Charging batteries with the engine
Hi all. I have a 2011 triple e senator 25d. Great motor home. E450 v10. Just curious, what is the output of the alternator vs the standard converter? It seems to charge the house batteries...
Forum Discussion
When drycamping I partially recharge our Class C's two paralleled 12V 115 amp-hour batteries (230 amp-hours, total) at times using our 2005 E450's V10 alternator. When the batteries need recharging, I often idle the V10 for about an hour to put heavy current into them before I use the stock converter for several hours powered by either our built-in 4KW Onan or our small 650W portable Honda. I've seen initial recharging current from the alternator as high as 80 amps while the V10 idles.
Our alternator is rated at 130 amps at full spin speed and up to 75-80 amps at engine idle spin speed. This is also shown on Ford's performance graph for the E450's 130 amp alternator. The alternator is over-driven by it's pulley, so it spins much faster at all times than the engine does. I suspect that at some point V10 engines later than our 2005 may have shipped stock with only a 120 amp alternator - but I'm not sure on this.
I don't think that the V10 is harmed by idling, as I understand that various emergency response vehicles with a V10 sit with their engine idling for hours at incident sites. However, we do use top tier synthetic oil in our V10 - if that counts for anything.
Especially in very noise senstive camping areas (such as around tent campers), partial recharging via the idling V10 is our quietest way to recharge. In those situations we skip further/full recharging via either the Onan or Honda because of their noise level being above that of the idling V10. The idling V10 noise is only a low whisper just outside the motorhome and can't be heard a few feet away. The idling V10 supposedly consumes around 0.7 gallons per hour when idling, the Onan probably consumes around 0.3 gallons per hour when powering just the stock converter for our battery charging, and the portable Honda consumes around 0.1 (one tenth) gallons per hour when powering just the stock converter for our battery charging. So, idling of the V10 is the most expensive way to put some amp hours back into our batteries - but we use it only sparingly to do this and we always use it in the special situations when ultra-low noise is the name of the game. We don't have solar, but even if we did it would not work in many of the very quiet and shaded camping spots we find ourselves in. Our RV batteries are AGM, so they charge faster than liquid acid batteries do regardless of the charging technique used (because of their lower internal resistance).
For what it's worth, decades ago the original owners of our very first Class C motorhome (a 1969 model Chinook) used to regularly idle it's GMC V8 to recharge it's coach battery and that V8 was of course still strong years later. RV generators were rare back then and RV solar was non-existent back then.
Our alternator is rated at 130 amps at full spin speed and up to 75-80 amps at engine idle spin speed. This is also shown on Ford's performance graph for the E450's 130 amp alternator. The alternator is over-driven by it's pulley, so it spins much faster at all times than the engine does. I suspect that at some point V10 engines later than our 2005 may have shipped stock with only a 120 amp alternator - but I'm not sure on this.
I don't think that the V10 is harmed by idling, as I understand that various emergency response vehicles with a V10 sit with their engine idling for hours at incident sites. However, we do use top tier synthetic oil in our V10 - if that counts for anything.
Especially in very noise senstive camping areas (such as around tent campers), partial recharging via the idling V10 is our quietest way to recharge. In those situations we skip further/full recharging via either the Onan or Honda because of their noise level being above that of the idling V10. The idling V10 noise is only a low whisper just outside the motorhome and can't be heard a few feet away. The idling V10 supposedly consumes around 0.7 gallons per hour when idling, the Onan probably consumes around 0.3 gallons per hour when powering just the stock converter for our battery charging, and the portable Honda consumes around 0.1 (one tenth) gallons per hour when powering just the stock converter for our battery charging. So, idling of the V10 is the most expensive way to put some amp hours back into our batteries - but we use it only sparingly to do this and we always use it in the special situations when ultra-low noise is the name of the game. We don't have solar, but even if we did it would not work in many of the very quiet and shaded camping spots we find ourselves in. Our RV batteries are AGM, so they charge faster than liquid acid batteries do regardless of the charging technique used (because of their lower internal resistance).
For what it's worth, decades ago the original owners of our very first Class C motorhome (a 1969 model Chinook) used to regularly idle it's GMC V8 to recharge it's coach battery and that V8 was of course still strong years later. RV generators were rare back then and RV solar was non-existent back then.
