Solar

offgrid

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Just bought a 100w solar panel kit, what voltage should a healthy battery be at when idle and then with a load on? its a deep cycle 125ah - and if a hook up another in parrallel does that mean the power lasts twice as long?

Wanting to run a little LED tv and laptop from it - how long in hours approx do you reckon it'll last for,

Cheers
 
Hi, can't answer you query though interested in answer aswel, also where did you get the solar kit. Thanks
 
Try bimble solar or ebay ,i got two 100w panels well under £100.
the ans to how much use just add up the watts on tv etc then devide by 12 which will give the amps,from that you can recon on being able to pull about one third of total from batterys or until the voltage drops to about 11.5,never run the batts down to low as they will never 100% recover and there life span will be very much shortened.
 
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offgrid said:
Just bought a 100w solar panel kit, what voltage should a healthy battery be at when idle and then with a load on? its a deep cycle 125ah - and if a hook up another in parrallel does that mean the power lasts twice as long?

Wanting to run a little LED tv and laptop from it - how long in hours approx do you reckon it'll last for,

Cheers
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Hard to answer how long as it depends on your solar panels output and the power draw from the telly at a guess I'd say 5 or 6 hrs over 3 days with out the solar and just the one battery
 
a fully charged battery at idle should be at least 12,8 volt. will drop to 11.5 when flat
how long it takes depends on age and condition of battery.
 
trevskoda said:
Try bimble solar or ebay ,i got two 100w panels well under £100.
the anse to how much use just add up the watts on tv etc then devide by 12 which will give the amps,from that you can recon on being abble to pull about one thurd of total fom batterys or untill the foltage drops to about 11.5,never run the batts down to low as they will never 100% recover and there life span will be very much shortened.
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Correct me if I'm wrong but when I asked similiar questions an age ago I was told never go below 12.2 volts as this is approx 50% discharged.
11.5 volts is virtually discharged and will knacker the batteries if done regularly.
Searching Google confirms this.
 
what about hooking two batteries together, does that make it last longer?
 
Obanboy666 said:
Correct me if I'm wrong but when I asked similiar questions an age ago I was told never go below 12.2 volts as this is approx 50% discharged.
11.5 volts is virtually discharged and will knacker the batteries if done regularly.
Searching Google confirms this.
Click to expand...

Thats about the size of it.

It's not so much that you must never take below 50%, rather that it's bad practice to do it regularly as it will shorten the battery lifespan significantly.

Also, traction batteries can be taken down to 80% discharged. So it boils down to whether its a proper deep cycle traction battery or a quasi-deep cycle leisure battery.
 
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100 watt pannel good day 5amps per hour x8 winter

125AH your pannle could give you 40 amps a day useage
ave you used the battery with your camper or is new 12 .2 volts is as low as you want to go
On the back of tv should be a pannel to explain Useage mine tv is 35 watts lcd
100 watt pannel should give you up 30 amp a day winter 60 amp or more summer
Charging laptops can be high ampage some are 17/18 volts inverters needed
100 watts = at 5 amps per hour input/ chargeing 30 amps= 100watts
There are charts
 
My 10" Nikkai TV draws 10 watts and when battery is full, it will give 6+ hours of TV, not sure exactly how long as 6 hours is about the max I use (it also plays video and music).

However running it through a 240v inverter will use more power, so better to use the 12v cable.

I have a 100 watt solar panel, and for 9 months of year, the leisure battery is fully recharged by about 10am latest. However, this time of year, the panel will only recharge from about 12v to 12.4 during the day, often less. So I have to ration my TV use during Nov - Jan unless battery is fully recharged by driving.

If you run TV direct off 12v, especially with a solar panel fitted, you will need a 12v stabiliser which means that the current into the TV remains at a level which won't damage the TV - most TV's will work between 12v and 13v input but anymore will damage them. I discovered this whilst listening to radio through TV on a sunny summer day when solar input to battery was around 15v, result was that the sound was ok but no picture, just a black screen. New TV required.

You can get a 12v stabiliser from the Boatshare website for £25. Or only use TV when leisure battery is under 13v, ie, not whilst engine is running or solar panel is charging.

I never run my leisure battery below 11.9v under load from TV which means that when TV is switched off, the battery settles back at around 12.2v. My battery is 85ma, 3 years old and was secondhand when I got it. When it does eventually go, I will replace with a 110ma battery.
 
band driver said:
125AH your pannle could give you 40 amps a day useage
ave you used the battery with your camper or is new 12 .2 volts is as low as you want to go
On the back of tv should be a pannel to explain Useage mine tv is 35 watts lcd
100 watt pannel should give you up 30 amp a day winter 60 amp or more summer
Charging laptops can be high ampage some are 17/18 volts inverters needed
100 watts = at 5 amps per hour input/ chargeing 30 amps= 100watts
There are charts
Click to expand...

I'd be very surprised if you could get close to 40a per day in winter in the UK from a horizontal panel that size.

Its only about 8hrs between sunrise and sunset at the moment, and at Max height the angle is still very low, leaving a side issues such as cloud etc.

I wouldnt bank on getting much useful from panels this time of year.
 
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swiftcamper said:
Forget solar in the winter it is about as much use as a chocolate fire guard.
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I agree with this statement 100%.
Solar is great for most of the year but from Nov-Mar in the UK can't be relied upon to put any meaningful current back into the leisure battery.We have a huge 275 A/H Elecsol leisure battery which can usually last 3-4 days in winter without a recharge,any longer than that and we are looking for a ehu.Remember when it's dark at 5 o clock you will generally use the tv,lights and heating more so that will take a sizeable chunk out of your available amp hours.
 
Last Winter I was in the South of France and a 100W panel struggled even with the blue sky every day, I have since fitted 5x50W panels, new solar charger and two new 100A batteries, last week in Wales no sunshine but bright although cloudy and I still had more power going in than I was using which was 22" 12v TV, 12v Satellite Receiver and the van stereo on for the sound system for probably 5hrs pn, all LED lighting and the laptop using a 12v adaptor instead of my invertor, the point I am making is increase your input and try to cut down on your usage by using low power products, you should have tried doing this 20yrs ago
 
swiftcamper said:
Forget solar in the winter it is about as much use as a chocolate fire guard.
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I disagree, I would say that the efficacy is much reduced but that it's better than nothing. Last winter my panel was charging whilst it was snowing, admittedly not much, but there was something going into my battery, which is better than nothing. And I never have to worry about a flat starter battery as the trickle feed which the panel provides in winter is enough to keep the starter battery fully charged even if the van has been stood without being run for several weeks. No need to run the engine or plug into mains elec, and no running costs.

So long as you are aware of the limitations, even in winter a solar panel can be the difference between the van starting OK and having to call out breakdown for a jump start.

Yes, its definitely much less effective, but not useless. On a cold crisp sunny winters day, my solar panel can charge at 13+ v gor a few hours which can be the difference between the battery remaining discharged resulting in damage to the battery, and it being given some recharge which may be enough to prevent damage.

And the peace of mind knowing that even after standing for a couple of weeks in midwinter, the van will start OK is a big relief for someone for whom their van is their only vehicle.
 
swiftcamper said:
Forget solar in the winter it is about as much use as a chocolate fire guard.
Click to expand...

Have to agree especially if like me you watch long hours of tv with a sky box and inverter.
My 80 watt panel with mppt controller is great in the spring and summer but in winter it barely covers what the motorhome alarm etc uses standing on my drive.
I take my E20i Genny if wilding in Scotland and use C&CC CL's in England, just had 4 days in Cumbria paying £3.00 per day for ehu.
As I said earlier I would probably use more gas than that with heating etc running 24/7.
 
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