Discussion in 'Solar Power' started by andyman, May 1, 2009.
Has anyone got or know anything about these panels.
60W Solar Power Kit > Maplin
60W is nearly 5 amps Andy.
Handy for charging up to a 50 amp hour battery.
A bit of use between 50 and 100 amp hour.
2 of their panels would be more sensible.
Waste of time above that, probably more harm than good.
Ok for keeping worn out batteries warm/staggering I suppose.
You need good regulation for solar panels.
It comes with one
Interesting topic this one
Can you explain how you determine the relationship between solar panel outputs and battery size, as i would be very interested
Seen these several times and have been tempted to buy one. Personally i think they are good value, 60w for that price.
I dont think you get quite 5a think the output is somewhat less than that; but still a good buy.
In theory yes, in practice you might be lucky to see 3 amps with full summer sunshine.
OK to keep a starter battery topped up.. not much else.
So what size do you really need?
I have 2 new 100 amp batteries and they never get any charge over 12.7 volts and my TV kills them easily with an inverter (one night viewing) but I hear people speaking of battery charging on 14 volts+, how do you get this charge level?
I apparently deafen people all day with my kipor running but does use 1/2 gallon of fuel.
Braunston, charger battery relatioships are a minefield.
Most authorities agree at least 10%, say 10 amp for up to 100 amp battery is best.
30% is probably the very best.
After that, not all batteries are equal.
Battery charging is controlled by a very complicated law, Peukart's Law.
It's complicated because it isn't commonsense.
Basically, using ball park figures.
If a 100 amphour will run a bulb for 10 hours.
Then 2 x 100 amphour batteries will run it for 25 hours.
3 x 100 amperhour batteries will run it for 40 hours.
The same applies to charging.
If you hook a charger to a 100 amphour battery it will take say 10 hours.
If you hook the same charger to 2 x 100 amphour batteries 25 hours.
If you hook the same charger to 3 x 100 amphour batteries 40 hours.
The above are just kick-about figure.
The situation is complicated in that the first few amps are wasted pushing teh current through the battery.
A 10 amp charger only gives a useful 70 amps say.
There are two answers.
Buy the biggest intelligent charger you can afford.
Buy several smaller ones.
I have thre intelligent 11 amp chargers.
I use them in parallel on the same battery bank.
It seems to work.
Road runner, you need the biggest solar panels you can afford.
Then you need to keep them at a right angle to the sun.
You will never see more than a 12.7v from your batteries.
Unless they are being charged, or have recently come off charge.
The Maplin panel comes with a regulator, I doubt if it's what I mean by a good one though.
A windcharger is probably a better bet in the UK.
14.4 volts is probably the best charging voltage Road Runner unless you have a very intelligent charger.
We get it from our alternators and or our chargers.
Personally, I run my engine at fast tickover to charge my batteries.
It's a diesel so I sometimes get complaints about the fumes, and have to stop.
I try to park to reduce the nuisance.
I use my Kipper and a couple of 11 amp intelligent chargers sometimes.
I take the Kipper as far as I can from others, and use a long lead to get power to my van.
I keep promising to make a wooden "dog kennel" to reduce the nuisance.
Braunston CORRECTION, sorry
A 10 amp charger only gives a useful 7 amps say.
Don,t go parking next to me with your Sunlight stealing Solar panel. A nice generator thats what you need hardhathardhathardhat
nearly bought one of these last year until i found they cant (easily) be roof mounted and they arent 100% waterproof.
blurb says showerproof but whats a shower......two minute deluge or an hour of drizzle ?
bought a proper one instead :thumb: 120w panel and regulator £400:thumb:
:thumb: :rollonfloor: :rollonfloor: :rollonfloor:
the Marlin 60W panel Will not charge at anything like 5 amps unless it is midsummers day and the sun is directly overhead with the panels pointed directly at the sun. My 50 has only manged a paltry 1.5 amp at any time so far this year, but don't forget it does put something in every hour no matter how small an amount. I will add details tomorrow, when I bring the data home of a full charge period dawn till dusk.
having said that I have a pair of 120 amp/hr batteries, they lasted us a week at Camarthen without running the Genny. Within one day of getting home the regulator has stopped the batteries from charging further. The leisure batteries are currently only charged by solar following mice damage to charging circuit. So 50w although small will cope with low level use. we used a TV 5-6 hours a day plus water pump and lights. A colour TV will pull the battery down but for B/W we cope. We always wildcamp never have a hookup and have not yet used the generator for charging. The panels kept all batteries fully charged all winter including the engine batteries (2 x 12Vx 88amp/hr). So for us they are worth the effort and cost.
My question is where do they get the 60W from 60W at 12Volt, well it charges at anything up to 18V so the Wattage will be much less. I think it is just a guesstimate and nothing more.
Wildman, batteries are resistances (resistors).
They have what's called internal resistance.
When you charge a battery, part of the current is wasted overcoming the internal resistance of the battery.
If you reckon the first amp passing through a good battery is wasted overcomeing the resistance of the battery, you'll have a starting figure.
After that, some of the charge is used overcoming the self-discharge rate of the battery.
Your paltry 1.5 might just about maintain a 100 amphour battery in cnjunction with an intelligent regulator.
With a less than intelligent regulator, there's a fair chance that it will do more harm than good.
Intelligent chargers only "trickle charge" (float charge) full batteries.
They vary the voltage and current to suit the state of charge and capacity of your batteries.
I know all about internal resistance of batteries, I do believe it or not have an HNC in electrical/electronic engineering one of the modules being measurement and test so I do know what I am measuring and what affect various things have on that measurement.
My observations are exactly that observations of a genuine setup, internal resistance has nothing to do with the charge rate of the solar panels it only affects the amount of useful charge reaching the battery. The fact is these panels keep my batteries charged on their own without alternator or generator help and that is the point I was trying to make. The longest trip has been 3 weeks and they remained full charged all that time those are facts, not fiction or book study or guesswork but fact.
whilst your observations are obviously trying to help they are I fear far too technical for most of the readers of this forum and will only cause confusion, it appears you always write as a result of research, whilst most of us write from practical experience. and there is a world of difference between the two.
Don't forget your voucher codes ,you should be able to save a few quid on top of that again :thumb:
Wildman, I put my responses at what I feel is a suitable level for the person to whom I respond.
In your case, I may have placed them below you level.
My estimate was influenced by your question "My question is where do they get the 60W from 60W at 12Volt, well it charges at anything up to 18V so the Wattage will be much less."
With an HNC, you really aught to know that the 60W is based on a nominal 12v, in just the same way as 12v alternators produce 14v.
Have you actually measure 18V when your solar panel is charging please?
Did you measure the current at the same time, if so what was it please?
Incidentally, does 18v suggest anything to you about your regulator?
Where my responses are too technical, I hope people will ask me for a clearer explanation Wildman.
Do you find that unreasonable?
I am at a loss however, to understand your point that "internal resistance has nothing to do with the charge rate of the solar panels it only affects the amount of useful charge reaching the battery".
I'm not quite sure how you consider that there is a charge rate of a solar panel.
From my point of view, my comments were solely directed at teh useful charge reaching the battery, it that means the charge that's useful in actual charging rather than overcoming the resistance of the battery.
Can you explain to me please how you measure the state of charge of your batteries.
Do you record the input and output of curreent from your batteries.
If so, what factor do you apply to allow for battery efficiency please Wildman?
As you point out, I try to make my observations from research.
However, your assumption that I don't research evidence of people's experience is incorrect.
I research, value, and collate other folks' experiences.
Hence my keen inters#est in your research and your methods.
We had our first weekend away in our camper last weekend for the Peterborough show. I have a 100 Watt panel on the roof, two 110AH Elecsol batteries and a compressor fridge (IndelB 100 litre). Very pleased to say that the solar panel more than kept up with the power requirements. Okay it was only the fridge, a few fluoro lights for a couple of hours and about an hour of TV each night. The batteries never showed less than 12.3 volts first thing in the morning and by teatime were back to 13.3 at least. Even in the workshop for the last week the batteries haven't fallen below 12.8.
I will be having 2 x Elecsol 110 A/hr batteries so looks like a good 100 watt panel will be required.
Just as a matter of interest do you meusure the voltage using a meter and test leads or is there a control panel which actually shows the voltage, as opposed to the silly green and red LED thingys which I always feel are a bit vague, I much prefer to see the actual voltage (Either in analogue or digital format)
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