How much power should I be getting? (1 Viewer)

Aug 27, 2014
1,910
4,091
Shropshire
Funster No
33,077
MH
McLouis Tandy 640+
Exp
Since 2014
My secondhand van came already fitted with a solar panel on the roof. The habitation battery is, I think, not in the best of condition - the battery is discharging such that every couple of weeks I need to hook the van up to the mains, before it discharges completely, despite the solar panel putting charge in every day. The only draw on the habitation battery is a small digital clock.

On a day like today - cold, overcast & cloudy, van parked between buildings but not in shade - I've typically been getting 0.3A going from the solar panel into the battery, according to the control unit. The panel has no indication of wattage on it, but as it's 650 x 1450mm, looking at websites selling panels I'm guessing it's a 120w unit. Does 0.3A in these conditions sounds about right?

I'm hoping that once the habitation battery is changed, the panel will in winter provide enough input to keep both the habitation and vehicle batteries charged - stop the alarm flattening the vehicle battery. They are linked with a Sterling battery maintainer, but at the moment that's not really doing much as the voltage in the habitation battery drops too low for it to switch on.
 

Minxy

LIFE MEMBER
Aug 22, 2007
32,741
66,848
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
Unfortunately at this time of year there's no way a solar panel will keep your batteries topped up on it's own, unless it is massive! We have a 75w panel on our van's roof and don't have any draw on the van's power normally, but still have to put it on hook-up every 2 weeks to ensure that the batteries don't get below 50% discharge (this can permanently damage them).
 

Wickolad

Free Member
Sep 10, 2013
490
542
Wickersley
Funster No
28,023
MH
Coachbuilt
Exp
Newbie to MH, 20yrs+ Caravanning.
Sorry I cant give you much info with this but in this sort of weather dull and overcast there isn't a lot of output from panel and even then, there are variables that can have a drastic effect such as dirty panels, shadowing etc. 0.3a/h though is very little, 8 hrs daylight is only going to have achieved 2.4a charge at whatever voltage the controller is putting out. I'd probably disconnect the clock, get the battery charged up fully with a decent multi stage charger before putting back in van then see how it goes. Just ensure theres nothing drawing current and it may just be enough to tick over.
Summer months are much better obviously. But you may have to wait till we get some decent sunshine before you get a good idea how well the panel is performing. I'll have a check on mine tomorrow, see what output is with 2x 100w panels with a mppt controller and let you know. (y)(y)
 

DP+JAY

LIFE MEMBER
Mar 17, 2010
2,538
14,788
Dalbeattie
Funster No
10,674
MH
Laika 5009
Exp
since 2007, 25 years tuggin before that.
I suspect your battery is past it's best. We have 2 x 80w panels which easily maintain 3x110amp batteries plus the cab battery all winter with no need for hook up, the only time the batteries fell bellow 12.7v was when the panels were under snow.
 

Bobby22

Free Member
Dec 15, 2013
1,537
6,408
Scotland
Funster No
29,386
MH
Rapido 680ff
Exp
since 2013
I don't know much about solar......but i would check the battery before you discard it, it may well need only topping up.
Take the cap from each cell and check that the plates are covered with acid......if not.......top up with water......and give it a full charge.

It may hold the charge better if this is the case.

Subscribers  do not see these advertisements

 

Cal54

LIFE MEMBER
Apr 25, 2014
3,826
62,707
Southport, UK
Funster No
31,130
MH
Leisuredrive Renoir
Exp
Since 1996
I have a 100 wt solar panel and it has kept my 2 100 amp leisure batteries topped up ok. The van has been stood for nearly 10 weeks with only one day trip in that period, and when checking the batteries yesterday everything was ok. Mind you we have had some great sunny days in Lancashire over the last week. Would suggest you check the battery first.
 

Daifuse

Free Member
Feb 20, 2013
183
310
Milford Haven
Funster No
24,764
MH
c class
Exp
Since 2011
I have a 100 wt solar panel and it has kept my 2 100 amp leisure batteries topped up ok. The van has been stood for nearly 10 weeks with only one day trip in that period, and when checking the batteries yesterday everything was ok. Mind you we have had some great sunny days in Lancashire over the last week. Would suggest you check the battery first.

Same here, in bright sun today my panel is only putting out 100mA - the batteries showing almost 14v.
 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,447
50,414
Dark side of the moon
Funster No
172
Exp
Since 2005
120w panel will, in theory, give you 10amps
in the real world that may be 7amps in high summer with the sun overhead.
this time of year i wouldnt expect much more than 500ma....the sun is too low to be of much use.
 
Sep 3, 2012
7,637
26,267
Cheshire
Funster No
22,759
MH
C Class Elddis 175
Exp
8+ years
I checked my 2 x 100 watt panel output on Sunday and it was pushing out 0.6-0.9amps--if that info helps ( van is parked on drive slight overhang from some branches to one panel and sloping down away from the sun -ie worst angle approx 20 degrees down)but sunday was better day

Subscribers  do not see these advertisements

 

Trikeman

Free Member
Aug 22, 2012
1,649
3,095
Wilds of Ceredigion.
Funster No
22,516
MH
AT 634 Apache.
Exp
Since 2011.
Our two 100w panels feeding through MPPT to two 110ah leisure batteries - batteries fully charged all over winter. Used yesterday and all electrics 'up and atom' running heater blowers, loo flush, water pumps and TV for a few hrs - both batteries fully charged by the time we got home and that was solar only charging.
Never used an EHU since we fitted the system.

Regards,

Trikeman. ;)
 
Nov 28, 2007
435
1,558
Funster No
935
One 120 watt solar panel keeps my two 105 amp batteries toped up plus my starter battery and runs the alarm all winter without any other use. If you have a 120 watt panel you should be getting much more than .3 of an amp unless it is really dull al day long.
I would expect it to show at least 1 amp on a dull day and any sun at all up over 3amp to 5 amp this time of year.

I am in Portugal at the moment and mine tends to top out at 5.4 amp this time of year but hits 8 amp easily in summer even in the UK.
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
54,151
152,988
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
This time of year and hour or so either side of midday I get a bit over 2 amps from my 2 x 100 Watt panels on the south coast. You say your van is parked between buildings this limits the hours of useful power as the van will only be in direct sun part of the day, a shadow over only a very small area of the panel will drastically reduce the output.

The battery sounds like it's well past it's sell by date, best to get that sorted first.
 
D

Deleted member 29692

Deleted User
We have 200W of solar and 2x110ah leisure batteries and they've been fine all winter. We can last indefinitely with no EHU and our normal usage, the solar more than copes
 
D

Deleted member 29692

Deleted User
We have 200W of solar and 2x110ah leisure batteries and they've been fine all winter. We can last indefinitely with no EHU and our normal usage, the solar more than copes

Subscribers  do not see these advertisements

 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Funsters who are viewing this thread

Back
Top