Gjac wrote:
When my stock 110 amp alternator went I replaced it with a 180 amp alternator thinking it would charge the 2 6 v GC batteries faster. 6 hrs of driving home did not recharge my batteries from 50% soc, It took my 40 amp B&B to complete the charge overnight. So I think there is more than just adding a bigger alternator that I don't completely understand. I read her that wire size and external rectifiers,and cooling are important. From what Phil posted 3-5 hrs of driving recharges his batteries. Have you guys added anything besides a larger alternator to charge your batteries faster?
Regarding us being able to recharge our coach batteries in 3-5 hours of driving:
Going from memory, I believe that a long time ago I checked the cabling size that Winnebago installed from the alternator to the coach batteries ... and it was 6 gauge, which is a pretty good size.
However, the big thing with our fairly qjuick recharging when driving is that our coach batteries are AGM deep cycle batteries, which accept more current when being charged at whatever voltage is being applied to them. We also don't let our coach batteries get too much lower than around 12.2 volts or so ... so they usually aren't discharged way low.
Also, our coach batteries are directly connected to the alternator's output so there is no voltage drop through any isolation circuit or diode ... hence the coach batteries see the largest voltage possible at all times from the alternator.
Our motorhome's alternator is what came on our stock E450 cutaway chassis - apparently the standard for that year Ford OEM 130 amp one.
Like Don mentioned above - our stock alternator to coach battery solenoid failed within a couple of years of us owning the motorhome ... but it failed intermittently and was difficult to notice that it was the problem until I mounted a voltmeter right on the cab dash that monitored what voltage was winding up on the coach batteries from the alternator. I quickly discovered that sometimes the coach batteries were getting 14.XX volts on their terminals and sometimes they weren't. I replaced the stock solenoid with a heavy duty solenoid with silver alloy contacts for reliability and to help insure that it's contacts wouldn't ever oxidize or corrode, and thus introduce high resistance into the charging path.
