Henry Botham

We are very new to all this, day 2 of living on our 58ft narrowboat. Our Vetus M4.15 engine fired up like normal tonight however in its 'on' position the buzzer sounded with the battery warning light coming on. To turn off the buzzer we turn the key to the 'off' position and the engine continues to run. However this is obviously not charging our batteries so we have quickly turned it off. Now we are slowly depleting the batteries with no way of charging.. my guess is there is a fault with the alternator but I'm not sure. I thought perhaps we could try and rev the engine with the buzzer going to help the alternator out however that didn't help. So now all out of ideas. If anyone has any suggestions then please help!! Henry