BMS of Delta Pro protecting battery pack from user?

[GrtLks]

I own two Delta Pro units (and extra batteries) and recently installed a Smart Home Panel (SHP). When charging the Pros from wall AC power, they can charge at user-selected wattage from 200W to 1800W. Now, when charging from the SHP, they can be charged at 3000W, each unit effectively from its own 30A circuit. That's a huge potential spread, 200W vs 3000W and EcoFlow says precious little about optimal charging rates and how those rates may (or may not) impact the life of the batteries.

Now, this post (and my questions) ignore whether to charge and discharge 100% to 0% because, as backups for power outages, I always want maximum power available and I want to keep the lights on as long as possible.

I've read, I've searched the forums, and there are many opinions about charging rates for LFP batteries. Since I'm using these things as backups with the SHP for power outages, I'd be inclined to recharge them at maximum rate whenever the grid comes back, so they're ready to go ASAP. However, I also want not to utterly abuse these things so they'll last.

So, what can we expect of the engineers at a company like EcoFlow, and what can we expect from their BMS on the Delta Pro? Part of me hopes that they have built in enough 'something' so that any of the allowable charging rates will be OK for the device, and that what the user sees as 100% or 0% actually provide 'margin' to maintain the battery pack in a healthy state. Car companies have taken pains to do these things from what I've read, but would love to hear from others about these issues. Really, these devices are targeted at the general consumer market and the user should be able to use them as the units will allow and not lose capacity or unit life span. But are the EcoFlow BMSs doing that?

 

[Wakintx]

I own two Delta Pro units (and extra batteries) and recently installed a Smart Home Panel (SHP). When charging the Pros from wall AC power, they can charge at user-selected wattage from 200W to 1800W. Now, when charging from the SHP, they can be charged at 3000W, each unit effectively from its own 30A circuit. That's a huge potential spread, 200W vs 3000W and EcoFlow says precious little about optimal charging rates and how those rates may (or may not) impact the life of the batteries.

Now, this post (and my questions) ignore whether to charge and discharge 100% to 0% because, as backups for power outages, I always want maximum power available and I want to keep the lights on as long as possible.

I've read, I've searched the forums, and there are many opinions about charging rates for LFP batteries. Since I'm using these things as backups with the SHP for power outages, I'd be inclined to recharge them at maximum rate whenever the grid comes back, so they're ready to go ASAP. However, I also want not to utterly abuse these things so they'll last.

So, what can we expect of the engineers at a company like EcoFlow, and what can we expect from their BMS on the Delta Pro? Part of me hopes that they have built in enough 'something' so that any of the allowable charging rates will be OK for the device, and that what the user sees as 100% or 0% actually provide 'margin' to maintain the battery pack in a healthy state. Car companies have taken pains to do these things from what I've read, but would love to hear from others about these issues. Really, these devices are targeted at the general consumer market and the user should be able to use them as the units will allow and not lose capacity or unit life span. But are the EcoFlow BMSs doing that?

I shouldn't reply. But this is why many of us build our own because we get to know what the specs of our stuff is.

For optimum long life of lifepo4 cells we don't drain them nor tend to fully charge them by customization of settings I don't know if those manufacturers even allow you access to

 

[DarrylG]

Hello @GrtLks
One question I would ask myself is how often is your grid power going down and what is the typical duration it is down. Of course our backup units are all about a convenience for us. You spent your money on the convenience, what is your personal priority?

The Ecoflow does have many customizable settings for its life duration. So you can adjust the charge rates as you mentioned. You can also set charge and discharge limits. I have seen setting them to 10 - 90% if your unit will be sitting at these levels for longer periods. Being in the top and bottom 10% is less damaging if the unit is only there for a short time. Having a lower charge rate is better to a limit.

I know you have a few small solar panels and a generator to recharge your unit if need be, so the 10 - 90% might be a good setting for you if you would like to preserve your battery a bit longer. Having a lower charge rate is better to a limit as the batteries build up less heat as well.

Personally my Delta Pro is recharged by solar and is running devices constantly in my house. I have my charge limits set for 10-100%. However I adjust my settings differently if I expect a power outage may happen. Then I would fully charge from the grid while its on and wait for the power to go off to start using the Delta Pro.

If you would like to know more about your Lifepo4 batteries and how to treat them, check out: https://batteryuniversity.com/ and look specifically at the info for these batteries.

 

[GrtLks]

Thanks both for your replies. I've got a lot to learn, but I see a LOT of different opinions from those who are knowledgeable about LFP chemistry about charging and discharging. Also, one has to wonder about whether we can treat all-in-one units as analogs to EVs that are sold to a non-technical consumer market. EV manufacturers have (essentially) held battery capacity in reserve, and also baked in to their BMSs the fact that drivers are non-technical.

As an example, the Ford Mach-E only allows the consumer access to a portion of the overall capacity of the battery pack so that they see the same capacity as the battery pack ages over the years. They also are working hard to make a consumer experience that does not require technical knowledge and makes for a positive consumer experience, whether fast charging or babying the battery. As another example, Apple would NEVER require the consumer to gain and maintain much technical knowledge to use their products. All-in-ones fall into a market segment in which it's about the needs of the consumer. The engineering and tech must be so good that the device seems simple, trustworthy, dependable to the average consumer.

So, it's not unreasonable for the consumer (me in this case) to expect that a company pitching an all-in-one product that includes advanced BMS will do the engineering required for it to perform well, whether I understand LifePO4 chemistry or not. If I buy my own inverter(s) and batteries, I understand it's up to me to learn how to manage the batteries, but should that same knowledge be required for a Delta Pro? I don't think so.

I guess what I hope to learn over time is the customer experience with Delta Pros, and I'll be part of that. What I hope is that, for example, when I fast charge to 100%, the BMS is managing the cells for best performance AND best life. I hope that what I see as 100% is not actually 100%, just like EVs out there, so that in five years my experience with the system remains the same. If average users cannot just USE these things, and also get quite a few years of reliable service from them, it's going to be pitchforks and bankruptcies for companies like EcoFlow. These things cost way too much for them not to perform for the average non-technical consumer.

Last, I know this is a DIY site, but if electrification is the future, and if average consumers are going to be getting on the train, products are going to be required to be MUCH more Apple and much less EG4. If it's much more complex than plugging in the flat screen TV, or if batteries don't instill confidence and maintain performance over time, consumers will cling on to diesel and gasoline.