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Solar Ready on a travel trailer
#21
When boondocking it is also possible to tailor one's electrical usage for how much recharging capacity they have.

"mornng voltage' the voltage before the sunlight hits the solar panels, can give good indications of just how much battery was used overnight.

One is hoping for 12.4v or higher morning voltage, but even if lower one is really hoping that 14.4+ v can be achieved by the solar panels by noon or 1 oclock and held there until late afternoon as this gives the best chance of actually fully charging the battery before the next discharge cycle begins, which is important to achieving good to very good battery longevity.

Many days in a row without getting the battery full will have the battery petulant and morning voltage will be lower nd lower each morning, and the battery needing that much more time to recharge.

A 10 amp solar charge controller does not leave much room for adding another panel to your 120 watt panel, but it is also possible to not bother using a solar controller, especially on a portable set up. One Can just hook a solar panel directly to a battery. The danger arises when that solar panel, by itself, can overvoltage the battery, which is not going to happen until the battery is closer to being fully charged.

So another panel hooked directly tpo battery in morning aimed at the sun, can allow one to reach absorption voltage much earlier, allowing enough time to fully charge the battery, and say at 2Pm the rthe solar panel on teh solar controller can take over holding the battery at absorption voltage by itself, and the directly attached solar panel can be removed.

Do note it is better for the panel and the 12v system, if the panel is not in Full sun when connected or disconnected. If the panel isin Full sun making 21 volts when hooked directly to the 12v system there will be a few microseconds of upto 21v in the wiring which some things may not like.

Disconnecting the panel from batteries in full sun could be considered a 'load dump' and perhaps blow the solar panel diodes.

The damaging effects can be instant or cumulative and perhaps a complete NON issue.

When hooking or unhooking solar panels I tilt/lean them away from direct sunlight, and have broken this 'rule' many times, so far without consequence.

Portable panel directions will likely not mention this 'cushioning' procedure, and it might not be required at all with a solar controller involved, but it cannot hurt, and could be, perhaps Will be, long term beneficial to the components involved, allowig them to live and perform well, well past their warranty period.
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  • waldenbound (07-03-2018)
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#22
I am confused on the disconnect causing an overload. 

I am not arguing but have a memory gap     Huh
Compared to parenting, Cat herding is less complicated
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#23
If a 100 watt solar panel is pumping 5 amps into a battery, and with panel still in direct sunlight, disconnecting it from the battery might blow the solar panel's diodes. This is similar to how disconnecting the battery on a modern vehicle while its engine is running, as an alternator test, is a bad test, as this is a load dump which could blow the alternator diodes.

By the way many people still think this 'Test' is a valid way to test if the alternator is working. Pull the battery cable with engine running, and if engine dies than alternator not working. This has not been a safe test, since Alternators started replacing DC generators in vehicles in the mid 60's. But it is still somehow recommended. on modern vehicles in this day and age.

Many solar panels say to not disconnect under load, and that basically means when amps are actually flowing from the panel into a load, like a battery or a battery with a load on it.

Most solar controllers also say to NOT disconnect the controller from the battery while the solar panels are in full sun. This instant removal of load can cause magic smoke to escape magic electronic components. or it might not, or it might be cumulatively damaging requiring dozens of 'load dumps' before the smoke gods call their children home.

I am surprised Portable solar panel kits do not have any mention of this, so either they have some circuitry or heavy duty overrated diodes so that it is Not an issue, or perhaps is simply unlikely to become an issue within the warranty period and the manufactuer sees this as possible job security..

So, if one is really practicing safe smoke retainment practices, One hooks portable solar panel to solar controller when it is not facing the sun, then after a solid connection is made, then tilts panel back at sun.

Before disconnecting panel from solar controller or battery also tilt or cover the solar panel.

Again I have no Idea just how damaging it is, just that it Might be.

So I personally do my best to not willy nilly hook or unhook panels or controllers or anything that would be expensive to replace, while a lot of current or potential current, is flowing through the circuit that will be disconnected or connected.
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#24
That’s interesting. I’ll tilt or put some fabric on the panel or something.
In the field, i would unplug the Goal Zero panel after it read zero anyways.

But yes, I’ll be careful with the panels, see if I’m brave enough to really hook them to the battery.
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