A grey stretch commences…

I want to thank everyone who has commented about charging house batteries with a truck or the RV itself. I encourage everyone to read through the comments on my last few points. I will address a few things here.

Airmon provided a good charging strategy (more on that below) and asked: “Did you set your linkPRO up with the capacity of your batteries and the float voltage charge profile from your solar controller?

Answer: Yes.

Croft suggested a battery cut off switch to separate the alternator from the batteries so that I can get more charge to the house batteries. I will research this further.

Dave chimed in to say that it’s easy to get a battery to 80%, but the last 20% takes hours. This goes with what Airmon said, that I should only use the truck to charge if I’m below 80%, get to 80%, and then let my solar do the work. He also said to attach the jumper cables before the shunt and fuse, but not directly to the battery posts. Dave, huh? I understand the theory, but the only thing before my shunt and fuse are the battery posts.

Finally, Alan said that folks who use their motorhome engine to ‘top off’ their batteries do get a little charge, but it will never truly charge the batteries to full capacity.

This morning is very overcast and I have barely 2A coming in. I did start the day with my batteries in much better shape than they have been in a week (12.4V versus 12.1V!). I finally rehardwired the little solar panel in and that’s giving me an extra amp. So I’m fine for power today… if I don’t charge my computers. That’s where I’m a little stuck. I ran the truck for more than two hours this morning (!) and got a full charge out of the PC and only 75% out of the Mac. The PC wins, right? Ha. That full charge out of the PC gives me at most 2 hours of run time while the 75% on the Mac gives me 3.5 hours. I have to scrap the library idea as it is closed on Mondays! 🙁 I really, really need the Mac today, so I may sacrifice some amp hours in the middle part of the day. And hey, it looks like it might be clearing a tiny bit! And I’m now at 2.5A!

Now that I really understand how the battery monitor works (and that it is working properly), I feel very empowered. I know that even though it is grey out there right now, as long as I don’t charge my laptops, I will end the day with more charge than I started with. That means that I can face tomorrow without fear of a dead battery. It also means that if I ever get to 4A coming in, I can charge the computer during that time, quit when the incoming amps go back down below 4, and still end the day ahead.

But that still leaves me the computer charging problem. I just can’t seem to get out of it. Running my truck for hours to charge a laptop is very inefficient! I am nowhere near due for a new computer, but the Macbook Air’s seven hours of run time on a single charge is starting to look pretty good. 🙁 My 17” Macbook Pro is four years old now, but there’s no reason it couldn’t serve me well for many more years. The hard drive on it is good, I’ve maxed out the RAM, and it has a new battery. So I’m back to finding a better way of powering it.

The day has come where I had to print something. Eeeeeeesh. My batteries are sitting somewhere around 82% (the battery monitor will be useless until I can resynch it when the batteries next get a full charge). It’s cloudy outside and I’m barely bringing in anything from the solar panel.

With trepidation, I turned on the whole house inverter. No problem, voltage held steady and so did amperage use. That confirms that I got all the bad connections and that my battery is operating at optimum capacity.

I turned on the HP OfficeJet 8600 printer. No problem, voltage dropped a point only and amperage use went from 3A to a mere 4A. Hit print, all the numbers held steady. My job printed beautifully.

To me, this was a worst case scenario for using the printer and it performed better than I could have dreamed! It truly is a low energy printer! It did seem a little slower than it does on 120V power, but that could be my imagination.