Using a charge/inverter with lithium ion

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pat-doherty asked Jun 23, '20

Using a charge/inverter with lithium ion

Hi,
I'm starting to design a system for a camper I am building. I am looking into using the Multiplus 24/1200/25 with a Lithium Ion (NMC) battery and I have a lot of questions.

1) For the software, looking at the voltage range the inverter should work with the battery (with a BMS of course). I would rather not have the BMS do the load switching except in extreme conditions, or double failures. It seems like these systems have a lot of configurations but I just want to make sure that things like under voltage shutoff, and charge voltages are all configurable as it isnt clear in the data sheet which settings are configurable. Also I have seen some reference to needing a password to change some of the settings, is this this case?

2) The data sheet says there is a "battery temperature sensor", can this be used to disable charging when the battery temperature is too low? My BMS has this ability, but again I would rather have the inverter switching the load. My BMS will allow charge current between 0C and 45C, so I would like the inverter to only allow charge between 5C and 40C.

3) Finally a common problem I have seen when integrating lithium batteries with inverters in the inrush current welding the contractor on the BMS or damaging the FETs, do these inverter chargers have any pre-charge circuit, or other way to limit the inrush current?

P.S. Is there a programmable shutoff voltage for the Orion 24/12-70? If not can I use the remote on/off with the inverter/charger?

Lithium Battery system integration

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Answer 1 · 2020-06-23T20:55:52Z

Hi @Pat Doherty, welcome to the Community! Please fully read and abide by the Community Guidelines while here, as it will make things simpler for all of us - in this case, please try not to post multiple questions in a single post, as that makes it much more difficult to answer and close questions and limits the effectiveness of the knowledge base here assembled.

Now, to answer in brief:

Be aware that the batteries you're proposing to use are not Victron-supported. That doesn't mean that you can't get the system to work, it just means that you'll be on your own with finding the proper settings for them, and that -since Victron components have not been tested to work with those batteries- the performance of Victron components connected to the non-supported batteries cannot necessarily be guaranteed.

1. All parameters of a MultiPlus can be programmed, including low voltage shutdown, charge profile, etc. You will need an MK3-USB Interface to perform the programming; there is indeed a password for the settings, and your installer or authorized distributor can provide that to you.

2. Yes, the MultiPlus has a lithium mode which will disable charging when its connected battery temperature sensor reads 5C or less (41F).

3. No, there is no pre-charge circuit in the MultiPlus. The inrush current only occurs when the caps have drained out, however, which does not happen when the device is connected to the batteries, which it always should be, so this technically should only be a one-time problem that if done carefully and properly will not cause any damage to the system.

4. If this is the Orion to which you refer, then no, the shutoff voltage is non-adjustable. The remote on-off could be triggered by various other products, however, such as a Smart BatteryProtect configured to your desired voltages.

Answer 2 · 2020-06-23T22:35:33Z

pat-doherty answered · Jun 23, 2020 at 10:35 PM

Hi @Justin, sorry about the multiple questions. Thank you for the succinct answers that are really helpful.

I have a pre-charge circuit I designed for another application, I think I will go ahead an install it to give myself the peace of mind.

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