How much power do I need?

How much power I need is a very intriguing question. This revolves around several different scenarios:

• For cooking and refrigeration I need 120v and probably at least 20A
• For lighting and air circulation I need 12v and about 2A
• For USB charging I need another 12v and about 2A
• For the shower pump I need probably 3A at 12V.
• In total if all my 12V electrics were used simultaneously (which is nuts) then I’m talking about 15A
• For ventilation I need 3.75A at 12V.

Right now the power is off. The extraction fans used so much in their 5 minute runs since this morning that at about 3pm the charge controller cut the power. It’s a bright, sunny day too. As the charge controller reckoned I was getting only 5W from my combined panels I took both of my watt meters out of the system as I know they both gobble power. I also put my twin 30w panels directly in the sun. 

I had an interesting issue this morning. The charge controller cut the power from the battery at 3pm citing low battery power and showing me the battery was at 11.4v. At 5pm the charge controller showed the battery was at 0% charge yet the power being taken off the panels was low. The controller also said it was administering a float charge - which would tine in with the minuscule power being taken off the panels. 

Curiosity overtook me as I noticed the controller was on “float” so I flipped the battery switch to turn the battery off and then on. Immediately I did, the controller went into boost charge mode then declared the battery to be at 100%.

For a 13.8v battery to have a top of 13.4v and to recharge from empty to full on 95w of panels in about two hours is little short of unbelievable. In fact, it is unbelievable. 95W will produce at maximum 7.9A and in two hours 15.7AH. For a flat 35AH battery that might just about be possible but given the panels are not all ideally situated and the twin 30W are partially shaded by tree leaves I’m going to say these battery figures are total poppycock.

We keep returning to the battery being questionable. I’m definitely going to say that I just don’t think the Harbor Freight battery was worth the money I paid for it. Given how little use I’ve had out of it and how unstressed it has been I believe that it was probably a customer return. What probably happened was a customer had a Harbor Freight battery and kept it looking good. They probably bought a replacement, wiped down the first one to make it look good, put a full charge on it using a car charger then put it in the box from the new battery, returned it as not required and took the money or the credit for something else. What a great scam. He could get a brand new battery every year like that and leave suckers like me buying the equivalent of used shoes.

Two things my mother told me never to buy secondhand. One was shoes and the other was underwear. I’d add a few extras like electronics. They’re not worth anything secondhand as they’re just somebody else’s problem being sold.

Going back to how much power I need, a small generator would not give me enough power to run my 120v electrics. I’ve looked at generators many times and found them both expensive and not all that good. 1.5KW would be the ideal size but there aren’t any that will fit underneath the bus without protruding below the skirt. They also all seem (in the economical range) to be pull start. The small generators seem to be 800w maximum and they still weight about 50lbs. That’s quite a bit, especially for something that’ll have to be hauled in and out regularly.

Returning to the battery - as the solar controller was giving me 100% charge, I turned my ventilation fans on for exactly 60 seconds. During that time the controller recorded the battery as dropping to 72% then as soon as the fans were turned off, it sprang back up to 94%. A minute or so later it was back at 100%. If I didn’t already suspect the battery was toast, I’d be banging my head on the desk wondering why I was getting such odd results. 

My battery connector left Houston via DHL a few days ago. No news as to whether it has gone anywhere else yet. The Chinese cigarette plug to SAE adaptor never left New York so I contacted the seller who managed to sound surprised and asked if I wanted a refund or for him to send another unit. I told him it’d been so long already that I had a work around in place and that a refund was in order. I’ve not heard back yet.

When the connector arrives I shall remove my existing battery. I shan’t fiddle with the connections under the bus - that’s too fiddly - I’ll just snip the cables off close to the terminals. Then I can add my real connector to the wires, put a connector on the battery, lift the replacement battery into place and see how it all goes.

It’s just a lawnmower battery but should be good for a test subject. If I can get better life out of that then I might stick with it or get myself a better battery. I really don’t see why a battery shouldn’t last a lot longer in actual use. My suspicion is that the Harbor Freight battery is confusing the solar controllers because it’s so much beyond the end of its life. I’m very tempted to buy a battery tester so that I can do a proper drop test on the battery. Thus I checked and Found Harbor Freight has a load tester for $21.99 but Walmart which is far closer has one for $23.28. I can guarantee that I’d spend more in fuel driving to Harbor Freight than I’d save over buying Walmart’s thing. It’s a darned sight easier to get to Walmart in the event of returns too.

As I’ve been without power in the bus the most part of the day, I’ve had the window open and a screen in place. That screen isn’t perfect. It needs some masking tape along the top and bottom to stop critters sneaking in but it stops 99% of the casual fly ins. I’ve had quite a nice cool breeze too.

Just now I watched an interesting video on how to recondition a battery. It just seemed to me to be a bit pointless because after reconditioning the battery still came up as weak. I think mine would come up as beyond the grave! So, yes, I’m going to have to replace the battery. I’m scratching my head over somebody reconditioning a battery so that instead of working like it was new, it works half as well. Seems to me they could have saved the effort and the fiddling about and just gone and got a new battery.

Meanwhile, those with long memories will recall the problems I had in acquiring this thing. It’s a remote operated video camera. As I’ve now got access to real (fast) wifi, I thought I’d try it. When I used it as a standalone device it was very sluggish and slow. Using it as a wifi connected device hasn’t changed anything - it’s still sluggish and slow. I’m so glad I didn’t pay a lot for it. Not only is it - as I said - sluggish but it also gets dreadfully hot. Now the reason for that I cannot fathom. I’ve never seen any other webcam get hot. Still, its something to play with further. I can put this outside and connect to a small solar panel and a battery to see just what it’s capable of. I suspect it’s probably a darned good yard monitor. I might set it up one day to observe the front yard. Or I suppose I could use it to observe inside the chicken coop. Indeed, put a small telescope on it and I can record the goings on elsewhere.

All now is dependent upon bits arriving. I need wire to be able to complete the back solar input so that’s on hold til my next trip to the hardware store. That’s bound to be coming soon since somebody mentioned they wanted me to drive a bus. No point in rushing and spending gas money, especially since I might still have to fork out for a new battery even though I’ll try to use the lawnmower battery.