Over-Discharge Protection

[dpdoug]

The MPPT doc says it has over-discharge protection. Do you still need a battery protect module to keep it from over-discharging?

 

[gnubie]

If your entire load is managed by the charger's load output, directly or via a relay, you do not need a separate low voltage disconnect device.

 

[dpdoug]

How do I know if the MPPT manages the entire load output?

 

[gnubie]

That'd be up to how you wired up your system. How is your load connected? Is it across the charger's load terminals. These are separate to the charger's battery terminals.

 

[dpdoug]

The BMS which will be wired directly to the battery has an over-discharge protection doesn't it? Here's what the Ad says:
Overview

◆DL8S24V80A/100A/200A PCB is used for 8 series 24V lifepo4 battery pack.

◆We can design it for various lithium batteries like LiFepo4, LiMn2O4, and Li-polymer etc.

◆The main functions are: over charge protection, over discharge protection, over current protection, short-circuit protection, temperature protection etc.

◆According to the customer request we can develop PCM in different sizes and structures.

◆BMS manufactured by high quality Mos and IC imported . Keep your battery long cycle serivce life time.

 

[gnubie]

Now you are telling me you have a BMS. How about you draw a diagram of what you are actually implementing, that way I will have something to see and be able to answer your question in your opening post.

 

[Supervstech]

The BMS which will be wired directly to the battery has an over-discharge protection doesn't it? Here's what the Ad says:
Overview

◆DL8S24V80A/100A/200A PCB is used for 8 series 24V lifepo4 battery pack.

◆We can design it for various lithium batteries like LiFepo4, LiMn2O4, and Li-polymer etc.

◆The main functions are: over charge protection, over discharge protection, over current protection, short-circuit protection, temperature protection etc.

◆According to the customer request we can develop PCM in different sizes and structures.

◆BMS manufactured by high quality Mos and IC imported . Keep your battery long cycle serivce life time.

That'd be up to how you wired up your system. How is your load connected? Is it across the charger's load terminals. These are separate to the charger's battery terminals.

I agree. The bms can only protect the system if your loads ALL connect to it.

 

[dpdoug]

The BMS is to protect the battery isn't it? I don't understand what you mean by "protect the system". (please excuse my ignorance, I'm a first timer and learning everything as I go)

 

[offgriddle]

My BMS shuts off my lifepo's at 11 VDC, but, when I'm running my invertor it starts to complain by beeping annoyingly before my BMS shuts off the batteries.

 

[dpdoug]

So what do you do to keep it from beeping when you run the inverter?

 

[offgriddle]

So what do you do to keep it from beeping when you run the inverter?

When the invertor starts beeping because the voltage is dropping below it's threshold of comfort, I shut the invertor off and go find something else to do that doesn't require electricity and let the sun recharge my system next day, (unless I was in the middle of an essential activity like watching Star Trek the Next Generation, which would then require that I start Jenny to operate the television, along with my shore power lithium ion 10 amp hour charger, while I watched TV).

 

[dpdoug]

Now you are telling me you have a BMS. How about you draw a diagram of what you are actually implementing, that way I will have something to see and be able to answer your question in your opening post.

I haven't actually built it yet. I've just done all the research to find all the materials I'm going to need, following Will's instructions on "The Minimalist Solar Package", but going with a 12V 200 Ah LFP battery (trying to take all the security cautions, correct gauge wires etc).