Batteries Boiling away Electrode

[Newbroom]

Batteries Boiling away electrolyte

Not had a chance to investigate properly but my Broom has 4 x 6 volt batteries wired in parallel and series to give increased amperage at 12 volts supply. If left on charge the batteries will boil away in a few days. This has got steadily worse through the season. The rather vague analog battery monitor on the power panel never shows more than 13 volts. The charger is original equipment fitted by Broom in 2003 but has no markings on the outside of the case.
My first reaction was that one of the batteries was beginning to fail confusing the charger into constantly charging rather than floating the batteries but the batteries seem to last well overnight using lights refrigerator etc.
I was thinking of testing the batteries by using a drop tester but have not always had satisfactory results as to a batteries condition by testing like this.
I haven't yet managed to find the output connections to the batteries from the charger but just getting a reading from them what voltage should i expect and will that prove that the charger is not over charging.
The charger charges all the batteries domestics and start batteries only the domestics are affected.
Besides testing the batteries as mentioned what next??
Dave

 

[Vitesse]

Hi,

If the electrolyte (assuming you mean this not electrode as per title?) is boiling away that suggests overcharging. A voltmeter across the batteries would show this - I assume you can hear them fizzing and there should be a smell. I reckon you've already cleaned all the connections and checked for any being loose. Perhaps disconnect them and test individually? Since only the domestic side is being affected that does suggest an issue there. Can you swap over the charging connections from the domestic and start batteries?

Since I only have experience with single battery setups I may be talking bobbins, mind!

 

[Newbroom]

Hi,

If the electrolyte (assuming you mean this not electrode as per title?) is boiling away that suggests overcharging. A voltmeter across the batteries would show this - I assume you can hear them fizzing and there should be a smell. I reckon you've already cleaned all the connections and checked for any being loose. Perhaps disconnect them and test individually? Since only the domestic side is being affected that does suggest an issue there. Can you swap over the charging connections from the domestic and start batteries?

!

Yes you right I did mean the electrolyte , really shouldn't post after a couple glasses of red.
I first found the problem from the smell I have checked all the connections but I think I need to charge the batteries then disconnect them before testing.
If all seems OK with the batteries that is a good idea re changing the charging leads over.
Dave

 

[Teddy]

Hi,

I have a 39KL (2005) and have replaced the domestics (4 x Trojans) twice since purhasing in 2010. The longest I got from a set was 6 years. The obvious signs were heavy use of water, distorted plates and of coarse, reduced capacity.
The Broom fitted charger is rated at 3 x 50A, but I have only ever seen a maximum of 45A on initial charge. This reduces as the voltage increases to about 14.5V, when the unit drops into maintenance mode, showing about 3A initially and about 13.3V. After several hours, the charge rate will fall to about 0.4A at 13.3V, IF the batteries are in good condition.

To monitor this, I have added a small digital voltmeter to the electrics panel ( easily accessed by removing the panel in the locker) and also fitting a Nasa Battery Monitor to the domestics in the panel under the side entrance, assuming your version has one. The battery monitor is wired as to show amps into the battery when being charged from the fitted charger, BUT not from the engines as this would potentially overload the shunt.

I suggest that you somehow check that the current into the battery is low when fully charged. It is the excessive current that will boil your batteries. The battery charger lead is clearly marked (by Broom) in the battery space and you could insert an ammeter temporarily into circuit to check. Once the batteries have been run dry , they will be damaged. Trojan batteries are high users of water as they get older.

Good luck.

 

[JerryC]

Agree with post no 2 ... FWIW, I would do this: switch battery charger off, totally disconnect all the batts from each other while waiting an hour for the chemistry to settle down. Measure and record the voltage across each battery. Measure and record the specific gravities of all the individual cells. Get a torch and record all the acid levels in each cell before topping up with distilled water. You should be looking out for a duff cell in which case that particular battery is garbage.
Don't reconnect charger for two or three weeks then repeat same checks. If all ok, pull charger to bits, repair or replace.