i dont know what the max alternator rating is on the bukh, but it is likely to be in the range between 30 amps and 60 amps. going "just into the positive" could be ok if the batteries are fully charged and nothing much else is running, but when the batteries are not fully charged you ought to see some more serious amps moving about. the batteries will be fully charged at about 12,7v but only half charged at12.2 volts. about 12 volts could be either. finally, you could have half flat batteries, 15v reading and few amps flowing because you have a high resistance in the circuit. this could be either in the wiring or the batteries themselves. if everything works, dont worry. if you have problems, get a decent digital meter
I have Bukh DV8 engine with an alternator built inside it. I have two batteries and both appear to be charging. I have a voltmeter which says abou 12 volts with the engine not running and tyhen goes up to 15 or so when it is. I have an ammeter also -30...+30. With the engine running this just goes into the + zone. I know all this is a bit long winded, is it normal? thanks
Everything sounds ok to me. The fact that the ammeter only moves slightly into the +ve when the voltage reads 15 suggests that the batteries are almost fully charged.
At some point, might be worth checking with a good quality digital v-meter to confirm not much above 14.5 volts when fully charged - a constant need to add top-up water would indicate too high a voltage.
cheers. Everything does seem to be working. I do though have two leisure batteries. No1 is 80 amp and No 2 is 110 amp. I use No 1 to start the engine. I was wondering wether to fit a proper starting battery to No1 instead of the leisure. I do have a digital meter, what should the raedins be when the engine is not running and then running? Thanks for any help. Dave
