Battery died, time for big conversion solar, fridge, etc

[oldhotrod]

I was in the same boat as you with zero knowledge of solar...here is my minimalist system for comparison only, 160wt flex panel, 50ahr lipo and 60l chest cooler. I chose the small battery (20lbs and size of a 6pc of soda cans) to be a starting point since I didn't know my needs and could always add another. In full and partial sun, it has proven to run my needs indefinity. My only improvement would be a larger 100ahr battery and a portable panel for a back up when boondocking. Note my camper is not connected to the truck battery.

 

[craig333]

160w may be enough. 400w is almost assuredly overkill though it allows for future electrical upgrades if you decide to go that way.

 

[Jon R]

I have 400 watts of solar panel. It definitely is overkill (at least twice what I need) in sunny conditions in the warm half of the year with high sun angles. The benefit I get from 400 watts in Western WA is I can fully recharge the overnight battery depletion even if it’s cloudy or a low sun angle in the winter.

 

[ckent323]

I always recommend starting with an energy audit and figuring out what your need will be 30 - 40 amp hours per day is pretty common. Decide on battery type.

If AGM (or any Lead Acid type) it is best not to routinely draw the battery bank down more than 50% and always fully recharge every day. That drives the charging system you need to cover partially cloudy days etc..

If lithium then you can draw it down to 20% or so (check manufacturer recommendations for the battery brand you select) and lithium does not need to be fully recharged everyday.

Now you know how much power you need from your charging system everyday.

I recommend putting the largest rigid single solar panel that will fit on your camper, even if it provides more power than you think you need. Preferably, get one around 320 W or larger. It will cost around $325 (maybe less on 2024 I have not checked recent prices). That panel will be lighter and cheaper than any combination of smaller rigid panels providing anything close to the same amount of power it will also maximize the ability of keeping your battery charged.

I still recommend avoiding flexible panels. The evidence still shows they have much shorter lives than rigid panels and they need to be mounted with a 1" air gap under them (between the top of the camper roof and the bottom of the panel) so they do not overheat. This is the same requirement for mounting a rigid panel. Also, the cost per watt for the semi flexible panel is more than that for a single large panel.

You will probably be glad you went with one large rigid panel later. Just look at all the threads about adding a second solar panel. That approach is more expensive and results in more weight. It often results in needing to upgrade the solar charger too.

While AGM or lead acid systems work well and can last 10 years or more if not routinely under or overcharged, I recommend lithium of you already have a solar charger and the DC-DC vehicle to battery charger which are needed for a lithium battery or if you just want to spend the $$$ and replace all of your charging electronics along with the battery(s). Otherwise, replacing the AGMs is still reasonable if you manage the charging and discharging. Also you do not need to worry about charging in cold weather (although that seems not to be much of an actual issue with lithium batteries in real world camper applications).

I hope this is helpful.

Craig

 

[craig333]

I don't know that I'd consider a dc/dc charger needed if solar is doing a good job. I added one because I got a good deal on it and there will be a handful of times it comes in handy.

 

[CPT Davenport]

These are the items I purchased for my system. It works great in four season camping situations. I have never depleted the battery but have come close in the winter (5 days of rain/no sun) a couple times. I have a DC/DC charger that I have yet to install (not wanting to go through taking the camper off and upgrading wiring) You could easily double the panel size and add another battery if you wanted some reassurance. If you plan to let the camper sit in the filtered shade I feel more storage and higher solar intake beats a DC/DC charger as it only helps when your on the move.

2022 Hawk and my power needs:
2 way fridge
2 max fans
On demand water heater
Water pump
Led lighting
Charging USB devices

175w panel on roof Amazon.com


135w folding panel (rarely deployed but nice if I need an extra bump) Bugout 130W Solar Charger - Four Wheel Campers


206ah lithium battery Amazon.com


MPPT charge controller Amazon.com

Smart shunt battery monitor Amazon.com

Total cost for system: $2,192

 

[craig333]

I almost forgot about my portable panel. Nice insurance but I haven't needed it yet.