I have recently had the pleasure of a brand new Beta 38 in TAMZIN.  With this new found reliability I'm starting to make plans for  more extensive cruising vs just day sailing and overnights in the past  because I was afraid to get too far from home with the old Volvo.  It has dawned on me that the basic Beta wiring harness supplied with the engine only charges the starting battery as the two systems are isolated.  The house battery only receives a charge while at the dock on the 120v charging system .  To date that has not been a problem however on an extended cruise it obviously would be.  My question is,  there does not seem to be any 'intuitive' means of charging both batteries while motoring. Could I simply use small jumper cable between the positive posts (while motoring) or should I look into a more sophisticated system? and if so how would it be wired ?  thanks  Larry

Larry:  I have the Beta 38 HP also and do love the engine.  I would recommend Nigel Calder Boatowners mechanical and electrical manual  (I think the 3rd is the latest edition) as a good place to start researching the issues with multiple battery charging. 

I found that on the Beta - you could turn off the key w/o the engine being shut off.  Since I wasn't sure how Beta handled the alternator output with the key off and the engine running - I rewired the output of the alternator to always have a load ( battery in this case).

There are also issues with mutliple batteries connected to a common charging point -- if one battery is weak - then the strong batteries will try to charge the weak battery - running all the batteries down etc.

Look into battery isolator ( there are two types - diode and relay) - a way to charge seperate batteries from a single output (your alternator in this case) .

Galvanic isolators are nice addition also.

Also there are multiple types of batteries and each has it's own charging needs/rates etc. 

Nigel does a good job with explaining and offers schematics etc. as this is a complicated subject. 

Here is a link to a battery watering forum topic.

Hope this helps - and Happy New Year!

Jay   

Hello Larry -

Thanks all.  I spoke with the tech guys at Beta and their recommendation was to run the cable from the starter to the common on the battery selector switch.  Then cables per normal to #1 and #2 battery banks.  Per Beta start the engine on Battery #1 run for about 20 minutes which should be sufficient for a full charge and then switch to Battery #2. Do not ever switch to the "OFF"  position while the engine is running.  Basis this I ran a cable from the #2 selector post to a single throw (0n/0ff) switch then to the house buss board.  Since most of my sailing is day sailing interspersed with long stretches of motoring on the ICWW (ie lots of auto pilot and chartplotter usage) this seemed like a good set up for me.  Again thanks for all the info and suggestions.   Larry