Battery saga

[DERF]

Over the weekend I arrived on board to find a completely flat bank (port bank) of batteries. I have 6x185ah lead acid. The batteries were partly dry and I am led to believe that this can be caused by excessive overcharging (on board charger not cutting out on full charge) or shorting/damaged internal plates.

Not a problem, started port engine using battery crossover... I then read the manual and it said... WARNING!! starting fully discharged batteries using cross over may cause explosion!! (hydrogen gas). On topping up with water the smell of hydrognated gas on recharging was ominously evident.

Have deicided that it would be wise to change ALL batteries to more robust GEL/AGM type.

Am trying to get more information on the differences between GEL batteries, the AGM (Absorbed Glass Mat) and regular Lead acid batteries.

As luck would have it there was (IMO) an excellent article in this months MBM on this very subject, but on talking to a battery manufacturer today, he basically said there was little difference between the performance of the different types Gel and AGM will last twice as long but cost twice as much.

Is he right?

There must be some learned forumites on here who can give me some guidance on this subject?

 

[jfm]

Derf there is a massive battery techy write up here. Looks good, though I have not had time to read it yet.

http://www.victronenergy.com/upload/documents/ElectricityonBoard_rev8_july2004.pdf

There's also a good write up in the Mastervolt brochure

I changed all our batteries 2 weeks ago. They were the original Fairline wet batteries, Exide EP9. I was a bit dissappointed that they were knackered after 2 years but I might be partly to blame for not keeping them topped up (access is awkward...). I bit the bullet and got 6x220Ah gel batteries, €1800 eek, but they do seem quite fab compared with the old sick ones.

 

[tcm]

i think the ever-increasing use of numerous low voltage lights gives newer boats a more significant battery bashing praps?

 

[DERF]

Thanx jfm. Have sent you a PM

 

[nedmin]

if there going to blow in doesnt matter whether there gel or ordinary lead acid they still will.but VERY unlikely.there is more chance of the hydrogen getting away on ordinary lead acid,as they are open to atmosphere. not good practice to put flat batteries across charged as the current can be tremendous.

 

[mjf]

I had the same issue when my boat was 2!

The starting bank was ok buts the domestics sick.

Princess fit the same units whatever the application - so my domestics were actually designed to be used as high load starting units.


These have now been changed to deep cycle domestic use jobs. Only been in a year but I think they are better IMO.

 

[DAKA]

Never used AGM but I noticed 30 % of the battery tips are made up of these odd shaped batteries.
Considering these are so NEW OUT why are there so many dumped already ?
Check out the dump in your marina and see for yourself !

I have noticed loads at 3 different sites.

Mine came with Gel batteries but if I was buying new ones I would fit standard ones and add EDTA+, this is a heavy metal additive that recycles the sulphate's and keeps the lead clean.

I kept my last boat batteries for 6 years and they were not new when I bought the boat !

I will look for the link and post but it is not expensive and it does work even on old batteries, in fact if you want to be green just help yourself to a set of dumped batteries and add this EDTA+, within a week or two they will be as good as new !

http://www.pure.gg/?merchantPageID=7&op=merchantPage-merchantPageDisplay

 

[jfm]

Yup, agree. Ours spends months per year cumulatively with 40A being taken off the domestic batteries, and 40A being pushed in by the battery charger. I guess ultimately they just wore out, especially as I didn't top them up enough (awkward access) and then found the plates a lot uncovered by acid, ahem

 

[DERF]

Thanx Daka, very interesting.

 

[DERF]

jfm,

I've just spoken to the techie at Fairline and he inforned me that there is no problem fitting GEL batteries to the boat PROVIDED the Mastervolt has been switched to the GEL battery setting.

I assume you have done this on your recent installation?

 

[tcm]

oh, i'm almost certain he has done so. he's very very particular about all aspects of batteries and battery maintenance.

 

[DERF]

Well the Mastervolt is easier to get to than the batts so I hope so, coz if he hasn't, the Mastervolt will "cook" his new batteries in less than 2 weeks..allegedly!

I rekon he'd beter go back and check.

 

[tcm]

Hm. Well, he is also expert at the Argh Expensive aspects of boating too, so not to worry either way i suppose...

 

[mjf]

EDTA+

Na, just flog him a heap of this EDTA+ stuff and he will thank you all the way to La Bank.


BTW Where do you buy EDTA+?

 

[jfm]

Happy to be corrected but I think that's wrong Derf.

Mastervolt chargers are shipped wit the dipswitches all off. That gives a 26.5v trickle/float charge.

Some gel batteries work better with an increased trickle charge, and altering one of the dipswitches increases the trickle charge (or "float") voltage to 27.6v (0.55v per 12v). But that is only some gel batteries, not all of them. For example Mastervolt's own gel batteries require 26.5 not 27.6

My new batteries dont have data sheets with them (!) so I'm leaving the dipswitches as set by the factory, 26.5v. If I cannot charge them well I'll zap it up to 27.6v. But no need to do that now.

I think the fairline guy got it worng - the risk of killing the batteries occurs if you select 27.6v on the charger when you have ordinary wet batteries, or gel battteries of the type that prefer 26.5v. If you leave the charge at 26.5v (as supplied by Fairline with wet batteries) you can't fry the gel batteries, rather you might just suffer slow charging of them

I'm not expert on this, just going by the mastervolt manuals http://www.mastervolt.nl/downloads/Chargers.pdf , happy to be corrected.