Solar panel help on amps needed

Turboman · May 11, 2019

kermit_rr said:
Don't forget your charge controller isn't 100% efficient and PWM controllers are less efficient than MPPT controllers, but MPPT are much more expensive.
Also remember to keep your panel clean and shade free. Because of the way solar cells are wired internally, covering 10% of your panel will reduce output significantly more than 10%

I wash the panels regularly, and more often is they get bird sh!t or muck from trees on them.
As you say, doesn't take much to drastically reduce power output.
I use car shampoo in a bucket of water, and a mop.

George25 · May 11, 2019

Turboman said:
That sounds like a good system, provided you will be running the vehicle most days. If you are intending to be parked up for long periods of time, without mains hook-up, your leisure battery capacity sounds on the low side.

Panels are useful for top up, but modern power usage is surprisingly high, water pumps, charging computers and phones, TVs, stereos, and the fridge chugging away all the time.

I have 600W of panels, 4x110ah leisure batteries, one same for starting, which is charged by a 45A alternator, there is a separate 130A alternator that charges the leisures.
I still turn the 230v fridge off at night, though, so as not to run the battery bank down too much while the panels and engine are not charging the leisure batteries.

Hi We sound a bit primitive compared to your system. No TV, No computer, No stereo. 12 v ARB fridge 30 or40 litres couple of LED lights otherwise its hurricane lamps, propane cooker with piezo starter. The propane water heater does have a small pump though which I had forgotten about. I think we will have to monitor what the fridge uses and worst case powder milk etc. If we can pick up ice locally we can use this to reduce how often the fridge cuts in .

Turboman · May 11, 2019

George25 said:
Hi We sound a bit primitive compared to your system. No TV, No computer, No stereo. 12 v ARB fridge 30 or40 litres couple of LED lights otherwise its hurricane lamps, propane cooker with piezo starter. The propane water heater does have a small pump though which I had forgotten about. I think we will have to monitor what the fridge uses and worst case powder milk etc. If we can pick up ice locally we can use this to reduce how often the fridge cuts in .

That sounds very good from a battery life point of view.

But wouldn't be adequate for me, because I am on the boat most of the time, I need the necessities of modern life.

Don't you have a domestic water pump for a shower?

George25 · May 11, 2019

kermit_rr said:
Don't forget your charge controller isn't 100% efficient and PWM controllers are less efficient than MPPT controllers, but MPPT are much more expensive.
Also remember to keep your panel clean and shade free. Because of the way solar cells are wired internally, covering 10% of your panel will reduce output significantly more than 10%

HI yep we are thinking to splash out on mono crystal. We are thinking not to mount the panel on the vehicle but on a stand so we can make best use of angle and shade problems. I kind of get the feeling that a 100 amph panel should do us maybe 120 with a hope of getting 10%

Turboman · May 11, 2019

George25 said:
HI yep we are thinking to splash out on mono crystal. We are thinking not to mount the panel on the vehicle but on a stand so we can make best use of angle and shade problems. I kind of get the feeling that a 100 amph panel should do us maybe 120 with a hope of getting 10%

Mounting the panel on a stand is a good idea, and will make washing easier as well as siting.
But don't forget you need to keep the wire run as short as possible, line loss is a big problem with low voltages.

George25 · May 11, 2019

Turboman said:
That sounds very good from a battery life point of view.
But wouldn't be adequate for me, because I am on the boat most of the time, I need the necessities of modern life.

Don't you have a domestic water pump for a shower?

Hi No its a propane water heating geyser made by Kampa and has a little 12v pump that sucks up water from any container. One pass through the systen raises the temp by 10 c then discharges it either through a spout to a sink or shower head or if you wamt hotter water back in to the container to raise it further. We are not likely to have a mains water hook up and don't want to carry a huge amount of water but top up every 3 or so days

George25 · May 11, 2019

Turboman said:
Mounting the panel on a stand is a good idea, and will make washing easier as well as siting.
But don't forget you need to keep the wire run as short as possible, line loss is a big problem with low voltages.

Hi Yep good point, hadn't thought of that

George25 · May 11, 2019

Turboman said:
Lot of dual purpose batteries are available now. Bit of stuff about the various types and their applications here.

https://www.shieldbatteries.co.uk/applications/leisure.html

Hi The smart thing would have been to come to this site before we bought the batteries. With hind sight duel purpose would have been a better idea

kermit_rr · May 11, 2019

George25 said:
Hi The smart thing would have been to come to this site before we bought the batteries. With hind sight duel purpose would have been a better idea

I've thought about them but not done any research. My question would be, are they ok at both, great at neither?

Si Click · May 11, 2019

How are you all securing your panels? I'm planning on putting about 200W onto the aluminium roof of a hard shell roof tent and want to put as few holes in it as possible. If I go for conventional mono panels then I can use brackets and bolt or rivet them, but even with lots of silicone I run the risk of leaks. I am toying with the idea of flexi panels and holding them down using silkaflex with maybe a rivet at each corner to prevent motorway liftoff.

What is the usual method for securing against 70+mph winds?

kermit_rr · May 11, 2019

Flexi panels are also not that efficient

The ones on my parents van are bolted with lots of stuff round. It's not silicone like the Flexi bath sealer type, its quite hard and so far doesn't leak

George25 · May 12, 2019

Si Click said:
How are you all securing your panels? I'm planning on putting about 200W onto the aluminium roof of a hard shell roof tent and want to put as few holes in it as possible. If I go for conventional mono panels then I can use brackets and bolt or rivet them, but even with lots of silicone I run the risk of leaks. I am toying with the idea of flexi panels and holding them down using silkaflex with maybe a rivet at each corner to prevent motorway liftoff.
What is the usual method for securing against 70+mph winds?

Hi Well for what it's worth my idea is to NOT mount them on the vehicle. Idont wont ti increase the roof height in any way so we canstill get into normal car parks etc. And I would be paranoid about leaks SO Rigid folding panel that has a rigid case bit like a slim suitcase. Comes with a sort of folding stand. I intend to put a couple of waterproof sockets inside a side locker and plug into one of these. We have a baker style tent that has access through the rear door so we can use the cooker etc but nothing capable of taking a solar panel. Still looking at panels but now have a better idea of output I need

Turboman · May 12, 2019

kermit_rr said:
Flexi panels are also not that efficient
The ones on my parents van are bolted with lots of stuff round. It's not silicone like the Flexi bath sealer type, its quite hard and so far doesn't leak

Could be Sikaflex, there are various grades, the marine ones are pretty good.

Turboman · May 12, 2019

George25 said:
Hi Well for what it's worth my idea is to NOT mount them on the vehicle. Idont wont ti increase the roof height in any way so we canstill get into normal car parks etc. And I would be paranoid about leaks SO Rigid folding panel that has a rigid case bit like a slim suitcase. Comes with a sort of folding stand. I intend to put a couple of waterproof sockets inside a side locker and plug into one of these. We have a baker style tent that has access through the rear door so we can use the cooker etc but nothing capable of taking a solar panel. Still looking at panels but now have a better idea of output I need

Sounds good. What sort of vehicle are we talking here?

George25 · May 12, 2019

kermit_rr said:
I've thought about them but not done any research. My question would be, are they ok at both, great at neither?

Hi My problem is that it never occured to me to look and its too late now If I was starting to play with the landy again I would take a look see. Thats whats magic about the internet and forums like this info at the touch of a button.

George25 · May 12, 2019

Turboman said:
Sounds good. What sort of vehicle are we talking here?

Hi I was hoping nobody would ask, my mantra is keep it simple stupid so no bells and buzzers SO why I here you ask why the 2.2 puma (110) it ani't simple and perhaps Iam the stupid bit

George25 · May 12, 2019

Turboman said:
I wash the panels regularly, and more often is they get bird sh!t or muck from trees on them.
As you say, doesn't take much to drastically reduce power output.
I use car shampoo in a bucket of water, and a mop.

Hi We are in Wales honest not Morocco but last week or so sand came from somewhere. Floor mounted there is no excuse for me not to keep things clean

Turboman · May 12, 2019

George25 said:
Hi I was hoping nobody would ask, my mantra is keep it simple stupid so no bells and buzzers SO why I here you ask why the 2.2 puma (110) it ani't simple and perhaps Iam the stupid bit

That explains a lot of your previous posts. When you said "camper", I had assumed a purpose built modern vehicle on a van base or similar.

Now I understand why you don't have much space, and few conveniences.

George25 · May 12, 2019

Turboman said:
True.
But don't forget all the other drains on the leisure side, that often occur during darkness, and when the engine isn't running.
Shower pumps, domestic water pumps, entertainment systems, phone charging, etc.

There really isn't any substitute for decent battery bank capacity.

In practice, you get a decent charge off flat mounted panels, but only around midsummer in the UK.

Hi Thanks like really thanks.(especially for the calculations) So Space for another battery is very tight but I will buy a 120amph mono crystal ground mounted rigid panel (not 100). Moving it around to follow the sun keeping it clean etc shouldnt be a problem and an MPPT controller. Worse case if the leasure battery, solar panel cant cope then the fridge getss turned off. The battery management system can't rob the vehicle battery unless I over ride it. Not the end of the world, warm water is OK cold beer not needed. Coffee black, white, hot or cold essential and we have several ways of taking care of that

Turboman · May 12, 2019

George25 said:
Hi Thanks like really thanks.(especially for the calculations) So Space for another battery is very tight but I will buy a 120amph mono crystal ground mounted rigid panel (not 100). Moving it around to follow the sun keeping it clean etc shouldnt be a problem and an MPPT controller. Worse case if the leasure battery, solar panel cant cope then the fridge getss turned off. The battery management system can't rob the vehicle battery unless I over ride it. Not the end of the world, warm water is OK cold beer not needed. Coffee black, white, hot or cold essential and we have several ways of taking care of that

No worries. In the interest of fairness, I should point out that it was somebody else who supplied the calculations. My advice was more general, and based on my experience with boats, which have lot more carrying capacity, and usually more room to mount the panels.

Solar panel help on amps needed

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