Battery set up advice please

[Dutch01527]

I have a 33 foot sail boat that has:

• 2 x 110amp hr dual purpose lead acid house batteries
• 1 x 110amp hr dual purpose lead acid starter battery
• a off/battery1/Battery2/combined switch
• Victron smart charger and regulator
• 70amp alternator
• Small solar panel and wind generator with controller
• A victron 12v to 12v charger which can charge all battery types and prevents over discharge of the battery providing the charge ( not below 13 volts from memory)

All works well and reasonably new. I would like to gain a bit more house battery capacity and also charge a battery to use with a small electric outboard that uses an external car type external battery. My power usage is average to high when cruising I would say, fridge, electric toilet, charging phones and laptops, led lights ect

I am thinking of the following set up:

• Add the current starter battery to the house bank
• Replace the current starter battery with a new AGM battery - maybe a 50 amp hr Optima
• Buy a new c. 100 amp hr Lithium Battery and use the battery to battery charger to charge off the starter AGM ( would only draw charge when voltage was above 13v, presumably when on shore power or running engine)

Is there a better way or flaw in my thinking? Would I need to upgrade my alternator from 70 amps? A 120 amp option is available from Beta but that would need new belts and pulleys - about £400 including the alternator which seems like a lot if the gain is not too significant.

Thanks

 

[Boater Sam]

I think you have the right idea. I would not bother upsizing the alternator, it will be fine charging 3 house batteries and your outboard battery. You can ignore the starter battery charging load as it will be fully recharged in minutes after you have started the engine.

 

[PaulRainbow]

I have a 33 foot sail boat that has:

• 2 x 110amp hr dual purpose lead acid house batteries
• 1 x 110amp hr dual purpose lead acid starter battery
• a off/battery1/Battery2/combined switch
• Victron smart charger and regulator
• 70amp alternator
• Small solar panel and wind generator with controller
• A victron 12v to 12v charger which can charge all battery types and prevents over discharge of the battery providing the charge ( not below 13 volts from memory)

All works well and reasonably new. I would like to gain a bit more house battery capacity and also charge a battery to use with a small electric outboard that uses an external car type external battery. My power usage is average to high when cruising I would say, fridge, electric toilet, charging phones and laptops, led lights ect

I am thinking of the following set up:

• Add the current starter battery to the house bank
• Replace the current starter battery with a new AGM battery - maybe a 50 amp hr Optima
• Buy a new c. 100 amp hr Lithium Battery and use the battery to battery charger to charge off the starter AGM ( would only draw charge when voltage was above 13v, presumably when on shore power or running engine)

Is there a better way or flaw in my thinking? Would I need to upgrade my alternator from 70 amps? A 120 amp option is available from Beta but that would need new belts and pulleys - about £400 including the alternator which seems like a lot if the gain is not too significant.

Thanks

What are you going to connect to the Lithium battery ?

 

[[70521]]

I also have a 10 metre sailing boat.

I've reduced my power usage as much as I can, e.g. Led bulbs, only ever fill the fridge with frozen stuff - I prefer warm beer to something that is chilled to within 0.01°C of its freezing point and tastes like wet carboard - the heads are manually pumped.

Current set up:

• 3 * 130 AH AGM for the house bank
• 1 * 70 AH AGM for the engine
• 1 * 80 AH lead acid for the windlass (only because it came with the boat and shows no sign of failing).

A duel circuit on/off switch and a VSR to disconnect the house from the engine when not charging.

200 Watt of Solar, Victron MPPT, ShorePower, SmartShunt and BatterySensor plus 70 Amp alternator.

I've never seen more than 35 amps from the alternator charging the batteries and would never consider one rated at more than 70 Amps.

You don't say what type of sailing you do. Is it weekend marina to marina or a month or so off grid? I am more towards the month or so off grid (or until I need to visit the laundry).

Personally, I think that Lithium is not needed for 95% of UK based leisure sailors and don't think that mixing battery chemistry, because of the different charging profiles, is a good idea.

AGMs were selected as they can take a charge faster than normal lead acid, if they crack they don't leak acid and are not fussy about being used at odd angles.

 

[Dutch01527]

What are you going to connect to the Lithium battery ?

Just use it for the electric outboard, no use for the boat systems. My sailing is mainly coastal cruising for up to a week at the moment but is going to change to longer and further as I approach retirement.

 

[MontyMariner]

My configuration is approaching Sandy's.
3x130 AGM and a 80 LA for the engine
2x80w Solar with a twin output regulator biased to 70/30% in favour of the house batteries and a 70 Amp alternator with a Sterling battery sensor regulator.
When I bought the boat it came with a 12 and a 24v setup, so two alternator's and two batteries in series to give 24v, I've done away with that setup and now use a 12 to 24v converter.
As long as the sun shines each day I can sit at anchor for a week +...? Watching TV in the evening or do a 4 day Biscay crossings using modern nav kit and occasional use of older generation Radar. The fridge is set to keep things on the cool side of cold.

If you want to improve anything I would suggest more Solar and go to AGM when replacing batteries. I used to have a Wind Gen but its cost to performance is rubbish compared to Solar and it's worse than useless running downwind. Ok, yes it works at anchor on a windy night!