BD722 Beta 20hp charging capacity?

[Star-Lord]

With the standard alternator what is the BD722 Beta 20hp charging capacity?

At present there are 2 battery banks. Sealed lead acid: 100ah starter and 100ah house. I want a diesel heater and so want to add more house power. Thinking of going AGM. Room for 2 house batteries bringing total to 300ah but there is space to also fit a long 250ah AGM.

Would the standard Beta alternator be good for charging 550ah?

How many AH would the standard Beta alternator be able to charge when chugging along?

Would 200ah be sufficient for the smallest 2kw Webasto? For say 50 hours? (15hrs per day) without running engine. (No Solar yet).

Any recommendations for upgrading the Beta alternator?

TIA.

 

[Tranona]

The standard Beta alternator is 40amp, option is 75.

You don't say what size boat and what other loads you are placing on the batteries. 300ah house bank is a decent size for a smallish boat that would need a 20hp engine. Whether it is enough depends on your typical daily consumption, how long you want to go without charging and what other forms of charging you have. The key figure for charging batteries is the acceptance rate which for LA batteries is relatively low (but higher with AGMs) particularly when the bank gets over 80%SOC. A 40A alternator would have no difficulty keeping up with the demands of a 300ah bank except perhaps if it were well run down.

You can work out the theoretical heater consumption from the data given with the heater, just as with any other consumer like your fridge, although in reality you need real world data from a battery monitor. You need to carry out an audit of your total consumption in your expected usage pattern before thinking about whether you need additional storage capacity and charging.

 

[Star-Lord]

The standard Beta alternator is 40amp, option is 75.

You don't say what size boat and what other loads you are placing on the batteries. 300ah house bank is a decent size for a smallish boat that would need a 20hp engine. Whether it is enough depends on your typical daily consumption, how long you want to go without charging and what other forms of charging you have. The key figure for charging batteries is the acceptance rate which for LA batteries is relatively low (but higher with AGMs) particularly when the bank gets over 80%SOC. A 40A alternator would have no difficulty keeping up with the demands of a 300ah bank except perhaps if it were well run down.

You can work out the theoretical heater consumption from the data given with the heater, just as with any other consumer like your fridge, although in reality you need real world data from a battery monitor. You need to carry out an audit of your total consumption in your expected usage pattern before thinking about whether you need additional storage capacity and charging.

At present there will be no other power loads when running the heater except charging the laptop and phone and lights. Thanks for the advice! Interesting about the 80% AGM. LA has always seen me in good stead. I will fit 100w solar at a later date. Boat is 31 foot. So modest size with no fridge yet.