Rather depends on what roof you have I guess, mine is a leisure drive , and SwMbO's is a auto sleeper, we both have 150w semi flexible panels
Frankly if you have the roof room, and are starting from scratch I would say buy the biggest you can fit , because it's cheaper per watt the more you buy , and you can never have too much free electric ! Definitely do not bother with anything smaller than 100w
Tintops present greater challenges in that respect and you'd have to do it in stages, ie 100 watt or two to make 200 watt. I agree though, 100 watt is a minimum given that you'll lose some of that power anyway but it'll still charge a leisure fairly rapidly on a sunny day (an hour from what I've observed) and say three to four hours if its slightly overcast. My view is that 200 watt might be nice, but not essential just to keep the battery topped up during the camping season. During the winter the best you can expect is a very small trickle charge when parked but allow you to run the Propex at night.
The fact I've been able to drive to work and back for a few days with no alternator, relying wholly on residual battery voltage and only a solar top-up each end, is fairly impressive. Obviously with a panel that just sits flat on top (albeit curved) won't compete with a panel aimed to capture the sun, but providing you park sensibly, you'll definitely charge up the battery ok and we're only in March. I guess if you do a good deal of mid-winter camping, 2x100watt would be about right. You've actually got the potential to fit 3x100 watt on a tintop plus smaller ones at the front and back if you really wanted to but it all starts to look ugly then. Mine does the job, is barely noticeable and that suits me.
The only slight change I'd like to make is a rocker switch so I can charge starter battery if required without messing with connections. Other than that, these basic flexi kits work very well for under £150 and you can add extra 100 watt panels for about £100 a go.
Builders clear silicone adhesive is definitely the stuff to stick it down with - not silkaflex.
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.
CovKid wrote:
The only slight change I'd like to make is a rocker switch so I can charge starter battery if required without messing with connections.
Why not just buy a dual controller then both batts get charged at whatever ratio you choose and when the primary is full the secondary gets charged.
Rocker switches are a lot cheaper than dual controllers. This is Ralph remember
Note he says "make a rocker switch" not go out, like a mad impetuous fool, and actually buy one
If you moved the charging lead (from the alternator) to the leisure battery, then used a voltage sensing relay the opposite way round, ie sensing the leisure battery voltage and "feeding" the starter battery when triggered. Then the feed from the solar (to the leisure) would automatically also charge the starter once the leisure voltage rose to the relays trigger level and the starter battery would still charge up when driving (via the relay).
If you moved the charging lead (from the alternator) to the leisure battery, then used a voltage sensing relay the opposite way round, ie sensing the leisure battery voltage and "feeding" the starter battery when triggered. Then the feed from the solar (to the leisure) would automatically also charge the starter once the leisure voltage rose to the relays trigger level and the starter battery would still charge up when driving (via the relay).
Ummmm
why, when a solar charger is about the same price and already does that job? and gives both the panel and battery protection against over charge and back feed..... no point !
ghost123uk wrote:
Rocker switches are a lot cheaper than dual controllers. This is Ralph remember
Note he says "make a rocker switch" not go out, like a mad impetuous fool, and actually buy one
NO reread that, he says the only change he would make, is a rocker switch........
CovKid wrote:
The only slight change I'd like to make is a rocker switch so I can charge starter battery if required without messing with connections.
Not short of controllers - got two. Just bear in mind I use a 5-pin relay to split charge while running so its energised by alternator trigger wire. As soon as I park the leisure is disconnected. I could power the relay I suppose in order to charge both but I'm inclined to take Kev's approach and charge leisure 70% of the time and starter 30%, so the simplest solution is to fit a two gang light switch (good for 16amps) meaning I can choose starter or leisure. I'd have thought that was the simplest solution. Its not about saving money, although as a single parent I do have to be careful, but I can't see it needs more than that.
Mind you, Ghosts plan is a good 'un.
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.
I'm a bit lost here, not too difficult to do though.
I too have the typical split charger relay system, ie relay triggered by alternator wire so only charging when engine running.
Then my solar panel is connected to both batteries via dual the controller which I can prioritise from 10%-90% through 90%-10% to whichever battery I deem needs the most charge, once the 'main' one is full the controller automatically starts to charge the secondary.
Forgive my ignorance but I thought this was standard practice regarding the solar installs, I'm a bit confused with the need for additional switches when the controller does it automatically.
Well I've got two controllers (each will charge one battery) so loath to buy yet another one just to charge both. That said its possible to split incoming power from panel to two controllers I've got, so could do it that way I guess. I don't have quite so much need to charge starter via solar as theres almost nothing on that circuit now other than when starting/driving. It was useful being able to charge starter this week but only because I had alternator problems. So yep, you're right I could buy another controller but have a feeling a switch, for those very rare occasions I might need to charge starter from solar would do it.
Actually, I didn't say I'd 'make a rocker switch' John. Thats going a little too far - even for me. Besides, I've already depleted the lads lego set.
20 tri-LEDs arrived today. Soldering iron heating up....
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.
Switching manually via a three way switch between the two batteries would work,( it's the same way I have my mains charger configured so I can charge either battery at the flick of the switch with centre being off ) but the split charge shouldn't have any bearing nor effect on what the solar panel is doing , other than telling the solar controller that the alternator is charging and therefore switching the panel in put off .
To be honest , I have a switch in the trigger wire to my split charge anyway , and it hasn't been switched on since I installed the solar panel other than to test periodically , it not needed mostly .
My controller is set to 90% leisure and 10% main battery and that seems to work fine .
But no you can't split the feed from the panel between two solar controllers , they would "argue" over the different voltages being reported back by the batteries I think
I assume you already had the chargers so made good use of them, I just couldn't see the point of having extra controllers/switches when one would do everything.
One came with the panel, the other was given to me. They both work. You can certainly split a panel between two controllers since each is only reading the battery its attached to and as each is therefore dedicated, it may actually be better than a dual. The downside (possibly - not tried it) is that each will see a reduced power input depending on what the other is doing and the 90%/10% thing wouldn't apply obviously. So far the rocker switch wins in terms of simplicity if not cost as I'm unlikely to need to charge the starter battery much except perhaps in an emergency or say a few hours before leaving camp. I do see the merit in a set-and-forget solution though although if I did get another I think its likely to be an MPPT one. Good ones cost a fortune in comparison to PWM controllers.
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.
Blimey.....i used to think this solar stuff was as simple as pointing the van into the sun and comparing amps for the rest of the day whilst holding a beer.
