Swift Distinction 686 (2016) battery problem

Motorhome batteries are usually fitted inside and are sealed type but within a battery box with a vent line to the outside for emergency. It would be very bad practice to fit a flooded cell battery in this situation because the battery box is not an air tight container and flooded cells if charged properly will “gas” and give off Hydrogen.

I am not familiar with the Swift but a flooded battery would be OK if in an outside locker (like a caravan) or contained within a genuinely airtight box with ventilation to the outside.

Note to self - check type of battery.

Our friends are going to take it up with the dealers when they get back this week - suggesting that anyone else buying a motorhome with a battery which requires top up is warned on purchase.

The Swift battery locker is like a caravan locker in that it opens to the outside, but even so the smell inside the motorhome was enough to alert them to the battery problem.  Apparently the battery was red hot to touch - and was so was the battery box!  Luckily they were in at the time.

I've since spoken to other friends in Spain, who have a motorhome, where the same type of battery was apparently fitted under the driver's seat in a 'sealed' compartment.  This too overheated and resulted in the motorhome going up in flames and being written off.

I would say that the vast majority of Motorhomes have "Traditional " lead acid batteries.  Others may have gel batteries, but these tend to have been specified for a use and have dedicated gel chargers.

I would suggest the hot battery is suffering from overcharging either via EHU or solar panels, either of which have gone over voltage.

The problem maybe an used battery (I use the term advisedly as a new battery that has been run down to anything below 10v in its life over a short period will have suffered internal damage, as well as any new battery badly handled to cause internal damage.  Usually dropped because the weight is unexpected, and slips from the users grasp)

Once damaged, overcharging causes the acid to overheat, boil. Lose water, Acid mix becomes stronger, takes less time to boil next time, until meltdown.  Batteries going this way can be heard boiling, and emit sulphuric acid fumes. Hence bad eggs smell.

while all this happening, the normal voltages are all over the place, and the charger will not know when to reduce the charging rate. This depends on how sophisticated the charging system is. Worst case , is a low voltage seen by the charger, because the cells are dying, so the charger ups the charge rate to compensate.

so check the charger, or have it checked, keep an eye on the battery until you are happy things are normal (ish).

rgds

Lead acid batteries are filled with sulphuric acid. When the battery is charged, it gives of hydrogen gas. This is why batteries are topped up with distilled water (H2O) Hydrogen gas is extremely explosive and is why it should be ventilated to the outside air. Light a small amount and it pop’s. Increase that amount and it goes bang! Hence why airship are no longer filled with the stuff. 🙂

If by “traditional” you mean a flooded wet cell battery with the ability to top-up I would be very surprised to see these. Even cars mainly have low maintenance batteries. The leisure battery could be gel but is more likely to be wet with special design which prevents venting except for an emergency relief valve. They are fairly tolerant of chargers and the setting would be the same as for a gel battery, 14.4 volts maximum. The old lead acid batteries would require boost charging at 14.7 volts which produces some Hydrogen gassing so must be in a sealed locker with external vent.

Whichever battery is used a charger or battery fault can create the condition described so even a sealed, maintenance free, battery needs to be in a battery box.