We just picked up a Sunseeker 2250LE on a Chevy 4500. We are doing the shakedown this weekend. I'm new to having a generator and had a few questions on the house?? and engine?? battery systems.
I will be putting at least 180W solar on it, but might be a month out.
1. Can I charge the house battery when its plugged into the generator bypass? I put my charger on the terminals while plugged in and had an odd charge reading of 50%, but had 12.8v accoring to MM. Should I disconnect battery completely to charge? (might be basic electrical i just failed)
2. All i have now is a 3 light indicator on my control panel for battery condition, and a 4th stating if its charging. I guess looking at that might answer this question, but is the house battery getting charged while engine running or only when generator running? (I know it does when on shore power)
3. I see that its a chassis ground, not a common ground like the TT, that changes my solar panel cabling i think, where i'll need to run one wire to the chassis and one back to the positive (hopefully Pianotuna will jump in on this one). I assume this might be basic automotive wiring too, but bear with me on my basicness, ill smerten up soon i promise.
4. Do i just keep looking at the control panel indicators and then when low turn on the generator? How longs a good time to run it? Should I run it every so often anyway? I know it will change with amount of usage, but just thinking of an overnight dry camping.
Thanks for any help and tips!
Summers a comin!
EDIT: Just found some cool stuff in the Class C FAQ, thanks HiTech for assembling that. I'm sure as I go on the trips alot of this will answer itself aswell.
* This post was
edited 03/22/12 12:44pm by adamroof *
If you put the charger on your battery terminals when plugged in, what the charger will see is output voltage from your converter charger, rather than whatever the battery voltage is, which is measured to estimate state of charge.
12.8V is a typical converter output when there is no separate charging circuit; that is what the 12V appliances on the house circuits want to see as a maximum. It is also about right for about 60% charge, while charging, as measured by a charger, because the charger is seeing surface charge. The same 12.8 volts measured on a discharging 12V battery represents 90-100% charge.
The manual for my converter charger, and for my motorhome, both tell me to disconnect my house batteries before using an external charger. It doesn't tell me why, but there are two reasons:
1. The charging current from the converter, or even just the phantom loads on house circuits, will confuse the charger about what is going on with the battery.
2. Bulk charging, your external charger will push voltages above design levels for some of your 12 volt equipment. 13.5-14.2 volts in the bulk charging stage may not damage anything, but might confuse some control circuits.
If you discharge to 50%, and charge using your external charger, you should get to 80% charge in 2-3 hours if your charger rated amperage is at least 20% of the number given as the battery amp-hour rating. Finishing the charge to 100% could take another 8-10 hours, as the charge rate slows down to protect the battery.
If you try to charge through the converter, for 50% to 80% figure 3 to 5 hours. The converter may not get the battery to 100% charge even over 20 hours or more, and can boil the water away trying.
Running the generator is the same as plugging in, except for the noise and cost of gas.
Many motorhomes have a circuit, protected by an isolator (mechanical relay or solid state device) that provides a charging current to your house batteries (and power to 12V house circuits) when the alternator is putting out enough to do that job. There is a voltage drop across a solid state isolator, so that the house does not see quite as much voltage as the chassis 12V circuits.
Here is an article relating to voltage measured at the battery when charging and discharging, how it relates to state of charge. The curves are for true deep-cycle batteries (comes from the home power community) and will be a bit different in shape for the higher charge/discharge rates compared to yours, which is likely either a RV/Marine dual purpose or a RV deep cycle, two more compromises in the battery type spectrum.