portable solar to trickle trailer battery

[KGs2108DS]

lots of off-grid camping. use Honda EU2200i to recharge 115Ah deep cycle battery. notice 2-3hr/day generator run not sufficient to come close to fully recharging battery. Maybe add 2nd battery - still left with two not fully charged batteries. What about 100W portable solar panels, such as Jackery SolarSaga 100X Portable Solar Panel $299. 2018 MicroMinnie 2108DS pre-wired for solar. do I have to buy a controller? how about a very expensive Lithium Ion battery? If the portable solar panel 100W were deployed in full sunshine for 4hr, what's the likelihood of substantially, maybe even fully recharging the battery with supplemental generator run time of 3ish hours? THANK YOU!

[creativepart]

Portable solar is a great addition. Most portable panels suitcases come with a built in controller. You'd want to look for 200w of portable solar as 100w will not provide all that much power.

This is a continuation to your previous thread you started about battery drain.

You'll find solar a real help, but it won't fully charge your battery if you are running it down to a low state of charge every day. Think of it as an auxiliary charger that helps out but it isn't putting huge amounts of current into your batteries like your onboard converter/charger.

[KGs2108DS]

thank you kindly! The price point (and size, wt, storage) between 100w and 200w solar is quite significant. Just for purposes of calculation, if trailer battery (27MFDC 115AH/MF Deepcycle) on a given morning were 50% depleted, is there a way to calculate the extent to which a 100w solar panel exposed to full sun for 4 hr would bring the battery charge up to? thank you!

[creativepart]

Originally Posted by KGs2108DS

is there a way to calculate the extent to which a 100w solar panel exposed to full sun for 4 hr would bring the battery charge up to? thank you!

Not really. Too many variables. Not only is solar panel output extremely variable due to location, time of year, time of day, weather, etc. But there is no way to estimate how much power you will use during that day at the same time you are charging.

The key to this is experience. Learning how much power you use. How much charging you see typically. And, understanding the variables that effect all of this.

[Bones2003]

Someone with more experience should probably check my logic but absolute BEST case would be you get 100W for 4 hours. That would be (100/12=)8.33 Amps per hour or 33.3 Amp Hours. In the real world you might get 60% of that or 20 AH if you're lucky. I don't think I've ever seen 8 Amps from my 100W rooftop panel but I have seen 5 or 6.

[BobC]

There's another, similar and current thread on this topic:

https://www.winnieowners.com/forums/...ml#post3924843

There are numerous Youtube reviews comparing the amp output of different portable solar panels and they're battery charging capabilities. The main variable for you is how many amp hours do you use in a day.

To answer a couple of your questions:

1. Pre-wired for solar doesn't include a controller. Many portable units come complete with controller but see the above thread for more info on the advantages and disadvantages of a built-in or seperate controller.

2. A lithium, or more specifically a LiFePO4 (Lithium Iron Phosphate Battery) can definitely be a plus, more usable amp hours, faster charging, etc. but I wouldn't put it at the top of my list. You will need to educate yourself a lot before taking this leap and isn't essential. I'd add a second battery similar to what you have and see what that looks like. If, by "deep cycle" battery, you mean the typical, dual purpose, flooded RV/Marine battery commonly installed on RVs, I'd replace it with two AGM deep cycle batteries. Keep in mind, however, that more battery capacity will increase the charging time.

For less than $32 more than the Jackery 100W panel, Renogy has a 200W solar suitcase for $330 with controller:

https://www.amazon.com/Renogy-200-Wa...sr=1-1-catcorr

Personally, I'd go with a combination of rooftop and portable panels. Portable panels have their advantages but there is the risk of theft. I wouldn't want to leave them unattended for long periods of time.

[Marine359]

Originally Posted by BobC

Personally, I'd go with a combination of rooftop and portable panels. Portable panels have their advantages but there is the risk of theft. I wouldn't want to leave them unattended for long periods of time.

X2 on Bob,
Due to risk of theft, we wind up stowing our portable away when we leave the camper. That limits the total amphrs you can farm in one day.

Also, always keep in mind that your charge controller needs to see a 5v delta between array voltage and battery voltage before it will turn itself on. So if your battery voltage is 13.2v and your array outputs 18v, there will be no charging. So, if your battery is near max SOC, your solar might or might not top off the battery.

[KGs2108DS]

thanks to all of you for your help and advice. after today's discussion, the next step will definitely be a battery monitoring system!