Hi everyone,

I have been a member of the forum now for some time and busy with installing a grid tie system. I have already installed a Sunsynk 5kw inverter with 20 x 275 panels.

I am looking to install proper battery back up so I can store excess power during the day and use at night. For some time now I have been looking at going Lithium, which does seem to be the obvious choice at the moment.

However after speaking to a local installer he advised me that they had lot of issues with Lithium batteries not coping with the heat in the Northern Cape and Namibia. His opinion is that lead acid batteries are tried and tested and they have almost no issues with these batteries once installed, up to 10 - 15 years life. Does this make sense?

Has anybody else experienced this type of issues with Lithium batteries?

Looking forward to your remarks.

33 minutes ago, Adriaan.S said:

up to 10 - 15 years life.

Wow, can he please supply us with the brand he uses. I want some...

I would like to ask him a few questions..

1. How long has he been an installer?
2. Has he ever personally witnessed a lead acid bank last 15 years?

And now to answer your question:

1. Out of all the Lead acid batteries i have worked with, the longest chemical design life was 8 years. 
2. The longest I have ever seen a Lead acid bank last was under 5 years.
3. Heat is a lead Acid batteries worst enemy and will reduce your battery banks lifetime with up to 50%
4. If a lithium fails in your area because of heat, a lead acid will fail as well and in my opinion much faster than a lithium. 

25 minutes ago, Adriaan.S said:

Has anybody else experienced this type of issues with Lithium batteries?

Maybe if we know what issues he is experiencing, we might be able to assist.

what do lead carbon batteries do for lead acid .some of the specs are impressive

17 hours ago, Adriaan.S said:

Has anybody else experienced this type of issues with Lithium batteries?

as pointed out by @Jaco de Jongh more details about the issues might better help members to provide opinions and maybe even solutions. 

I think many vague generalisations confound the matter a bit - I see the following 

16 hours ago, Adriaan.S said:

they had lot of issues with Lithium batteries

At the very least there are many different makes of lithium batteries and from different makers there are different models. Some lithium batteries will work easier with some inverters/chargers than others. Some lithium batteries can seem a bit "fiffely" to set up. If a lithium battery BMS repeatedly disconnects the battery because some setting on the inverter is incorrect or the comms cable is plugged in the wrong port this can seem like a "battery issue" while it is actually an installer/user issue.

So, what is meant with "issues"? (Never been able to switch on the battery... battery keeps on switching off at some time during the day/night.... battery when fully charged only lasts 10 minutes but 3 months ago it lasted 8 hours and 6 months ago it lasted 12hours.. etc)? 

18 hours ago, Adriaan.S said:

Lithium batteries not coping with the heat in the Northern Cape and Namibia.

This is probably most relevant for you - does Northern Cape/Namibia type WARM temperatures break lithium batteries? In terms of total lifespan of the batteries it probably can but those same temperatures will likely do the same to lead-acids. 

All battery (including lithium) specifications are generally rated at a temperature of 25 degrees C and when going outside of this temperature the performance will differ. For lead acids there is a basic rule of thumb that for every 10 degree increase in average temperature the expected lifetime for the battery is reduced by 50%. (if the battery was designed with an expected life of 10 years and it is operated at an average tempertaure of 35 degrees you will likely only see 5 years from the batteries if you are lucky)

From a VRLA manual

Lithiums like any battery are not immune to heat. In one experimental study lithium cells stored fully charged (not best practice) at 35 degrees showed minimal capacity loss even after almost 2 years (still mainatianed about 90% of their starting capacity) but cells stored (again fully charged) at 60 degrees barely made it to 4 months (maintained only about 10% capacity).

The day-to-day use of the batteries is also influenced by temperature.  Temperature compensation during charging being especially relevant for lead-acids. If this is not done the battery lifetime will be reduced.  Many lithium batteries will indicate different temperature specs for charging vs discharging - charging having a lower max temperature (generally around 45 degrees C) than discharging (50-60). The lithium battery BMS might temporarily disconnect the battery during charging if the temperature is too high - while inconvenient at times it is not a sign of a malfunction - it prolongs the battery life.

With that in mind it is probably safe to say average temperatures above 40 degrees C will cause premature loss of capacity in any battery. (i.e. don't put any batteries in an unventilated corrugated shed in the full sun during the summer in vioolsdrif).

So, If we assume "issue" means the battery will not switch on, how do they know the heat caused the issues and not the 80km trip over a corrugated dirt road that shook lose some solder joints on the batteries (and the bakkie's bulbar...). If the battery capacity is prematurely low, is this because of heat or were the charging parameters perhaps incorrectly setup (maybe same parameters used as for lead acid?). Were these some once-of  no name imports or batteries from a fairly reputable manufacturer ?

16 hours ago, Adriaan.S said:

lead acid batteries are tried and tested

They definitely are but at the same time some installers/users that are used to one thing sometimes struggle to use/accept newer/different technology. (someone referring to lithium batteries as Star Trek batteries sometimes being a clue).

16 hours ago, Adriaan.S said:

have almost no issues with these batteries once installed, up to 10 - 15 years life. Does this make sense?

While not impossible I would be curious how many of these 15 year sites there are compared to the number of 3-5 year sites. 

 

Lead acids could very well be the more appropriate solution  for you but that will likely be determined by more than just whether it is warm where you ive.