Where forward?

As usual I am criticized for everything to do with my solar setup to the color of my socks. I looked at replacing my solar controllers because I’ve  been told they’re Chinese and therefore crap. I’ve looked at replacing my Harbor Freight battery because it doesn’t seem to be working and I’ve been told it’s Chinese and therefore crap. It seems everything that doesn’t perform as it should is called “Chinese crap”. It’s so depressing to hear all this name calling.

China managed to launch a small space station and their own men in space. China managed to put a lunar rover on the moon. These do not seem to me to be in the least bit “crap”. This mudslinging has to stop. Look around your home... how many things do you have, love and use without issue that are made in China? Most tablets, laptops, phones are made in China. Most electronic components come from China. Isn’t this “It’s  Chinese so it’s crap” argument getting somewhat tiresome? Blame the retailer if something is Chinese and not good. The retailer buys the stuff from the wholesaler and the wholesaler just orders it from China. If the retailer wants cheap, the Chinese will ksupply cheap. If the retailer wants good, the Chinese will supply good. If the retailer wants cheap and good, the Chinese will supply cheap and good.

I looked at the figures for a USA made Morningstar PWM solar controller that cost $95. They were the exact same voltages for start, cutoff, float etc as my “crap” Chinese controller. Not just that but the same figures that I have observed using my meters. In fact, looking at the specifications for all the PWM charge controllers, the figures were very similar.

Reading into MPPT controllers, some commentators say that they’re not worthwhile unless you have 200w of panels. One reviewer noted that many MPPT controllers needed 10W to start up. Then there’s the cost. Most of the MPPT controllers are very costly if they’re actually made in the USA. Most are made in China for western companies. A typical American made controller is about $200. That’s just not worth the money.

Hindsight is a wonderful thing but if I was starting my power system from scratch, I would not have used any of this solar stuff. I’d have saved the $200 I spent on panels and the $90 on the assorted batteries and the $50 on assorted controllers. Instead I’d have bought two or three car batteries or marine batteries if they cost the same or less. I’d have put a diode regulator so that the batteries charged when the engine was running and carried a car battery charger for times I’m plugged in and used a small harbor freight generator as backup.

Looking at the figures, my extraction fans burn 58W. Over the hot part of the day that’s about 8 hours use or 38AH. Assuming 3 batteries of 100AH each, that’s four days without needing to replenish the batteries. Solar power is so enticing but unless you’re going to put a lot of panels, it’s just an expensive pain in the arse and, of course, no end of people are willing to tell you how to fix things and that always entails buying yet more expensive stuff with no cast iron guarantee that it’ll fix things.

Given that I believe my charge controller is fine, I’ve left the batteries on charge for a couple of days. I won’t touch the batteries today and didn’t yesterday. Tomorrow afternoon I’ll time the fan again to see how long I get. Last time it was 20 minutes. If I get more then it’s a charging issue. If I get the same or less, it’s a battery issue as I suspect.

Replacing the battery is an option. I have heard that used as a deep cycle battery, $20 lawnmower batteries last 6 months. That sounds a pretty good option. Given that my $50 (without coupons $75) battery lasted just a year, lawnmower batteries seem a more economic option. $20 twice a year rather than $50-$75 a year.

In that picture you can see 75W of solar panels. Two 30W and one 15W. On the back of the bus there are two 10W panels. That’s 95W of panels. The charging light on the charge controller is flashing rapidly. All 3 charge lights are lit. Now another quick calculation. Let’s assume we’re getting just half the panel amperage during the 10 or 11 hours of daylight we have right now. That’s still 47.5 watts times ten hours for 475 watt hours of power. Divide by 12 and that’s 39.58 amp hours of electricity.

I won’t touch the system til tomorrow afternoon. If an afternoon, a day and a morning of sun totaling 79 amp hours have not filled that poxy little 35ah battery then there’s something seriously wrong with the battery. As a last resort if tomorrow the fans work for only 20 minutes I’ll build a new strap to hold a lawnmower battery in place and will commence using an old lawnmower battery. I suppose I could also put the deep cycle battery on a charger overnight just in case. The signs so far point to a dead battery.

The culprit is identified!

Yesterday I forgot to turn my solar panels back on then remembered after I’d finished my blog entry. Today the sun has been switched on for about 8 hours. Assuming half the 65W of panels currently in use have been receiving sunlight then that works out at 30Wx8 hours or 240 watt hours or 20Ah. That’s around 2/3 of the battery capacity and I’m being conservative because it’s bright and sunny with no clouds.

I’d been using inaccurate button volt meters and portable volt meters when I realised my watt meter has a digital volt meter accurate to two decimal places. Anyway, that measured 14.37 volts. I turned the panels off and waited for 30 minutes for the battery to settle down. So, after 30 minutes the battery voltage read 13.33v which is an unusual voltage for any form of lead acid battery. I’d have expected 12.6 through 12.8.

After leaving the solar panels hooked up for another hour or so, I disconnected the panels and set the extraction fans and one light going. The current draw was reported as 58W and 4.2A which would be about right. The figures varied about 5% despite there being no solar power coming in. After 8 minutes the watt meter was reporting 12.31v.

At this point I’d like to remind everybody that a 35AH battery used down to 40% should be at 11.9V and should have used 21AH with 14AH remaining. When the charge controller starts pulsing the power I will have no idea what my watt meter will have recorded as current starvation will have robbed it of its records.

After 20 minutes the fan speed dropped and the lights started flashing. Battery voltage was recorded as 10.9v. So, lacking a comprehensive record, a quick calculation of 58W over 20 minutes yields about 20 watt hours or 1.4AH. Doing the math, that battery is not 35AH but 3.5AH. It’s not even the 15AH that some people accuse it of. That’s hopeless!

I now have a starting point for the rest of my mission. I have to dump that battery. Now I know where the problem is. A cheap-ass Harbor Freight battery. The coupon made it worth buying but I still spent $50 on it. I can undoubtedly get a better bargain from pretty much anybody. No wonder I found my battery was getting drained from charging my tablet!

One dollar - that’s all the Harbor Freight battery should cost. In fact, given how singularly poor the one I have is, perhaps instead of paying for it, customers should be paid to take it - straight down to the dump!

Even using the C8 calculation where current draw should be no more than 1/8th of the battery capacity, 35 ÷ 8 = 4.375, I’m still slightly under the (recommended) maximum current draw for battery longevity. There is just no possible way that this battery could have been anything but bad when I bought it. When I bought it, I checked the package and the battery carefully. It did not appear to have been used nor even out of its box. This battery must have been a lemon waiting for some fool to pick it up!

So, where now? I’ll have to head down to one of the battery suppliers - perhaps Interstate - to buy a real battery rather than this Harbor Freight battery. Now in Harbor Freights defense - most of the stuff I’ve had from them has been pretty decent. Their grit blower tool needed a little adjustment. Their angle grinders don’t last too long and can be faulty from the start. Their batteries are so-so but the rest sees to be pretty much OK. They do sell too much of the garbage LED flashlight stuff though.

Trying to track down the problem

My problems with the solar power system on the bus likely come from one or two sources. In order to track this down I put my watt meter on the load from the charge controller. Here’s what I found...

• The current usage from the door unlocker is between 0.01 and 0.02 amps which is in line with the stated 160ma.
• The current usage from my bigger LED bulbs is between 0.09 and 0.15 amps.
• The current drain on the 2.1A setting of my USB charging socket is about 0.9 of an amp
• The current drain on the 1A setting of my USB charging socket is about 0.88 of an amp
• The current drain of my smaller LED bulbs is about 0.03 of an amp
• The current drain of my shower pump is about 2.8 amps
• The current drain of my CPU circulation fan is about 0.25 amps
• The current drain of my twin ventilation fans is 3.8 amps

I think we are all probably agreed that is not really very much power at all. I am, however surprised by a couple of things.

• The CPU fans and larger LED bulbs draw slightly more current than I had expected.
• The twin ventilation fans and the small LED draw less than I had expected.
• The shower pump draws less than I had expected

Overnight the watt meter should have recorded far more power usage than it did, leading me to suspect the system ran out of power and shut off. This is just a theory - though I was awake at 5:00 I did not go to check.

My total current draw - assuming everything is turned on...

• 4 big LED lights 0.6A
• 2 small LED lights 0.06A
• 4 twin USB chargers 7.12A
• Both ventilation fans 3.8A
• Both circulation fans 0.5A
• The shower pump 2.8A
• The door unlocker (not counting the unlocking relay/motor) 0.02A

A grand total of 14.9A plus the unknown door unlocker. If I lay under the bus to activate it, in the 3 seconds it takes to work, my watt meter would not adequately record the amperage. Not only that but I physically could not roll out from underneath, rush up the stairs and down the aisle in 3 seconds.

Given that the battery voltage drops very quickly but hovers around 13.1v when seemingly fully charged, it’s a fair guess that there’s something very wrong with the Harbor Freight battery. It is supposed to be 35AH. There have been many anecdotal accounts however of it being far less than that with some estimates going as low as 15AH.

The charge controller is not exonerated. The charge controller is a diabolical nightmare. Looking around though there are quite a few other options. The MPPT controllers interested me but I was perplexed by the size and the massive heatsinks needed. Indeed one fellow commented that he had an EPEver charge controller that caught fire after a couple of months usage. That was a little alarming and as no details were forthcoming I don’t know whether he did something silly, whether it was a faulty unit or a faulty design. 

According to what I’ve seen from another reviewer, the MPPT controllers work as PWM until they have more than 10W of solar power as an MPPT conversion would be inefficient. Clearly then there’s a bit of power loss in an MPPT system that probably wouldn’t be noticed much if one was not normally running on 35W. I have two extra 30W panels but they’re not designated for regular every day use.  

Checking the system voltage with an independent voltmeter then checking it again with another independent voltmeter showed that the onboard voltmeters are inaccurate. These are the button voltmeters from China. Mind, the hand held voltmeters (one from Harbor Freight and one from Walmart) are hardly paragons of virtue both also hailing from China. The onboard voltmeters measured 13v while the handheld measured about 11.9 to 12v. That’s pretty much an empty battery.

The interesting thing is that the charge controller has three dots for the battery level and two are lit at 11.9-12v which to my mind should just have one LED illuminated when the battery is that low. Sadly, today and tomorrow are scheduled to be fairly overcast. I have my extra solar panels out, waiting to see how much power I can pull in. The panels have been reading 19 volts most of the day during the dry patches. I might have to do a part two of this entry tomorrow. I don’t want to pull the battery and put it on a car charger just yet. That’s a plan for another day.

I wish now that I’d bought two of these watt meters. They’re very handy when it comes to debugging a solar system. I’ve established my solar panels all generate pretty much what they should be and that the charge controller reduces what’s coming it, Putting the one I have as shown here between the battery and the devices really showed me how much power I’ve used and how much power each device uses.

My cunning plan now is to wait until the batteries are full then put both fans on and one light. The flashing of the light will tell me even if the fan noise desn’t when the battery is out of power according to the charge controller. I just time from when I turn the fans and light on until the fans and light go off. I check the current consumption a few times during this and know exactly how much power has been consumed between the point the charge controller declares the battery full versus empty.

In theory I should get 60% out of a 35AH battery or 21AH. That means the fans should run together with the light for exactly 5 hours and 7 minutes. I guarantee this won’t be the case however. I’m not even sure the charge controller will be able to fill the battery.

Transferring the watt meter to the solar input from the twin 30W panels was interesting. That proved very little current was going into the charge controller. Putting a 2.5W bulb onto a portable 5W panels produced plenty light from the bulb - just holding the panel up to the cloudy sky. It looks very much as though the charge controller is the bottleneck in the system.

There could still be two outcomes and not just one. The battery could indeed be bad and the charge controller could be bad. Indeed, I’m thinking favorably given the worthlessness of using MPPT on such a small system of just getting a linear controller. They’re pretty cheap and as we already know, I have an absolute maximum current burn of 15A. The extraction fans spike over 5A because they blew. 5A fuse and I had to replace it with a 7.5A fuse.

In other news, I found my missing pack of LED bulbs. These are the 1.5w bulbs that I prefer in the bathroom and back closet. Whether I’ve mentioned it or not I did also manage to complete the wiring for one of my cigarette lighter plugs. It was a significant challenge but it is done. The second plug seems to be missing its collar. I know its here somewhere and I might still find it.

At the moment, the finger seems to be pointing at the charge controller as being the problem child. More on this as I proceed!

Known Unknowns and Unknown Knowns

I was working with the solar system on the bus today and these are my findings....

• The LED charge controller gets to a certain battery high charge point then starts pulsing the supply from the solar panels.
• The LED charge controller get to a certain battery low charge point then starts pulsing the power from the battery
• The watt meter does work and reads correctly. When little power is being used, it tells me (confusingly) that there’s very little wattage. 
• The two 30W panels do produce at least 50W between them (maximum measurement point)
• An MPPT controller is likely to set me back over $120.
• A cheaper MPT charge controller is likely to be as bad as my existing MPT controllers.
• My blue digital charge controller throws a wobbly when the fans come on.
• I should have enough power from the panels to be able to run my ventilation fans straight from the panels.
• The batteries deplete when using the ventilation fans despite there being plenty power.
• The battery depletes rapidly but charges rapidly
• The battery is about 18 months old.
• I’m getting rather frustrated with the problems
• An LED bulb blew
• I need to install my rear solar input
• Maybe I need to install a mains trickle charge option for the battery.
• The portable solar panels are OK placed on the hood. 
• I managed to get one of the cigarette lighter plugs soldered.
• The cigarette lighter to SAE adaptor I ordered is still sitting in New York (according to the USPS website), having arrived there on the 24th. It has until July 17th to arrive so if it’s not here by Junly 18th I’m filing non arrival.
• A better place to house the house battery would have been the existing battery compartment. It can house 3 group 31 batteries. I only use two for driving.
• The amp/watt rating on a charge controller is controlling the amount of power that can be taken out of the battery. 

The bus is complete aside from sorting out teething issues such as the solar power. After the solar power there’s a buzzing relay under the hood and a power leak. Those two are probably linked. Other than that, the turn signal switch needs work and there’s a strange wire dangling under the bus that needs removal. The oil pan gasket needs to be changed and since the oil is 4 years old that too.

Resolutions (which may change with my mood)

• Replace the charge controller. If I can get a Harbor Freight 500W controller cheap then I’ll do that but it has to be under $20. Otherwise it’ll probably be an MPPT controller.
• Replace the LED bulb
• Install my rear solar entry.
• Chuck out all the cheap Chinese charge controllers and put a bullet through each one lest I be fool enough to pick them out of the trash and try them again.
• If the battery is toast then rather than buying a 35AH battery for $50-$70 at Harbor Freight, buy a 125 AH battery from Walmart and locate it inside the driving battery compartment rather than where my current battery is located.
• In the case of battery replacement, Install another line to power the fans directly from solar.

And I’ll probably moan about it all on whatever social media that I use. The solar panels do look quite pretty on the hood. I do believe though that the problems right now as far as the battery and ventilation lie squarely at the door of the charge controller and possibly the battery too. If it’s a dead battery then the cheap charge controllers killed it. 

Despite what I said yesterday about adding extra batteries, a quick calculation ow what tow well sited 30W panels will do is that at 50W they will produce over 5 hours, 250WH or 20AH of electricity. Add in what the other 35W produces and it’s sufficient. 20AH would power my extraction fans for 4 hours straight.

I’m thinking that because I don’t get many minutes from my 35AH battery, the cheap charge controllers have probably fried the battery. Now the advantage of the house battery in the main driving battery compartment is I can disconnect the driving battery as normal and if I need to jump start - it’s right there - I can jump the bus off the house battery or connect the house to the bus batteries to keep them all topped up when the bus is parked up.

Happy Renegade Colonial Hoodlums Day

Today a few years back some renegade hoodlums threw some tea in the harbor and considered that by breaking free from Britain they’d make themselves tax free. Hardly - America is now on its way to being one of the most heavily taxed nations on the planet. Taxes will soon have to rise as all the baby boomers retire and due to having worked for next to nothing all their lives and having no pensions will need to live off welfare.

Anyway, today I pulled the suspect SAE to cigarette lighter adaptor apart and found the problem. One of the contacts had slipped out of place inside the plug part of that adaptor. That’s now wedged into place with some wood. The end result is that the plug now works. So, will I now go ahead and buy extra SAE sockets? I don’t think so - it’s extra expense.

Today was a pretty cloudy day and I struggled to get more than 2 watts from my two 30 watt panels. I wasn’t out there early. I had a bit of a lie in this morning. Heaven knows why but I woke at 7 then felt very tired an the next thing I knew it was 10.

As can be seen by the lack of a point source of light, the sky was pretty overcast. The morning might have been sunny but as said, I didn’t know too much about the morning.

Just as I put the portable panels away I put my suspect meter on the battery connection. It seems I’m up from13.1v to 13.4v. That’s encouraging. I did see it briefly in the green earlier today but I’m wondering more whether the batteries are out of charge because the fans suck too much power. I might have miscalculated the amount of time I can have the fans switched on.

This is a video of what my watt meter says. Apparently the two panels have pulled in between the pair, about 1/4 of an amp hour. That was from the time I put them out which was probaby some time after midday until about 8pm. That’s not greatly encouraging.

I can see that I’m probably going to have to upgrade my solar capacity further. I looked to see how some people have attached their panels and wasn’t impressed. One guy simply riveted brackets to the roof panels and riveted brackets to the edges of his solar panels. Personally I think it would be better to mount two rails on the roof, attached to the roof supports then attach the panels to the rails. Riveting is good but the rails will have to be spaced off the roof in order to allow flexing and to stop the beams from causing stress fractures. In fact it makes sense to have some kind of bracket riveted to the roof and the rails just bolted to the brackets and the panels bolted to the rails.

If I can get the same size panels as I have now then I could probably put up to another 7 on the roof - along the very top, behind the air vent. That would give me a grand total of 305 watts of power. Perhaps enough to merit a second battery. On a poor day like today with just 1 watt per panel I’d still only get 10 watts total. Oh for a small generator! In fact, it would be possible to run a line from the front to the back and put a split charger connection where I could charge the battery straight from the alternator. That would help on a run but not if I’m parked up for a few days as I’m planning for September.

Those ventilation fans are the killer. Everything else will happily run off solar. My circulation fans use hardly any power. My lights use hardly any power. My shower pump isn’t on long enough to make much difference. Without the ventilation fans, everything would run perfectly off my existing 35w of power. I can tell you now, hefting those panels in and out is beginning to be an issue. I’m very  opposed to poking holes in a perfectly good roof but it’s looking like I might have to roof mount some panels. I could use stainless steel brackets riveted using stainless steel rivets then bolt galvanized slotted still angle. That’s available in both 6 and 8 foot lengths from the hardware store though it’d probably be cheaper in 20 foot lengths from the local metal supply place. Food for thought!

Two guilty parties?

No, I haven’t swept the sand off the step. Shocking, isn’t it? My old boss when I used to drive schoolbusses would have crucified me for having one grain of sand anywhere in the bus. Truth be told, I swept a goodly pile out yesterday and this is the result of just one or two entries and exits.

Today I put both my 30W solar panels on the hood and connected to my meter. That lot was all connected to the bus via the cigarette lighter port I’d installed. The amperage climbed to about 25W which was strange. I should have had 60W from those two panels. At one stage the meter reckoned I’d had 1.5AH of power which would have been consistent with about 40 minutes at 25 watts. 

As I held the meter to read it, the wattage dropped to zero. That was mighty strange. Well, the best I can figure having tested the whole system is that the SAE to cigarette lighter adaptorin the photo had died. Indeed I pulled the fuse out and replaced the spring too. Nothing. The fuse is good and the spring is new. It’ll read power one minute and not the next. It doesn’t surprise me. 

If you remember I had no end of trouble trying to solder wires onto a cigarette lighter plug and gave up on it as a waste of time. I’m pretty much there with the SAE to cigarette lighter plug adaptor that came with my Harbor Freight solar panel. The panel is good. The adaptor is just plain worthless.

Checking the website to see where my other SAE to cigarette adaptor is, it’s still swanning around in New York. I have grave doubts as to whether it’ll actually arrive since it has been there for over a week. For the moment my solar expansion plans are on temporary hold.

Clearly if SAE to cigarette lighter adaptors are as flakey as this and cigarette lighter plugs are as difficult to solder as they are, it’s time to pursue an easier path. Looking around there seems to be no panel that I can fasten to the side of the bus in the manner of my cigarette lighter socket that will allow me to plug in my MC4 connectors. There is, however, an SAE input panel. It fastens to the side of a vehicle and allows insertion of an SAE connector. I found the SAE connectors tough to pull apart but then so were the MC4 connectors. Thus, the SAE panel connector might well be the way to go. Since I already have plenty SAE connectors and can get them from the auto parts store fairly cheaply, that could be the way to go.

Meanwhile I ordered some more MC4 connectors. That’s so that I can make the two leads into one long lead with a double MC4 connector on the very end. Discussing the problems of soldering connections, somebody mentioned the availability of something called solder sleeves. Now I’ve not yet ordered any nor have I ordered any SAE panel connectors yet. I want to check my bank balance first.

Tomorrow being the 4th of July and Independence Day in the USA, Harbor Freight has a sale on (when have they not got a sale on). I might manage to get their $75 solar charge controller for $55. This doesn’t please Eric because he thinks I should get the ultra-expensive charge controller. Maybe he’s right but as I said - I’m a bit tired of buying stuff online that can’t be returned. None of this stuff from China is worth returning because the return postage costs more than I would lose just by taking the loss. Never pay more on ebay than you can afford to write off!

So the plan is to get SAE panel connectors - probably two of them. I have to wait 3 weeks for my MC4 plugs to arrive. I also have to get the Harbor Freight charge controller. Again, the write-ups are pretty contradictory and of low quality so it’s pretty much of a guess as to whether it’s good or not. If not then I know where to go to return it!

Some intreaguing thoughts came to mind. I looked at somebody installing solar panels on their bus roof. Now I am not super keen on that idea but if I must then... I figure I can probably do it and keep them down the centre line of the bus. If they’re all 30W panels which measure 26” x 14” (not the 18”x13” as claimed on Walmart’s website) then I can probably fit another 7 if I want, straight down the centre line of the roof, neatly behind the sole roof protrusion - the vent. That would give me 9 x 30W or 270w for a grand total of 305W. Of course, 7 more panels would cost another $220. I’m into minimalism though. I want to get what I have working before considering super duper expansions. Put straight down the centerline it would look a bit like a clerestory roof which would be fine. As long as it does not look like a camper!

So, it looks like I’m on the way toward nailing two of the problems. The charge controller and the connections. The old charge controllers I’m not sure quite what I’m going to do with them. Apparently it’s now a faux pas to shoot things in the back yard. I can’t very well shoot in the front yard because of traffic and other residences. I guess I’d best take up skeet shooting using crappy charge controllers as targets.

And now some intrigue. I wanted to harang Harbor Freight about their poorly made SAE to cigarette lighter adaptor. The best way to do this apparently is via Twitter. Thus, despite my sheer hate of Twitter, I set up an account. I put a name, gave an email address and put a profile photo of an orange. When that was all done I sent the normal Hello World message. That’s all I did. I put it to one side and came back an hour or so later to find a message stating that my account had been suspended. So I went through a silly little game they had me do - identifying the pictures in a grid with cars. Well, I did that and then it told me to go back and do it again. I did and got through that. The nonsense there was mindblowing! Then it told me to had to give it a phone number. That was when I realised that Twitter was probaby just collecting phone numbers to sell. I get enough spam so I deleted the app and went back to having nothing to do with Twitter. I’m really not surprised that Twitter is failing to attract users if it makes new users jump through hoops.. I don’t regard myself as unusual in that I won’t give out phone number. There’s also a limit to the amount of faffing about I’m prepared to do online. I’ve been asked to do numerous surveys etc and after the 3rd page if it’s not all done and dusted, I just quit out of them as it’s not worth more of my time. Twitter isn’t worth my time.

Working out the kinks

Charge controllers are supposed to do two things: To charge a battery unit it is full and no more and to permit discharge of a battery until it is at the point of maximum safe discharge. That’s a very narrow range between 12.7/12.8v and 11.9v. I’m never sure with my LED charge controller just whether I’ve got there. The LCD charge controller used to tell me that. I suspect the LED controller is cutting out way before the battery is full. In short I am singularly unimpressed by the charge controllers I’ve had so far.

I had a good 10A controller that was LCD and didn’t worry about my fans starting. The only problem was I blew it up. The rest have been a catalogue of woes. Reading what is said on the various solar websites, the’re all claiming there’s no point in a solar system less than 200W. I beg to differ. My system works just fine. The problem is that the charge controllers are singularly useless.

I switched my fans onto automatic and left them running for 5 minutes on the hour every hour from 10AM until I went to the bus at 4pm. By 4pm the charge level had dropped tremendously. In fact the fan started at 4pm and the voltage steadily dropped over the two minutes before I stopped the fan from 13.4v to 10.9v when the lights started flashing on and off. I could hear the power of the motor dropping way before that.

Given that I didn’t use the power much at all yesterday, the batteries should have been pretty well fully charged. The door control only uses 160ma apparently. The mystery is still what’s happening. It has been plenty light and the battery is a deep cycle battery and is only 18 months old. The fans will have used 5A between them for a grand total of 35 minutes or around 2-3AH. The battery is 35AH which means that even if there had been no sun at all, I’d still have used at maximum, 1/7th of the batteries capacity. Even allowing for the 160ma of the door controller that’s still just 1.6AH over 10 hours. Even at 1/6th of the battery being used there still should be more power left than it took to power the fans for 5 minutes just now. This is a total mystery and I’m going to have to say (I know there’re no current leaks because I know how I did the wiring) that it’s going to be either the charge controller or the battery that’s at fault with my money being on the charge controller. With a full battery and 5A usage I should have had at least 3 hours out of those fans before they stopped.

My second Hopkins to cigarette lighter adaptor still has not arrived from New York. According to the post office records it’s still there. Heaven alone knows why. I’m sure that if it had drugs in the shipment I’d have had a nice little visit from somebody by now. I can’t fathom why it has been stuck in New York for the last week. Thus I looked at my supplies and found I have more Hopkins adaptors. Thus I made a Hopkins splitter. This allowed me to plug both 30W solar panels in simultaneously. Currently then I have 5 solar panels interconnected for a total of 95W.

After I’d done that, I realised I’d blundered earlier. When I made the dual cigarette lighter plan, I. Should have realised that I could have run a single cord and had the Y connection close to the panels instead of  way away from them. That would have probably eliminated the need for an extra input at the back. Still who said I know what I’m doing? I’m working all this out as I go along! As it so happened I have enough leftover Hopkins connectors to be able to  convert both cables into an extendable single cable. That should work well. Had I found before I went for a cigarette lighter input, the SAE/Hopkins 2 pin terminals then I’d have got a few.

I put the infamous watt meter back on my panels - the twin 30W panels that is. Now I know how much extra power I’m generating. Heaven knows how accurate the watt meter is. That’s one of the problems I just don’t know how accurate any of these tools or measurements actually is. It’s like tyre pressure gauges. Try to get two of them to agree!

There, for the first time in recorded history are my two 30W panels side by side. What I have mounted permanently on the bus is fine for most of the year. I don’t need to use ventilation as much in the winter as in the summer. Thus there’s no point in permanently mounting more panels. In any case my reservation on mounting stuff on the roof is based on years of driving schoolbusses and encountering low hanging branches. It’s just not possible to see a lot of them either.

That’s my fancy cigarette lighter splitter. Had I used the Hopkins splitter then I wouldn’t be waiting for things to arrive!

As far as the charge controller is concerned, this pulsing nonsense when the battery gets too low is just sheer nonsense. It’s as much nonsense as the other charge controller going bananas when the fans go on.

I’m still at a loss to know exactly how a PWM charge controller is better than using a straightforward cut-out circuit that cuts out when the battery is full and just connecting the panels direct via that. As far as automatically cutting out when the battery hasn’t enough charge in it - that’s a whole load of nonsense. None of my charge controllers seem to do that properly. The LED version just pulses the power while the LCD version just waves its hands in the air futilely. As far as the LCD version having multiple settings, that’s a total load of baloney. It has settings that make you feel good about setting them. Whether they’re more than window dressing with no actual effect is open to conjecture. I rather suspect they don’t actually do anything but rather make the user feel as though they have done something.

My pal in France suggested I used a German or Danish charge controller as he doesn’t think much of any of the other varieties. He recommended Xantrex as a good manufacturer. Looking at the prices I almost fainted. Thus I looked at MPPT controllers instead of PWM. If you’re going to get expensive they you might as well get something worthwhile! Then I found worthwhile meant paying $500!

My next step was to look on Amazon. eBay is fine for cheap stuff up to $20 but once you go over that, it’s not worth the risk. Amazon can be a bit the same way which is why I usually end up ordering from Walmart. It’s so nice to have a counter you can go to to return things.

Looking at the costs I’m wondering whether a mode cost-effective solution would be just to wire the portable solar panels directly to the fans and leave the charge controller alone and let that handle things that the system was designed for - lighting and cell phone charging. Those with very long memories will recall that originally I had two CPU fans running from my two 10W solar panels. I had no battery and the world was excellent. That worked very well though it took forever to change the air in the bus.

There is a very basic charge controller. I suspect it’s what you’d call a linear controller for about $8. I gather that connects the panels directly to the battery to avoid faffing about. It costs off the panels when the battery is full and presumably cuts off the circuits when the voltage is too low. Nice and simple!

Anyway, it turned out the cheapest Xantrex 40A controller was $500. I’m not sure whether the amperage means input amps from the panels or output amps from the battery. In fact, it’s getting to the point where I’m just thinking of wiring directly to the battery and putting an over-voltage cutout circuit from a car. Then just pressing the button to check voltage occasionally! This fancy electronics just doesn’t work and costs too much.