Thread: Lithium Battery Install Instructions

Yes, I realise lithiums normally need a DC-DC if they're running straight off a smart alternator because they need 14 volts to charge properly.
However, is that still true if they're also getting solar, particularly if it's not a smart alternator?

lithium don't like to have voltage up their butt when they are fully charged so whatever you use to charge them needs to drop off when the lithium is fully charged.

to maximise available space, i use a 24v house panel and an epever mppt controller which has a lithium profile and the ability to setup your own custom profile if needed.

i run my 55ltr fridge, the oven, canopy lights and the compressor from my 100ah lithium battery and it isnt attached to the 130's charging circuit as yet as it hasn't been needed

so far, on cloudy days my setup has the lithium back at full charge by lunchtime at the latest so a lot of solar potential is lost.

i was looking at using a solenoid based setup so that i can use the solar through the controller to top up charge the two red tops i have under the passenger seat of the 130 when at rest and isolate the lithium when driving. there are some substantial issues involved in doing this due discharge rates etc with the lithium, if the wet cells are a little low.

when the caravan is attached to the 130 it hooks into the 130's charging circuit to charge the two 100ah agms.

at rest the caravan has a 160w 12v solar panel setup on a lead that keeps it happy

i haven't had to implement the lithium / wetcell setup above, as my traxide controller and the batteries have coped with everything i have thrown at them thus far

having one of these new fangled alternators would throw the cat amongst the pigeons i think ......

Yes, I realise lithiums normally need a DC-DC if they're running straight off a smart alternator because they need 14 volts to charge properly.
However, is that still true if they're also getting solar, particularly if it's not a smart alternator?

Sent from my A1601 using AULRO mobile app

Hi Mick, while you can charge lithium batteries direct from an alternator, even some variable voltage type, the problem is that the current capable of being supplied by an alternator, particularly a large alternator, can easily exceed a lithium battery’s safe maximum charge current.

If you have a bank of lithium batteries, as the load is spread over a number of batteries, then you could bulk charge the lithium’s and then finish the charge with the appropriate type of charger.

I read that most if not all Lithium batteries have built in BMS to protect them from over and under charge. Does this not control limit both over discharging or over charging, or is this marketing BS than fact?

To be fair, this is a little tongue in cheek too as I don’t trust anyone or anything lol

Hi again Mick, the BMS protects against over voltage charging and under voltage discharging.

Discharging and charging currents are not controlled by the BMS.

While the BMS is supposed to protect against too high a voltage being applied to the lithium’s cells, Caution should still be used to make sure over voltage charging does not occur.

Originally Posted by drivesafe

Rod, you’re trying to setup your own DBS to suit your requirements, which is admirable, but as for having any genuine knowledge of this field, you are somewhat lacking.


I explained why no one with any real knowledge now uses thin cabling, but no I’m wrong because you have an “EXPERTS” statement saying otherwise.


Well below is a link to one of their videos, which is based on a total fabrication and I won’t say why, as I imagine others will pick it pretty quickly.

They are anything but experts, just know how to advertise.


I have been in this field of automotive electrics and electronics for just over 40 years, I run an honest business and I do my best to help others, even when they don’t have my products.


But I have to compete against companies like your EXPERTS on a daily basis. Whether you take my advice or ignore it is no longer of any concern to me, but as I have stated a number of times now, there are others reading this and they now have the option to setup in a way that is to their best interest, with the correct info to do just that.


https://www.youtube.com/watch?v=RlNTqEqRF0Q

Sorry to prolong this but I wanted to understand why 8 B&S gauge cable is apparently too thin for this application.
Surely it's dependent on practical requirements which in turn influence the design parameters.

I used 8 B&S for general charging of a second battery: it was more than satisfactory. For a 5m run carrying a max of 15 amps, the difference in voltage drop between a 6 B&S and 8 B&S was a theoretical 0.063V (0.094V for 6 B&S and 0.16V for 8 B&S). In the scheme of things for charging a battery this difference is " in the noise".

In line with this, I wondered why virtually all mains powered battery chargers (including my good mate's expensive CTek collection!) have charging leads of approx 2m of seemingly 3-4mm cable which has about 10 times the resistance of 6 B&S!

So with due respect to all the practical knowledge in these contributions, perhaps 6 B&S isn't necessary as a one size fits all approach. Surely as long as the gauge of cable used ( in this case 8 B&S) is "fit for purpose" ...which I believe has been demonstrated, then why the angst?

Maybe I'm missing something...

I am hooking up a lithium battery to a CTEK ( new lithium suitable one )
and my starter battery (calcium lead acid)

The ctek has a bifurcated cable that come out of the side

a red branch that is connected up if you have a smart alternator . I don’t so left this unconnected

The BLACK branch is the battery selector cable

the instructions in the ctek manual say

normal battery ……not connected
AGM …………………….earth
lithium………………..+12 v

QUESTION ……where do I connect it to ?