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Small Cabin Forum / Off-Grid Living / Time to replace batteries
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groingo
Member
# Posted: 13 Dec 2018 21:32
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Creeky, I know your lurking.
Have small 600 watt 12 volt solar
looking at lithium need 5kwh or 7, will this mean changing charge controller and inverter?

Have 2 235 Ah Crown deep cells but the started crapping out after very light (always kept no lower than 70%) use 2 years ago and I bought them in 2014.

justinbowser
Member
# Posted: 14 Dec 2018 00:25
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Trojan has came out with a lithium line, Trillium. Kind of pricey but claim a 5000 cycle life.

https://www.trojanbattery.com/trillium/

Nate R
Member
# Posted: 14 Dec 2018 08:20
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Woah, interesting! I like the idea of Trojan selling Lithium. I wonder if the internal BMS will keep float from overcharging the cells?

Looks like prices might be around $1K US for the 92AH model? (I'm seeing $1500 CAD for the 110 AH model, and estimating from there) At that price, from that brand, I start to get really curious. And they allow SOME charging under 32 degrees, which was another concern for me with Lithium. (I may see temps slightly below freezing, and I have small continous draw, so I need winter/cold charging.) And I see Morningstar has a way to taper that charge for cold on Prostar controllers: https://www.morningstarcorp.com/lithium-batteries/

I like the idea of 2 of these 12V batteries instead of the 2 FLA I was looking at. I'll have to definitely think harder about Lithium!

FishHog
Member
# Posted: 14 Dec 2018 10:35
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why do you need 5-7kwh when you had much less than that with lead. Considering you were only using the top 30% of that 470 ah capacity.

Since you can easily use 80% of lithium I think you don't need near that size, unless your expanding. No point paying good money for something that you won't use.

groingo
Member
# Posted: 14 Dec 2018 11:59
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The 5 to 7 kwh is for future demand and buffer.

creeky
Member
# Posted: 14 Dec 2018 12:33
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Your charge controller should be upward capable. At least to 24v.

At 5-7 kw storage (just a bit above my base "grey owl" system at 4.5) you will be well served to run most appliances etc. 1 to 1.5/2 kw of solar panel?

You really have a variety of choices. There are good batteries from China. And the Trillium (finally!!! congrats to Trojan). As well as small solar mfct on ebay. I have seen a lot (and I mean a lot) of really good lithium batteries now.

Don't overlook the recycled electric car solution. It does offer very good low cost and there are some good "EV" companies in California shipping modules daily. I do recommend a BMS now. The prices are dropping. Reliability is still an issue tho. So. If you're the careful type using manual balancing and monitoring is not a bad thing.

You got 5 years out of your lead acid. This, for folks who take good care of their batteries, is pretty much what I see. There are those with older but very expensive lead acid packs. I replaced a 12 year old high end pack last summer. The new lithium pack is making the customer very happy. He's grid tied and has seen a dramatic drop in grid provided power. Including this summer with no grid power used. Something he's never done before.

Personally. If you're upgrading the battery pack. I would see if I could find a good repurposed electric car battery and then use the money saved to update the solar controller and inverter.

With the solar controller: The new faster mppt algorithms might help. I don't know how much shading you experience.

And if you go 48v. An upgraded inverter will offer a combination of much lower idle overhead and a 6% increase in inverter efficiency. Benefits not to be sneezed at.

Congrats on 5 years! Folks don't realize how awesome it is to make and use only your own power. And that you can now upgrade to a more robust storage system. Pretty great.

There should be a "5 year" pin for solar. You know. Just to mark the occasion.

groingo
Member
# Posted: 14 Dec 2018 13:46
Reply 


Thanks Creeky, seems like a lot longer than five years, solar has been great, really babied and pampered the batteries but the clock just kept ticking, will let you know how it goes.....anyone know what ever happened to Mtn Don?

Nate R
Member
# Posted: 14 Dec 2018 14:27
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He still hangs out and is an admin at the countryplans site. I think he said something to the effect that there wasn't enough going on here?

https://countryplans.com/smf/index.php?action=profile;u=1495

Just
Member
# Posted: 14 Dec 2018 16:28
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MtnDon commented on a thread here on Dec. 10 he keeps track..

creeky
Member
# Posted: 15 Dec 2018 11:03
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Quoting: groingo
really babied and pampered the batterie


ah ha ha haaaaa. I so remember my 5 years on lead. Boy you get tired of watering, taking care not to discharge too deep. Etc.

Lithium rules! Freedom from worry!

Nate R
Member
# Posted: 15 Dec 2018 11:15
Reply 


creeky
Do you set up a charge controller for Lithium to stop charging below 100% of full charge somehow? Or do you not worry about keeping the voltages high in the cells?

groingo
Member
# Posted: 15 Dec 2018 11:59 - Edited by: groingo
Reply 


Yes Creeky, the Crown flooded actually took a steep dive 2 years ago after being replaced prior after just 30 days, something to do about incorrect blend of lead
in the cells preventing ion transfer, my batteries slipped through their Q C cracks, ultimately they never did perform for shit and I would absolutely never recommend Crown for anything.
Lithium is at the top of the list even looking at Tesla Power Wall, not cutting corners anymore, got my feet wet with current setup now time to move ahead.

creeky
Member
# Posted: 15 Dec 2018 12:21
Reply 


Quoting: groingo
time to move ahead


Same way I felt. 5 years was enough. I had good luck with my Crown's. Despite beating the hang out of them. But lead. shiver.

There are some great options out there. And the thing about full time off grid. It makes sense to spend a bit more for better quality.

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