How to charge batteries from generator?

[xbr443]

We were dry camping for a few days and plugged the electric plug into our new Yamaha 2000 generator. It charged the batteries but didn't fully charge our batteries. We were wondering if there is anything else we need to do to charge our batteries or if we just need to run the generator longer. We're going to o dry camping again in the near future and wanted to be prepared.

[TG Twinkie]

Sounds like you need to run longer. What type of converter and how many batteries?

[xbr443]

We have two batteries, I'm not sure what type of converter we have. I guess thats my question, do we need something between the generator and the trailer? We're new to RVng in case You couldn't tell. LOL

[TG Twinkie]

Nothing is required between the generator and trailer. If you have one of the Univolt type converters. They are a primitive device and are not as intelligent as the more modern multi stage converters. You can locate the converter by following the battery cables.

[idroba]

I don't know what type of converter/charger was on your '04 rig, but it could be one of the not too great charging types. Often they put a minimal amount of charge into your batteries over a long time. The newer 3 stage chargers will dump quite a lot of power into the batteries during the "bulk" phase when the batteries are low and can take it. That will bring them to about 80% charge. Then they taper to an "absorption" phase to run them up to the mid 90% range but that takes many hours. The final few % is done on the "float" phase and takes 24 to 48 hours.

So, you really can't fully charge your batteries in any reasonable generator run time, even with the best converter/charger. However you can bring them up to 80% or so fairly quickly which should be good enough. By fairly quickly, I mean 2 to 4 hours, depending on their state of discharge.

Once again, this assumes a good three stage converter/charger, and someone else may chime in to say if the one in your '04 has such a beast. If not, you may wish to change it out. A good one is not too expensive, under $200 probably.

[garry]

IMO the best bet is to buy a good battery charger to charge the batteries and not depend on the converter.

[lewster]

Originally Posted by garry

IMO the best bet is to buy a good battery charger to charge the batteries and not depend on the converter.

The best solution is to install a proper electronic converter with automatic 3-stage charging (what Airstream should have included in their 'premium' trailers, like the IOTA or PD) so you no longer have to worry about correct battery charging!

[xbr443]

Thank you everyone. We were charging our batteries for two hours in the morning and two hours in the evening and by the next morning we were in the red again. We'll have to upgrade that converter.

[Ridgerunner3]

We have a PowerMax 65 three stage converter with 2 group 27 AGM batteries in our AS. Our experience has been it takes two hours plugged into a Honda 2000i for the converter to bring the batteries to 80% charge from a low 50% charge range.

I used individual 15 amp good quality chargers plugged into the generator with my old SOB. I disconnected the negative cable on the batteries during charging. I may be wrong, but I felt that having the batteries connected in parallel with two chargers in service and a converter would confuse the charger control circuits. The charging results were good, but it took time to setup each day. I have not tried the two individual chargers on the AS yet.

[TG Twinkie]

I have a portable solar panel (85 watts) which I plug into the trailer. We took a 10 day trip off the grid and the solar panel worked great. Also have an 1100 watt inverter which enables us to charge all the devices like cell phones and camera batteries as well as watch TV and/or a movie.
Of course we can't run the AC. But the solar panel is really quiet. LOL

[bovk]

Please, get your own data!! Get a cheap 10 amp meter and measure what charging current you getting, 2 batteries may need as much as 200 hours of charging if you charge with 1 amp. My AS charges with 13.9 volts and batteries nearly never charge over 13 volts. Usually 8 hrs of charging (and it does not matter if you are using the generator or the hook up, it goes through the same converter) makes it about 75 % full, 12.5 volts.

[idroba]

Originally Posted by xbr443

Thank you everyone. We were charging our batteries for two hours in the morning and two hours in the evening and by the next morning we were in the red again. We'll have to upgrade that converter.

How old are your batteries? When they behave like that, they may have just lost capacity and are at the end of their life. No converter/charger will help in that case. Rapid charge to "good" and rapid discharge to "bad" is an indication that the batteries are shot and have little capacity left.

Just one more thing to consider.

[xbr443]

We bought the batteries in March @ Camping World, probably not the best batteries. Thanks.

[Jammer]

The stock converter that came with your trailer takes around 24 hours to charge the batteries fully from a mostly discharged state. The only way around that is to replace the converter.

[Wazbro]

Well I don't really believe battery brand makes a noticeable difference in quality and your batteries are new so "should" be good. If you are not using the heater or an inverter to power 110 appliances you would need to use a lot of lights and/or a TV to run down the batteries in 1 night. It might still be worth the effort to take your batteries to an auto parts store to have them load tested (new doesn't always mean good). Switching to LED lights will help reduce power use to.

[xbr443]

It was very hot so we were using the two Fantastic fans. I try not to use too many lights but we probably should switch to LED lights.

Thanks

[68 TWind]

Here is an excellent little book on 12 volts systems. I think I got mine from Randy at Best Converters when I ordered my IOTA 55 from him, but Amazon has it. I think it is a must read for all Rv'ers.

Amazon.com: Managing 12 Volts: How to Upgrade, Operate, and Troubleshoot 12 Volt Electrical Systems (9780964738621): Harold Barre: Books

[Phoenix]

Two FantasticFans running 24/7 will drain batteries similar to using the furnace blower in very cold weather. You will probably have to run the generator every day for an hour or two in the morning during breakfast and/or lunch, and a couple of hours in the evening during dinner prep through television/movie/video game viewing afterwards, to replenish the charge.

If you can get by with using one FantasticFan when running only on 12-volt power, generator time can be reduced. Also, when on battery power, limit usage of 12-volt incandescent lights and other devices (e.g., a television or appliance that uses 110 volts supplied by a 12-volt INVERTER). Then, when your generator is on, go ahead and turn on whatever you want.

Replacing incandescent lighting with LEDs is expensive. As an alternative (until prices come down like CFLs did), I have replaced some of the 12-volt lamps in our Bambi with lower-wattage bulbs. For example, my wife reads in the evenings, so the fixture over her seat at the dinette table and the one over her side of the bed have bulbs rated at about half the wattage as normal. Also, the double-bulb fixture in the bathroom has one lower-wattage bulb installed. That way, late at night, the dimmer bulb comes on first; and, if you need more light, just turn both on.

When boondocking, we use a couple of strategically-placed portable LED fixtures that run off of AA batteries. One of the LED fixtures frequently left on for extended periods is located over the dinette table, and another drops out of an overhead bin in the sleeping area. This limits overnight battery drains to only the FantasticFan(s) or furnace blower, which helps the batteries last longer.

The first 12-volt LED bulbs we will probably replace will probably be the one over the stove, which we use as an indirect light in the evenings, and the one centered over the dinette table. The other incandescent bulbs are used infrequently, and are only on for a couple of minutes at a time.

Our two granddaughters now have iPhones, MP3 players, etc. that need external power. In the evenings, I give them my portable jumper/booster battery to use, which has a 12-volt plug for their USB cables. Surprisingly, these devices can draw up to 1/2-1 amp or more, each, which adds up; so it helps to disconnect them from the house batteries. Also, they can use the portable battery in the tent, if they decide to camp outside, which is frequently the case.

[handn]

I have a 2004 25 Safari like the author of the thread. It has a Paralax 7355 converter, a single stage converter that is known for taking a long time to charge the batteries and eventually overcharging and shortening their lives as well.
We hunt in our trailer and live off the grid for weeks at a time in cold fall weather in Colorado. In the mornings, after running the furnace during the night, the batteries were always low. After cold nights, they were critically low.
We got by for several years with our poor converter because we had a 10 amp solar charger. In sunny weather, it would almost charge the batteries in a day. An hour and a half of run time on the generator was all that was necessary to charge the batteries for the next night. In cloudy weather, generator run time jumps to an annoying three to four hours.
After replacing the batteries for the umpteenth time after only two years of life, we upgraded the converter to a three stage one from bestconverter.com. It is advertised as "plug and play" and was almost so although I had it professionally installed. I anticipate increased battery life that will cover the modest cost ($215) of the converter.
The bulk charge feature will charge the batteries faster and the float charge feature will not kill them. I anticipate shorter generator run times.

[Lumatic]

A comment and a question. My Honda eu2000i comes with a cable to directly charge a battery. Is this any better or worse than plugging the trailer power cord into the generator?