Lithium battery charging


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I have noticed that unlike our old set up the solar and Redark will run at boost or full charge rate until it is pretty much 100%, the old system would drop back a level much sooner.
I have also heard that storing Lithium at 100% is not good for them over the long term. If anyone can chime in on that with advice it would be appreciated.
I guess I just have to trust the batteries inbuilt BMS and the Redark , which is the latest top of their range , to do their jobs properly


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I've been running a 100a/h Lithium for around 7 years, for the first 6 years I was using a standard Redarc BCDC-1225-LV that wasn't lithium compatible. I discussed this with EV power in WA who said it would be no issue, I had to turn the charger off every few days to force the charger into boost mode, as it wouldn't go into boost by itself.
I found that 25 amps was just too slow and requried hours of driving and I wanted a better solution, so for the past year I've been using an Enerdrive EN3DC40+ charger. This has proved to be a far better charger as it is lithium compatible with some user programmable settings. It has a max 50 amp ouput, but I find I need to limit the charge to 40 amp or the Battery control unit (BCU) that is attached to the battery will shut off occasionally when my fridge is running while it is getting max amps from the charger. I haven't quite worked out whats going on there yet, but as a workaround I've dropped the charge current to 40 amps. My battery has individual cell monitors attached which balance the cells when it is charging, this is connected to another BCU which monitors over/under voltage and will shut off the battery if necessary.

So Basically my battery has been getting fully charged for 7 years or so with no issues. Despite what all the doomsayers said when I first set this system up, it's worked perfectly for me in two different vehicles and it's been abused most of it's life ;)


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One thing I do have now is a proper Lithium AC charger to boost it above 0 if ever it goes flat again. Only reason it has in the past is when i go an work offshore and not properly organising to have it on solar trickle. Did that last time though and all was good.


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My battery has individual cell monitors attached which balance the cells when it is charging, this is connected to another BCU which monitors over/under voltage and will shut off the battery if necessary.

Which battery is that?


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Which battery is that?

This one from EV Power in WA. You can see the cell monitors attached in the pic below, along with a battery control unit attached to a latching relay.



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Mines an ev power 60ah. Been on 6 years now, I killed one cell due to having a parasitic draw I didn't catch until to late. Added a better low voltage cut out and a kill everything switch to avoid that

Mine is just running off the alternator after discussing it with Rod (the owner) and has no issues at all.


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Discomatt I recommend you look around for a Lithium specific 5 stage battery charger that also has a battery recovery function. None of these chargers are cheap. But if it saves a couple of batteries and extends the service life of your batteries it will more than pay for itself. When charging from low voltage there is a risk a cell will become unbalanced and overcharge if you use a SLA charger. Worse case the battery will catch fire. Usually they just don't last under load.


Active Member
Lithium is so simply, the language of batteries is volts and amps, not profiles. Here is what you do if your serious about going lithium.
Get a proper programmable charger like sterling, victron etc. Redark gear is aimed towards those who drink the bms koolaid.
Have some acess to cell voltages and learn about the voltages and watch em every now and then. Without cell voltages you are going blind as they tell you straight away what you batt is doing. Monitors and fancy management usually lie, but volts never does. Pack voltage is good if your cells are all well.
You must know how to differentiate between:
Resting voltage
Underload v
Charge v
Surface v
All radically diff but once you master them bang! You can straight away know what you batt is doing anytime.
For longterm storage you keep your li in the 40% region (about 13- 13.1v resting no loads) and as cool as possible. All cells should read around 3.2v but the voltage curve between 20-80 is so flat...You can hit 50% with the charger then manually stop once you know the volts and amps with whatever sized batt and charge rate you got. Usually charge to 13.5v at .3-.4C but cant remeber exact. Best disconnecting them in storage so there are 0 loads Or you can float them at 13.1-13.2v if you have some constant loads like fridge. Thats were the programmable charger comes in. A dumbed down power supply mode always the way to go over some canned "profile" with bs stages that do jack, an example of ps mode is setting both absorb and float to say 13.5v for a set and forget. For solar you can disable the smarts as the are geared for daily cycling more.

Really the big mistake is going lithium without doing some sizable research. Master battery charging with lead acid first, then once you know go li. Sorry to say but you must learn the basics, ohms law, cc/cv physics etc. Then you will see just how uninformed the masses are. Both lithium and lead are the same and follow the same exact rules, just slightly diff set points and maintainence. Also there are diff grades of quality so cheap stuff lived much of the time at full wont last as long like good quality.
Beware of those who may lack the realworld experiences...buwhaha... seriously battery recovery??? If you let the pack voltage fall below 12.2 resting or a cell below 2.8v that is plain neglect. :( Good thing about lead acid flooded i let it drain down to 4v over weeks from laziness and hit her with my enerdrive in ps mode and then equalized and she was back up and running, albiet maybe some loss in capacity.
For causal users Li can be cycled right down to "empty" no probs. I usually stop at 90%dod to get best bang for buck and leave a small amount if reserve.
And yeah like steel wool rubbed a few times across highly polished 0.1mm thick stainless sheet, this aint even scratched the surface. The bms is a can of worms and is so misunderstood :(