Lithium Battery System

Wednesday, Mar 21, 2018 at 05:15

Downunder

Thank you to all those who provided information when i was planning the transition from AGM to Lithium. I will attach some photos of the completed system for those that are interested but beforehand I will give a description of the system I put together.

Batteries:
3x 160 A/HR Lithium packs from EV Power in WA. I wanted packs that would fit in the same space, height wise as the existing AGM's and the 160 A/HR units fitted the bill. Had to do a small modification to the length of the space to give me working room and wriggle room to run cabling.
The supplier required a separate C/B and feed wire from each pack to the Battery Control Unit.

Solar Array:
4x145W and 2x135W Kyocera panels. Panels are series wired in 3 strings comprising of 2 panels each. The wiring from each string goes through a circuit breaker (C/B) in an overhead cupboard before paralleling on a busbar and going down to an array isolation switch in the load space. The string gauges and the C/B's are a nice to have as it allows me to read individual string voltages. Not necessary I know but allows me to monitor their pefomance. When rolled out into the sun for the first time, string voltages were between 38-40v, with 56 amps showing on the regulator.
In theory this array generates 24 amps at up to 48v yet yet i am getting much more than that, the magic of MPPT.

Solar Regulator:
60 Amp Morningstar Tristar MPPT. These regulators would be familiar to many owners as Bushtracker use them, they are one of the better units you can buy. However, like nearly all manufacturers, Morningstar regulators do not come with a charging algorithm for Lithium.

You can select predetermined algorithms via dip switches inside the unit for the likes of lead acid, AGM and Gel with but Lithium requires re-programming if you want specific settings. I am told that some use the Gel setting as it is 'close' to what they want.
Morningstar have online videos which walks through all the settings that are there but frustratingly, it does not tell you what you have to do to get the laptop to 'see' the regulator.
As I found out, simply connecting the two with a Cat 5 cable is insufficient. Youtube came to the rescue and provided the missing information and I was able to make the necessary changes on the laptop so that they could see one another. Making changes after connection is a follow the prompt process as long as you understand what all the settings are and what they need to be.

It also has settings that can reasonably be described as safety features that can be adjusted/enabled but understanding what they meant required me to contact Morningstar for answers, very helpful they were to. Non of this info is in the paperwork.
I now have MS View on my laptop and a Cat 5 cable permanently connected to the regulator and routed to the bottom of a cupboard in the van should I need to make any changes.

DCDC Charger:
I have a 40 Amp unit that hopefully I will not need to use much given the size of the battery and plenty of solar to charge it.
This is a recent purchase due to a problem we had last year whilst travelling. Long story short, our 240v charger went U/S just before we left Trilby Station, the weather also turned bad so solar was minimal at best. Prospect of no power. Made it to Wilcannia where I reset it and it worked, periodically. Ordered new one from Enerdrive and installed it at Broken Hill.
DCDC bought when we came back just in case this happens again..

240V Charger:
This is a 40 Amp Enerdrive unit, again I suspect quite familiar to a lot of Bushtracker owners.
All charging sources have C/B's fitted between them and the batteries which are not only for safety but quite handy for simple disconnection of a charge source.

Inverter:
Xantrex 1800i hard wired, auto changeover etc.

Battery Monitor:
Enerdrive E-Pro Lite. Seems to be the only way to know the state of charge as voltage alone is almost irrelevant with lithium.

Cabling:
Probably went overboard here but better larger than too small.

Summary:
It was an interesting exercise trying to source further information and finding out that there is not a lot out there at least what some people were willing to share. I also found that people in the game are guarded with their advice with respect to Lithium and that opinions from experts varies significantly.
A cramped working environment and a strong desire to not create a "spaghetti junction" required plenty of thought and a few metres of conduit. I have cycled it a few times now and all seems well and I have to say I am pleased with the end result.
We are going away in about 4 weeks so the proof of the pudding as they say is in how it performs in the real world. I am thankful I never had to pay an hourly rate for my time, I would be broke.
Cheers, Bill


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