New battery charge Question

[FNQCairns]

After 15h on the 8amp charger I let the battery sit for the last 24h and now have 12.2V on the garmin GPS and much the same on the analogue multimeter (it's hard to tell exactly).

So thats around 60% full brand new battery do I need a new charger or in the real world is this what I can expect and should live just live with it?

I am starting to understand why I more often opted for a bigger battery than I thought I would needed, but didn't think I should have near doubled the capacity each time

cheers fnq

[station-rat]

Go any buy a hydrometer---$5.00 Then charge it until the hydrometer say it is at 100%

[driveon]

Hi FNQCairns, put your battery back on the charger for a few hour ( or more ), then before you turn the charger off or disconnect the battery, see what the voltage is at the battery terminals.

If your charger is a single stage type and working properly and it sounds like it could be the problem, not the battery, the volts at the battery should be 13.8 or higher then this would indicate that the battery is not holding a charge but if the voltage at the battery is less than 13.8 then there is a good chance your charger is not working properly.

Cheers

[Fed]

You could fit the battery into your car and go for a nice relaxing drive.

Just out of interest below is the specs for my car alternator. (Falcon)

Make- Mitsubishi
Rated output- 110 Amps
Regulator- Integral
Regulated Voltage- 14.1--14.7 Volts at 2500-3000 RPM and 5 amps output.

I'm taking that to mean the alternator can push out 110 Amps and not the 5 Amps mentioned, this would make sense because a normal running drain on a car battery would be well in excess of 5 Amps and if the charging rate was limited to just 5 Amps then all our car batteries would be slowly running down.

I'm thinking once you get it charged right up then your little charger will be OK to keep it topped up.

[driveon]

Hi Fed, thats not a bad idea about trying some other means to charge the battery but the 8 amp charger is not small. It’s suitable for charging up to a 200 A/H battery and this is why I suspect the charger as the problem.

Cheers

[FNQCairns]

Thanks fella's for hanging with this, in the last 5 days the battery has been on the charger for 30+h, I took your advice driveon and connected it back up again before 10am to do the test then read Feds reply so have kept charging and it might be working I have 13.9-14V while charging when I checked just then and the 100% LED is starting to dim the 75% is completly out now so possibly this battery just needs to be charged a loooong time to get up there where it should be. Will keep going to see if I can get the LED to go out then let is sit for 24h again and take a V reading.

Been chasing up the specs on my charger and cannot find any but did find some that are almost the same unit and they seem to state around a 4.4 Amp constant rate when in the 8 amp mode so that could be part of the reason?

If I do get it to charge to 80%+ now and when it gets back to 12.2 after use each time is it OK to re-charge for such a long time, possibly like over 30h straight??

Will be getting a hydrometer also very soon s-r and nail that part, Whitworths has them on a good special ATM.

thanks fnq

PS just checked again while charging and the charger voltage is starting to increase now near 14.2-.3 .

Black magic happening

[driveon]

If I do get it to charge to 80%+ now and when it gets back to 12.2 after use each time is it OK to re-charge for such a long time, possibly like over 30h straight??

Hi again FNQ, if your charger is a single stage type then you will have to keep an eye on it while it charges and as soon as the battery is fully charged, disconnect it.

If your charger is a multi stage charger then you can just leave your battery connected all the time the battery is not in use.

Cheers.

[oldboot]

OK FNQ...... we are starting to get well away from generalisations...... to make any further sensible comment we need to know some secifics.

firstly
tell us about this battery.
what specific type is it.

what is the aproximate amp/hour rating.

this charger....what sort of chargere is it.
what is its maximum continuous charge current.


if it's a common or garden charger, what is the open circuit terminal voltage.

Personlay I think you are getting more worried than you need to be.

Is the charger capable of bringing the battery up to the point of gassing on all cells wthin 12 to 24 hours.

Unless the charger is a modern and decent multi stage charger with a float charge function...or simply a charger with a terminal voltage of 13.2 to 13.9 volts it isn't a good idea to leave the battery on charge for long periods.

If you are trying to read these voltage off a relativly cheap analogue mulitmeter....you are kidding yourself.....get out a buy even a digital meter, half decent ones are cheap as chips thes days.

the voltage function on your in boat electronics may be giving you an inaccurate measurement........it may be giving you an accurate measurement inside the unit but there may be errors due to length of cable.

Do Not expect to get 100% capacity out of your battery......remember what I said about a battery not being a precision device.

make some reasonably accurate measurements at the batterey terminals with a meter that CAN give you an accurate reading.

It sounds to me like the battery IS charghing to what is reasonable, and I think you are getting a bit carried away with concern.

Yes I do think you may be able to do better buy getting a decent high capacity multistage charger...... but don't lose sleep over it.


OH.... BTW..... how many charge cycles has this battery been thru......I have seen it many times where new batteries dont settle till they have had a couple of cycles after storage.........again this may be another minor issue.

here's a couple of brpoad brush concepts

If the battery is a standard car battery size & shape thing (40 to 55 amp hour), an 8 amp charger should charge it from a low state of charge to a reasonable state of charge over the period of a day 12 hours, should be well and truly enough
If the battery is truck battery proportions....90 to 120 amp hour, the same charger should do it in 24 hours, no problems.

If it is a common domestic type car charger that puts out 4 to 5 amps ringing wett. double that.

Fundamentlay lead acid batteries arent a high performance product......if you expect to get more than.... um......basic performance.....you need to be speding decent money on the gear you use to look after it and be able to continuoulsy supervise the battery and take accurate measurements.

cheers

[FNQCairns]

Gee oldboot you are testing me here going to fail on a few counts though! battery is a generic brand 600cca (forget amp hour now) flooded lead acid, not low maintenance, n70 typical 4wd/light truck battery.

Brand new never used, unitl monday when they load tested it for 3-5min wound up to 14.7V.

Charger is a manual type Arlec 8 6/12V, 2/8 amp, cannot find it's specs seems discontinued, other like chargers seem to spec around 4.4 amp constant on their 8amp chargers. Open circuit V - I have no idea what or how! it was a good (in price anyway) domestic charger when purchsed.

The multimeter cost me $100 10 or so years ago, dunno the true quality though, it's another Arlec.

I have near 0 V drop over the boat power circuit and both the Garmin and Furuno give near nil variance same as the multimeter when compared to them I am confident to with most readings over the 3 units but do have a little trouble with the analogue getting it within a volt.

No not looking for 100% out of the battery would like to see 80%+ change after 24h off the charger seems I am getting not much better than 50% ATM.

Lead acid so far has been the best bang for my buck over time will stick with them until some technology with a decent warrenty to back up their claims and my time comes along, will stick with the charger also unless I can prove it faulty, suspecting this is a borderline quality battery and like you say it has not been cycled yet, so far my other slightly bigger batterys in capacity that have only ever known this charger and the boat/4wd are 4 and 2yo and they charge higher it seems than this new battery but this time around the new one has been hogging the charger a fair bit so cannot say for sure.

Will keep charging this battery overnight, the charger is getting warm now...unless I am gassing it for too long overall, what is too long trying to reach a fair level re-charge.

Yeah I could be getting too conserned, I am less so now than earlier, although it would be nice to find out what is not quite right or is this normal of sales speak and marketing and I should I expect it as typical?

Regardless an interesting journey so far, the bloody volts have dropped at the charger again back to 14

cheers fnq

[driveon]

Regardless an interesting journey so far, the bloody volts have dropped at the charger again back to 14

cheers fnq

FNQ, 14v is fine.

As long as it stays over 13.7, you will be charging the battery if the battery is OK and it sounds like it is, it just needs a good charge.

You will still probably get some gassing while charging, don’t worry about it, you can always top up with water after you have finished charging.

Cheers

[oldboot]

Ok
this sounds like the old "Charger 8" if you've had it for some time.
it will be a typical domestic automotive charger & should have a charging voltage of arround 14 to 15 volts..... ....you say it has a string of LED's on it....... it might be a bit more recent.

either way these things are pretty rude.....they will probly be no regulation of any sort in there, just a tranny and a rectifier...... so you cant depend on the voltage being all that stable.


check that the wires where they connect to the clips are making good connection.
these units are better with some better clips too.

Most certainly not a good idea to leave a battery on such a charger long term.

At the moment your best investment would be a decent multi stage charger of at least 10 amps capacity.

Multimeters have plumeted in price and improved in quality in the past few years.
I just baught the fatherinlaw an new meter.... cost me a bit over 20 bucks and wasnt the cheapest I could get bay far......it had better features and accuracy than the AWA ( chung instruments ) unit he was issued with on the ship.

Stick with lead common lead acid...... yeh I recon so.

It is possible that your charger is struggling to deliver sufficient current to make a quick job of it.

check the open circuit terminal voltage of the charger.
then check the battery terminal voltage with the charger connected.
If the charger is pushing 15 volts or so open circuit and only 13 or so on the battery, it is still trying but not got the job done.
Sounds like the battery would be about 70...80 amp hour.
If the charger is only delivering 4 amps maximum charge ( it would have to be better than that) it is going to struggle charging that battery in under two days.
It may even struggle to get a full charge at all......not good.
Even when " fully charged" a battery of that size will still be sucking about 1.5 to 2 amps out of a standard auto charger and just disapating it in heat and bubbles.

Most will argue that you want to get a battery up to charge quickly rather than slowly stewing it.....and then switch to a float charge.
It seems to be the neither here not there charge rate that is looked down on particularly by those who are strongly out against sulphation.

One of the most important things I recon on a battery charger is an ammeter....it shows you whats going on.

yep.... a new charger I think.

cheers

[FNQCairns]

Hi Driveon more shopping! I need water too!! and a hydrometer, new multimeter and possibly a U beaut charger...crikey!

Thanks Oldboot, if open circuit means leaving the charger on then reading the V from the dangling clips I got 11V, tried twice. What does that say? I also checked V just before the clips and there is no drop, interestingly if I switch it to the 2 amp trickle the LEDs tell me by not lighting up at all that it doesn't need it?

What brand was the multimeter you purchased? would be nice to have a digital version that was acurate.

There is an Ac delco 4 stage 15amp charger in the supercheap catalogue for $199 sounds like a deal? anyone? Doesn't seem to have an amp meter but.

Thanks fnq

[driveon]

Hi FNQ, personally, I wouldn’t touch Arlec with a barge pole.

You only need a 4 amp charger but if you want to go bigger it won’t hurt anything other than your pocket.

BTW most battery manufacturers recommend a low charge current rate as being the best way to charge their batteries.

Try to get either a 2 stage or a 3 stage charger so that you can just leave the battery connected to the charger all the time without having to keep checking the state of the battery.

Cheers

[TheRealAndy]

Measuring the output of the arlec with you multimeter will not help a single bit. The output of the arlec charger will be rectified AC, which probaby means nothing to most, but more or less will give you a lower reading. I will not go into detail here (unless requested), but suffice to say the charger output means nothing.

If you can afford to buy the AC delco charger, then do it. Hopefully it will have a light on it to say its in float mode, if it does not then forget it and buy something that does. Even with a 15A charger expect to wait 24hours or more for the battery to fully charge.

BTW: Hydrometer is the only way to accuratley mesure battery charge, but I reckon its too much screwing around. If you want a hydrometer reading then take it to a battery shop!

[oldboot]

Sorry but here we go again.

drive on
show me where a manufacturer of car batteries recomends a low charge rate.

It simply does not reflect reality..... no car or truck charges at a slow rate.
most cars have at least a 40 amp alternator 90 amp isnt unreasonable in a truck or 4WD.

a 4 amp battery charger will take for ever to charge a truck sized battery.
4 amps into 80 amp hours...... thats 20 hours at least... acount for charge tapering and losses it will probly end up taking at least 48 hours to come up to charge properly.

At least 10 amps, 15 or 20 would not be unreasonable to charge any car sized or bigger lead acid battery.

Thanks andy I forgot about the lack of filtering and the error measuring these crude chargers..... dead right it will be quite inaccutate.

check out the marine shops like bias boating & such.
they have some decent chargers too.

I think bias stock the Min Kota charger ( which is quite reasonable in both function & price) and a couple of otheres thet look suspiciously like the ones jaycar import.
The AC delco sounds a reasonable thing...... It sounds a bit dear to me.... but I'm not used to paying retail .

An ammeter is less important on a proper multistage charger, because it should know what its doing.... where as otheres you need to keep an eye on them.

I have an old arlec "charger 4" which I've had for over 20 years it will push 5 amps short term......It works & it does a job. but it is a crude charger and it has to be watched like a hawk... I have several other chargers I'm much happier with.

the range of digital multi meters from jaycar are quite reasonable and even the realy cheep ones in their range will do the sort of job you are looking for.

I have an older up market model from jaycar that I have had for ages as a workshop meter......Hey its as good as the fluke I carry in the field, has more features and was less than half the price...... but customers like to see a fluke.

cheers
They also have a very good little book on how to use a multi meter.....very worthwhile for the average bloke.