re-charging via generator

[pdholz]

What's the best, fastest way to recharge batteries using a generator (Honda 2000, though that shouldn't make a difference)? For this discussion, ignore having to run anything else while charging, either 12 or 110V. The options are
a) Go through trailer converter via umbilical cord.
b) Turn battery isolation switch to Off, then hook up generator to charger then to batteries, using a three stage "smart" charger.

With latter approach, it took a bit over two hours to get two new Group 24 Interstates from 80% to almost 100%, after letting the freshly charged batteries sit overnight to get a valid reading.

For what it's worth, in eco mode, the generator never came off idle in either configuration.

Any way to speed things up?

Thanks in advance to what may be one of the sharpest forums on-line.

[dznf0g]

I THINK that using the shore power cord and your onboard converter would be faster, since it is (probably) a 55 amp unit and your battery charger is a 10 amp unit.

[TG Twinkie]

The shore power cable or the generator plugged into the shore power cable. Both will charge at the same rate since the converter being 55 amp will require about 800 watts when you figure in the losses.
A 2,000 watt generator can handle 1,600 watts continuous load.

[Foiled Again]

Back when I had the EU-1000 it wouldn't charge through the umbilical cord. I don't know if the cord's length might have caused resistance or whether I'd done something else wrong. (could I have hit the disconnect battery switch?) Duh.

I also had a plug-in battery charger so I plugged it into the generator and applied the clamps to the batteries. That worked fine, though I did replace the batteries about a month later when they stopped holding a charge.

The EU-1000 had some lightweight cables that would allow me to charge a battery directly, but there were a lot of cautions to avoid overcharging and possible explosions - so I used the plug in charger where I could monitor the charge going onto the batteries.

Now I have a 3000 Handi and I rarely carry it - the new low draw LED lighting and the solar that came with my new to me Eddie Bauer has rendered it unneeded except for very long trips.

Paula

[dznf0g]

Well, Paula, the standard converter up until recently, at least, draws 900 watts when batts are low, so that doesn't surprise me with a 1000 watt gennie. I'm sure it prolly only puts our 7 or 8 hundred watts continuous.

[idroba]

Because of an electrical issue known as Power Factor, the littlest Honda 1000 will not stay functioning with a converter/charger larger than 45 amps. It is a somewhat complex issue and the best I can say is "trust me" as I have been there, done that, and finally figured out the reason.

But the Honda 2000 should be fine.

Don't get too excited about charger capacity. In most cases a converter/charger larger than about 45 amps will not charge batteries usually used in Airstreams any faster than the smaller one (45 amps). This is because batteries have a rate of acceptance which is based on their state of charge, the closer to full they are, the less current they will take. If you try to force more into them (by raising voltage) thinking it will speed things up, all you will accomplish is to damage the batteries.

When my two golf cart batteries are low, and I charge them with my 45 amp PD converter/charger, I usually only see the max charge rate of 45 amps for maybe 15 or 20 minutes, then it drops down to 40, then 35, then 30 pretty fast. Then it may taper to 20 and stay there for quite a while. That is the rate the batteries that I have want to charge at. If I had a larger converter/charger, say 65 amps, the same thing would happen. They might take 65 amps for a few minutes, but very rapidly would taper down to 55, 45 etc. You don't want to force it more, and the converter/chargers today simply won't do it anyway.

So, to answer the OP question, use the built in converter charger with your generator and you will maximize the charge and minimize or eliminate any battery damage, especially if it is a more modern 3 stage converter/charger.

[Phoenix]

From the Honda EU2000i owners manual:

"The DC receptacle should ONLY be used for charging 12-volt automotive type batteries. The DC charging output is not regulated."

"Maximum charging output= 8A."

[TinTin]

Originally Posted by Phoenix

From the Honda EU2000i owners manual:

"The DC receptacle should ONLY be used for charging 12-volt automotive type batteries. The DC charging output is not regulated."

"Maximum charging output= 8A."

Do some use the 12 volt outlet on Honda generators for charging their batteries?

I've always assumed that this would only be used if you didn't have an in-trailer converter or standalone battery tender, both of which are powered from the generator's 110 volt outlet.

[Ahab]

I use the umbilical cord and let the 3 stage charge my Gr 29 battery.