Cooked 24V Battery pairs? terrible smell and 2 pairs warm / hot

[Strads]

Folks,

 

Its been a while, but tried searching for an answer but couldn't see anything specific.

 

My boat has 24, (2 x 12v) per pair,

I have a victron invertor charge 3000x/70/24 which I believe is working ok.

 

I recently purchased a new pair of starter batteries (leisure type) and also wired these in,

 

That makes 3 pairs of leisure batteries wired in with one pair used to power the starter.

 

I have moved the boat onto a new mooring with mains power, and knowing that the older two pairs were near flat, plugged in,

at the same time the new pair where found to be flat (a surprise as used twice about 6 weeks ago)

 

When I installed the new pair there were no issues and no surprises.

 

On returning to the boat yesterday greeted with terrible smell ( stink bomb type) thought the loo had an issue but that smelt fine

 

Then investigated, having opened engine room hatches when we entered.. to find the older 2 pairs of batterys were warm and the other hot.

The hot pair were sealed type, one was hissing (like a gently heated kettle).

 

Immediately turned of the mains, then disconnected (carefully) all the batteries this led to them cooling and the hissing to stop.

 

Copper pipes around the engine room have taken on a silver hew and 2 very close to the batteries almost look burnt.

 

 

The questions are:

 

Any idea what might have happened?

 

what has caused the pipe "staining".

 

At the weekend I will carefully remove from the position to inspect. ( I need to get rubber gloves eyewear and cat litter in case of leaks )

 

I can then check to see any has spilt/failed and test volts etc.

 

I have no issue changing failed/knackered kit, but any suggestions on what to check are appreciated.

 

Many thanks John

[LEO]

Hi,

 

I had a similar problem - soon all the silver copper will turn black.

 

It's worth buying several large containers of Bicarbonate of Soda, which if mixed with water will neutralise any acid spills.

 

Batteries need renewing - I got £10 per battery (4 of them) off the local scrap merchants (less a £10 environmental charge).

 

Does you charger incorporate a heat sensor switch?.

 

Best of luck.

 

L.

[Phil Ambrose]

Yes there is something going on because of the fact your starter pair are flat, a new pair should have been able to do the 2 starts that you did without batting an eye and should have been back to full SOC in a very short time. I have no knowledge of combi invertor chargers so you will have to wait for the bright guys to get here.

Phil

Edited July 17, 2014 by Phil Ambrose

[The Bagdad Boatman (waits)]

Seperate and check each battery voltage. They have been overcharging. Rotton eggs is explosive hydrogen gas which batteries give of when charging.. Look carefully at your 24 volt layup: Battery one pos to battery 2 neg. battery 2 pos to starter motor or cabin electric. Battery 3 pos to battery 4 neg battery 4 pos to starter motor or cabin supply. Somtimes when a bank of batteries are linked the first bank do all the work. Try to link to the starter motor/ cabin with heavey cable of the same lenght.

[smileypete]

What charge voltage is the Victron set to? For bog standard leisures, 14.4V is usually enough, in high summer a bit less could be preferable, and 14.8V may be waaay too much and contribute to 'thermal runaway'.

 

Also, whenever charging from a high power charge source, it's always good practice to monitor the charge current. It should tail off to a low level, if it remains high there may be a problem somewhere that must be checked out.

 

If the batts are packed in tight together, a loose connection could cause one to go into thermal runaway and then spread heat and set the the other one off too, like a domino effect.

 

For unattended charging something like 10A is much safer, or just enough to cover the idle DC loads.

 

cheers, Pete.

~smpt~

[pearley]

If I know I'm going to be on a shoreline for more than a few days I reset the Victron settings to Battery safe and a lower charge rate.