This message is mostly directed towards Victron Energy’s product developers.
The products I am using are missing support to properly charge nickel based batteries, in my case Saft Ni-Cd batteries. Hardware vise the products can easily support nickel based batteries, only software changes are needed. I would like to see this implemented on all products since I am using both solar chargers as well as battery chargers.
At a minimum, these two functions are needed:
Constant current charging
Detection of negative delta voltage (and being able to act on it)
Some more flexibility in the settings would also be good, for example disabling functionality that is not needed. The configuration tools seems to be designed around how lead or lithium based batteries operate, which is different from nickel based batteries. Note that I have not tried all your tools, so some may support it already.
All of the Victron chargers can do CC, this is what happens in the bulk phase. The max voltage can be set with the absorption voltage.
However, the chargers won’t detect the small voltage drop Ni-Cd’s typically generate at the full charge point. you may be able to implement that with node red. Similarly, this (node red) can also be used to detect end of charge by temperature rise.
You can charge nickel based batteries with Victron chargers, but it is far from optimal and it is not possible to detect when charge is completed. In order to not damage the batteries, the settings needs to be set with a lot of margin, resulting in the charging being slow and the batteries not being fully charged.
It is technically possible to implement negative delta voltage etc and doing so would be a positive for Victron since not many products have that flexibility.
Using Node red is not a viable options in all situations. It works in large installations, but not for smaller, usually stand alone, battery chargers. I also see no reason why such a solution should be necessary when each individual hardware is capable of handling it itself with a software update.
I would appreciate some help with finding the optimal battery settings in VictronConnect since I am doing some trial and error.
The batteries I am using are 2 nickel cadmium NIFE (now Saft) type M 304-5 connected in series for a 12V system. I cannot find the specifications for these specific batteries, but I guess 304 stands for the ampere hours and 5 the number of cells.
The “mess” around it is load testing using an inverter and a cooler box. It is powered by a 30V bench top power supply.
The charger I am using is a simple MPPT 100-15. More than enough for what this needs. Biggest loads are charging a laptop with a theoretical max power draw of 90W (which will never be reached) and the cooler box that draws 40-55W depending on the settings.
The system will be installed in a van with rooftop solar panels. One or two panels will be used (30V/8.5A-ish/245W each). One is enough, but two won’t hurt for cloudy/shady/low light angle situations.
First load test shows me that I have not been able to charge these batteries even close to full. They have been unused for a few years so they might need a commissioning charge. Settings for that also appreciated.
I’m doing a constant potential charge at 1.55V/cell not exceeding 0.1C A (which my setup cannot reach anyway) for a minimum of 24 hours as recommended by Saft.
Aren’t NiCd/NiMh batteries the absolute worst when paired with the intermittent energy sources like solar or wind? I only saw them in the backup systems where the grid/generator is reliable so you charge them in controlled conditions.
IMO the best solution would be to make a buffer LFP/LTO battery that can absorb your daily production and then use it to slowly charge your main NiCd battery overnight. 100Ah/12V LFP box costs peanuts nowadays.
They are extremely cheap when purchased second hand. If you know where to look they are free. I have an almost unlimited supply of them for free. Even if you buy them new the longevity of them makes them by far the cheapest.
They last forever. Mine are 30-40 years old and will last decades more.
They are almost maintenance free.
They handle over charging very well without being damaged (unless you really cook them).
They not only can take being discharged, you should discharge them periodically (any other battery technology will lose capacity when discharged, meaning when used).
They can usually be serviced and retain more or less full capacity again. A flush and new electrolyte and they are reborn.
They do not drop voltage in the same way as other battery technologies.
They are a little more difficult to charge. But that has less to do with the battery itself and more to do with that the charger manufacturers do not implement nickel battery charging functionality in their products. I guess it is because they have realized they will not sell as many batteries when nickel based batteries lasts for decades. Manufacturers and resellers love lead and lithium batteries because they suck.They last a few years before they need to be replaced. And not to mention if lithium batteries ignite…
As long as you have the space for them, no other battery type stand a chance against them. I would argue nickel iron is even better. I’ve seen 100+ years old batteries still working.
The individual cell voltage currently range between 1.45-1.56V. Most of them are around 1.55V. Still doing the commissioning charge which will last at least until tomorrow.
Does anybody know if they will self-balance when charged in series? I have read that charging in parallel can be problematic, but have not read of any problems charging in series.
Just a small update to document my “journey”. Hopefully the information in this thread will be useful for others that explore nickel based batteries.
I did an almost full commissioning charge and the capacity of the batteries increased significantly. The load test showed a 3.7 times improvement. But the cells are still uneven.
So now I am discharging the batteries to 0 volts. I first discharged both batteries in series using a light bulb. After that some cells are almost fully discharged, some are not and some have become polarity reversed. I discharge the cells that have a higher potential using the light bulb until they read reasonably low. After that I short them out and keep them shorted for 24 hours. This is all documented in various manuals.
When each cell reads 0v I will do a new commissioning charge.
Valid points about the qualities of the Ni batteries.
But what about this below?
Particularly, in a solar installation, as they say there, you can’t guarantee that the cells will daily charge to “overcharge” and you can’t guarantee that the cells will discharge to less than 1 volt.
These mean to vary the voltage between, for example, 40V and 60V on a regular basis. Quite extended range for a 48V equipment.
As per charging in series, for sure some will reach “overcharging” point quicker than others. So you need a method to delay that, otherwise those cells will overheat, not to mention the pressure inside. Not good.
The memory effect is the propaganda’s number one reason to scare people off using nickel based batteries. Yes, it exists, but it can easily be remedied by fully discharging the batteries and charge them again.
Not a big deal. Nickel based batteries take overcharging extremely well. Only if you really cook them for an extended period of time will they be damaged.
Nickel based batteries thrives when they are used. Lead and lithium based batteries are damaged when they are used. That’s why I use 30-40+ year old batteries and the rest of you are happy if yours last 4 years.
Just do the math when it comes to cost of running each battery technology. Nickel based batteries are by far the cheapest.
Choosing battery technology is an IQ test that 99%+ fail because they listen to propaganda and do not question the information they gather.
That thing with fully discharging them before charge, I remember that was the first step taken by good chargers.
But in a solar system it’s pretty difficult to have this once they get “out of balance” with this memory effect.
But what about charging/discharging energy efficiency?
Of course, if you have plenty of PV power, this (maybe) smaller efficiency isn’t a problem.
You almost make me want to try them… Really.
Now I must find a source for them and then to have a nice summer time project to play with…
The same problem exists with lithium batteries. They solve it by monitoring each individual cell. The same concept can be utilized for nickel batteries. But unlike lithium batteries, nickel batteries wont ignite if overcharged…
You could double up the battery bank and take half of it offline for maintenance (they are cheap second hand, usually free). Or you could service each individual cell while they are in service. I don’t know how the professionals do it. Maybe there are some reading this thread that can answer?
Don’t know, don’t care. The Achilles heel are the batteries, not the PV’s. Nickel based batteries are so much cheaper to run that you could just up your PV array to compensate if you find them inefficient. This is also a propaganda point they are using and to me it is another fail of the IQ test. People do not use their brain. “Ok, nickel based batteries are more inefficient, so I go and buy this lithium based battery bank for 10.000 USD instead.”
Rail and air industries are two big consumers. Remember that due to corrupt politicians that do not want you to use technologies that actually work, there is a heavy fee when scrapping Ni-Cd batteries*. That is why it is so easy to get them for free; it is cheaper to give them away. Where I live there is no fee for private individuals to scrap anything, only for corporations.
* It is because they say cadmium is bad for nature, which they also claim for lead. There is no fee for buying or scrapping lead batteries, as there is for Ni-Cd. Funny how that works… IQ test again that everybody fails.
OK.
Let’s say that I will go to a train repair station and manage to get some NiCd batteries.
At which aspects should I look, in order for getting pretty good ones and not get “depleted”/useless/lemon ones?
They are usually all good. Nickel batteries are tough, they are survivors.
Locomotives have a sh*t ton of batteries. They are usually decommissioned with the batteries left intact. But they can often be lead acid. All the rail signaling are backed up by Ni-Cd batteries. They are replaced from time to time.
If I were you I would ask around people that work around rail. Even if they do not know, they might know someone who knows.
Airplanes have Ni-Cd batteries for backup since lead not only suck, they are very heavy. Lithium are better in most aspects except when they ignite they will take the entire plane with them. So they use Ni-Cd. Access to the air industry is a lot more difficult, so I would go for rail. You can also ask your local battery reseller that work towards industries if they have some or if they have clients you can talk to. You can also talk to scrappers/recyclers.
And that’s the propaganda you hear about Lithium.
The commonly used LiFePO4 cells are very save and don’t ignite on it’s own.
Overcharging only causes them to release the magic smoke without fire.
Most lithium batteries should last at least 10 years.
Lithium burns and it is almost impossible to put out. Some compositions are worse than others, but they still burn.
Overcharge nickel batteries and nothing happens, unless you really hit them hard. And I mean hard. One of the manuals I have states that you should avoid charging at more than 0.1C A when they are full. 0.1C A in my case is 30A. That is how much abuse they can take without being damaged.
No they don’t. They might hold a charge after 10 years, but it will be nothing compared what they were designed for.
Strange how everybody have to replace their phone batteries when their phones are no way near 10 years old. They are closer to my stated 4, more if they charge them often (as I have mentioned, lead and lithium batteries are destroyed when they are discharged, meaning when they are used).
Strange…
Why manufacturers of LiFePO4 batteries give you a warranty that the battery has still 80% capacity after 10 years?
There are many different types of lithium batteries each with different pros and cons.
The batteries in phones are most likely Li-Po or Li-Ion and have shorter lifetimes than other types like LiFePO4.
I just searched for LiFePO4 and the first search result stated a life guarantee of 2000 cycles or 6 years (2000/365=5.4). It did not state what that guarantee entails. I guess you find that impressive and have no problems paying the price they ask?
When owners are on their fourth or fifth LiFePO4 bank, Ni-Cd owners are still on their first bank with decades left in them, and their initial investment was a fraction of that of the LiFePO4’s.
Lithium batteries have their place and that is when low weight or low volume is of essence, and in some situations their performance. But it comes at an extremely high price.
This is the problem with the internet and looking for information to prove a point.
All batteries are not equal.
If you look at the supported batteries, those that are tried and tested, have been around a while and have good warranties.
The design life is 12-15 years and offer 6000 to 8000 cycles.
They do this with a smaller and lighter form-factor, better energy density and a fairly low cost, and zero maintenance - the bms keeping everything healthy.
All warrantied to hold the majority of their charge after 10 years.
Everything degrades, and how something lasts depends on how you treat it.
Many are happy to swap them by then by as the technology would have changed as would all the related equipment so the next generation of gear would replace it. And if it’s working fine, then just leave them alone until something dies.
There is good reason that NiCad has not achieved global commercial success in the broader consumer/business ESS market.
It is a better but more expensive alternative to lead.
We used to use them to power the starter motor on aircraft turbine engines, they lasted 4X longer than a cheaper Pb battery.
In the global market you are swimming upstream with Nickel. Much like Salt, they are all destined to be footnotes in battery evolution.
Nothing wrong with being an enthusiast and advocate for them, but you are very much in a small and diminishing club.
