DS 50 Electrical storage

[hebdensailor]

Calling all electrical engineers.

I have just bought into a share in a Sun Odyssey DS50 2012. Stock batteries, though not original.

On a recent week in the med, I found the storage capacity very poor. Just the fridge alone overnight would have the battery warning horn sounding before 1:00 am.

Also the engine battery was draining, why, I thought the engine battery was isolated for starting the engine.?

How can we improve storage?

Anyone any experience of this.?

Many thanks.

[MickeyB]

First question is how many/size/age of the batteries.

Then you need to know if they have been abused....from there we can be far more helpful :-)

[vasko]

For this size of boat if changing the batteries better directly go to LiFePo4 technology for both starting and house :

Starting: www.ev-power.eu/LiFeYPO4-batteries-12V-1-1/Lithium-Battery-LiFePO4-12V-20Ah.html

[vasko]

For house bank:

www.ev-power.eu/Sinopoly-40Ah-300Ah/12V-3-6kW-LiFePO4-yacht-set-with-300Ah-cells-BMS-mobile-monitoring-and-protection.html

[sitara]

My SO36i had an incorrectly installed battery isolator which meant that the batteries were combined all the time. It did take me a while to figure out what was happening and why voltage figures were strange. Check your battery isolator by turning off the main house battery switch and turning on the engine start battery switch. Then turn on a light or appliance that is connected to the house circuit. If it lights up, as it did in my case,  the isolator is not working or is incorrectly installed. The wire between the starter motor and alternator had not been removed in my situation which meany there was always voltage to the isolator when the engine battery was switched on.

[peterguppyii]

I bought a 2015 50DS and have been dealing with this issue since new. (Jan-16)
Dealer agreed to change out four house bank batteries and engine battery with no help. Shut down engine the last weekend and reading 13.2 volts. 50 minutes later and one tack using electric winches and showed 12.3 volts. Alarm sounds at 12.2. These are group 31 12v 105amp batteries. Normal amp draw shows 3-7 with fridge, freezer, instruments and autopilot.
Definitely not an electrical engineer. Any suggestions appreciated as boat is still under warranty?
Thanks!

[vasko]

hmmmm on first look sounds like a dead battery cell to me ...

- disconnect the 3 house batteries and measure the voltage in them while disconnected - is it the same ? 

- get some proper multi-meter with clamps that can measure large DC current(about £25)  and measure the  actual current drawwhen engine is off from the battery bank - may be someone forgot to switch some huge consumer off ? like a inverter ?

[abgreenbank]

You cannot rely on any voltage reading from the standard electrical panel, install one of the many battery monitor systems. Fit more batteries, I have 6 115ah, standard cheap exude as supplied by Jeanneau.
i can sail for 24 hours using autopilot, winches, fridge, freezer and all electronics batteries and the batteries are more than 75% so they need around a 140 amp charge to get back to full capacity. However I tend to run the generator twice a day for around an hour each time to get to around 95%, the last 5% takes too long.
yes if I have just used the winches the voltage dives but given resting time it increases, but ignore the voltage readings on the standard panel.

regards
ab

as vasco says if you feel rich buy a lifepo4 bank and multiple battery chargers.

[so36idavid]

My $0.02. 12.2v sounds too high for a low battery alarm. While batteries are under load the voltage is going to drop, it rebounds when the load disappears. Tables that show state-of-charge vs. voltage assume that the batter has been "resting" for some period of time.

It's possible that you have a bad battery or that your batteries have been abused to the point that they're all bad. Or that your charging system isn't working the way you think it is. You need to figure out which of these problems you have. None of this is complicated, you don't need to be an electrical engineer to figure it out. But you will need to either educate yourself or hire a marine electrician to figure it out for you. As others have said, the very first thing to do when trying to figure out battery issues is to install a battery monitor. They're not terribly expensive or difficult to install, here's a tutorial. That will tell you exactly what's going in and out of your batteries so you can figure out if the problem is charging, load or batteries.

Try to make some progress in the right direction and feel free to come back here to report and/or get more tech support . If you are willing to publish where you sail there may be someone on this board nearby who's willing to come over and give you a hand.

David