Mahe 36: Batteries And 12vdc Systems

[lstyles]

Most of the cruisers I know are using unsealed batteries unless they can afford the pricey AGMs. I really cant and the Trojans are so highly thought of in the cruising community. I think if my boat flips I got a lot more to worry about then the electronics!!
Lori

[solarbri]

Originally Posted by lstyles

Most of the cruisers I know are using unsealed batteries unless they can afford the pricey AGMs. I really cant and the Trojans are so highly thought of in the cruising community. I think if my boat flips I got a lot more to worry about then the electronics!!
Lori

You can afford a Mahe 36 but can't afford sealed batteries for it?
What does the boat come stock with?
What does a life lost at sea cost?
Hell, I justified the cost of a sweet Li-Ion powered bicycle headlight ($700) because that is WAY cheaper than a single visit to the emergency room.
Maybe my thought process is all wrong though...

[Southern Star]

Solarbri, most of us have budget limitations and concerns that go beyond ultimate safety. In a catamaran, unlike a monohull, the risk of spilled battery acid is much lower because the boat does not heel. Furthermore, in the extremely unlikely event that the boat capsizes, your electronics, with the exception of units with self-contained batteries, will be of no use anyway.

Furthermore, your EPIRB, hand-held VHF and hand-held chartplotter/GPS units (your required rescue backup) will still be usable if properly stored, regardless of the type of house/starter banks the boat had originally employed. Simply put, your comment 'what does a life at sea cost' is a gross overstatement, all while acknowledging the fact that the water in the overturned cat is eventually going to contain a somewhat toxic mix of diluted diesel fuel, cleaning fluids and yes, diluted battery acid after the capsize. Even without battery acid, the idea is to save your life and get out of the boat through the quickest means possible after a capsize.

Further, all is not quite perfect in the world of sealed, even glass-mat batteries. They are reputedly much more sensitve to overcharging and, to date, seem to have a life-expectancy that is less than top-of -the-line lead acid batteries such as Surrettes/Rolls. I think you will find that a great many cruisers have chosen these as a house bank, even in monohulls where the risk of spillage is greater. They have done so after weighing up the pros and cons, of which initial cost is only one factor.

Brad

[solarbri]

Originally Posted by Southern Star

Solarbri, most of us have budget limitations and concerns that go beyond ultimate safety. In a catamaran, unlike a monohull, the risk of spilled battery acid is much lower because the boat does not heel. Furthermore, in the extremely unlikely event that the boat capsizes, your electronics, with the exception of units with self-contained batteries, will be of no use anyway.

Furthermore, your EPIRB, hand-held VHF and hand-held chartplotter/GPS units (your required rescue backup) will still be usable if properly stored, regardless of the type of house/starter banks the boat had originally employed. Simply put, your comment 'what does a life at sea cost' is a gross overstatement, all while acknowledging the fact that the water in the overturned cat is eventually going to contain a somewhat toxic mix of diluted diesel fuel, cleaning fluids and yes, diluted battery acid after the capsize. Even without battery acid, the idea is to save your life and get out of the boat through the quickest means possible after a capsize.

Further, all is not quite perfect in the world of sealed, even glass-mat batteries. They are reputedly much more sensitve to overcharging and, to date, seem to have a life-expectancy that is less than top-of -the-line lead acid batteries such as Surrettes/Rolls. I think you will find that a great many cruisers have chosen these as a house bank, even in monohulls where the risk of spillage is greater. They have done so after weighing up the pros and cons, of which initial cost is only one factor.

Brad

Brad,
Well said.
Please excuse my ignorance.

[kev&jo]

Hi Lori,

No we don't have a water filling system (but I think this would be a good idea) and space is tight as you can see.

I use a small mirror to keep an eye on the water level.

Kev & Jo

[lstyles]

I am trying to decide whether to go water filling route or water miser cap route. I will be only at the boat intermittently for the first couple of years so I wont be there to be able to monitor the batteries regularly. Has anyone else changed out their batteries and dealt with this?
thanks,
Lori

[jean1146]

I think that my batteries are on there way out,still don't know for sure since they are in such a tight space.I will go with sealed batteries since you almost cannot access the top,it is too tight unless some one has a trick. Every week the house bank is down,the refrigerator is pulling those down to nothing,so either my battery charger has a problem,or I have a dead battery wich is pulling the others down. When we leave the boat it is charging and somewhere down the line the charger shuts off......the breaker is fine so I am puzzled. Any one has any suggestions? Thanks.
JC.

[LarryW]

J C

I had a simular problem with my orginal charger, after the lighting strick. It would charge until float then shut off and only charge again if you shut it off and back on. The charger should float contiously at 13.5, when the battries are chargted. Your battries when full charged should hold your frig for a couple of days, holding 12.00. How long they hold is a function of their condition. But it sounds as if your charger is shot. I hope this helps.

Larry

[IrieCat]

Is there anyway to check the state of the charger? I am in the market for a new set of batteries and want to make sure the charger is in good shape. Thanks.

[jean1146]

Larry. I think it is either my battery charger or the batteries though I disconnected the fridge Sunday and went back on the boat today and found my batteries holding pretty good so I need to check the charger.
JC.

[Scott730]

I'm adding one extra group 31 to the 3 house batteries to go to 420 amphours. We added a freezer so the 3 group 31's were pushed to the limits and had to run the generator about 3 hours per day to charge the batteries and make water (that amounted to about 3/4 gallon of fuel/day, not a big deal, but the noise bothers the wife). Don't think you need 300 amphours more, the extra wieght and lose of storage space off sets the need, IMHO.
Also note that under the bed is a sealed flotation compartment, don't mess with that. I also don't like the idea of lead acid batteries gassing off in a sleeping space. I guess sealed AGM would be best in that environment.

Scott

[Jef & Marin, Netherlands]

Hi all, a very long one:

I have been reading that people are not satisfied with the standard batteries, and want to upgrade in battery capacity and type.
Last year I was also unhappy how long the batteries would last during longer trips, and I was blaming the autopilot. However, last winter I found out what is going on:
I found out that after having the batteries on the charger continuously for 2 months, the batteries were quite empty. The battery indicators showed the batteries to be below 50 % charged. These are the indicators on top of the batteries. Yes, you need a mirror to view this. So what was going on?
I have been studying a bit on the batteries and the charger. Useful link is Welcome to Battery University. This is what I found:
- The batteries are "Freedom Marine Stationary Maintenance Free calcium batteries". These batteries need a higher charging voltage than standard open lead-acid batteries: a charging voltage in the boost phase of 14.8 V. In the float phase they need a voltage of 13.8 V.
- The Tecsup charger which is mounted standard has 4 setttings, a,b,c and d. Look in the manual. C is for standard open lead-acid batteries, this is the factory default setting. This gives a boost voltage of 14.4 V and a float voltage of 13.4 Volts. Fountaine Pajot, when mounting the battery charger, leave it in the factory-default setting.

This means that default:
- When charging with mains, the batteries are charged slower and no fully.
- When the battery is charged without disconnecting for a long time, the float voltage will be 13.4 instead of 13.8 V. This means that the batteries will actually (self)discharge when on the charger!

I have sent the battery manufacturer an email asking for their recommendation. Here is their answer:

"Dear Sir,

Freedom Marine Stationary batteries are lead calcium batteries and should be charged with a higher voltage than normal lead open batteries. Your tecsup charger indicated two possible positions for lead calcium (first position with deep cycle application and last (4th) position with normal use).
We suggest to first try to charge the batteries with the A position (TAKE CARE of electronic equipment as the voltage goes up to 16V / disconnect if needed) and then put the charger in D position. If you frequently deep discharge the batteries then we recommend to frequently charge with the deep cycle possition.

Keeping batteries in discharged position do harm batteries. Discharged batteries with negative temperatures can freeze and be destroyed.

Hope we were of any help,

Best regards,

Alexander Detailleur
Sales Manager

Freedom-DRB n.v. / s.a.
Mechelsesteenweg 277
1800 Vilvoorde
Belgium
tel: --32 (0)2 673 27 30
fax: --32 (0)2 675 17 16
email: mail@drbbatt.com"

This confirmed my own ideas. My next step was asking Fountaine Pajot for confirmation. They have asked the battery supplier and Tecsup to come with a joint advice, and would come back to me. This was over half a year ago, and I have heard nothing from them since, even after repeating the question. I have urged Fountaine Pajot to answer, not for my own peace of mind, but expecting that many people will have incomplete charging, and it's not good for the batteries either to have them half-discharged all the time.
I have waited with writing this on the forum to give FP a chance to confirm, however reading about all your battery issues I decided to inform you all.

I have set the charger in Miss Poes to "d". I have also mounted a Nasa BM-1 battery monitor which is pretty cheap when ordered in the UK.
The situation has improved very much. The batteries charge to 100 %, so you can really use 150 ampere-hour. Our ship uses on average 5 Amps during the day, 7 A at night. Which means that you can have a day-night-day sail of around 30 hours without charging, which we have already done a few times this summer. Voltage stays above 12.0 V, contrary to last year.
Charging goes very well, I see the maximum of current of 40A from the mains charger, and I have seen values of 70-80 Amps from the engine. An hour of engine charging gives you 10 hours of sailing.

Please note that the alternator (Volvo engine generator) will not fully charge the batteries, since this one gives only 14.4 V. I have asked Volvo whether it is possible to connect an alternative alternator regulator. They advised against this, since the alternator is not suited for connecting another regulator.
Also note that if you have solar cells, you also need a voltage regulator with higher boost & float voltage for optimum result. There are some, but not many.

Hope that this information is useful to you, and not too technical. The summary is: I advise you to set the charger to D setting, see the manual. This is a 1 minute job, you just have to remove a cover on the charger and flick a dip-switch. First disconnect the mains!

Legal disclaimer: of course I can not be held responsible for any damage caused by my advise above (-;

Kind regards,
Jef Pijnenburg
Now in Helsinki, after the weekend to sail to St. Petersburg. Yes, Russia.
Had 44 knots of wind last Wednesday when crossing from Tallinn, Estonia, to Helsinki, Finland. Sailed on 4 m2 of jib only, still at moments over 9 knots. Wind from 100-150 degrees. Great ship.

[Scott730]

Thanks Jef
Excellent info., I'll change my battery setting and see if it improves the charge state. I will say that I have a Xantrex battery monitor on board and check the state of charge regularly and have seen the batteries at 90% while on the battery charger, lets see if I can get to 100% with the new setting.

Scott

[Jef & Marin, Netherlands]

Scott,
Thanks for your appreciation. If your battery monitor sees the current becoming low at 14.4 V, it might wrongly conclude that the battery is full. So the 90 % may have been a flattered figure.
Jef

[Cotemar]

Jeff,

Great info in post #42 on TECSUP HI-TEC charger and well written.
I will also change my Charger setting to "D" and let everyone know how it goes. This is exactly the kind of info we need on the Mahe36 forum and welcome all your effort.
Thanks,
Mark