Hi, 
I am considering a battery bank consisting of:
6 * Deltec Lead Crystal FA BC 6-CNFT-170 batteries
Do you know if this is a good battery for a stand-alone off-grid home solar system?

Your input would be greatly appreciated.

Kind regards,
JJ Clark

I have it on good authority from someone at a major solar equipment manufacturer that the lead-crystal craze was a big scam. These batteries are no better than the average gel and/or AGM, in fact the newer gel batteries might just be better. You should not pay a premium for them. I think they are still good (for AGMs), but the long cycle life and deep discharge reports is probably a little exagerated.

I will gladly stand corrected if someone has more info on this. To be honest, I have always found Deltec products to be quality stuff, and I expect no different here.

I have tested these at length (200ah version), and concur with plonkster.

Plus 3.

UPS guys a few years ago sold lead crystal batteries. I was very interested in them for UPS usage.

When I ordered some they told me no, they are removing them from all sites as they did not last as advertised.

Here is video entitled "Lead Crystal vs Lead Acid" where a local South African tests the performance of the two battery types.  Both batteries are hammered over a period of several months by completely discharging and charging daily.  The lead acid battery soon dies.  Interesting video.

55 minutes ago, Garthvs said:

a local South African tests the performance of the two battery types

The MJLorton one? Martin left South Africa a few years ago :-) He lived in Cape Town when he did the test.

As I recall, the lead acid opposition wasn't exactly a top-rated battery. I think you might get the same results if you tested a silver-calcium against a good quality gel battery.

Yes, that's the one @plonkster

So you think that AGM batteries are just as good when compared to the Lead Crystal batteries?  The Lead Crystal seem to have much higher discharge cycles.

17 minutes ago, Garthvs said:

So you think that AGM batteries are just as good when compared to the Lead Crystal batteries?  The Lead Crystal seem to have much higher discharge cycles.

AGM represents just one aspect of the battery: The absorbent glass matt between the plates. It tells us nothing about the electrolyte or the composition of the plates. So I find the term a bit vague. It should be noted that lead crystal batteries are AGM batteries, they differ in the rest of the chemistry.

Generally speaking though, most AGM batteries on the market are made for UPS duty: Charge quickly, discharge quickly, last 5 years on float. 500-1000 cycles at 50%. Lead Crystals are better than this by the looks of it.

But I also have it on good authority that the Lead Crystal units are not as good as they are cracked up to be. Yes, they are good, but not that good. So don't pay a premium for them.

The discussion happened here.

I have attached Data sheets for Vision AGM, OmniPower AGM/GEL and Deltec-Betta Lead Crystal (because I like looking at pictures). Note that the data is manufacturers claim and may be complete nonsense, however both Sinetech and Deltec seem to be reputable organizations and if Vision are lying they could have done a much better job of it.

At 50% DOD which is available on all 3 documents the comparison is as follows;

• Vision AGM                               1200cycles
• OmniPower AGM/GEL               about 1600cycles
• Deltec-Betta Lead Crystal         also about 1600cycles

Now the Omni is about 20% more expensive than the Vision so that ratio seems reasonable - but the Deltec-Betta is more than double the cost of the Omni so that seems out of whack to me.

If you are in a camping situation with low tech charging equipment (often just the alternator) and little knowledge of how to treat your batteries then maybe the Lead Crystal famed ability to take 100% DOD in its stride makes it a worthwhile investment, but I think in a home solar situation which should be a more carefully controlled environment I dont believe that they offer sufficient added value to warrant the cost.

I haven't included any flooded cell data because I am far to lazy to run around filling cells and measuring specific gravity and suchlike unseemly behaviors.

Battery - Vision 6FM100P-X.pdf

OmniPower Battery.pdf

Sorry, the Deltec is uploaded in a separate post because it is chock full of marketing drivel which exceeded the 3Mb upload limit in the previous post.

Deltec-Lead-Crystal-Batteries edit.pdf

i think lead crystal more durable but i didn't test it  yet 

Reviving this old thread, since it's ranking well on Google for Lead Crystal batteries.

I have tested the Deltech 12V 7ah batteries in series to create a 72V battery. 

After 4 years and about 40 cycles they are completely dead. Internal resistance is very high, can no longer hold a charge.

Horrible battery. Get a Lithium Ion Posphate instead. 

I was very disappointed with these lead crystal batteries, I bought 8 by 6V 200 amp hrs Beta batteries. I thought I was onto a winner. They cost me close to $5000 dollars.

They are being charged via a 3KW solar system and also the inbuilt charger in the inverter can switch via the grid. Later on I found that they needed to be charge at 2/3 of their rated capacity . This was a very rude shock to me. That means my solar system would have to charge the bank at 120 amp !! Even charging from my Diesel generator could "only" deliver 80 amps at 50V . I then started to realsie   I had been sucked in , they look in good physical condition after 4 years but I feel their capacity is around 50% of what they claim. I tried contacting the Betta Battery web site in Holland looks like it has disappeared.

Yes I am afraid to say these batteries are a scam. Very disappointed, well you live and learn. 

On 2021/12/17 at 1:04 AM, Alan Idris said:

That means my solar system would have to charge the bank at 120 amp

It is unlikely that lead acid batteries could take charge that rapidly.  One of the big downsides with Lead Acid is the inability to take charge rapidly

Ironically for the naming of these batteries, lead sulphate crystals are the main killers of lead acid batteries.

There are lead acid variants that can be charged and discharged quickly, like starting batteries, but deep cycle types (as needed for solar energy systems) usually have to be charged and discharged slowly, well under 1C charge current.