Solar battery charger.

[JerryRtilt]

Does anyone have any experience with Solar battery chargers ? I'd like to use one to maintain the battery and compensate for the parasitic drain from the immobiliser and tracker on my 8 toner while its not in regular use.
As usual there's a bewildering choice on Amazon and Ebay, don't mind spending a bit for something that actually does what it claims to do and lasts more than a fortnight

 

[Gecko]

I don't use an 'out of the box' solution, but I do the same using 2nd hand domestic roof panels and mid-range solar regulators. Trouble is they are roof mounted and I'm guessing you're after a compact solution you can put in the cab window? (I built one like that too, but yet to convince myself how useful it is).
I was given a 'car battery maintainer' (just a solar panel about 12"x4") - it has no regulator at all and relies on a low output not to damage the battery. Avoid that type.

 

[6feetdown]

Does anyone have any experience with Solar battery chargers ? I'd like to use one to maintain the battery and compensate for the parasitic drain from the immobiliser and tracker on my 8 toner while its not in regular use.
As usual there's a bewildering choice on Amazon and Ebay, don't mind spending a bit for something that actually does what it claims to do and lasts more than a fortnight

I bought 1 for about 20 off amazon 2 years ago seems to do the trick doesn't charge past the state the battery is in

 

[JerryRtilt]

I don't use an 'out of the box' solution, but I do the same using 2nd hand domestic roof and mid-range solar regulators. Trouble is they are roof mounted and I'm guessing you're after a compact solution you can put in the cab window? (I built one like that too, but yet to convince myself how useful it is).
I was given a 'car battery maintainer' (just a solar panel about 12"x4") - it has no regulator at all and relies on a low output not to damage the battery. Avoid that type.

Thanks, i think i'll try this one, has a charge controller and i think i'll have it on the cab roof

 

[V8Druid]

Thanks, i think i'll try this one, has a charge controller and i think i'll have it on the cab roof

looks good .... I bought a panel on @Grahams recommendation to keep the P38's battery alive when parked up and locked (alarm saps power) worked OK for circa 4 weeks at a time, but obviously wasn't putting enough out to cope continuously .. but did double the time it took to drag the battery down ... maybe a second might've trebled it
main issue is making sure it's pointing in the right direction to maximise what little sun we do get

 

[Russell]

I'm interested in how this goes as I would like a solar panel to run a small fridge in the car for when working away. I hadn't thought of looking for a second hand domestic panel. I've had a quick look and it looked like a dc-dc charger with dual imputs ,PV and alternator, was £200.

 

[JerryRtilt]

I'm interested in how this goes as I would like a solar panel to run a small fridge in the car for when working away. I hadn't thought of looking for a second hand domestic panel. I've had a quick look and it looked like a dc-dc charger with dual imputs ,PV and alternator, was £200.

Mr Amazon hasn't delivered yet, when I've got it set up and running for a while post something .

 

[Gecko]

I hadn't thought of looking for a second hand domestic panel. I've had a quick look and it looked like a dc-dc charger with dual inputs ,PV and alternator, was £200.

The common reg for doing that is the Ctek, but it's pricey and not suitable for domestic panel.
Keeping to explanation brief:
A 12V nominal panel puts out ~21V no load (the Ctek can cope with that).
Domestic PV's range from 35V to 50V (that's why they are cheap 2nd hand).

The cheap ebay regulators also won't cope with the higher voltage, so you need to use a 'better' reg (which has other advantages).
You definitely want an MPPT reg, but there are more fakes on offer than real, so you need to select carefully.

An alternative source for panels is your local installer. Just about every shipment is a slightly different shape/spec to the last, so if they've got a couple left over, the 'end of batch' price can be very attractive.

Mine has been a "Work in Progress".
One problem I found as a fixed install is that the regs don't like having full sun and then the battery gets disconnected. Since the last pic, I've added a capacitor to each that acts as a "fake battery" and suppresses any transients when a battery is disconnected.

 

[Giles]

I’ve a few of the Aldi ones on bowsers and rollers and infrequent use stuff

 

[Gecko]

I’ve a few of the Aldi ones on bowsers and rollers and infrequent use stuff

The (smallish) aldi chargers have a 'winter mode' which is perfect for maintaining a battery in good condition.
I got caught out when someone wanted the power point and pulled the charger - a few months later and the battery was a total loss