Lithium Vs. More Solar

[obiwancanoli]

Having learned so much from members here since my initial posts in early 2018, I've been grateful that the learning curve has been relatively steady, and informative. I've truly appreciated the guidance...

Today, considering replacing my standard deep cells - each 115 min @75 amps, 220 Ah at 20 hr - with 100 Ah Lithium batteries is on my mind. I'm thinking 3 would do the trick, but have room for 4...

My rig is a 2017 Newmar Ventana LE 3436. I've got 480 W Zamp solar producing 26.1 peak Amps, a 30A Controller, plus a external, portable solar panel at 120 W.

The Li choice seems clear to me, as a distinct cost advantage over time, and fits well with my goal to enjoy more dry camping...

The question is, should I consider adding another 160-320 W solar? Of course, would need to obtain new controller, thinking MPPT would be best - note that I ask because of my tendency to plan for worst case scenarios, and feel a certain peace of mind knowing I'd have sufficient power to last a week without sunshine... shade is nice, but that doesn't help the solar much...

[ppine]

Li batteries are clearly superior in every way, but I have never liked the idea of $2,500 worth of batteries just sitting there on my trailer. Maybe if they were locked up in a compartment.

[obiwancanoli]

Update:

I went for 4 - 100Ah Battle Born Lithium batteries, though the battery tray must be removed to accommodate them. No problem reconfiguring this... Victron 712 and new 100A/50 Victron Controller should be installed this week. Once completed, next step is monitoring system to determine additional solar panel needs (fixed vs. portable on another thread...)

[pianotuna]

Itinerant1,

I was referring to the shorai design. I believe it should have "refused" to charge at too low a temperature.

The technomedia folks should have just done outside storage and their LI bank would have been fine.

[Itinerant1]

vermilye wrote:

3 tons wrote:
Per Pianotuna:

“I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.”

I suppose almost anything is possible in ‘one case’ (or say, even several cases - ??) where a defect might be present, yet I don’t necessarily see that as an ubiquitous flaw that affects an entire genre of battery type - the literature I’ve read appears to suggest otherwise...Either way, leaving any battery unattended for a full year will not be one of my real concerns - lol!

3 tons

I agree that it must be either a poorly designed BMS or defective. I have a pair of Battleborn Li batteries, drained them to 80%, and let the trailer sit with the battery disconnect switch off. After 6 weeks, the Victron monitor read 79.9%.

I believe you would be wrong of a poorly designed bms or defective it did exactly what it was suppose to do.

They put the bus in storage plugged in thinking that they would be back in 6 months and not shutting the batteries down. Sometime during the 1.5 years in storage while they were away sailing there was a power outage, the batteries were on powering the bus till the bms did shut them down for low voltage, but on the Elite Power Solution GBS batteries there are sense boards (part of the bms) on every cell which has a 2 LED lights, 1 will stays on if it's connected to the battery and the other led will turn on if balancing is happening on that particular cell. That led light on 20 cells was enough to eventually suck the juice from the cells.

There is a "max" of 3% discharge per month claimed by the Elite. If they had stored the batteries at their full 380ah and properly shut the system down they would of been ok for roughly 30-33 months. We know that if they will be stored for unknown period of time all you have to do is take the sense boards off and they will last even longer.

Their battery failure was their own fault.

Here is their video. https://youtu.be/0j0zcRXTDRk

I have the same battery system. 😉

[pianotuna]

Itinerant1 wrote:

pianotuna wrote:


I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.

Are you talking about Technomads?

Yes--thanks for coming up with the name--I could not remember who it was.

[vermilye]

3 tons wrote:
Per Pianotuna:

“I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.”

I suppose almost anything is possible in ‘one case’ (or say, even several cases - ??) where a defect might be present, yet I don’t necessarily see that as an ubiquitous flaw that affects an entire genre of battery type - the literature I’ve read appears to suggest otherwise...Either way, leaving any battery unattended for a full year will not be one of my real concerns - lol!

3 tons

I agree that it must be either a poorly designed BMS or defective. I have a pair of Battleborn Li batteries, drained them to 80%, and let the trailer sit with the battery disconnect switch off. After 6 weeks, the Victron monitor read 79.9%.

[Itinerant1]

pianotuna wrote:


I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.

Are you talking about Technomads?

[3_tons]

Per Pianotuna:

“I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.”

I suppose almost anything is possible in ‘one case’ (or say, even several cases - ??) where a defect might be present, yet I don’t necessarily see that as an ubiquitous flaw that affects an entire genre of battery type - the literature I’ve read appears to suggest otherwise...Either way, leaving any battery unattended for a full year will not be one of my real concerns - lol!

3 tons

[pianotuna]

CA Traveler wrote:

pianotuna wrote:
3tons,

I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.

I do know of one person who attempted to charge an Li when it was too cold--that also resulted in destruction.

Shorai battery recommends a refresher charge every six months.

Sounds like a faulty BMS system or design for one case and ignorance in another.

The BMS was operating as designed--so not faulty.

I agree that the low temperature charging was an issue--but that leads to poor design of the BMS. It should have included low temperature protection.

I do agree that the person attempting to do the charging was not willing to listen to his little brother (me).

[CA_Traveler]

pianotuna wrote:
3tons,

I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.

I do know of one person who attempted to charge an Li when it was too cold--that also resulted in destruction.

Shorai battery recommends a refresher charge every six months.

Sounds like a faulty BMS system or design for one case and ignorance in another.

[pianotuna]

3tons,

I do know of one case where the battery management system totally drained an Li bank and destroyed the batteries over the time frame of one year.

I do know of one person who attempted to charge an Li when it was too cold--that also resulted in destruction.

Shorai battery recommends a refresher charge every six months.

[3_tons]

The Power-sonic blog has some sound information on FLA vs LiFePo4 charging curves and for long term storage:

https://www.power-sonic.com/blog/how-to-charge-lithium-iron-phosphate-lifepo4-batteries/

3 tons

Upon edit, I should add that Power-Sonic recommends around 50% SOC for long term storage.

[3_tons]

pianotuna wrote:
3tons,

I thought the battery management systems of at least some LiFEPO4 would slowly discharge the jars. If that is so, 80% may be a safer storage level than 50%.

Of course, since I'll be doing SiO2 I don't have to worry about such things.

From Solacity:

“The very low self-discharge rate makes it easy to store LFP batteries, even for longer periods. It is no problem to put a lithium-ion battery away for a year, just make sure there is some charge in it before placing it in storage. Something between 50% – 60% is ideal, that will give the battery a very long time before self-discharge brings the Voltage close to the danger point.”

[pianotuna]

3tons,

I thought the battery management systems of at least some LiFEPO4 would slowly discharge the jars. If that is so, 80% may be a safer storage level than 50%.

Of course, since I'll be doing SiO2 I don't have to worry about such things.