Solar panels and deep cycle batteries

[Vaquero]

I've got 200 watts of PV panels and controller on the way. Now I'm researching storage options.
This will be the primary power system for a remote building/ cabin.
No big power draw. A recent build ceiling fan and less than 2amps @120 volt of led lights.
A CPAP once in a while.
If I need to run anything over 700 watts @ 120V I'll fire up the ICE generator.
I'll also be powering the RV DC system on occasion. That is a whole 'nuther box of questions.

So, y'all got any suggestions on what battery or bank of batteries?
Considerations are, budget, longevity, maintenance.

Thanks.

 

[deemus]

A buddy has a bank of 6 batteries daisy chained together on a similar setup. His runs regular house lights for a few hours.

The batteries are in a closet on a metal bread rack to keep them off the concrete.

I’ll find out what kind of batteries, but I’m pretty sure they are deep cycle batteries.

 

[Axxe55]

To the best of my knowledge, most solar power systems do utilize deep cycle type batteries.

 

[Vaquero]

Let me rephrase the question.
Is there a brand of battery that's to be sought? Or avoided?

Is li-po worth the added expense?
Is AGM the best compromise right now?

 

[FireInTheWire]

Subbed

 

[kbaxter60]

To the best of my knowledge, most solar power systems do utilize deep cycle type batteries.

Yes, that's correct.

If you have not already done so, you want to look at charge controllers for your system. They keep the batteries topped off and maintained (usually) and prevent your batteries from charging your panels at night. And they typically work with sealed batteries, often of the AGM type quite well. Sealed cells can have issues with a limited number of charge cycles and also are affected by temperature (high and low). The point to all that is that you need to know that your controller works with the battery technology you choose.

In many larger systems, I have seen the Trojan series batteries used. I believe they are "flooded" cells and have better lifetime tyepically. One of their more popular units is a 6V cell, so you'll need to put them in series to get to your system voltage. Also, check the weights before ordering. They are heavy.
https://www.trojanbattery.com/

If you want to go beyond those, you probably want to consider a Tesla Power Wall. And now, the sky's the limit!

 

[tangoparson]

Battle born lithium batteries are the hot ticket for RV solar right now. Like everything else, get at least twice the A-H than you think you need.

Lithium offers a better discharge curve the anything else. They can be discharged to like 20% without damage opposed to less than 50% for traditional batteries.

Drawback is the charger and controllers better support them.


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[Brains]

I'm curious if you'll find 200W worth of panels isn't enough to keep up with the demand. Might want to overplan the charge controller just in case you need to bump up. If it were me building the setup, I'd very likely go with LiFePO4 (Lithium Iron Phosphate) batteries.

 

[kbaxter60]

Battle born lithium batteries are the hot ticket for RV solar right now. Like everything else, get at least twice the A-H than you think you need.

Lithium offers a better discharge curve the anything else. They can be discharged to like 20% without damage opposed to less than 50% for traditional batteries.

Drawback is the charger and controllers better support them.


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Those look really good. Great energy density, it appears.
Do you know if they have the balancing issues of the early LiPo packs? Since they appear to have only the two terminals, it looks like "no", but that would be a nonstarter for me, I think. Also, are they stable? In the early days, the RC guys were charging their cells in ammo cans, as they had a bad habit of going boom.
If these are safe, and you can afford them, they look like a great way to go.

 

[TipBledsoe]

Yes, that's correct.

If you have not already done so, you want to look at charge controllers for your system. They keep the batteries topped off and maintained (usually) and prevent your batteries from charging your panels at night. And they typically work with sealed batteries, often of the AGM type quite well. Sealed cells can have issues with a limited number of charge cycles and also are affected by temperature (high and low). The point to all that is that you need to know that your controller works with the battery technology you choose.

In many larger systems, I have seen the Trojan series batteries used. I believe they are "flooded" cells and have better lifetime tyepically. One of their more populare units is a 6V cell, so you'll need to put them in series to get to your system voltage. Also, check the weights before ordering. They are heavy.
https://www.trojanbattery.com/

If you want to go beyond those, you probably want to consider a Tesla Power Wall. And now, the sky's the limit!

+1 on Trojan lead-acid batteries. Quantity of six conditioned 8VDC Trojan batteries are a hard to beat setup for 48VDC electric golf cars.
Remember that you'll need an inverter to convert DC to AC for your cabin AC appliances. And remember that inverters do not have 100% efficiency when making your storage calculations.
I'd think that quantity 15 of the Trojan 8V batteries ahead of the inverter would likely meet or exceed your needs, but if more storage is needed you can go with quantity 24 of the Trojan 6V batteries assuming the 6V batteries have a higher Ah rating than the 8V batteries.

 

[AZ Refugee]

I had a pair of Die Hard Platinum AGM Deep Cycle batteries that I used on my toy hauler for dry camping. They would run the lights, radio, & water pump in my trailer for a week. If I ran the heater at nigh the time was a couple of days. I cannot speak to the solar aspect as I charged mine off of house power or a generator, but as far as performance they were the best I ever had. I believe they were made by Odyssey. I paid about $225 each for them. I can Imagine if I had more of them and a solar panel I could have stayed out indefinitely.

 

[Axxe55]

Just an observation, and opinion. I would do the calculations to see what or how much was needed, then factor in for possible addictions to that energy system, and add more than you need currently.

 

[Vaquero]

Just an observation, and opinion. I would do the calculations to see what or how much was needed, then factor in for possible addictions to that energy system, and add more than you need currently.

This is what I have done.
I'm currently seeking opinions and experiences with different battery brands and types.

 

[Fishkiller]

My only contribution is if you use lead acid batteries they give off hydrogen gas, so you need ventilation at the ceiling level. Natural ventilation is usually adequate.

 

[Vaquero]

My only contribution is if you use lead acid batteries they give off hydrogen gas, so you need ventilation at the ceiling level. Natural ventilation is usually adequate.

Good advice, and I've got that covered. Building has a roll up door that prevents sealing off at the top.
Flying insects love it.

 

[Axxe55]

My only contribution is if you use lead acid batteries they give off hydrogen gas, so you need ventilation at the ceiling level. Natural ventilation is usually adequate.

That is exactly true. Plus they can also leak acid so they need an area where acid leaking on the floor wouldn't be an issue.

Lead acid batteries, especially most deep cycle type batteries have to be maintained by checking the water/electrolyte levels periodically, with distilled water. If the cabin is only used occasionally, that could be an issue for lead acid batteries that need to be maintained. Another type of battery like a AGM or "gel" battery might be the better option for such a situation.

 

[tangoparson]

Those look really good. Great energy density, it appears.
Do you know if they have the balancing issues of the early LiPo packs? Since they appear to have only the two terminals, it looks like "no", but that would be a nonstarter for me, I think. Also, are they stable? In the early days, the RC guys were charging their cells in ammo cans, as they had a bad habit of going boom.
If these are safe, and you can afford them, they look like a great way to go.

They are the new tech lithium iron like the poster above mentioned (LiFe..). Much safer than the old LiPo.

I haven’t used them yet on my camper because I haven’t started full timing in it yet but all of the reports i am reading from the serious boondocker RV guys they are nothing but good.

https://www.technomadia.com/lithium/ for example.


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[Vaquero]

Got a couple of these.

Should be more than enough for my immediate plans.
If I decide to increase capacity, I'll move these to the RV.

 

[pronstar]

6v batteries are the most cost/effective solution IMHO.

Thick plates, and they’re built for deep discharges in applications like golf carts.

I ran (4) 6v batteries in my Toy Hauler. They can take a lot of abuse. Bought cheap ones at Costco, but know lots of folks who swore by Trojans.

Vaq, consider these battery caps. They capture and re-introduce water that would otherwise evaporate out.

Water Miser Battery Vent Caps

Stored our RV in the high desert...indoors but not climate controlled. I checked, but never had to add water, for the two years I had them before I sold everything.

That company has a lot of cool things that make maintaining batteries easy, just poke around their website if you’re interested


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[kbaxter60]

Got a couple of these.
View attachment 228279 Should be more than enough for my immediate plans.
If I decide to increase capacity, I'll move these to the RV.

Those should be excellent for your application. Curious: what is size and weight, if you don't mind?