Best option for recharging Batteries

[kdlamoreaux]

I have a question for all of you who are much more experienced then i am about recharging batteries. If you don't look a fuel consumption but only recharge times is it faster to use the main engine/alternator combination vs the generator/battery charger option? I don't have any data but it seams like the batteries recharge pretty quickly while driving. From a noise perspective the main engine is a lot quieter then the gen.

[Chance]

Depends on alternator size versus converter size, but if motorhome isn't being driven so there is less load on alternator, the answer is probably yes. Alternators often have higher current capacity than the converters that come with many motorhomes. You may have to fast idle engine though.

Also depends on how alternator is wired to batteries.

[Chance]

By the way, if looking for hard data, these curves for optional 240-Amp extra heavy duty alternator from Ford for 6.2L V8 E-Series show that there is a wide range of capacity. On some motorhomes manufacturers specify the standard alternator, which may be as low as 120 Amps.

Higher-capacity alternators should make a greater difference when motorhome has multiple batteries. This alternator is rated at over 3,000 watts which could go into battery bank if large enough to take that much current. I'd sign up for that option for sure. The added cost is minimal.

[Laco]

Another consideration, would be the main engine you have. If its diesel, according to Cummins for theirs, and Mercedes for theirs, unloaded idle time should not exceed 5% of the running time.

[Techn0]

I know that my battery charges at 14.4 when main engine is running at only 13.6 on generator so yes the engine would charge quicker just not sure about fuel consumption. Plus not sure if I would want to put that many hours on my engine idling. I would rather run my genie for a few extra hours.

[Shawn62]

I asked this same question on another forum a few months ago. This is what I learned.

Your vehicle alternator is more of a battery maintainer than a battery charger.
Your coach converter is a battery charger. Your alternator amperage output is low at idle rpm. It is higher at cruising rpm.

Your converter is designed to charge banks of batteries. Your Sears charger is designed for a single battery.

Some find it handy to use a 2000 watt inverter generator to power the converter. This is quieter and uses less fuel.

So many options.