Solar build and I’m a little unsure if I have everything...

[Pilotamis]

Disclaimer: Longish post about something I know very little about. This will be installed in a FWC Grandby where 4 of us are traveling full time.

After some quick calculations I believe my average daily power usage to be about 50ah. This doesn’t include a 20a max draw air compressor that will be used as needed to air up tires, but I don’t see real way to factor it in. I’m going to instal 2-100ah AGM batteries. I’m planning on installing a 40a DC to DC battery charger to help supplement the panels and allow us to “bulk” the batteries as quickly as possible. Since I’ll be using the DC to DC charger I’m planning on installing only 2-100W mono panels. This puts me about 30W south of where my calculator has me. I’m hoping this won’t be an issue since we plan to spend most of our time in the tropics. Roof space and weight are issues which is why I can’t add another panel. I’m also looking into the 160W panels and possibly using 1 of those and a 100W. I’ll be using a Victron 75 15 MPPT charge controller to keep it all happy. I’m contemplating adding a Victron battery monitors well. I’ve heard great things about Renogy so I’m planning on using their panels and batteries.

Besides a distribution panel and fuses, what else am I missing? The positive from the DC to DC just goes to a terminal strip with the positive from the charge controller output along with the inverter? Is there a way to add a line for shore power, but it’ll automatically detect the incoming voltage and hertz and adjust for it?

 

[dreadlocks]

If you want shore power you didnt mention anything about it, just DC and Solar.. for AC power w/world wide support look at ProNautic AC Chargers, 40A would probably be fine... You are going to be underpowered on Solar, you really need about 2x that.. but w/out space for em your going to have to pickup the slack w/Driving or Shore power.

 

[shade]

This doesn’t include a 20a max draw air compressor that will be used as needed to air up tires, but I don’t see real way to factor it in. I’m going to instal 2-100ah AGM batteries.

Keep your engine idling while running the compressor and it won't be a factor at all.

I'm surprised @dreadlocks didn't give you his standard AGM advice.

Basically, unless there's a special reason to use AGM, don't bother. From what you've said, two Duracell GC2 SLA batteries would cost less and do the job just fine. If you have the cargo capacity, four GC2 batteries might help you get past the solar panel deficit if you're able to charge regularly from the alternator & shore power.

 

[dreadlocks]

He's a full timer, if he wants to spend the money then have at it.. definitely should have all sorts of monitoring and data gathering on consumption and charging.

GC Batteries still seem more suitable, even for fulltiming IMO.. for world travels id want a flexible and cheap system, not tied to any specific battery format/size but room to fit whatever I can happen to get my hands on.. mebe instead of a 4 bank I'd tend to lean towards dual two seperate banks with manual switch over, let the chargers work on the idle batteries and put the load on the others.

 

[Pilotamis]

What’s the advantage of using 2 gc batteries vs 2 12v batteries? I can’t tell from the link you posted what their ah rating is, but I saw that with Renogy batteries I can squeeze a few extra ah into a 6v system vs a 12v. I’m just not sure if there are other benefits.

 

[Photobug]

Disclaimer: Longish post about something I know very little about. This will be installed in a FWC Grandby where 4 of us are traveling full time.

I hope at least 2 of those 4 are cats.

Since no one has mentioned it yet. Putting two dissimilar solar panels together may not be best for efficiency. Either 2-100w or 20-160w panels would be best.

 

[dreadlocks]

You can get Costco or SamClubs 6v Golf Cart Batteries and together they are ~220-240AH, for ~$200

In simple terms, since they are 6v, they have half the cells in the same footprint of a similar 12v battery.. so the cells are twice as robust w/twice as much lead.. this makes em pretty friggin durable.. its the most lead you can get for the least money, and lead is amp hours, and more heardy cells is what makes something a true deep discharge.. two 12v batteries compared to two 6v batteries is no contest really in price and performance.

AGM's on the other hand, tend to be rather intolerant to electrical abuse.. so more money might not get you anything if they live hard and die young.

 

[Pilotamis]

I hope at least 2 of those 4 are cats.

Since no one has mentioned it yet. Putting two dissimilar solar panels together may not be best for efficiency. Either 2-100w or 20-160w panels would be best.

Lol. No cats, but I did forget to add the dog in there. Let’s call it 4.5.

I was wondering if there would be an issue with panels of different sizes.

 

[Pilotamis]

You can get Costco or SamClubs 6v Golf Cart Batteries and together they are ~220-240AH, for ~$200

In simple terms, since they are 6v, they have half the cells in the same footprint of a similar 12v battery.. so the cells are twice as robust w/twice as much lead.. this makes em pretty friggin durable.. its the most lead you can get for the least money, and lead is amp hours, and more heardy cells is what makes something a true deep discharge.. two 12v batteries compared to two 6v batteries is no contest really in price and performance.

AGM's on the other hand, tend to be rather intolerant to electrical abuse.. so more money might not get you anything if they live hard and die young.

I was just reading up on this. They would be a FLA vs an AGM then. I’d need to make sure all my parts were good to use with FLA and make sure there’s good ventilation for the, since they’ll be housed under the kids beds. What about ambient air temperature when charging and how fast can they be charged. I read that AGM’s can only take 20% if their total ah during the bulk portion while Lithium can handle 50%. I haven’t read anything like that for FLA.

 

[Photobug]

Lol. No cats, but I did forget to add the dog in there. Let’s call it 4.5.

I was wondering if there would be an issue with panels of different sizes.

I am no expert, what I know I learned from this site in the last few months. A recent thread was talking about a lesser panel bringing down the capacity of the greater panel. There was no consensus but it sounded plausible.

4.5 seems like a lot of people/dogs in a single unit. We do two people plus two dogs for a few days at a time, in a truck with shell and it's tight. I want to see how you can full time in a popup.

 

[dreadlocks]

FLA and AGM are fundamentally the same, they are both lead batteries in the end, any charge system you build should be able to handle any battery chemistry at this point in the game, especially for global travels.. unless your sleeping in an airtight area the batteries wont be any harm.. they wont be getting charged while your sleeping and thats when the'd gas out, but it wont be enough to worry much about IMO and is far overhyped to sell AGM's.

Your going to have 40A AC/DC Charging, and nowhere near that in solar.. 40A is like 16% and will be just fine.. if you had LFP you could dump 40A into a 100A battery and charge it up in like 2.5h of driving..

 

[Pilotamis]

I am no expert, what I know I learned from this site in the last few months. A recent thread was talking about a lesser panel bringing down the capacity of the greater panel. There was no consensus but it sounded plausible.

4.5 seems like a lot of people/dogs in a single unit. We do two people plus two dogs for a few days at a time, in a truck with shell and it's tight. I want to see how you can full time in a popup.

We just did almost 6 weeks in version 2.x. Drove across country and I gutted that build in favor for this one. The left side is bunks. The right is storage with a countertop. Straight ahead is more storage and our bed. Today we just about finished it up. This pic is when we were still laying it out. I’ll post another when it’s done. We found that we spent no time in it, so why have seating and places to hang out. Ow my wife and kids can collect more crap...

 

[Photobug]

We found that we spent no time in it, so why have seating and places to hang out. Ow my wife and kids can collect more crap...

My wife wants something enclosed and I am considering a popup. I don't want much more because of similar reasons. Not about collecting too much crap but I really want to enjoy outside more than inside. I am considering a popup on a truck bed trailer. I look forward to your final layout.

 

[larryqp]

I'm unclear if you have 1 x 160 watt solar panel or 2 x 100 watt panels

according to DIY solar warehouse: "A 100 watt panel produces an average of about 6 amps per peak sun hour, or about 30 amp-hours per day."
So with a 160 watt panel you should be producing 48 amps per day, you should be fine.

You have 2 x 100 amp Hr, 12 v batteries so you have 100 amp hrs of useful storage assumimg you don't want to go below 50% DOD, depth of discharge. So without any charging you have 2 days of power.

But solar is making 48 amps per day, if you use 50 amps per day you have a net loss of 2 amp hrs per day, so all things remaining equal it will take you 50 days to drop to 50% DOD. And that's without and alternator current.

If you have 2 x 100 watt panels then you should produce 60 amps a day so you will have excess and should be fully charged each day.

With regards to AGM vs FLA. As someone said you have to seal the battery compartment and vent it to the outside with FLA batteries, they must be mounted vertically, and they require maintenance in the form of checking water levels. AGM batteries do not need to be vented, they can be mounted in any orientation and don't require maintenance.

Good luck, but I think your setup will be fine.

 

[Photobug]

If you have 2 x 100 watt panels then you should produce 60 amps a day so you will have excess and should be fully charged each day.

What if it rains a few days or there is a few days of overcast and you have less than ultimate solar input? Even if you are in the tropics it would make sense to plan for less than 100% potential output each day.

@Pilotamis: while driving my truck today I was thinking about solar setups mostly mine but came up with a solution for you. Put a solar set up on your roof of a set configuration. Add a folding or suitcase panel of similar output/capacity. You could put a 160w panel permanently mounted on your roof and have a folding 120W portable panel that can be deployed when stationary. Hopefully, the portable panel can output similar to the permanent panel through better angles to the sun.