Solar controller to aux batt connection.

Hi Konradical, and first off, you are unlikely to ever drive long enough to replace used battery capacity after some heavy use while camping before the drive.

So that info is basically correct, but it is not imparitive to fully charge the batteries after each use, but you do need to be able to replace the amount of battery capacity you did use.

That may sound like double Dutch but it is quite straightforward.

To give you a rough idea of what happens, you start you holiday with three 100Ah fully charged house batteries.

At your first free camping stop, you use say 150Ah of house battery capacity, discharging the batteries down to 50% SoC and then you hit the road.

Let’s say you drive for 4 hours. In that 4 hours you might replace 120Ah of used battery capacity, then you stope for your next camp. This leaves your batteries at 90% charged state.

Again you use 150Ah of house battery capacity, but as the batteries were at 90% SoC to start with, this discharges your batteries down to 40% SoC, and you drive for the same 4 hours, only this time you will replace the 150Ah used, getting them back to the 90% SoC, and you can do this as many times as you like.

This type of trip use is quite common, and it’s not until you get to a powered site that you will be able to fully charge state again.

The reason for being able to replace more capacity in lower discharged batteries, it that the last 10 to 20% of the charge cycle required to fully charge batteries, takes much longer to achieve so literally just ignore the top 10 to 20% of your batteries capacity, while you’re on the road, free camping.

Thanks guys, this information was exactly what I needed. I was hoping I wouldn't need to have to have a secondary system in place to prevent alternator charge from destroying the solar controller or have to mess around connecting things when stopped.

So far for the trip we will basically have a Engel 40L with "two zone" extender and run it on setting 4 or freeze and some LED lights for night time. For most of the trip there won't be phone reception (yay) so no need to charge phones, but may have sat phone on charge in case. This is our normal camp set up and so far we haven't used the solar panels for a top up. But saying that, we have usually done about 6-8hrs of driving between camps.

BUT, I am considering a second 40L Engel and an inverter for the things that need it (not sure as what yet, but the minister will surely have a need). This and the fact we will probably have a broken drive of no more than 5-6 hrs a day once we hit the route.

Also if I mount the panel to the roof I can turn it into a wind deflector for the roof rack.

Thanks heaps again.

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Originally Posted by Konradical

Thanks guys, this information was exactly what I needed. I was hoping I wouldn't need to have to have a secondary system in place to prevent alternator charge from destroying the solar controller or have to mess around connecting things when stopped.

So far for the trip we will basically have a Engel 40L with "two zone" extender and run it on setting 4 or freeze and some LED lights for night time. For most of the trip there won't be phone reception (yay) so no need to charge phones, but may have sat phone on charge in case. This is our normal camp set up and so far we haven't used the solar panels for a top up. But saying that, we have usually done about 6-8hrs of driving between camps.

BUT, I am considering a second 40L Engel and an inverter for the things that need it (not sure as what yet, but the minister will surely have a need). This and the fact we will probably have a broken drive of no more than 5-6 hrs a day once we hit the route.

Also if I mount the panel to the roof I can turn it into a wind deflector for the roof rack.

Thanks heaps again.

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For my Simpson trip 10 years ago.....way back when solar panel were just getting popular I mounted a solar panel on the roof rack and it served as a wind deflector..

I also ran two Engels, one as a freezer and one as a fridge.....I’ve never run on as a freezer since, we cryovac now which works better for us.

Quote:

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Originally Posted by Konradical

Thanks guys, this information was exactly what I needed. I was hoping I wouldn't need to have to have a secondary system in place to prevent alternator charge from destroying the solar controller or have to mess around connecting things when stopped.

So far for the trip we will basically have a Engel 40L with "two zone" extender and run it on setting 4 or freeze and some LED lights for night time. For most of the trip there won't be phone reception (yay) so no need to charge phones, but may have sat phone on charge in case. This is our normal camp set up and so far we haven't used the solar panels for a top up. But saying that, we have usually done about 6-8hrs of driving between camps.

BUT, I am considering a second 40L Engel and an inverter for the things that need it (not sure as what yet, but the minister will surely have a need). This and the fact we will probably have a broken drive of no more than 5-6 hrs a day once we hit the route.

Also if I mount the panel to the roof I can turn it into a wind deflector for the roof rack.

Thanks heaps again.

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Your alternator won't do anything to 'destroy' your solar. The batteries will simply absorb the charge from both as required. While driving your alternator will be more powerful so it will control the state of the batteries. When stopped, the engine isn't running so the power will come from the solar. They should both work fine. Neither will affect the other.
I have an 80 watt solar panel on the roof of my Defender connected to the PWM regulator and starting battery, because you always want to be able to start the vehicle. Everything works just fine. No problems at all.
Also, I recommend against using the solar panel as a wind break, as it will increase your fuel consumption unnecessarily. Just mount the panel flat, so it is getting sunlight all day. If it's on an angle it will only charge when facing the sun, but for three-quarters of the time your panel is likely to be facing away from the sun, so it won't work well. Just mount it flat, like they do on caravans, to get some sun all day.
My experience is a permanently mounted flat panel is a set and forget solution. Hope that helps.

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Originally Posted by DiscoMick

Your alternator won't do anything to 'destroy' your solar. The batteries will simply absorb the charge from both as required. While driving your alternator will be more powerful so it will control the state of the batteries. When stopped, the engine isn't running so the power will come from the solar. They should both work fine. Neither will affect the other.
I have an 80 watt solar panel on the roof of my Defender connected to the PWM regulator and starting battery, because you always want to be able to start the vehicle. Everything works just fine. No problems at all.
Also, I recommend against using the solar panel as a wind break, as it will increase your fuel consumption unnecessarily. Just mount the panel flat, so it is getting sunlight all day. If it's on an angle it will only charge when facing the sun, but for three-quarters of the time your panel is likely to be facing away from the sun, so it won't work well. Just mount it flat, like they do on caravans, to get some sun all day.
My experience is a permanently mounted flat panel is a set and forget solution. Hope that helps.

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I should add that this solar set up won't be a perminant fixture. It will primarily live on my RRC. But I will if required move it across for a trip where I feel as though I need the extra electron security.

I'm curious though as why it wouldn't help deflect some of the air over my roof rack, saving a fraction of fuel? For some reason I only chose to get a 3/4 frontrunner roof rack and when I have stuff on it, it becomes a vertical wall pretty much at the stepped up section of roof. Cos we have the extended roof rails I can mount a panel at about 30 degrees or so and it wouldn't be too much of a different angle to the windscreen slope.

In regards to getting the best sun, I can easily point the car to a north direction and get enough when not needing it.

But there may be an option to mount the panel flat in the same spot, might mean I get a smaller panel than I had originally planned.

It's a bit like people who drive around with a rooftop tent, increasing their fuel consumption.
A flat panel on an angle is like a wall, but having several objects of different sizes and shapes lets the air flow around them.
Anyway, whatever works best for you is fine.

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Originally Posted by Konradical

I already planned on taking a portable solar panel and connecting it to the rear Anderson plug, but I am currently toying with the idea of fixing one to the roof so we don't have to mess around unloading/loading panels when we stop.

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I saw a cunning idea in a recent 4WD Action mag where the vehicle owner fitted the panels under the roof rack and attached to drawer slides. When he stops, he slides the solar panels out. It leaves the roof rack free.

I am now wondering if I can do the same thing to my Rhino Racks Pioneer Platform. The only downside I can see is that it could limit running straps over and under the rack when loading the rack.

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Originally Posted by p38arover

I saw a cunning idea in a recent 4WD Action mag where the vehicle owner fitted the panels under the roof rack and attached to drawer slides. When he stops, he slides the solar panels out. It leaves the roof rack free.

I am now wondering if I can do the same thing to my Rhino Racks Pioneer Platform. The only downside I can see is that it could limit running straps over and under the rack when loading the rack.

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I have also seen this idea.

Unfortunately for my set up I have the frontrunner table under my roof rack, BUT, it gives me the idea to use two smaller panels to lay flat in front of the roof rack by having one on top of the other and the top one slides away to expose the second when stopped. Hmm.. I like this idea. Just need to figure out weights and mounting.

Quote:

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Originally Posted by Konradical

I have also seen this idea.

Unfortunately for my set up I have the frontrunner table under my roof rack, BUT, it gives me the idea to use two smaller panels to lay flat in front of the roof rack by having one on top of the other and the top one slides away to expose the second when stopped. Hmm.. I like this idea. Just need to figure out weights and mounting.

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I have also seen this done. I believe one problem with sliding mounts on roof racks is stopping them from rattling, particularly on corrugations. They have to be well-clamped.

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Originally Posted by DiscoMick

I have also seen this done. I believe one problem with sliding mounts on roof racks is stopping them from rattling, particularly on corrugations. They have to be well-clamped.

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