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101RRS
11th February 2021, 10:53 PM
My 101 is 24v and my aux 12v battery will be powered by a OEX 24v to 12v Dc to Dc 3 stage charger (when I wire it in). My current battery is a big old heavy UPS lead acid 120Ah battery. It runs the trucks ignition and when the charger is connected up the fridge etc.

The current battery is on its last legs and I wouldn't mind getting moderately priced lithium of about 100ah as a replacement - smaller physical size and weight is good. However the battery must be able to be charged by the 24v to 12v charger and via my 120w Mppt solar panels.

So I am open to suggestions - as I am tight - something that is not going to break the bank. In my experience cheap is cheap, expensive is good but maybe not so good when value for money is taken into account, where the sweet spot in the middle, might not be quite as good as the expensive stuff but value for money it is often the best [thumbsupbig]

Thanks

Garry

drivesafe
12th February 2021, 04:35 AM
Hi Garry, before you go buying a lithium battery, you best make sure your DC/DC device and the MPPT solar reg can charge a lithium battery properly, or you may have a very expensive short term operation.

What programmable settings, if any, are available on both devices?

101RRS
12th February 2021, 04:20 PM
Hi Garry, before you go buying a lithium battery, you best make sure your DC/DC device and the MPPT solar reg can charge a lithium battery properly, or you may have a very expensive short term operation.

What programmable settings, if any, are available on both devices?

No settings just 3 stage charger (it predates mainstream lithium use) - I thought the electronics in the battery can sort the charger input so the actually battery gets the right sort of charge. So what does the electronics built into the battery actually do?

So lithiums are not really fit for purpose in vehicles without specialist additional chargers? If so then I will just get an AGM.

Thanks for your input.

Cheers

Garry

W&KO
2nd March 2021, 06:32 AM
No settings just 3 stage charger (it predates mainstream lithium use) - I thought the electronics in the battery can sort the charger input so the actually battery gets the right sort of charge. So what does the electronics built into the battery actually do?

So lithiums are not really fit for purpose in vehicles without specialist additional chargers? If so then I will just get an AGM.

Thanks for your input.

Cheers

Garry

Iíve spotted a couple of comments online that BMSís will manage charge voltage into the battery.

If your alternator, solar regulator or three stage charger has a voltage output higher than what the lithium requires than it seems the BMS will manage it. One of the jobs of tie BMS is to protect battery from over voltage. Unsure if you will get to 100%.

I didnít dig deep into the comments as I purchased chargers with lithium settings......it more than likely people trying to save a few bucks and not purchase the correct equipment.

An example is DCS batteries, these are advertised to charge direct from alternator, I believe your alternator needs to put out a minimum amount of volts.

***edit, a bit more digging indicates installing lithium selectable DC-DC and Solar Regular is the correct way to go...which is what I did. Seem people are looking for short cuts.

Pedro_The_Swift
2nd March 2021, 01:03 PM
From the little I have read--
a 100% SOC is not really needed for( or particularly good for) Lithium.
A nice mind-set change from lead acid.

W&KO
2nd March 2021, 01:40 PM
From the little I have read--
a 100% SOC is not really needed for( or particularly good for) Lithium.
A nice mind-set change from lead acid.

Gets mentioned a lot.......I believe itís pretty common for big installs say in you house.

some van owners change the settings to stop accepting charge at say 90%

Problem is when your running low on a particular day for a number of reason you cannot wind back the clock and charge to 100%

I charge mine to 100% capacity each day.....

drivesafe
2nd March 2021, 02:28 PM
From the little I have read--a 100% SOC is not really needed for( or particularly good for) Lithium.
I have seen this claim/advice quite a few times, but have never seen what would happen if you kept a lithium battery fully charged at all times, while not using it.




I charge mine to 100% capacity each day.....
This is how I have always charged and kept my lithium batteries and some are coming up to 10 years old with no signs of capacity loss!

101RRS
2nd March 2021, 03:55 PM
Just to close this - it is clear that a lithium is not the right battery for my purpose so I will just stay with some sort of AGM.

StormCamper
6th April 2021, 03:53 AM
the big no no's of lithium are: don't cheap out, and learn how batteries charge or else you will forever be in the dark.
a 3 stage charger can be used, but it must have the right absorption timer, many are too long and will overcharge. for example its commonly
said the GEL setting is safe, this is true voltage wise, but some can have a long absorb timer. with lithium the absorb timer is key
if the charger has a powersupply mode of usually 13.8v (both absorb and float capped at 13.8) then you can hook it up direct but the overall charge time will be noticeably slower.
the bms is mainly to protect against short circuits, cells going dangerously high or low and nothing more really. but alot of people mysticise it to confuse. it is just a failsafe safety feature.

for alternator charging no voltage can harm the cells as the bms will cut out, but 13.7-13.8v is minimum needed, 14.2 is plenty.




[COLOR=#000000][FONT=&amp]I have seen this claim/advice quite a few times, but have never seen what would happen if you kept a lithium battery fully charged at all times, while not using it.

It won't last long as it could and will degrade faster, how fast comes down to many factors, mainly heat, quality of cells. lifepo4 is float charged at near 100% in places with acceptable lifespan. there are probably additives and tweaks that could make it last longer. but obviously keeping near 100% all the time is very foolish, for stand by service 70% is much better.

Hoges
30th April 2021, 08:18 PM
Following a fair time reading various threads on this forum and a phone call or two (thank you DriveSafe!) I came to understand that along with Li battery comes more cost and a different 'approach' to maintenance and charging...

So, I took the leap and bought a 100AH Li battery (SB2215) from Jaycar with a 3 yr warranty.

Intended main uses: Bushman and/or Brass Monkey fridge (15L), CPAP machine and LED lighting for occasional w/e camp.

To charge the battery, I bought a 160watt folding solar panel with built-in PWM controller from K Mart for $149;
a Projecta 25 Amp Lithium battery DC/DC charger which takes either alternator or solar input (inbuilt MPPT solar controller); (for Bris locals...Springer Solar at Lawnton were as good as if not better than ebay for price) and a Victron BMV-712 smart battery monitor (also Springers). Those in the know advised that the Victron is essentially an "in-out coulomb counter" to keep tabs on the state of charge.

All of the above together with Anderson plugs, Merit sockets and USB outlets are housed in a $15 heavy duty plastic box I bought from Bunnings and cut the appropriate holes to mount the various components.

The best part is that it weighs less than 12kg all up...much kinder to my lower back than the 44 Kg I've been manhandling for similar net useable capacity... In fact the new battery box plus the Bushman fridge plus food weigh less than the previous bank of 4 x 33AH AGMs!

The battery had a voltage of 13.01 out of the sealed box when I bought it, and after a couple of days camping near Yandina using the small fridge it was showing 12.95 on the multimeter. I've yet to run an 8B&S cable from the alternator to the rear of the Santa Fe .... so after the camping trip, I 'tapped' the circuit on the solar panel to take a feed directly from the panels, pre- the PWM input, to the Projecta MPPT controller and let the sun do its work. By the end of the first day (6 hrs direct sun) the DC charger was showing 'full'.

On this basis assuming a 100% SOC, I then connected the battery monitor with the requisite programme settings. Then 'life' got in the way so I haven't had a chance as yet to use the setup to its full capacity. Time will tell..