around 12-15 Amps from alternator to battery.
Ammeter reading after car has warmed up for 30 min (motor water temp 185°F) 2-3 amps.
Resting voltage immediatly after engine turned off 13.48V.

I think I got lucky with this battery. Wasn't ruined after all.

Matador

I don't know what's the amperage load of the starter during cranking, but most car battery load tester have a 100A load resistor at 12V... And for a 600 CCA battery, if the voltage doesn't drop below 10.4V, seems like the battery is in good shape. Mine only dropped to 11.01V so I think I'm good to go.

[youtube]tVHlG9qgr8k[/youtube]

Matador

measure for 30 seconds under load if you want to do a fair test.

most starter motors are rated at about 1kW. so roughy 100A. but the first turn will be a basic dead short, so that first second is usually well above the 250A mark and once the engine speeds up the current will drop and depending on the engine be around 70~120A when sustaining cranking.

The transient peaks, hard to capture with cheap tools can go well over 600A.

300A for three seconds should be conservative as a thermal safety guideline.