Electrical Q - Solar Panel

[binge]

Not bike related I'm afraid, but I know there are a few sparkies on here.

I was servicing a machine at a customers in Faversham last week, and one of the technicians there got chatting to me about my Transit.
I told him my plans etc, and he wondered off.
Came back with a solar panel.

The panel is about 3ft long, and about a foot wide.
It's got Battery Saver Pro, written on it, and 24v - 15w

It's also got something else written on it, like 'Maximum 50v - 80w'. But will double check exactly what it says.


It's got 2 wires, which have been chopped off about 4" long, so will need to extend them obviously.

My plans were to have it hooked up to my leisure battery on the Transit to keep it trickle charged all the time. Ideal for when I'm at festivals with no hook up, as it'll charge the battery during the day when we're in the arena, giving power during the night when we're back at the camp.


I took it outside the other day. No direct sunlight as it was about 7pm, but under natural 'light', it was kicking out 13.4v. Didn't check amperage as I'm not too clued up on that.


Now being a 'battery saver pro', is this thing likely to have a built in regulator for charging a lorry batter (24v system)? If not, what will I need, to have it fitted to my Transit (12v).

I've attached a picture of what it looks like (Found online), but will get some better photos of it tomorrow.

I also need to test it in good strong sunlight to see if it actually throws out 24v.

[binge]

Found the proper info:

Wp= 15W, Voc=24V, Isc=1002mAmps, Vspec=15V, 1@Vspec=966mAmps. System voltage max=50V.


And a better pic

ICP Global Technologies BatterySaver Pro 15-Watt 10008

https://img.epinions.com/images/opti/0c/25/pr-Shop_Tools-ICP_Global_Technologies_BatterySaver_Pro_15-Watt_10008-resized200.jpg

[kramdra]

This is a thin film type. All panels have some voltage drop, but this looks like designed for a battery without any electrics.

24v is open circuit. Vspec=15v is probably max power, 15v x 966mA = 14.5w.

15w likely to much to be permanently connected, but charge controllers are cheap, look on ebay.
Battery voltage should be under 14.7, so very close to Vspec, but it probably has a built in diode to prevent discharge and keep it under 15v.


Im not sure what I will get. 12v panels are expensive and large. 0.5v/4w silicon 6x6 cells are cheap, so prob best for me to get a few cells and a step up converter. Ideally I want a small panel on each bike - probably on topbox to top up battery and slighty bigger each garage for car batterys use for lighting/tools.

https://www.ebay.co.uk/itm/281431865484

[WD Forte]

That things just a panel and apart from a protection diode
wont have any inbuilt controller.
It will put out 1A at 15V on a good day which is at the limit you'd
want to charge a battery.

24VOC I assume is 'voltage open circuit'
this would drop as soon as you put a load on it and with load be closer to 15-12v.
If it was flat-ish it wouldn't be a problem as the panels limited
output would prevent it from doing any harm.
The snag is, as the bettery gets charged the voltage will climb and
this could overcharge it left unattended, so some sort of control would be advised.

this cheap enough for ya?

https://www.ebay.co.uk/itm/Solar-Charge-Controller-Solar-Panel-Battery-Regulator-10A-12V-24V-Safe-UK-Stock-/331128006254?_trksid=p2054897.l4275
____________________
bikers smell of wee

[Taught2BCauti...]

Plus 1 for the charge controller, but I would go for a 'MPPT' type rated at 10A or higher. Cost about the same but more efficient.

If you can get to the innards of the panel, remove any electronics (carefully so as not to damage the connections to the panel) and connect the panel output direct to the controller.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[G]

It seems this panel was intended for 12v, but using with an appropriate charge controller - some versions came with a charge controller, the internet says.

What sort of use are you expecting and what's the spec of your leisure battery?


15w really isn't much at all, getting to the point of wondering whether it's worth it.
As an idea, earlier in the year I paid £80 for an unused 240w (or so) 24v panel. Can mix this with a £15 charge controller and get a decent recharge - at Glastonbury it powered my reasonably efficient mains fridge just fine despite being in shadow a fair bit.
A similar panel would power my daily use (laptop,

An MPPT will make the most of the panel, but not sure it's worth spending the cash on a panel of that size.
I'd just connect it up to see how the voltage looks when connected to a battery in bright sunlight and if you've got a reasonably chunky battery, consider just using a diode.

Or, if I wanted actual solar charging, I'd probably consider just getting a more appropriate solution generally.

[binge]

Cheers guys. Some helpful input there.

I wasn't expecting it to be ground breaking, but just as a second source of power/charge for the leisure battery.
I've already got a split charge setup to fit, and it'll also have a hook up point for AC power/charge.
The solar is just an extra / free way to keep the battery topped up.

Website recons 30 hours will charge a leisure battery from dead flat. I wont ever really run it down that low, so on a daily basis on site, I should imagine the 5/6 hours a day it'll get of sunlight should be sufficient to keep the battery healthy.

Will buy myself a charge controller.

Just looking at that one on ebay. I see it has 6 terminals along the bottom. What is the far right one for? Is that for running an application directly from the panel?



Cheers,


Ben

[Taught2BCauti...]

The terminals on the right (with a 'bulb' symbol) allow you to connect a small load so that the solar panel powers it when there is sufficient solar energy, and the battery runs it when there isn't.

You could use it to power an ornamental garden pond pump, garage alarm or a shed light.

Depending on the model of controller, this output is usually regulated - so wouldn't be used to charge the battery.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[G]

You won't get more than 15w really and that's with no cloud. 15w × 30hours = 450wh.
450wh/12v=37.5ah.
Realistically, we're probably talking even less than this. Your leisure battery is probably significantly bigger than this.
A panel like this is probably ok if you're not using any power to keep it topped up, but not sure it'll be useful for anything more than light use.

We could equate that to needing an hour of daylight per hour you want to use a single small strip light. So if you used two strip lights for 5 hours and had 10 hours of sunlight, that bit would be 'balanced', but any other power use

Personally, I wouldn't get a controller for this.
I would select a controller for the panel you want to get in the future if that's your plan. Depending on your leisure battery, a diode is probably fine for this panel alone.

[binge]

Unless Solar Panels significantly come down in price, I don't think I will be replacing this one.
I really don't use the van as a camper, enough to justify huge power needs.

Anywhere I will be using the van in the daytime (I.E, race circuits with the bikes etc), they provide 240 hook up.

And places that don't, I will be using the van in the evenings anyway, where the solar will be useless.

So the main aim for this, is just to have something to trickle charge the battery at all times when I'm not in the van, and it's sunny.


In terms of a diode for this panel. Would it be wise to wire it via a switch too, so I can isolate it? Or do you think it's safe to just have it running the leisure 24/7?

[G]

The general rule of thumb used is that the power in watts should be 10% or under of the AH rating of your leisure batteries to run it with just a diode.

So if you have under 150ah of leisure battery, it's probably better to go for a charge controller.

The diode prevents a voltage being put back through the panel at night, if you didn't know.

If the van's being used regularly, I probably wouldn't bother at all.

If it's not being used regularly, I'd be tempted to have it setup to charge both batteries, but that'd require a bit of a different setup and more cost.

If this is for the ickle van you've had pictured before, not entirely relevant, but for my VITO, which needs a new battery, I'm tempted to replace the battery with an ultra-capacity pack for starting, then have two leisure batteries (as I happen to have two spare) for 'leisure' use as well as being hooked up for smoothing while running (though the 'caps will likely be fine for this).

[Taught2BCauti...]

Best to leave the solar panel connected to the controller and battery at all times, and if you disconnect the solar panel for any reason, cover it up.

Solar panels can be damaged if not connected to a load.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[binge]

https://scontent-b-lhr.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/10665868_10152699474660606_8623965661427250932_n.jpg?oh=a2ca9bce1ed00176a2509f0a2a8bb760&oe=5487E8A0


And as for damaging the panel. I didnt know.
It's currently in the garage in the dark, and before I got it, it was stored in a workshop, and had about an inch thick of dust on it.

Will remember that one though. Although I'm probably going to fit it, and leave it connected.
Only want it for charging the leisure. The Sub, amp, and head unit are connected to the leisure circuit, so there will always be a constant trickle drain on it, to keep the solar working anyway, as the head unit has memory storage etc.

[WD Forte]

Haven't looked at solar panels for ages
last I looked they were weedy (milliamp) little things and expensive
now you can get 12v 100W ones for not much.

I would use some sort of controller on yours though
even if its just 15W.
leave the van on a sunny day when the battery is charged and the
panel voltage will rise to well over the float charge voltage.
It looks like the old school panel so I'd just buy the cheap controller
____________________
bikers smell of wee

[G]

As above; £80-£100 for an unused 24v/220-250w panel on ebay.
Or bimble solar will do you a lightly used 220w in the quantities you require for £90.

[kramdra]

What about my idea of running some cells = 2v into a cheap boost circuit set at 14.5v? that gives no chance of over charging.

The only downside is the fairly massive current of 8A which might exclude cheap boost circuits. Can buy smaller cells but they are the same price, so much more £/watt.


Im not sure on the construction of silicon cells. I know they can be cut smaller and used in series but that often cracks/chips them. I wonder if just the connections could be cut allowing it to be wired up in series...

[G]

Why do you want a solar panel on 'each bike'?
I can't see a situation where this would be a great solution personally.

I'd just go for a cheap low power panel 12v panel with a diode if it's just keeping rarely-used panels topped up, or possibly with a cheap charger controller.

What sort of boost circuit were you thinking of using? Generally it works better to use a MPPT to reduce a higher voltage than the other way around - and as you note, this would mean less amps rather than more amps - that's another reason people go for MPPT in bigger systems - you don't need as much copper to transfer the power from your solar panels to your controller thanks to significantly lower amperage.