Limited Battery Options

[Sylvan Secrets]

I'm looking to upgrade my solar system to help weather the Canadian winter. I've recently upgraded my solar panels. I now have 2 100w mono panels from Renogy on tilting mounts. My current charge controller is Renogy's Wander a 30a PWM controller. The battery is 105ah marine sealed battery that came with the van and has definitely been cycled frequently.

I want to upgrade the batteries to around 200ah as well as to AGM deep cycle. The only batteries I can find in my area are both around the same price. The brand name is Motomaster - Nautilus. The 12v battery is advertised as marine/rv agm with 105 ah. The 6v battery is advertised as golf cart/ solar application and the brand name is Motomaster without the marine label. It is also an agm deep cycle battery. Either way, I'd need 2 batteries to meet my goal of 200ah. With 12v I would have 110ah, with 6v in series 190ah.

I've heard that marine batteries aren't as good. Is the difference worth using the 190ah 6v batteries? Are there any disadvantages to using 6v in series?  :huh:

The other thing which has been recommended that I upgrade is my charge controller to MPPT. I'm looking at the EPEver Tracer AN. And wondering if I should get the 30a or 40a version. There is a $50 CAD difference between them. I would like to upgrade to 300 watts of solar down the line. The Renogy 100w panels have a short circuit current of [font=Biryani, sans-serif]5.75a. So assuming I add another 2 panels, that would give me a maximum of 23a. My understanding is that you shouldn't put through more than 80% of the rated current. So 23*1.2 = 27.6a. If my napkin math is right, the 40a version isn't really worth the additional $50.[/font]

[font=Biryani, sans-serif]Am I missing anything? Any suggestions are welcome.[/font]

[font=Biryani, sans-serif]EPEver Tracer AN: [/font]https://www.amazon.ca/gp/product/B06ZZRSDB8

 

[mpruet]

Be extra careful with tilt mounts.  They tend to raise the panels a bit higher than a non-tilt mount and that can make it easier for the wind to get under the panel.

Also - most tilt mounts use wing-nuts because you have to undo them to raise them up.  The wing-nut can loosen while driving. 

I had mine to fly off while driving on a windy day while in Alaska.  I believe that a similar thing happened to Nomadic Fanatic.

 

[John61CT]

You need true deep cycling, big box retail or auto sources will usually not sell those in 12V.

In the US the best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

Trojan T-105s are usually a bit more, but excellent.

US Battery, Crown, Superior all great too.

Rolls / Surrette are the best.

AGM will be pricier and not as robust.

 

[Sylvan Secrets]

Be extra careful with tilt mounts.  They tend to raise the panels a bit higher than a non-tilt mount and that can make it easier for the wind to get under the panel.

Also - most tilt mounts use wing-nuts because you have to undo them to raise them up.  The wing-nut can loosen while driving. 

I had mine to fly off while driving on a windy day while in Alaska.  I believe that a similar thing happened to Nomadic Fanatic.

I made the mounts myself so they are the same height as the regular mounts. As for the wingnuts, I see where your concern is coming from. Checking the nuts regularly is a really simple thing to do though. Not only that, but wingnuts aren't really any less secure than a regular non-locking nut when tightened with a socket wrench. The tilt would only really get used in the winter when I'm stationary anyways.

 

[Sylvan Secrets]

You need true deep cycling, big box retail or auto sources will usually not sell those in 12V.

In the US the best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

Trojan T-105s are usually a bit more, but excellent.

US Battery, Crown, Superior all great too.

Rolls / Surrette are the best.

AGM will be pricier and not as robust.

What constitutes a "true" deep-cycle battery? How does one tell?

As for the rest, thanks but none of that is relevant to my question or country. I'd really rather use AGM for two reasons: I don't have to worry about filling them up and they don't off-gas. That just makes my life a lot easier.

 

[B and C]

A deep cycle battery will not have CCA (cold cranking amps) listed. If they do they are a hybrid.

 

[Trebor English]

If you are so inclined, a third 100 watt panel will increase your available power by 50% over the two panels you have now.  MPPT controllers will give 30% more according to the literature for about the same price as a third 100 watt panel.  The same logic applies to the fourth panel.  It will give 33.3% more than the prior three panels.  On the Canadian Amazon page 2 Renogy 100 watt panels are cheaper than twice the price of one.

With 4 panels you can have 2 series pairs to better take advantage of MPPT if you still need more power.

 

[Spaceman Spiff]

What constitutes a "true" deep-cycle battery? How does one tell? . . .

A deep cycle battery is heavy:  about 60 lbs per 1200WH (12V & 100 AH or 6V & 200AH).  It takes a lot of lead to be a deep cycle battery.

 

[MrNoodly]

Check with places that sell batteries for wheelchairs, mobility scooters or golf carts. And companies that build off-grid solar systems, of course. Those will be true deep cycle batteries.

 

[John61CT]

What constitutes a "true" deep-cycle battery? How does one tell?

As for the rest, thanks but none of that is relevant to my question or country. I'd really rather use AGM for two reasons: I don't have to worry about filling them up and they don't off-gas. That just makes my life a lot easier.

You tell by asking, a great reputation takes decades to earn. Any suggestion of cranking usage or "dual use" by other vendors is a big red flag.

For AGM in the US market, Odyssey, Lifeline or Northstar are the top three, can trust their claims.

But again, AGM should only be used if truly needed. Your cost per AH per year will be much higher, and care requirements are much more difficult, they do not stand up to abuse nearly as well.

______
What is a Deep Cycle Battery? – Marine How To

https://marinehowto.com/what-is-a-deep-cycle-battery/

 

[Weight]

John beat me to it. Rod Collins has performed some sophisticated testing to explain "what is a deep cycle battery". He has even dissected some and posted the bloody images right here on the internet. https://marinehowto.com/what-is-a-deep-cycle-battery/

 

[B and C]

He really seems to only be comparing golf cart/sweeper batteries with marine batteries. He is not comparing true deep cycle AGM batteries at all. Marine batteries are rated with CCA (cold cranking amps) so not true deep cycle.

I agree that the golf cart/sweeper batteries are superior to marine batteries.

I'll take my low maintenance AGM deep cycle batteries any day (for my application).

 

[MrNoodly]

...and care requirements are much more difficult...

What care requirements are you talking about?

 

[AnFear]

Yes, what care requirements are need for AGM's. I went with Trojan T 105's wet cells and after two years with them I'm sorry I didn't go with the
AGM's. My reason at the time was to get more AH's. I would gladly trade in the slightly less AH's for the maintenance free AGM's.
Before I went on the road I checked a bunch of forums and websites trying to find out about batteries. Turns out I should have ignored most of them. Seems like people really obsess over the subject.
No harm done but with 225 AH's I way over did it. I know everyone's needs are different but to anyone just getting started I recommend not worrying to much about it.

 

[B and C]

I only check connections on my batteries once a year. Other than that, I don't do anything else. I do cycle them shallowly though, about 20% DOD (depth of discharge). I guess I do keep an eye on my BMS (battery monitoring system).

 

[bullfrog]

I use AGM batteries because of vibration going off road, less corrision issues, no checking acid levels, I don't have to worry about battery acid when I flip over, or fumes as they are in my living space. But mainly I'm just lazy and the current set of Optimas has lasted 7 years but they are now no longer made in the USA but Mexico and are no longer carried at Batteries Plus so I guess my next set will be Duracell. We will just have to see if they do as well. The reason I started using AGM's was I crashed and the battery mount broke jerking the positive post out of the wet cell battery as it went through the windshield loosing battery acid. It is a hard desision to decide if you are gonna use what little water you have to try to top off a broken battery and wiggle a positive post to get the starter to work while stuck nose first in a 10' wash 40 miles past the last ranch with both front wheels bent and broken off the hubs but you know God smiles on you sometimes.

 

[John61CT]

The three brands of AGM I listed are true deep cycling, if that's what you really want and are willing to pay for.

Even if they list CCA and mention cranking, will last many years longer than anything you find in auto or big box retail.

Call the mfg to find distribution near you, do not have them shipped unless absolutely necessary.

Get the technical specs for charging, voltage setpoints with temperature compensation, minimum amps current, Absorb V held until what trailing current (endAmps spec), and makes sure your charge source regulators can be programmed ideally matching, or close as possible.

This often requires upgrading other equipment.

Careful not to allow overcharging, neither too high voltages, nor holding Absorb voltage too long, or the electrolyte gasses off and can't be replaced.

 

[Seminole Wind]

given the choice, i would go with the 6v golf cart batteries every time!

i am not a big fan of AGM, but if they make you sleep better at night and can afford them, go for it. but just cause they are AGM does not make them deep cycle.

if you want to compare batteries for a deep cycle application. contact the manufacturer and request the depth of dischage vs number of cycles chart and see how many cycle they state at a similar depth of discharge.

not sure what makes you think you need to derate a charge controller and only use 80% or so. i would never waste my money on a controller from a company that falsely inflates their rated current capacity. in fact these days i wont even use a controller that will fault or shut down if over loaded. plenty of quality mppt controllers available now that will self limit when their max current is exceeded and continue to provide full rated power.

at the moment, "back home" in the pacific north west i have 1180 watts of panels running through a single 50 amp 12v controller. since it is winter and low sun and clouds prevent full panel out put most of the time. when we do get a clear sunny day and the panels "over load" the controller it self limits and puts out the rated 50 amps.

ANY decent mppt 30 amp 12v controller should handle 300 watts easily and should handle 400 watts. but occasionally you could have a situation where you have a pretty low battery AND full sun on a clear cold day that would exceed the 30 amp rating. for example if a low battery while receiving 400 watts of input was only coming up to 12 volts you would see just over 33 amps. used a fuse or breaker it could fault out and shut down. if it was self limiting it would just happily pass the 30 amps to the battery and clip the excess. the mppt controller by design can reduce the output of the panels by running the panels at a less than maximum power point. even a pulse with modulating controller should be able to limit over current via the pwm dwell. think of it this way. both controller types mppt and pwm essentially have to limit max current once a battery i full or close to full. that is their primary fuction. if not having 400 watts from an unregulated pannel array would cook a full battery

i personally would not waste my money and limit my charging capability with a controller that cant self limit. especially these days when panels are so cheap