Generator and Battery Charger

Rick · 05-06-2013, 02:50 PM

I still have a problem with running out of battery power with my PW. There is only one house battery. I believe Marko said in a previous post that it takes a while to charge a very low battery just running the gen set for an hour, or for that matter running the vehicle engine for a short while. What about running the gen set and connecting it to a battery charging unit connected to the house battery? I know they have a fast charge rate and a slow charge rate. Would that be do able?

Rick

markopolo · 05-06-2013, 03:43 PM

One hour or so of running the generator in your Pleasure-Way should bring the battery back to 85% to 90% charged. Maybe two hours ....
You can run the van engine and the generator at the same time to provide maximum charging amps. The battery will only absorb so much though.

Neither running the van engine nor the generator is efficient for taking the batteries from 90% to 100% though. That is what takes a longer time. (If you happen to being driving then that is efficient because you're running the engine anyway)

Repeatedly deep cycling (80% discharged) will shorten battery life. Couple that with not fully charging the battery then plan on replacing the battery more often. That is not as bad as it sounds and might be cheaper than upgrading the converter/charger or buying a second charger or adding solar etc. Depends on how long you'll keep the van and how often you use it etc.

Do you know what brand and model number converter/charger is in your Pleasure-Way? I could look up the specs of the charger.

Do you have a multimeter or voltage meter? You could check the voltage at the house battery when the generator is running. With a low battery, when you first run the generator, you will hopefully see 14.4 volts or so at the house battery. If you only see 13.6 or so then run the van engine and the generator and check again. 14.4 volts is a charging voltage. The quicker your low batteries see that voltage then the faster they'll get at least to 90% or so charged.

Rok · 05-06-2013, 08:19 PM

Thanks for the explaination, Marco, but I have another question about batteries. Everyone says that you need to not drain your batteries more than 50%. My question is how I know when that is.

Our Great West Legend SE has two meters in it to tell what the voltage is (one in the solar charging module, and one in the control panel as part of the reading unit for % used for black, grey, and fresh waters. Both of them register in volts, not percentages. It usually runs somewhere between the high 11's and the low 13's, depending on how much we've use it, how much the van has run, and whether or not the Solar panel is cooking some out.

Anyway, since we only have voltage meters, how do we know when the battery is nearing 50% and it is time to turn on the generator or drive the van. (Unfortunately, the two meters don't always jibe with one-another, but theyr are pretty close.)

Our rig (GW Legend SE) is blessed with some large battery capacity. I was told by their rep that the 2 12 volt coach batteries are 200 AH each in parallel totalling 400 AH. The EX has 4 6 V batteries totalling 500 AH, I've been told. We've also been told that the Microwave can be run using the batteries and the inverter. When we tried this, however, an alarm sounded and the inverter led meter pegged out. We've been told since that our batteries might have been low, or that we might have had some additonal load on the inverter. We're going to try it again to see if it works.

Anyway, how do you know when your batteries are low?

............Rocky

Davydd · 05-06-2013, 08:59 PM

I printed this out, laminated it and put it on the inside of a cabinet door for reference.

Rok · 05-07-2013, 02:04 AM

Thanks Davydd!! (for the chart)

.........Rocky

markopolo · 05-07-2013, 02:33 AM

It is "at rest" battery voltage that gives you an idea of the state of charge. Ideally everything would be off in the RV. Don't worry about the voltage dropping under a load - it should bounce back after the load is removed. That chart is handy

In your Great West Van, with the solar panel, it'll be hard to see an "at rest" voltage. If it is light out then the panel will be outputting some voltage and at night you'll have a light on. Anytime you see the voltage over 12.7v that means the batteries are charging. The solar panel is a nice option. It's fun to see that your batteries at more than 12.7 volts throughout the day harnessing power from sunlight.

Rok · 05-08-2013, 02:48 AM

Marco,

I was skeptical as to whether a single 85 watt solar panel was more of a gimmic or something that was usable. It seems to actually keep the battery topped off and it's kind of neat to see the little window say the battery is charging. It actually seem to be something worth having on top of an RV.

..........Rocky

markopolo · 05-08-2013, 12:55 PM

85 watts of solar theoretically could output almost 40 amp-hours per day at this time of year in your region according to this calculator: http://www.where-rv-now.com/Notes/Solar/#Calculator (I used the the latitude for Portland, Oregon) The calculator reports 4.4 peak amps output at noon using May 8 as the date.

40 amp hours - for example - could run my Fantastic Fan on high for almost 23 hours.

Rick · 05-08-2013, 03:46 PM

Thanks for teh great replies. i have a multi-meter but it is a cheap one. it has a volt setting but it is either 10 volts or 250 volts. So one setting the scale is too low the other scale is to high to get accurate readings. if I am using it right, not sure. I will see if I can get a better meter.

Rick

Rok · 05-15-2013, 03:49 AM

Quote:

Originally Posted by markopolo

85 watts of solar theoretically could output almost 40 amp-hours per day at this time of year in your region according to this calculator: http://www.where-rv-now.com/Notes/Solar/#Calculator (I used the the latitude for Portland, Oregon) The calculator reports 4.4 peak amps output at noon using May 8 as the date.

40 amp hours - for example - could run my Fantastic Fan on high for almost 23 hours.

Interesting that you should mention it that way. We were "airing out" our new rig using the fantastic fan, and were going out every once in a while waiting for the time we would have to start up the van or generator or something to recharge the coach batterys. We were surprised that we never had to. Your explanation above explains why. (We didn't have it on high, though, but it sounds like we could have.)

.........Rocky

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