solar panel

Good afternoon all, I have been in the search and cant find what I need to know. I have a 60 watt folding solar panel that i used a few time on my caravan, that was easy as I had no other solar panels so just connected straight to battery through a controller . So can anyone tell me an easy way to connect this folding panel now and again if we go off grid can I just connect straight to leisure battery or would I need to some how wire it it the original solar system. Any help please but nothing too complicated. Kevin

Have a look for Anderson plug and socket with cable , connect one to the + and - of the battery and connect the other to the solar controller wires, you can then just open the back doors connect up and shut the doors

Hi Chris I new you would be the man to answer me. Yes that is how i had it connected to the caravan battery but i was not sure if having two panels connected independently might damage/overcharge the battery. The way you just said makes sense to me. Thanks. Kevin

As long as a solar regulator on each panel is fitted there are no problems. Just remember to connect the battery first to the regulator then the panel

It sounds as though you already have a panel fitted. Isn't that sufficient? Do you suffer with a flat battery?

Hi Chris thanks for that. matchlessman no i have not had a problem yet as we have only had the van for a couple of weeks but have a 60 watt folding panel that iused on caravan the roof solar panel is 80 watt so i thought as i had a spare panel and if it was easy to fit i would use it. Kevin

I have thought about using a temporary folding panel to supplement my fixed 80W panel but haven't done it.  If the existing panel is connected through Sargent's smart charging system which charges one battery at a time depending on need, I wonder if applying the folding panel output to the LB will make the Sargent system think the LB is fully charged and flip the 80W output to the VB.  This could be overcome by turning the solar smart charging off but that would leave the VB without charge.  A Forum member in 2019/20 connected the outputs of two MPPT regulators to his LB which worked fine but that was after he replaced the Sargent PWM controller with a MPPT controller that bypassed the Sargent smart charging system and trickle charged the VB.  Just a thought - others may have a view.

Should not affect it as as both regulators sense the voltage and will send charge to the battery till the regulator goes into float, the charge from Sargent System should only switch once certain conditions are met as it’s not on a timer,

FreelanderUK wrote:Should not affect it as as both regulators sense the voltage and will send charge to the battery till the regulator goes into float, the charge from Sargent  System should only switch once certain conditions are met as it’s not on a timer,

I understand that the outputs of two solar controllers connected to the same battery somehow don't interfere with each other but I still wonder if the same applies to Sargent's less sophisticated smart charging system.  It may simply be triggered by the terminal voltage it sees at each battery.  If the LB is showing an elevated voltage caused by the folding panel's controller output, might this be enough to flip it to the VB.  Once flipped it stays flipped for a number of hours.  One could only be sure by testing.  That said, the obvious thing to do would be to carry out the modification many of us have done by bypassing the Sergeant system with a MPPT controller that charges the LB with a trickle going to the VB.

Not really my subject but I can’t help but think that two differing panels charging through two differing controllers might somehow interact adversely. In any alternator charging system where there are multiple alternators charging a battery bank one can cancel the other out (i.e. cause it to largely shut down) if the delivered voltage to the battery is just slightly higher from one regulator than from the other. This happens on my ship when I have two engines (propulsion and generator for example) shoving separate alternator outputs into the same battery bank. The 35 amp 24 volt alternator on the geni causes the 65amp 24 volt alternator on the main engine to cut right back even though there is only a fractional difference in the delivered voltages.

So hypothetically the output from one panel (through one controller that is delivering a fractionally higher voltage than the second controller on another panel) might cause the second controller on another panel to cut back? Diminished returns? But perhaps solar controllers have some tricks up their sleeves that I am unaware of.

If there is any truth to my theory then an additional panel plugged in series, all routed through one controller, might seem to be the answer so long as the controller can handle the enhanced voltage?

Certainly from what I read here the best solution for my van might be to wire the existing standard panel direct to the VB and fit a new separate bigger panel with MPPT controller to the HB. Forget the Smart gubbins!

How Do Charge Controllers Interact With Each Other?

Charge controllers sense the internal resistance of a battery and send their current to the battery terminals based on the resistance of the battery. If the battery is at a low state of charge, the resistance will be low and the charge controller will charge in bulk mode (depending on the battery type).

If the resistance increases, the charging current will decrease because the battery is almost full.

If two or more charge controllers charge the same battery, the battery will be charged quicker. The multiple charge controllers will not compete with each other because they all sense the same internal resistance of the battery. If charge controller A puts in 100Watts, charge controller B will also put in 100Watts into the battery.

This should not affect the workings of the Sargent Smart charging

In terms of both simplicity and panel size, connecting both via a dual battery controller, via 10A inline fuses at the Batt+ves will give more and more useable energy than going via anything Sargent.
And be totally automatic, work 365 days and have both batteries 100% full  most of the time and when being used, certainly in a few hours.
80w may be a bit small but should be enough for most needs.

BTW saw a folding panel recently nicely placed to get max solar gain, quite impressed, initially. Then I considered storage of not only it but the 5m of seriously heavy steel chain attaching it to the van towbar!!!!