PV Trickle Charger ?? | MotorhomeFun | The Motorhome Support and Social Network

PV Trickle Charger ??

Klentta

Free Member
Nov 14, 2020
1
0
S.Yorks
Funster No
77,809
MH
Symbol + Bedford CF
Exp
20 yr
So I begin my foray into the PV world.
Having read a few posts, it all sounds rather complicated - lots of numbers etc !
This is probably a really basic query that you all have made (sorry) but I gotta start somewhere.

I am presently running my engine for 1Hr every 6 weeks or so, (vehicle is SORN) to keep batteries (both) charged. Obviously not an ideal scenario.
So, initially my query is whether I can SAFELY plug just a PV panel to cig. lighter socket and magically escape the battery going flat ( and avoid running a cold engine for 60 mins).
Or will I need some controller device to be sure of not cooking the battery(s) ?

Following from that, the domestic heater burns diesel and won't run when the leisure Batt falls below about 75% charge (according to gauge - which I've never seen show 100%). All my use is parked up off grid. Running motor on tickover for 1hr puts enough charge in for about 1.5 days heating. So I will need to move to some PV solution for spring trip. For this I will really be starting from scratch.

I have read posts about splitting the charge to both Batts etc - all sounds daunting for a Newbie. And although I have maintained my own vehicles all my life, Solar/PV is an unknown for me !

Any suggestions (including sources to become more knowledgeable) would be welcome . . . . .

Thanks
Steve
 
Jun 8, 2019
2,860
9,917
Bexley West Kent
Funster No
61,505
MH
Autocruise starlet 2
Exp
May 2019
I have a trickle charger on 24/7 connected to Cab battery and solar for habitation batteries works for me.
 

DBK

LIFE MEMBER
Jan 9, 2013
15,694
34,281
Plympton, Devon
Funster No
24,219
MH
PVC, Murvi Morocco
Exp
2013
You can buy portable panels which have a regulator built into them which are designed to do exactly what you want. Assuming you have a window facing south with no trees in the way you stand the panel behind the window pointing about 30 degrees up at this time of year. I would suggest one at least 20W in size should work but 30W or more would be better.

A few on here:


You might get away with using the cigar lighter socket but only if it is live with the ignition turned off, alternatively just use crocodile clips directly to the battery. For the leisure batteries you could probably just disconnect them as some van systems have a small permanent drain of current. But just monitoring the voltage first would be a good first step.

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Coolcats

LIFE MEMBER
Jan 24, 2019
1,626
2,513
Funster No
58,207
MH
HymerCar Ayres Rock
So I begin my foray into the PV world.
Having read a few posts, it all sounds rather complicated - lots of numbers etc !
This is probably a really basic query that you all have made (sorry) but I gotta start somewhere.

I am presently running my engine for 1Hr every 6 weeks or so, (vehicle is SORN) to keep batteries (both) charged. Obviously not an ideal scenario.
So, initially my query is whether I can SAFELY plug just a PV panel to cig. lighter socket and magically escape the battery going flat ( and avoid running a cold engine for 60 mins).
Or will I need some controller device to be sure of not cooking the battery(s) ?

Following from that, the domestic heater burns diesel and won't run when the leisure Batt falls below about 75% charge (according to gauge - which I've never seen show 100%). All my use is parked up off grid. Running motor on tickover for 1hr puts enough charge in for about 1.5 days heating. So I will need to move to some PV solution for spring trip. For this I will really be starting from scratch.

I have read posts about splitting the charge to both Batts etc - all sounds daunting for a Newbie. And although I have maintained my own vehicles all my life, Solar/PV is an unknown for me !

Any suggestions (including sources to become more knowledgeable) would be welcome . . . . .

Thanks
Steve
A lot of the Panels you see in places like halfords ebay etc are from Solar technology international check thier site and then a stockist

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Apr 3, 2018
807
1,570
Funster No
53,151
MH
PVC
Exp
1995-2004 & 2017》
You need to sort something because running engine for one hour every six weeks is killing it.!!!!
And not really doing batteries any good either!!!
 
Apr 6, 2019
1,393
2,159
Peterborough
Funster No
59,702
MH
C Class?
Exp
1999 Autocruise Impala, bought 2019
I have my cig lighter socket wired permanent live so can put solar on dashboard and into said socket. Just 10watt but maintains battery.
 
Apr 27, 2016
2,368
2,154
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
So, initially my query is whether I can SAFELY plug just a PV panel to cig. lighter socket and magically escape the battery going flat ( and avoid running a cold engine for 60 mins).
Or will I need some controller device to be sure of not cooking the battery(s) ?
If the socket is live when the engine is stopped (not all of them are) then it's a good way to make a temporary connection to charge the battery. A small panel (up to about 30W) can be connected directly without a controller. Anything bigger is best wired via a controller to avoid overcharging on a sunny day.

I'm not sure how your MH is wired, and probably charging the leisure battery does not charge the starter battery. There's a number of ways round this. In the past I've used two solar panels, one for each battery.

It's a common problem, and some MHs have a small trickle charger that automatically tops up the starter battery from the leisure battery. For example a Vanbitz BatteryMaster.

I've had some success with even a tiny 2.5W panel, but that was in a very sunny spot, so more like 20W as DBK suggests would be a safer bet.

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Reactions: DBK
Jan 19, 2014
4,912
12,400
Derbyshire
Funster No
29,757
MH
Elddis Accordo 105
Exp
since 2014
During the first lockdown I put a 5w panel in the car windscreen facing south, after about a week of sunshine the battery voltage was approaching 15v 😳 all day. So I removed it, obviously not a lot of current was going in but 15v is too high and it might have gone higher if left on another week.
Thing is if you put a controller on with a tiny panel, the controller can use more power than the panel makes in winter.
 
Apr 27, 2016
2,368
2,154
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
Following from that, the domestic heater burns diesel and won't run when the leisure Batt falls below about 75% charge (according to gauge - which I've never seen show 100%). All my use is parked up off grid. Running motor on tickover for 1hr puts enough charge in for about 1.5 days heating. So I will need to move to some PV solution for spring trip. For this I will really be starting from scratch.
Unfortunately you have to work out the numbers so you can see what your requirements are, and what system you need to meet them.

First, I'd guess that the engine alternator is probably pushing out at least 20 amps to the leisure battery. Over a period of 1 hour that's 20 x 1 = 20 amp-hours. You say that's enough for at least 24 hours.

A 100 watt solar panel flat on the roof will yield about 30 amp-hours over a good sunny day. So in the summer that will be enough, even if it's a bit cloudy.

The problem with solar is, you run the heating more when it's not sunny. So you can get more solar panels to give more output on cloudy days. Or a bigger battery/second battery to store the energy when it's sunny to tide you over the dull days. Or both.

Some manage fine with 100W of panel and a 100Ah battery, some struggle with 500W of panel and 400Ah of battery. It depends on your lifestyle. And whether your trip is to Morocco or the Hebrides.

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Reactions: DBK

Coolcats

LIFE MEMBER
Jan 24, 2019
1,626
2,513
Funster No
58,207
MH
HymerCar Ayres Rock
So I begin my foray into the PV world.
Having read a few posts, it all sounds rather complicated - lots of numbers etc !
This is probably a really basic query that you all have made (sorry) but I gotta start somewhere.

I am presently running my engine for 1Hr every 6 weeks or so, (vehicle is SORN) to keep batteries (both) charged. Obviously not an ideal scenario.
So, initially my query is whether I can SAFELY plug just a PV panel to cig. lighter socket and magically escape the battery going flat ( and avoid running a cold engine for 60 mins).
Or will I need some controller device to be sure of not cooking the battery(s) ?

Following from that, the domestic heater burns diesel and won't run when the leisure Batt falls below about 75% charge (according to gauge - which I've never seen show 100%). All my use is parked up off grid. Running motor on tickover for 1hr puts enough charge in for about 1.5 days heating. So I will need to move to some PV solution for spring trip. For this I will really be starting from scratch.

I have read posts about splitting the charge to both Batts etc - all sounds daunting for a Newbie. And although I have maintained my own vehicles all my life, Solar/PV is an unknown for me !

Any suggestions (including sources to become more knowledgeable) would be welcome . . . . .

Thanks
Steve
If you keep it simple just go to Halfords and get a a PV, they are not expensive and designed to the job you are looking for I have two one I am using on a Golf that is not moving very much at the moment and one I have used for the Lotus (I just have a notice on my steering wheel it there as its under the window in the rear Hatch) and no they have not cooked the batteries even in summer.

Screenshot 2020-11-17 at 07.57.33.png
 

Coolcats

LIFE MEMBER
Jan 24, 2019
1,626
2,513
Funster No
58,207
MH
HymerCar Ayres Rock
2.4W might work if it catches a lot of sun, but you might not have a lot of choice with positioning your vehicle - it might be in shadow all the time.
Then a Solar trikle charger may not be a suitable product, all I can say is that 2.4W or even a 6W is ample even in Winter from my experience, the Lotus has a 3.6 Litre engine never had a problem with the trickle charge from the Solar panel and yes like most vehicles the battery goes flat in around a month due to the background consumption of alarm system etc. My guess is Halfords would not sell them if they did not work. It really is a simple solution to keeping a battery topped up, and cheap enough to just try it out.

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Apr 27, 2016
2,368
2,154
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
but do you 'need' 10W? even a 2.4W works
I found that a 2.5W panel worked for the starter battery. However for 200Ah of leisure battery a 2.4W panel wasn't quite enough, and the voltage slowly went down. I didn't try a bigger panel because circumstances changed and I didn't need it, but was thinking of getting one. The MH was parked where it caught the winter sun.
 
Last edited:
Nov 28, 2018
163
231
Edzell Scotland.
Funster No
57,399
MH
Autotrail Cheyenne
Exp
2018
I know a number of people have had different results with these small dash solar panels but I would not buy another one, I purchased this based on reasonably good reviews from amazon and monitored the readings at least every other day in the summer, The readings only ever moved slightly higher on a really good sunny day, but most of the time the battery began to deplete so not much good where I stay anyway. I am now in the process of looking to fit something like a ctek battery maintainer for my engine battery.

Amazon product
 

Coolcats

LIFE MEMBER
Jan 24, 2019
1,626
2,513
Funster No
58,207
MH
HymerCar Ayres Rock
I know a number of people have had different results with these small dash solar panels but I would not buy another one, I purchased this based on reasonably good reviews from amazon and monitored the readings at least every other day in the summer, The readings only ever moved slightly higher on a really good sunny day, but most of the time the battery began to deplete so not much good where I stay anyway. I am now in the process of looking to fit something like a ctek battery maintainer for my engine battery.

Amazon product
The product you show is for 30ah battery. Most MoHo and larger cars will have a bigger capacity so maybe you needed a slightly larger panel.

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Nov 28, 2018
163
231
Edzell Scotland.
Funster No
57,399
MH
Autotrail Cheyenne
Exp
2018
The product you show is for 30ah battery. Most MoHo and larger cars will have a bigger capacity so maybe you needed a slightly larger panel.
Yes you are more than likely correct , If there are dash solar panels out there that do keep engine batteries topped up even in overcast conditions I am all for buying one.
 
Apr 27, 2016
2,368
2,154
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
Yes you are more than likely correct , If there are dash solar panels out there that do keep engine batteries topped up even in overcast conditions I am all for buying one.
When I was working in Germany, I saw loads of these in cars belonging to people who lived in blocks of flats. No driveway, no chance of mains hookup. Very popular there.

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Jan 19, 2014
4,912
12,400
Derbyshire
Funster No
29,757
MH
Elddis Accordo 105
Exp
since 2014
When I was looking for a 5w panel most of them looked really cheap quality plastic things. The one i eventually bought was a tiny version of the big ones, aluminium framed monocrystalline. It was ex demonstration so only a tenner 👌😎
 

Coolcats

LIFE MEMBER
Jan 24, 2019
1,626
2,513
Funster No
58,207
MH
HymerCar Ayres Rock
When I was working in Germany, I saw loads of these in cars belonging to people who lived in blocks of flats. No driveway, no chance of mains hookup. Very popular there.
@ Peskyrabbitt mentioned the small fold up Solar panel and as you can see I had one of these and it really is only suitable for a small battery 30ah and very little if any drain via security system I have two of the 6W and they really do keep the batteries in the car and Van topped up I also have a large folding Solar Panel 80W which I used for leisure battery on our old MoHo that was enough for summer trips. Our MoHo currently has 100W and trickle charges both the engine and leisure batteries and has been sufficient for the past two winters.

You can see even with a head torch you get a couple of volts output, then when you look at the small folding solar panel you can see a much smaller footprint which does keep smaller batteries topped up struggles with anything else.



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