Will the silver calcium type batts handle higher Amps ...?

[whazzatt]

Hi. Gradually going to change from this:

* 2 silver calcium type batteries, each 102Ah, paralleled for a 204 Ah total 12 volt
* 20A CC/regulator mppt
* 130W panel

To this:

* 2 Trojan T105RE 6V 225Ah in series for a 225Ah total 12 volt
* 40A CC/regulator mppt
* 320W panel

First step will be to change the controller / regulator. Then the panel. Then when the batteries reach end of life, get the Trojans.

Problem might be the current from the new panel, once in place, will be max at 26.67. This is higher than the C/8 (where C is 204) of the silver calcium batteries of 25.5.

Unless the silver calcium type batteries can handle the slightly higher current rate?

Or unless dividing the panel W by 12V to get to the max Amps is only a rough guide and in reality it's not so low.

Help appreciated. Whazzatt.

[SunEagle]

Hi. Gradually going to change from this:

* 2 silver calcium type batteries, each 102Ah, paralleled for a 204 Ah total 12 volt
* 20A CC/regulator mppt
* 130W panel

To this:

* 2 Trojan T105RE 6V 225Ah in series for a 225Ah total 12 volt
* 40A CC/regulator mppt
* 320W panel

First step will be to change the controller / regulator. Then the panel. Then when the batteries reach end of life, get the Trojans.

Problem might be the current from the new panel, once in place, will be max at 26.67. This is higher than the C/8 (where C is 204) of the silver calcium batteries of 25.5.

Unless the silver calcium type batteries can handle the slightly higher current rate?

Or unless dividing the panel W by 12V to get to the max Amps is only a rough guide and in reality it's not so low.

Help appreciated. Whazzatt.

Dividing the panel wattage by the battery voltage is just a rough guide. If you think about it the charger is sending a voltage higher than 12V to the battery so your charging amps are going to be less. Also most panels will never put out their nameplate wattage so again the amount of charging amps will be reduced.

Chances are you will fall closer to a C/10 charge rate unless the sun is at it peak location and the panels are real clean.

[Sunking]

OK silver calcium lead acid batteries are a newer alloy and have some advantages. They can take and supply higher charge/discharge rates. Ford Motor company now supplies them in all vehicles. Sounds good, but there are a few kinks. To start with they require higher charge voltages of 14.8 volts which is higher than most charge controllers can supply. The addition to silver helps fight corrosion of the grids and plates which is the number one killer of Automotive batteries. Corrosion in Pb batteries is a result of over charging and all automotive batteries are over charged by design. So the advantage of Silver Calcium Lead Acid batteries is they last longer in automobiles up to 5 or 6 years.

However automotive batteries are a special purpose application called SLI (starting lighting & ignition) where they are designed to provide very short quick burst of current and recharged very quickly. They cannot be cycled and if pressed into cycle service will only last 50 to 100 cycles before lead dioxide crystals from and harden on the plates. They should not be used in solar. Between the lower voltage used and partial state of charge operation is going to do a number on silver calcium batteries. Sulfate crystals will start forming on day one and with the lower voltages wil harden and continue to compound and in short time will ruin the batteries.

OK as for C/8 maximum charge rate on FLA is a safe generic recommendation that can be applied to any FLA battery manufacture. Understand? Trojan is a high quality battery and can easily be charged at a higher rate up to C/4 if needed. In fact if you were to send a battery back to Trojan, they would put the battery on their battery tester they sale to distributors to do factory test for warranty claims. They charge at 50 or 75 amps. 50 amps on 100 AH and smaller batteries, and 75 amps for anything larger than 100 AH, then they discharge at the same rate and conditions. It is the only way to be able to test a battery in a 8-hour shift. They fully charge the battery at 75 amps, and fully discharge at 75 amps. Once done they use a Peukert Correction factor chart for the higher discharge rate. If the battery test at 80% or more than rated specification the battery passes, otherwise fails.

What I am trying to tel you is a Trojan T-105 is a hybrid battery made for golf carts. A hybrid tries to be both a SLI and Deep Cycle battery. They can supply higher discharge rates a EV demands, and can be deep cycled. Trade off is they cannot supply the extremely high cranking amps a SLI battery can, and they do not last as long as a true deep cycle battery. It is a trade off all batteries have. You can have either high rates or long life. You cannot have both. Hybrids try to do both, but cannot do both exceptionally.

[whazzatt]

They should not be used in solar

Thanks. I have read this in another post of yours. I instantly felt duped when I found it out because when I bought the batteries, I made it clear that they would be used for a solar application and asked if they were suitable for solar apps and I was told they were. The damn things have a huge sticker that say 'suitable for solar applications'. After querying this with the supplier, I was sent spec sheets displaying cycle information: 2000 cycles at 10% DOD.

Anyway, as said in a different topic I started recently, school fees. Relatively cheap ones at that. Small starter system, and I'm changing things for the better, I hope. The answers I received put my mind at ease about starting with a new large panel and a better charge controller, and I'll ride the batteries until death, which I assume is soon.

What I am trying to tel you is a Trojan T-105 is a hybrid battery made for golf carts. A hybrid tries...

I also am aware of this from a different post of yours. I wasn't planning on using them, rather the T105RE, as I wrote in the first post.

Interestingly, when I asked the supplier for true deep cycle Trojans, he came back with the hybrid options. I pulled him up on this and asked for the T105RE, and he said they don't have stock and this would have to be a special order. I said yes, indeed.

The charge controller / regulator I am looking at (in South Africa) is a Microcare MPPT 40A. I wonder if you could look at it online and confirm that it looks legit. It is programmable and I can try to set it to max smoke, though I would appreciate guidance on the right numbers for first the present silver calcium and then the Trojans that will replace them.

My concern with the CC/regulator is that is only has two breaker inputs: 1 for panels, 1 for batteries. I hardly ever use an inverter, the load being a small 12V one. In the CC I'm replacing, there is a load output from the unit. I like this because, in theory, the CC would have a more accurate indication of battery SOC. I'll be adding a small 12V fridge to the setup at some stage, and attached directly to the battery this seems like the battery would always have a draw on it, while if through a CC load output the CC could divert directly to the load on those long sunny days where the batteries could be fully charged by noon. Am I wrong about how this could work?

[Mike90250]

Thanks. I have read this in another post of yours. I instantly felt duped when I found it out because when I bought the batteries, I made it clear that they would be used for a solar application and asked if they were suitable for solar apps and I was told they were. The damn things have a huge sticker that say 'suitable for solar applications'. After querying this with the supplier, I was sent spec sheets displaying cycle information: 2000 cycles at 10% DOD....

When they die, claim it on warranty

[J.P.M.]

When they die, claim it on warranty

If that's the plan, just be sure you can verify you stayed within warranty requirements/terms including DOD. That may be a tricky gotcha'.