Hello. I have a 2003 Beneteau
50 and we're having some undervolt problems. We replaced the three house batteries
with new lead-acid filled 135AH batteries
a month or so ago. The starter battery
is isolated, though it shares a common ground with the house batteries.
If I measure voltage at any one of the the house batteries with no load it reads say 12.3 volts -- but the voltage at the panel is 11.7. As I turn on different loads there is a marked voltage loss at the panel ... If I turn on everything at the same time pulling some 20AH of load on my amp-meter, the voltage drop at the panel is to something like 10.8 or so volts -- I have verified this as well by several means -- the Garmin chartplotter
says the same voltage as the voltmeter at the breaker panel ... also my digital voltmeter says the same thing. and my inverter
starts an audible alarm
below 11.0 volts.
When I measured the volts at the battery
instead of losing nearly 2 volts when everything is turned on, the voltage loss at the battery is only 0.1 or 0.2 volts.
We are not particularly careful in terms of battery usage -- we are anchored out about 3/4 of the time but run a generator
to charge batteries and our computeres for a few hours at least a couple of times a week. We are often charging computers
via the inverter
but have a policy that they can only charge when the engine
We have an 80amp Hitachi alternator
... with the battery charger
on we get 13.25 volts at the house and starter batteries and about the same with the engine
running and alternator charging
. At the breaker panel we get about 12.5-12.7 when the engine or charging system is running.
My guess is that we might have some corrosion
in the system somewhere -- either that or the wire from the house batteries to the breaker panel is too small.
We haven't added too much in terms of load from the original delivery
manifest from Beneteau
and recent replacements
and going LED for mooring
lights has taken off more for more load than anything we have adding.
So ... what I was planning to do is to chase each connection from the batteries on out to the breaker panel and clean and measure the resistance across each of these wires as power makes its way from the batteries to the breaker panel. (e.g., battery connections -- fusible link, battery switch, breaker panel wire, etc.)
I doubt it is in the ground circult as the starter battery is not affected ... but will probably check there first anyway as that would be a likely problem area.
Any ideas or recommendations would be appreciated. Does anyone else have some direct experience in this or advice that we can use? Thanks for the assistance.