Lithium battery question

[Bob S]

Been reading a lot on the subject as I am planning on upgrading soon. I’ve read Charging Marine Lithium Battery Banks | Nordkyn Design many times along with Rod’s How To, facebook and cruising forums. There is a lot to absorb. To those who have been running lithium for a while, I’m curious how often if ever have you experienced a battery disconnect event?

 

[JBP-PA]

Never. A reasonable design will avoid it.

 

[dlochner]

I've been running LFP full time for about 6 months. I'm still trying to figure out the BMS, unfortunately the company that made the batteries (KiloVault) is no longer.

When motoring, the BMS will disconnect when the battery is fully charged or near fully charged. It seems to taper the charge acceptance before disconnecting. When motoring there is always a load on the system, instruments, AIS, VHF, AP, etc. So I don't think the regulator notices the disconnect. To the best of my knowledge I have never had a disconnect at a high charging rate. Nonetheless I do have a Balmar alternator protection device installed.

Thanks for the link, I'll have to spend some reading it.

 

[Ralph Johnstone]

Nonetheless I do have a Balmar alternator protection device installed.

I don't get out much but I'm wondering why you couldn't just have a small load of, say 1.0A resistive load permanently attached to your alt. output to avoid having the alt. run with 0.0A should you experience a disconnect while charging.

 

[dlochner]

I don't get out much but I'm wondering why you couldn't just have a small load of, say 1.0A resistive load permanently attached to your alt. output to avoid having the alt. run with 0.0A should you experience a disconnect while charging.

The issue isn't the alternator running with no load, if there is no load the there is no circuit, can't make electricity if those electrons can get back to where they came from.

The answer is in Ohm's Law, E = IR. Voltage is equal to the amperage times resistance. When the resistance (load) goes from some number to infinity, the voltage spikes, because anything times infinity is infinity. Alternator innards can't handle infinite voltage. The Alternator protection module simply sits there minding its own business until there is a voltage spike at which it provides a load and dumps the voltage to ground thereby protecting the innards and saving the alternator. How the module does this is mostly a mystery to me.

 

[Bob S]

I'm still trying to figure out the BMS, unfortunately the company that made the batteries (KiloVault) is no longer.

I bought a 325w solar panel from Alte. I could drive there. I was planning on buying their Kilovault batteries but they stopped selling them. They were bought by another company, I spoke with them hoping they would continue selling batteries. I ended up buying 2 300ah Vatrers from Maine's link on black Friday less than what I paid for 6 GC batteries 8 years ago.
I'm curious what app you use for the BMS. I set mine up with Overkill Solar. I'm assuming most batteries being sold now are using JBD BMS's. The Overkill Solar app can configure a lot of features in the BMS. Have you tried that?

 

[dlochner]

The batteries I have a built in BMS, I really don't have access to the settings. In light use it seems like it's trying to keep the SOC at about 70%. The OverKill looks like it is for batteries without a BMS and homebuilt batteries.