Power Geeks! I need your help!!

[BeardyMan]

I've just bought a cheapo 4w solar panel and a 12v motorbike battery in an attempt to get me some off-grid power (only for baofengs/CB etc)

Question is: Do I need a charge controller? If so, can anyone recommend one that'll be fine for my little system?

I know the battery will take a while to charge from this panel, but when it's up and running it'll be permanently attached to the BOV, and I'll get something bigger for the home.

TIA

BeardyMan

[Prepper1]

Thats the same setup I'm getting.
I've got the array just not got a battery yet.
I wasn't going to use a charge controller as I've read that there only for arrays pumping out more juice than the battery can handle.
The controller thereby reducing it to a safe charge level.
But the array we've got is just a trickle type so produces less than the maximum allowed charge anyway.
It's something that's supposed to be left on constantly trickling into the battery.
I think theoretically if your battery was fully charged and the array was keeping it topped up, you just have to be careful not to take out more than the charger puts in.
The array I think produces 4 watts which is 0.33 amps @ 12volts so tha'ts not a lot of charge.
I used an online converter for that reading so....I presume that would charge at 0.33 amps per hour?

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therefore I presume you couldn't take more than 0.33 amps per hour out? or slightly less to maintain a small charge say 0.30?
Just my idea of the situation, I was going to try and combine at least another two or three of these arrays as money allows to help boost the charge rate and also let me run more stuff.
I maybe talking boll**ks I'm not sure, maybe an expert can tell us...

[Straight Shooter]

I,m off to maplins tomorrow to get a set up simular to yours

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let you know what i pick up

[BeardyMan]

(14 December 2012, 21:52)Straight Shooter Wrote: I,m off to maplins tomorrow to get a set up simular to yours

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let you know what i pick up

NNNNNNNOOOOOOOOOOOOOOOO!!!!
DON'T go to MAPLINS!!!
Get it off ebay. The identical solar panel in Maplins is £39.99! Ebay it's £19.99.

So does anyone know if I need a charge controller? I think I do, I don't want the battery trying to charge up the solar panel...

[Prepper1]

Ha!!! I got mine off ebay for the princely sum of £2.80!!!
Well lucky, mind you it was local pick up only so that helped I think.
Love the ebay!!

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(14 December 2012, 22:24)BeardyMan Wrote:

(14 December 2012, 21:52)Straight Shooter Wrote: I,m off to maplins tomorrow to get a set up simular to yours

---

let you know what i pick up

NNNNNNNOOOOOOOOOOOOOOOO!!!!
DON'T go to MAPLINS!!!
Get it off ebay. The identical solar panel in Maplins is £39.99! Ebay it's £19.99.

So does anyone know if I need a charge controller? I think I do, I don't want the battery trying to charge up the solar panel...

It has a thing on it to stop reverse flow to the panel from the battery.
cant remember the tech name, think its a diode.

[BeardyMan]

£2.80?! Jesus. Can I give you a shopping list

Cool, so that should stop the discharge from the battery then. Dog ate the paperwork that came with the panel, so haven't got a clue on the specs!

(14 December 2012, 22:56)Prepper1 Wrote: Ha!!! I got mine off ebay for the princely sum of £2.80!!!
Well lucky, mind you it was local pick up only so that helped I think.
Love the ebay!!

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(14 December 2012, 22:24)BeardyMan Wrote:

(14 December 2012, 21:52)Straight Shooter Wrote: I,m off to maplins tomorrow to get a set up simular to yours

---

let you know what i pick up

NNNNNNNOOOOOOOOOOOOOOOO!!!!
DON'T go to MAPLINS!!!
Get it off ebay. The identical solar panel in Maplins is £39.99! Ebay it's £19.99.

So does anyone know if I need a charge controller? I think I do, I don't want the battery trying to charge up the solar panel...

It has a thing on it to stop reverse flow to the panel from the battery.
cant remember the tech name, think its a diode.

[Prepper1]

I'll see if I can find them and post them, thats the name a reverse flow protection diode...

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Designed to trickle charge 12V lead acid batteries with no additional running costs. Ideal for cars that will be left standing for long periods, as well as for maintaining batteries in caravans and boats. The built-in blocking diode prevents reverse charging from the battery to the solar panel at night. The briefcase comes complete with an adjustable angle support that allows you to position the solar panels in prime sunlight. The solar panel is an amorphous receptor and is ideally suited to the northern European climate to enable the optimum use of daylight hours. It can even operate behind glass.


Solar Panel Features
Designed to charge 12V lead-acid batteries with no additional running costs

Portable solar generator built into a protective briefcase making it ideal for camping, caravanning or marine use

This charger requires only daylight to work, charges even if the weather is overcast or dull

Ideal for cars that will be left standing for long periods of time, as well as for maintaining batteries in caravans and boats

Built-in blocking diode prevents reverse charging from the battery to solar panel

Charge indicator

Interchangeable connectors: cigarette lighter plug and crocodile clips - 1.2M cables

Durable ABS outer casing

Integrated adjustable angle support

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This page has the operating pdf...

http://www.ecofreak.co.uk/pdf21701/4W%20...ctions.pdf

[BeardyMan]

Cheers Prepper1

[Skvez]

A general rule of thumb is that if the Watts of your panel (4 in this case) is smaller than the Ah of your batter (7 in this case) then you probably don't need a charge controller as the solar panel is too small to overcharge the battery. It will probably be able to do very little more than compensate for self-discharge.
However on a series of very sunny days in the summer if you're not taking power off the battery I'd check the Voltage as the two numbers are close.