Solar Power Part 2

Sneakers

Just sneakin' around....
Just noticed that 100 AHr LiFe batteries are down to about $300 now.
Gotta be real careful about them. Lots and lots of dealers with lots of offerings, but from what I'm reading very few are liable. Both the battery and the dealer. Even formerly reputable dealers like Renogy have gotten very poor customer reviews lately.
 

PeoplesElbow

Well-Known Member
Gotta be real careful about them. Lots and lots of dealers with lots of offerings, but from what I'm reading very few are liable. Both the battery and the dealer. Even formerly reputable dealers like Renogy have gotten very poor customer reviews lately.
Thanks for the heads up. I have been reading a forum where people buy the individual cells and build their own packs, often buying these cells is a crapshoot because they all come from some shitty Chinese seller.
 

GURPS

INGSOC
PREMO Member
I'd build on out of a couple of AGM Truck Batteries, a Trickle Charger and an appropriate inverter
 

PeoplesElbow

Well-Known Member
I'd build on out of a couple of AGM Truck Batteries, a Trickle Charger and an appropriate inverter
Not a bad idea for something bigger, but an AGM truck battery costs about $300 and weighs what 30-40 lbs? Add a pure sign wave inverter, some good charging circuitry and you're hitting $1k easily.

Only about half the capacity of a deep cycle AGM battery is usable vs a LiFe where you can use 90% of the capacity.
 

GURPS

INGSOC
PREMO Member
Indeed, most of the decent off grid power supply's with a good sized capcity are $ 1500 or more
 

Sneakers

Just sneakin' around....
A LiPo cell can be assembled as well .....
"Can be". Way too many horror stories about bad cell vendors, bad cells, meltdowns.... Don't want to deal with that kind of frustration for something that you want to be available and working at a moment's notice without fail.

Until the battery tech is a lot better, my home-built projects are still using AGMs.
 

Sneakers

Just sneakin' around....
I think I found some good info on this page.

After my mom is gone I'm building a camper van with a solar system.
His videos and website prompted my first builds. Lots of good info. His forums are a good source of user experience, if you can look past the constant repeat of the same newbie questions over and over and over.

For battery builds, this guy is good too.
 

Sneakers

Just sneakin' around....
Update:
Finally got back to working on the solar charger, prompted by the receipt of the portable solar panels. Replaced the temporary 750w inverter with the 1000w pure sine wave inverter from my original solar project. I was going to upgrade to a 2000w inverter, but after using the 1000w, I'll stay with what I have for two main reasons: When pulling a 750w 120vac load, the 2AWG battery cables are getting warm. Not hot, but pretty warm. If I use a larger inverter, I'd have to replace the battery cables with 1 or 0 AGW. Makes it a bit inconvenient for portability. Also, not seeing a real need to exceed 700-800W when used as a backup.
20230422_110833.jpg

Since the new PV panels use the XT-60 connector, I modded the solar charger with XT-60. After working with them a bit, can't say I'm thrilled with them. Rated for 30amps, more than the twist-lock connectors I had been using, but only accept up to 12 gauge wire. I built my solar charger with 10 gauge. Got them soldered in, but it's not as clean as I would like. The XT-60 is also not nearly as robust and I can see them being easily damaged.
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The new portable solar panels work great. On an overcast day, I was getting 285W out of a potential 400W. I'll need to test when there is full, clear sun.

Screenshot_20230404-122308.jpg
 

Sneakers

Just sneakin' around....
But the biggest change was the battery. My 100AH AGM failed. Boooo. Looked for a replacement keeping in mind the horror stories of LiFePO4 batteries on the market. Came across a YouTube review of a new LiFePO4 with a great review, and all the features I was looking for.
1) MADE IN USA! Ok, the cells may be made overseas, but they are high quality, reputable vendor cells.
2) 300AH in the same form-factor as my 100AH AGM, and weighs less.
3) Built-in heaters for low temp charging.
4) 8 year warranty.
5) BlueTooth status.
6) Lead Acid direct replacement. Don't need special chargers, just swap out and use.

Ordered one, testing with it now. The vendor had a sale on them as they were new to the market, plus a package deal, and I got some money off for using a code from the YouTube review. Free shipping. Got the battery, 300W plug-in charger, power cables with Anderson connectors, insulated carry bag (for low temp use when the internal heater is on), and optional heater over-ride for less than the list price of the battery.

Screenshot_20230422-121143.jpg Screenshot_20230422-110516.jpg Screenshot_20230422-110602.jpg

Pricey, but I'm at a point where I don't really care what something costs. If I want it, I get it. Don't need to justify it anymore.
 
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Sneakers

Just sneakin' around....
Used a small inductive heater to pull a consistent load. Showed about 740W at the 120V plug. The line meter shows 1.7kWh over 2 hours and 25 minutes.

Battery stats showed a draw of just over 800W. At 50% battery, there is still 150Ah remaining. An AGM 100Ah battery has a useful Ah of between 50 and 70% (50 to 70Ah), so at 50% of the LiFePO4 used, it has more than 3 times the total available capacity of the AGM still remaining.

Very cool.

The 800W load put the load meter into the yellow zone, so I wouldn't want to increase the inverter size with the intention of higher wattage loads. However, a larger inverter may be a consideration because while a fridge draws less than 100W running, it can surge to 1500W. Might be a bit much for the 1000W inverter repeatedly.

Screenshot_20230422-143012.jpg Screenshot_20230422-143046.jpg
 

PeoplesElbow

Well-Known Member
I have an Ego lawn mower and string trimmer, they are great so I have a large battery and a small battery.

Ego made a 150W modified sine wave inverter, I emailed them last year and said if you had a 400W pure sine wave inverter I would buy one. They emailed me back and told me they used my idea now buy one lol.

So I'm $150 poorer, but its some good insurance in a power outage since I already have the batteries.

The big inverter is pretty cool, but four batteries is a lot of money.

 

Sneakers

Just sneakin' around....
The big inverter is pretty cool, but four batteries is a lot of money.
Looks nice, clean.

That's always been the case. You can buy or build a pretty powerful backup system for not a lot of money, but to make it worthwhile or have any duration, the batteries are the really expensive part.
 

Sneakers

Just sneakin' around....
I won't tell you what I just spent on one LiFePO4 battery... :ohwell:

Just finished making some new 175 amp power cables.
 

PeoplesElbow

Well-Known Member
Looks nice, clean.

That's always been the case. You can buy or build a pretty powerful backup system for not a lot of money, but to make it worthwhile or have any duration, the batteries are the really expensive part.
Oh I know, right now I just want some backup power for the short outages I occasionally get. Router, laptop and maybe a heating pad for my mom if its in the middle of winter like last January's outage.
 
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