Is my battery ruined

[AndyLou]

Hi

Just checked my leisure battery and noticed there appeared to be no water in it.

I topped up each cell to just above the plates.

I have 2 questions.

Is that topped up enough or should I fill them?

Is the battery irreparably damaged?

 

Thanks

 

Andy

[Tracker]

Does it still work? What is the voltage both after being charged fully and after being left standing disconnected for a few days?

 

To work a battery needs the right concentration of acid as it's electrolyte not just water so you need to check the specific gravity of the cell contents.

 

I can't remember the values you need but no doubt someone else will!

 

I could be wrong but I seem to recall that when the electroyte evaporates it leaves a stronger solution of acid behind so you might get away with just topping it up with purified water?

 

Just above the plates is fine, any more and you risk leakage when the electrolyte expands.

[Ocsid]

Unless it has evidently cracked and lost the acid then it should only be topped up with pure water.

 

Time will tell if it is ruined, does it fully charge, is that charge worth while and does it hold it?

 

Fully charged is roughly checked by holding 12.7 odd volts 24 hours off fully trying to charge it.

 

Worth while charge is can it store enough of its original capacity to be tolerable living with. Batteries lose "capacity" with age, a process that abuse accelerates. We as owners just need to decide if what it holds is enough not to fork out on a new one.

 

If the voltage dies by even a small amount within say 48 hours with no connection draining it, then it is past its usable life.

[Tracker]

Much depends on how you use it?

 

If you use ehu on sites it is unlikely to be an issue whereas if you camp without ehu any loss of capacity may well be an issue especially in colder climes or for more than one night.

 

Another aspect is the extra load on both the engine alternator and the on board ehu charger and it is cheaper, easier and a whole less inconvenient to fit a new battery and avoid those expensive complications and hope to be safer than sorrier!

[RogerC]

If you topped it up with deionised water there is a remote possibility you might recover it.  However if you merely added water to the battery and not a sulphuric acid/water solution at the correct SG I would think your chances of recovery are minimal to none.  Either way with a dry battery there is the question of why is it dry?  an indication of something wrong with the charging system or simply poor maintenance.  If the later then IMO it's better to bite the bullet and buy a new one.  If the former then a check up will hopefully uncover the reason for a 'dry' battery.

[Tracker]

A battery goes dry for several reasons, assuming the case is intact and not leaking, usually because the electrolyte level has not been checked for years, but sometimes because it is getting too much charge so it overheats and the electrolyte evaporates.

 

Why or from where it gets too much charge is difficult to isolate, maybe the engine alternator or maybe too long on ehu, or maybe a tknackered battery but it is next to impossible to check voltages with an iffy battery so you might have to fit a known good battery to test properly?

[ham]

I had the same problem with one of my 2 leisure batteries one was low on electrolyte the other ok. so, I topped the one up the van was left on hook-up at home and on checking next day all was ok.

However, I stayed on an Aire in North France no hook-up running 2 phone chargers overnight and Tv. Next day we drove for two hours and stopped for a break only to find when we got back in the van it would not start the battery was flat now why. I used a set of jumps leads to connect to the leisure batteries and the van started so we decided we would drive on to Saumur where we stayed on the Aire with hook-up checking the van would start and it did. So, it was time to think no engine management so alternator ok. I have a B2B charger between cab and leisure battery so I disconnected that as my thought was one of the leisure batteries was going down. I left the hook-up connected and this morning started to do some checks again and found the battery I had topped up was very hot to the point you could not touch it. (now I know a bit about Batteries as I used to maintain Batteries in BTs exchanges) on check the levels when the battery had cooled they had dropped so it now sits in the van disconnected awaiting to be dumped

So, if you have topped up a battery always check sometime later after it has been used for a period of time.

Because the battery was going down it was drawing power from the cab battery through the B2B charger and I was lucky the battery did not explode

 

[Cattwg]

I had a similar situation with a car several years ago. The alternator diodes failed and the resulting excess current ‘boiled’ the battery dry. I fixed the fault and topped up the battery as you have done and it was still starting the car six months later when I sold it. Yes you could charge the battery off the ‘van and monitor the voltage as has been suggested. But if you’re not going to be ‘off grid’ somewhere then you’ve nothing to lose by simply waiting to see what happens.

My reply assumes that there is not a fault causing your leisure battery to be overcharged – e.i. the battery was simply allowed to run dry over a period of time.

Cattwg :-D