Gel Battery Chargers

I suspect he had no idea.

If a lead acid battery is left for a long time the plates inside the battery sulphate, and to a larg degree this process is not reversable

http://www.batterystuff.com/tutorial_battery.html

http://www.batterystuff.com/tutorial_chargers.html

a battery maintainer is just that it maitains the state of charge, it is not a charger, and does not have the output to charge a flat battery.

You need to go to spares shop ad get a gel/lead acid charger

Check this out

http://www.batterystuff.com/tutorial_battery.html#3

basically it says you need to take more time to charge your Gel cell battery, but says nothing about degrading it's life

Why am I the only one to give you a GA up to now?????

I am amazed, does nobody else understand a few simple but true facts about lead acid batteries?????

(Which probably explains why so many get replaced each and every year!!)

You are not the only one, Andy, but the GA's seem to pile up NOT answering THE QUESTION(s). This info as info though is worth a good answer.

I was the first to give you an GA and your answer had been there sometime already.....

if you look at the first lot of links i supplied you will find the link you put on there

your not looking at others answers

I visited the websites you referred me to, but none explained whats the difference among a regular lead/acid and a gel charger. If I did not get it wrong the main conclusion seems to be that Gel batts tolerate less Voltage amplitude L/A´s. This would mean gel batt chargers additionally seem to have a over-current filter / switch. Am I correct? Is it only that?

Guest/OP: You are on the right track!

Unfortunately, much of the post went on a tangent into lead/acid batteries and not what you cited.

It is possible that you killed the gel cell with the charger that you used; but maybe not (i.e. don't feel bad). I'm not an expert but from my experience with them: Allowing them to remain idle for extended periods, they just poop out and will not hold a charge.

You didn't say how old the battery is (should have a date code).

In any event, use the recommended charger, or equivalent charger for the replacement (your destiny).

Good luck!

Hi Bill, you got my idea, and as you stress I learned a lot about batteries, but still don´t know why not to use a "regular" batt charger for a gel battery!!!

Bill I do agree with most of what you´ve said in this post. Like "birds of one feather", being memeber of the good responders club, etc. When I joined this forum in 2007 rules of play were very different and participants shared their knowledge defying each other with witty replies. To me a wrong, but witty reply had more walue than an academic explanation that was copied and pasted from Wikipedia.... inquisition came, a rating system showed up, participants started censoring each other... this got boring, and I decided to look for some fresh air somewhere else; so I was off for about 18 months.

I agree with your sentiment on the GA's Bill ML, it does seem odd that the same posters/repliers are always adding to their GA's. every one else just gets swamped. We should rather cut the GA and only concentrate on off topics, now that abounds. Having said that, i DID vote yours a GA. My own post was "hijacked" by another poster (tongue in cheek). CWARNER7 11, if i have the name right have got the same idea as i have, at least my reply would only echo his, thus, GA for him too.

When a battery discharges the lead in chemical reaction changes to lead sulfate. If the battery is left discharged for a long period the lead sulfate becomes hard. In its harden state it has a higher resistance. Most charging systems are voltage regulated. They will sense this harden state as a fully charged battery and drop the charging current.

The battery maintainer would have sensed as fully charged and also dropped the charging current. May have only been putting out .5 amps maybe less. At .5 amp may have not been enough to reverse the chemical reaction at the high resistance. The 5 amp charger did.

In the past have worked on getting sulfated industrial batteries back to working conditions if possible. The charger we use had controls for voltage and current. Have seen some that I had to push 10 volts or more above its finished voltage in order to get any current to move. Some you can save some you can't.

Thank you folks for the explanation about batteries. Remember you still owe me an explanation about battery chargers: why is the Lead acid NOT GOOD for gel batts, but a Gel charger can be used on BOTH types ???? ...had forgotten my password, so I initially posted as "Guest"

There are many good answers and many good links.

Summarized, I want to explain that your battery suffered more from being DISCHARGED.

However, when you charge too long, with too much current, a gel battery can have the electrolyte composition changed.

Higher acid concentration.

When the vapors can escape. If that battery is a sealed one and it has no bubbles that point to overpressure you might have not killed it by charging.

You speak of charging "for a couple of hours" with 5 amps.

This tells me that probably your battery has not been overcharged.

Sometimes batteries recover, with charging a few times again. It all depends on the condition of the plates inside. It is good that she takes some charge. Measure the voltage after charging and when between 12- 14,4 Volts, you may be lucky.

Yes yes yes- most facts have been mentioned such as sla?gell cell being floated at 13.8v & wet lead acid at 14.2v- as also said the worst thing anyone can do is discharge a battery below a shallow curve & leave it!- as said sulphation occurs- most people throw the poor!offending thing out!-BUT!!!!- there is a process whereby further life CAN be obtained- I have made my own rejuvenator which works on sla & wet cells- it sends 300v pulses to the terminals at about 3kHz- powered by the batt if volts above 5v- otherwise add donor batt- very low current drain- as an example- a large sla in a jump starter(you know- the thing in a plastic case) was perfectly good- the owner let stand for about a year or more out in the open- went to use- result batt dead as dodo!. Came to me!- batt volts= 0- ran pulse rejuv for 2 days- now 6v- put charge for 1 day= 11v- ra pr for another day- put on charge for 2 days= perfect!- sitting at 13v!. Much better not to have to do this!- Educate owners!. Cheers.

I wonder if I can clear up a few misunderstandings here for nominally 12 volt car/Motor/Leisure/SLA/Motorcycle batteries.

1) Charging a battery above 13.2 volts will give it more capacity, but also results in gassing. Stopping the charge at around 13.2 will give about a 70% capacity and no gassing, even 13.4 should not be a problem.

2) On all except leisure type, leaving them for any length of time at a voltage of 12.6 or less starts sulfating. Even leisure are better recharged than leaving empty though in the long run. leaving a normal battery under 12.6 volts for a month or more will seriously reduce its life span.

3) The charge and the trickle charge (which I personally never use) must be calculated for the size and the type of battery in use. See manufacturers data for this. For example, if the trickle charge results in the battery's voltage increasing, it is set too high. If it results in the battery voltage decreasing, it is set too low.

I personally prefer to set upper and lower limits to keep the battery "cycling" between 12.6 and 13.2 volts, I personally feel that this is like training your muscles so to say. My caravan battery is getting old and still works fine under such a regime.

4)If you don't charge above 13.2 volts and you charge at C/10 or lower (I charge at C/20), you also do not need to worry about temperature compensation, which makes the charger design even simpler.....

5) Gassing must always be taken into account safety wise except with SLA batteries, though as I never go above 13.2 volts, gassing never happens with my battery, so it only needs topping up about once every 4 years or so.....a warmer environment will of course increase this.....

Following manufacturer's tips is always a must, but use lower terminal voltages if you want a long life.....

Cheap unregulated chargers ruin more batteries per year than any other single fact.....even some of the regulated ones are set too high voltage wise for good safety. Check it out on charge with a good multimeter.

Gel batteries ARE lead-acid batteries, but they have been chemically treated so the electrolyte doesn't spill as easily(gel), then they are SEALED, so that when you dump the bike in a sandy curve, the acid won't spill out and ruin your leathers. Because they are sealed, the gas emitted from the plates has nowhere to go during charge. Enter the gel battery charger, which sequences the charge-cycle so the gas doesn't build up and warp the plates, and create a high-resistance barrier betwixt the plates and the electrolyte. Using a standard car battery charger on a sealed-gel battery will not only ruin it, I have seen them explode due to the gas build-up. If you are storing a gel battery, completely charge it with a proper sealed battery charger, then disconnect it completely and isolate the case from ground. It should hold the charge for several months, but recharge after that time. The same applies for AGM batteries that are also sealed for safety.

Errm- the gas is not emitted from the plates but from the electrolyte- which electrically/chemically forms a path between- whether gel or wet lead acid electrolyte. Now how gas can warp plates I don't know-The plates in a cell are all subject to same pressure- what really happens is that excess voltage/current between plates(thru electrolyte) whether charging or discharging is to blame. Your other facts are correct generally.

If the electrolyte gets too low, all the starting current for a car for example is running through a smaller plate area, though I have no facts to support this, I was told that this can cause plates to bend over a period of many starts and or long starts............

Andy- if electrolyte gets too low will not be enough current to start car(imagine bare plates- no conn as connector ie electrolyte is low)- with correct level plates are bent by overheat which occurs by excessive current flow whether discharge as in starting or by excessive overcharge voltage/current- either way batt life is reduced. Never crank engine more than 5 secs at a time- never charge batt with ext charger up to more than 15.5v(briefly- to equalize strata). Not to mention other things like o/c conn to 1 or more cells- or swollen batt case- either way batt is finished- do the right thing & recycle batt- will get back as new 1 made in China!!!.(No matter what brand /sticker is displayed!!).

What I said was when only say 50% of the plate is covered, not an empty cell....

Lead acid batteries have a very low internal impedance/resistance (very low, thats why a simple car battery can supply 400 or more amps when starting an engine for example!)

This means that the current per square inch is doubled (half empty cell), if only 25% is covered, it will be even worse.....

I can well believe that under such circumstances that things get hot!!! especially when cranking say a diesel for a long time on a cold morning....

(you are talking to someone who has done the full RN battery course!! Not a raw beginner!!)

Andy,Andy,Andy!. May I say that we(all of us) are only as good as our present(NOW!!!) doings- no matter WHAT we/you/I may have done/learnt in the past(gone forever!) Sob!. Now I may be doing you an injustice-for example if you have a photographic memory(if you have- my kindest commiserations- those who have can never forget the slightest details- it drives em MAD in later life). Yes I know new batts have very low impedance- that is why I made impedance tester that measures in milli-Ohms!-BUT-Far simpler to use volt meter across batt posts under load(eg cranking). Lets face it- all this sorta stuff is just to say to OP etc "Hey!-I'M alive!- I've done this sorta stuff!". Such is the tragedy of human existence.

I am not quite sure what you wanted to say, sorry (me->), but its ALWAYS very nice to chat with you no matter what the subject, weather/whether or not!

I don't have a photographic memory, but I have a good memory.....I also enjoyed my RN training, all of it.....even the battery part!! Some RN lead acid batteries are/were 50 or more years old.....just well looked after.....whether or not they are still in use on conventional boats (and Nukes), I cannot say anymore.....perhaps someone with more modern info can butt in.....

As we don't know the level of competence of the OP, its always difficult to know at what level to aim for.....I always assume that as he is asking us, his knowledge level is not very high.....otherwise why would he ask in the first place?

Also, I try and include the detail, that should help him and anyone else interested.....I personally always like a complete info, not half......

I hope this answers you in some (funny?) way...... apologies if not!!

Have a great day anyway....

I checked the specs of my bike´s battery: surprisingly it only delivers 12V/ 14 Amps/h. According to all the info all of you contributed with, I understand that the main issue with gel batts is to avoid an aggresive charging. Now, what about using my current Black and Decker "maintainer" to keep it loaded? This B&D (model #BBC02) is a high frequency 12V / 1-2 Amp/h charger, that supposedly alternates between charging and maintaining. Does this sound reasonable?

Pay attention to the battery temperature. If the B & D does not cause the temperature of the battery to rise significantly, then it is probably OK. Also, check the "float" voltage, make sure it is not too high.

Have you looked on the manufacturer's web page for the recommended maximum charge rate? This is variable. I would go for a max of C/10 if you find no infos, which would be a max of 1.4 amps....so your charger in the 1 amp mode would be fine, but with 2 amps max would be a bit too much.

What is more important is the maximum output voltage and at what point the charger either shuts off or goes to trickle charge......that can only be ascertained by measuring the voltage of the battery while under charge and see what happens and when.

Its also possible that the trickle charge (if used) may be too high, and may continue to charge the battery further, even though slowly.....

Trickle charge should theoretically at least, just maintain the charge, not increase or decrease it, even slowly. In a practical sense you need some very sophisticated electronics to achieve that (which in my experience, few charger have!). It best if its not intelligent, for the trickle charge to be lower than the battery really needs......eg. the charge drops ever so slowly.

Trickle charge rate is dependant on such things as:- manufacturer, age, type, size, temperature, history to name but a few.......which is why I personally ignore it completely in the chargers I have designed over the last 15 years or so! I do not consider it to be needed as I always put in batteries that can supply 100% of my needs with a max of 70% capacity. Simply put, buy a bigger battery than you need!! An extra 30% does the trick!!

I set the maximum allowed charge voltage (which has a direct correlation with the % of charge in the battery) to a specific level for the application concerned. The charger turns off but monitors the batteries charge. At a specific level of voltage drop, the charger turns back on again. This allows the battery to flex its muscles, remains fit for many years and uses almost no water.

I also never charge to 100% as to get there, some gassing occurs, which implies a similar amount of loss of water.

If you have no voltmeter and no control over the rate of charging, then you need to install a time switch of some type to say remove the charge after a max of say 2-4 hours.....or say set during the winter for 30 minutes charge per week. If using a daily timer, set it to say 5 minutes a day or less.....check voltage to be between 12.6 and 13.2 at all times, this will keep the battery in a good condition.

As I don't know your technical level of expertise, so its difficult to set rules, but what I have used (and still use for certain things!) are old fashioned mains timers (the ones that turn a dial with a tiny synchronous motor) that I have modified simply by attaching the motor supply to the mains at a point AFTER the contacts that open and close.

This allows me to set a length of time up to a max of 23.75 hours (or thereabouts on a daily 24 hour timer) and when it switches off, it also switches itself off. Not all models allow this change, but mainly the very, very cheap ones do......

Its so simple, that many do not fully understand what there is to do.......I have used them for many, many years mainly to do with charging NICAD batteries when the chargers were very simple, or today for power tool chargers that never switch off properly....

Hi Andy, thanks for your interesting comments! As I do not have much faith on the health status of my current batt, I left the B&D charger connected to it for the last 36 hours. The charger has 3 leds: red (no need to explain) yellow and green. It started displaying a blinking yellow (??) but this morning it lit the green one: good news?? for how long?? During this time span I controlled the temperature of the batt and in a few occasions it was slightly warm, the rest of the time: at room temperature. Tomorrow I will measure the V on stand by and while cranking the engine... TO BE CONTINUED....

NO. It must be a smart charger that will completely shut down when the battery is full, and then kick back on when it needs a refresh, otherwise you are going destroy the battery.

There is no much difference between LA and Gel acid batteries and chargers.

Your problem is that you left the battery for very long time discharged.