Solar Panel Charging Regulator

JoeHymer

Free Member

Messages
26
Solar Panel Charging Regulator

Any advice on which brand or model of MPPT Solar Panel Controller/Regulator is best to charge Leisure batteries?
I have 100W panel and two 75AH leisure batteries. Getting poor charging current with a cheap PWM Voltronic controller even in bright sunlight. I may add another 100Watt panel in the future.
Also have a 30W panel which is original from Hymer, I think. This is disconnected at the moment but I hope to connect it to the engine battery using the PWM controller when I replace it on the 100W panel.
The Motorhome is an 1998 Hymer and has an Elektroblock EBL 104-3.
Thanks in advance.

 
hi joe

1 thing i would note is that this time of year the sun is lower and a solar panel will give out less power

the most you should expect from a solar panel is just under 6 amps if the battery is low and the sun is pitching down onto the panel

im in portugal and the sun is low so only get around 3a from each 100w panel last may it was up to near 6a

from my experence a extra 100w panel and a cheap controller is a cheaper option

barry
 
Hi Powerplus,
That's an interesting angle on it.
You may well be correct regarding the sun intensity vs current. However, I noted that even in mid summer sunlight, I never got more than 1 amp, but in hindsight, perhaps that's explained by the fact that the batteries were probably fairly well charged anyway.
I need to reflect on the optimum route.
Would I be correct in thinking that if I use two 100W panels, I would be wise to connect them in Series and use an MPPT controller?
Thanks both Barrys for informative advice.
Joe


 
hi joe

i think parallel as you would need a higher voltage controller for series

from what i can understand if you use series and 1 panel is partially shaded by a tree or building it is not good for the panel and also the output voltage would be lower from the panels going into the controller

on my van i have 100w going into the main control panel through a cheap controller and have seen just under 6a in the summer the control panel charges both engine and habitation batterys as required but has a max of 100w input

recently i installed a second 100w panel with a cheap controller that is connected directly to the habitation batterys so far i have seen 3.4a from this second panel in portugal but the sun is only at around 30 degrees to the panel




barry
 
Good point Barry.
My thinking was that in lower sunlight climate UK, Irl. etc., when the light is poor and the panel output voltage is low say 13/14V, even two or more panels will give little or no charge at that output, but if in series (although the total Current capacity is lower) the voltage will be higher and give some charge to the batteries. Probably not much difference in practice though.
I think perhaps a somewhat similar system to yours might be simplest. In my case, two panels, two controllers one charging the Habitation batteries and one charging the Engine battery. I might change the 30W panel for a 100W and put it directly on the engine battery with a new cheap regulator/controller.

Thank you Edina The link describes the possible combinations of panels very simply. Will study this further before deciding finally on my new set up.
 
Hmm Very Good Point Alec. I'd forgotten about that possibility. I simply used the existing cable, which appears to have been original to Hymer, by the odd colour of cables.
Possibility of resistance there OK.
Definitely needs examining further. Will look at that and try running better cables -even without burying them in the wall to test the difference/improvement.
Thanks for thinking of that and taking the trouble to point it out.
Joe
 
hi joe

from my experiences and if you have the spare i would connect the 30w panel with a cheap controller directly to the engine battery

and if you have the space get a second 100w panel and join in parallel through a cheap controller to the habitation battery

then you have both batterys covered

barry
 
Thanks Powerplus,
2 X 100W to Leisure batteries and 1 X 30W to direct to Engine battery sounds like a very good system.
Your comment makes me wonder if there any advantage or disadvantage in also going Direct to the Leisure batteries from the 200W panels?
While the Elktroblock appears to work perfectly, in terms of charging on EHU and in feeding the Solar panel voltage through to the batteries, I guess it is very old (1998) by current electronics standards. Could it (along with possible inadequate cabling )be introducing resistance to the system and reducing charging current?
 
hi joe

nope keep the inverter on the batteries

not sure about the electroblock

but find sometimes that things get to complicated

in my case the sargent control panel wants the solar to fully charge the engine battery before the leasure and both sargent and the solar controller seem to fight
especially when the day is a bit dull

it was sargent that suggested wiring directly to the batterys through a controller and the good thing is that you know what is going where as apposed to the control panel deciding


im also thinking of getting a solar controller that charges both batterys for 1 system andit can be set to 80% / 20% charge between the batteries or anywhere in between so that the engine battery gets a llittle but the hab battery gets the most

barry
 
Thanks Barry.
Good point that wiring separately and directly to batteries allows you to see whats going on re charging for both hab and engine batteries, without the van Control Panel managing the distribution.
New cables and that set-up is the route I'll go I think.
Thanks to everyone (Barryd, Powerplus, Edina, Livotlot) who took the time to guided me through this and greatly adding to my understanding.
Joe
 
you are welcome please do let me know how you are getting on

barry
 
My own observations having fitted a few panels, the seasonal influence of the sun definitely impacts upon performance, this time of year it is invariably hitting the panels at an oblique angle rather than square on which you get in summer months, The only way this can be improved is to be able to tilt the panel but easier said than done

Secondly Mppt over PWM controllers, We accept has giving better performance but do your research a lot of MPPTs sold are far from it and are really PWMS, this is often reflected in the too good to be prices

Route cabling , the shortest route possible to avoid voltage drop,

Whenever I fit I measure the open voltage on the panel , indicates it is not damaged , take a reading at the controller input and output simply gives an indication of what is happening and finally at the leisure batteries which will indicate the voltage drop, Base reference points that can be tweaked
 
I have my 100w panel connected to the elektrobloc as it does it’s job and provides a charge to both the leisure battery and motor battery. If you connect directly to the leisure battery then it is possible that the charge coming from the engine when traveling may not get anywhere. The reason being that the solar panel is giving a charge voltage that could fool the electro bloc into thinking that the battery is fully charged (assuming good sunlight) and so it would not divert the engine charge to the leisure battery. You could have a situation where the leisure battery is almost flat and being only trickle charged by the solar panel and no charge being provided by the engine as the solar panel voltage is greater than the engine voltage (going via the electrobloc charger). When you get to your destination the battery may not have a full charge.
Hope this makes sense.
 
Thanks Owlhouse. Interesting Point and really helpful to be aware of that possibility.
I'll check the voltage on engine charge to make sure it is working.
I'd never have thought of that point and if it happened it may not have been very easy to diagnose the cause.
Thanks for pointing that out.
Joe
 
You must log in or register to reply here.

Users who viewed this discussion (Total:0)

Back
Top