With a lithium-ion battery is it better to run it down or keep solar plugged in?I have an Engel compressor refer/freezer that draws 36-37 watts when it runs..I also have a portable 100 watt solar panel that puts out on average about 65 watts..It has been as high as 81 watts if I take the time to aim it right..My question is,when I hooked it up,it quickly charged the battery to 100% with the Engel running and then it showed 0% input from the panel for a while then back to 64-65 watts input then 0%..Is this method better or worse for battery cycles/longevity than running the battery down then charging it?Completely new to solar and trying the portable solar for now...So I am a solar dummy of sorts for the time being..LOL

Suggest you call your battery manufacturer for advice on correct charging with low current.My research has discovered Li-FO4 batteries can discharge and charge at high rates, are happy to sit partially charged, and are good for 3000-4000 cycles to 20-30% when operated and stored properly. It makes them particularly suited for generator and vehicle alternator charging with the right equipment.

Li batteries don't really care what SOC they're in.

Hi,For greatest longevity Li doesn't like to be charged above 90% of full, nor discharged below 40%, especially for storage.The deeper the discharge the fewer total cycles. Attempt to not go below 20%.All the recommendations I find are charge to 90% before storage. Refresh the charge from time to time.Do not store below -4 f (-20 c).I'm going SiO2 instead. They can survive being discharged to stone bone dead 620 times. Of course, that is not recommended. They appear to be better than LI in every category except for weight. The SiO2 are similar weight to lead acid. They can be used and charged at -40.This solar series in plain English may help: https://freecampsites.net/adding-solar/

I wish Don would buy those batteries so we could have a real world report. I’m hoping for great results.

100W solar might keep the battery charged with no other loads. Do a energy audit and determine your usage and then what's needed. A battery monitor will be even better. You're asking about a very expensive battery that has different charging needs than flooded. Maybe experiment with flooded first before spending the big bucks.

Lithium-ion and solar panel life cycles? | Good Sam Community

pianotuna
Nomad III
Aug 20, 2020
Steve,

$455 per 100 amp-hours with 80% usable. Cost per cycle may be lower than GC.

1500 cycles to 20% state of charge, or 2800 cycles to 50% state of charge.

Surge capability is much superior to LI, so they are ideal for large inverters.
StirCrazy
Moderator
Aug 20, 2020
pianotuna wrote:

I'm going SiO2 instead. They can survive being discharged to stone bone dead 620 times. Of course, that is not recommended. They appear to be better than LI in every category except for weight.

This solar series in plain English may help: https://freecampsites.net/adding-solar/

what kind of price do they carry out there compared to lead acid. I have 470AH of GC batteries that need to be replaced soon in my 5th wheel.

Steve
pianotuna
Nomad III
Aug 20, 2020
noteven wrote:
It looks like the SiO2 Grp 27 size 100ah Soneill battery has a max charge rate of 25amps

This would make them well suited to solar vs Big Amps via a generator?

Yes, but, anyone who boondocks would want more than one. I'll be planning on four--but might just jump to six, or seven. I may put one in the Chassis as well. But 4 would want 100 amps if they were hungry.

The other issue is the "big amps". So far as I am aware 100 amps @ 12 volts is about the limit for converters. So the generator would be loaded to about 1400 watts (boost mode from a 100 amp boondocker converter) maximum.
noteven
Explorer III
Aug 20, 2020
It looks like the SiO2 Grp 27 size 100ah Soneill battery has a max charge rate of 25amps

This would make them well suited to solar vs Big Amps via a generator?
pianotuna
Nomad III
Aug 18, 2020
2oldman,

Similar in weight to lead acid--I think 70 lbs for a 100 amp-hour jar.
2oldman
Explorer II
Aug 18, 2020
pianotuna wrote:
What sold me, other than cold weather performance, is the SiO2 can be discharged to stone bone dead 620 times. That flabbergasts me.
That's amazing. My Li pack has had 5 discharges (BMS stops it at 42v). Then you have to 'reboot' it by disconnecting it from any draw or charge.

I can't find the weight of the SiO2 jars.
MrWizard
Moderator
Aug 10, 2020
Yes... That's Phenomenal
pianotuna
Nomad III
Aug 10, 2020
MrWizard wrote:
I did a quick look on Amazon,
There it seems process are more like 1/2 of Lithium not 1/3
Still that is a big savings

https://azimuthsolarproducts.com/product/12v-100ah-sio2-battery/

$449.12 USD for a 100 amp-hour 12 volt jar. They do offer a small discount starting at 3 units. I'll probably want five, and wish I could afford eight. (seven house, one starting).

Prices are dropping on Li batteries.

What sold me, other than cold weather performance, is the SiO2 can be discharged to stone bone dead 620 times. That flabbergasts me.
MrWizard
Moderator
Aug 10, 2020
I did a quick look on Amazon,
There it seems prices are more like 1/2 of Lithium not 1/3
Still that is a big savings
pianotuna
Nomad III
Aug 10, 2020
Lwiddis wrote:
I wish Don would buy those batteries so we could have a real world report. I’m hoping for great results.

* Cheerfully accepting donations.... * LOL

I will certainly do a report once I have them.

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