Solar - battery charging

Hey Guys:

So I have a situation where I will park my bass boat in a covered storage unit (rental) that does not offer electric hookups. The only reason I'm considering this scenario is that I can almost throw a rock to it from my house and the price is right.

I have a Skeeter ZX225 with 4 AGM batteries and up until now I have always used shore power with the MK charging system that is standard equipment on this rig.

Is there a reasonable solar set up that I can rig up to trickle charge my 4 batteries and offer them some charging as opposed to none? I do realize I can pull my boat to my house to charge it, but that becomes a hassle and with 4 AGM batteries I do not want to forgo giving them some kind of regular charge.

I have to think somebody has been or is in this very situation.

Thanks for any advice you can offer.

I’ve never heard of a solar system that would do what you have in mind. AGMs hold a charge better than wet cells. You might call the battery mfg and ask how often you would need to put them on a charger. You may be surprised at hoe infrequent they will need charging.

You might check out a website called Powerwerx.com. They offer a variety of solar panels and charge controllers. Note that most (if not all) of their charge controllers are for LiFePO4 batteries, but they might have some for lead acid.

https://www.batterystuff.com/solar-chargers/

Thanks Guys for the insight.

I'm curious with the solar charger set up....it appears one of two things has to happen. Either you periodically swap the solar connections between the 4 batteries or can you deliver a trickle charge to all 4 simultaneously. I'm thinking since the TM batteries are all inline this could work. Then it would be a matter of swapping the solar connection between the starting battery and the TM batteries?

Can anyone clarify if this thought process has logic?

Nevertheless going from simply plugging in your onboard charger and paying it no mind to having an ongoing management situation is a PIA.

I might just let these batteries, which are the original dealer installed, eventually cr_p out and replace with a lithium set up.

Check out lithium batteries and cold weather. Some of them won’t crank a motor when it is cold.

I hadn't heard that, so I did a little research and came across this well written article and lab test that offers some insight to this misnomer....

https://mortonsonthemove.com/lithium-batteries-cold-weather/

It appears the logic is cold weather affects the charging of lithium batteries, but they still perform better than their lead counterparts.

I would also add Texas never gets cold enough consistently to impact the charging of lithium batteries on a regular basis and most enclosures will hold just enough heat to stay above freezing.

Run power to where you charge your boat. Dig a trench conduit and a plug done not that hard.

Yes, that would be a simple solution.....however, I don't own the multi-tenant storage facility that I'm speaking of.

My only option is to rig a solar charging solution.

If the temperature of a battery with LiFePO4 cells (today's common/leading Li technology) gets down to 32 degrees F, irreparable cell damage will occur if charging is not stopped/prevented. I understand damage is cumulative, and may completely fail a battery over time. Warranty will typically be voided if cell examination shows sub-freezing charging damage. Some suppliers have claimed that the BMS on their battery has a temperature sensor and will not allow charging voltage to reach the cells unless the temp is above 32. I recently saw a comment here by an owner who said his BMS did not seem to cutoff charging when it was that cold even though the supplier said it would, so proceed with caution. This battery technology is gaining popularity, so there are quite a few "suppliers" who are just resellers making a buck, and they may not know as much as you think about what they are selling. While you can RUN said battery technology at very low temps, the physics of how it works precludes charging below 32. I recall seeing some charging controllers from the off-grid industry that advertise having a temp sensor to block charging as needed due to cold.

you need a min. 50 watt solar panel to maintain 2a trickle charge (2a = 24 watts).

so 4 50 watt panels, one panel per battery with a 4 battery system.