Bought a LiFePO4 battery for the boat. Not sure I'd do it again.

[tjspiel]

What prompted this is that awhile ago my son, who's not really a sailer, asked if he could spend the afternoon on the boat with a friend. He just wanted to use the trolling motor.

It ended up not happening but it made me a little nervous because the battery I'm using is an 11 year old AGM that was originally in a car. It's fine for a trip between the buoy and the dock plus operating the lights and radio but not really suited for a lazy afternoon of trolling around the (small) lake.

So a few weeks ago I saw an add for a pretty inexpensive LiFePO4 battery and after doing a little research decided to go for it since it had more Ah that a group 24 lead acid battery and might end up being cheaper in the long run if it lasts as long as it should.

But there are some quirks with it. LiFePO4 batteries don't show a voltage drop as they discharge in the way that a typical battery does. It only drops a small amount and then it falls off a cliff as it's almost completely discharged. And they operate at a slightly higher voltage anyway.

Initially this sounds good. But in practice, both the trolling motor and the charge controller meters/displays are calibrated for lead acid batteries. So they show the battery as being fully charged even if it's almost discharged.

And though I haven't experienced this, what happens is that rather than the trolling motor just slowing down as the battery starts to get low, the battery shuts down completely. So you don't get any warning.

Likewise, the charge controller will say 100% charged even though the voltage would indicate something less, - and that's with the charge controller on the "Li" setting. I will have to talk to Renogy about that.

So if I really want to know if the battery is close to discharged or not, I have to pay close attention to the voltage.

The other oddity is related to the charge controller too. I get reports emailed to me from it a few times a day. At noon, it's now saying "charge not ready". Usually I see that when there's no light hitting the solar panel. But with the LiFePO4, I think this may because it's at max charge.

Normally it would say "float charge" when the battery is charged meaning that the controller has gone into float charging mode. But what I think may be happening is that the battery's built in management system is shutting off the charge.

None of this is really "bad" and maybe I just need a better charge controller. But it has me thinking that a regular deep cycle battery was all I really needed.

[Shesaidno]

Could it be the inexpensive LiPo battery? I have a had a couple of them and they have worked very well. Did a long trip this weekend, although with just the auto tiller running, some 35 miles round trip. Frank has one too and maybe he will chime in.

[tjspiel]

I should clarify. I think the battery is operating as it should and is probably a good choice for a lot of people. For me it might have been overkill and slightly problematic because my normal ways of easily knowing how discharged the battery is don't work.

And I haven't personally had the battery shutdown on me but that's my understanding as to what happens with them, - full power, then nothing once they've discharged.

I'll likely never have an issue with it but it's a little disconcerting that I'm not seeing the normal charge behavior on my controller and that I can't really tell the state of charge without paying close attention.

Probably more information than what you want but here's 4 screen shots of what the controller was showing at 4 different times today; sunrise, 10:00 am, noon, and 2:00 pm

It discharges a bit overnight to power the charge controller, bluetooth module, and it keeps an iPhone charged.

You cannot view this attachment.You cannot view this attachment.You cannot view this attachment.You cannot view this attachment.   

With the AGM, you'd see "Charge Not Ready" in low light situations, "Boost Charge" when the battery was discharged (but charging)  and "Float" when it was fully charged.

Now I never see float but at noon it consistently says "Charge Not Ready". It's like the panel is getting shut off.

And it always says it's 100% even though 13.4 volts for a LiFePO4 battery should be 90%.  I have had it as low as 13.2 (70%) but it still said 100%

[Quantico Frank]

Tom, remind me— you have a Renogy Wanderer controller, don't you? I have one too, and I remember a couple years ago we were talking about the Bluetooth module and the iPhone app. I have to say that I'm not getting the use out of the app and the Bluetooth module as much as you are. I used it when I first installed it and the boat was out in the driveway, and it was just barely within Bluetooth range to my living room. Since then I don't think I've ever used it; however, I do use the display on the controller.

So I replaced my deep cycle lead battery with a LiFe Po4 battery this spring because the lead battery gave me a bunch of problems and finally it up and died on me. I got the same WestMarine battery that Talbot had earlier been talking about. Since then, it's been on my boat in the Quantico Marina just doing a great job. It showed 14v when I took it out for a sail last week, and I haven't dug any deeper than that. I hope what I don't know isn't hurting me...?

[Riggerdood]

Tom, I'm using that same app. Have you checked the settings for the Equalize, Boost, and Float Charge limits? You might need to change them for the particular battery you have. I'm sure Renogy could assist.

[tjspiel]

I'm sure you're fine Frank. You're just running electronics off of it if I remember right so it probably doesn't drain much at all.

Yes, the controller is a Wanderer. I'm curious, have you ever seen it drop below 100% ?

FWIW I went motorsailing tonight to get a sense of whether I was getting 100 Ah out of the battery or not. Kind of a waste of a good breeze, but there was science to be done.

After an hour of running the motor at full throttle, and stopping occasionally to check things, the battery had dropped down to 13.1 volts and then went back up to 13.2 after being off for awhile. 13.1 volts is 40% according to the charts for LiFePO4 batteries and 13.2 is 70%.

That seems about right. 

I also noticed that the "High Voltage Cutoff" setting on the Wanderer is 16 Volts. And that might be why it's shutting down at noon (the charging, not the battery). Today it had the panel voltage at 14.3 volts at noon but maybe a cloud had just come over. Other days at noon I've noticed it being over 16 volts. The app is flakey at times to and doesn't always show numbers that make sense.

The other change I made was swapping solar panels. The old one was self-regulating meaning that it kept the voltage lower on its own. The new one is not which is maybe why I'm seeing different charge controller behavior. Might not be related to the battery, or at least not all because of the battery.

Well see what tomorrow noon brings when the battery will still be somewhat discharged from my motorsailing.

[tjspiel]

Tom, I'm using that same app. Have you checked the settings for the Equalize, Boost, and Float Charge limits? You might need to change them for the particular battery you have. I'm sure Renogy could assist.

That could be. Maybe the Lithium setting on its own isn't quite right for the battery. I took a snapshot of the settings while I was out tonight and I'll check them against what's in the battery manual.

[Quantico Frank]

Yes, the controller is a Wanderer. I'm curious, have you ever seen it drop below 100% ?

Tom, the wx forecast for tomorrow is looking ideal for a sail, and I'm not going to miss it, so I'll have a look at the percent charged reading, and at least give you one or two data points. I also have a Blue Sea "meter" on a panel that also gives me a battery voltage readout that I can compare with the controller reading. Interesting....

[tjspiel]

Yes, the controller is a Wanderer. I'm curious, have you ever seen it drop below 100% ?

Tom, the wx forecast for tomorrow is looking ideal for a sail, and I'm not going to miss it, so I'll have a look at the percent charged reading, and at least give you one or two data points. I also have a Blue Sea "meter" on a panel that also gives me a battery voltage readout that I can compare with the controller reading. Interesting....

I'm curious as to what you'll find.

Renogy support was not a lot of help but I did find out there is a newer app called DC Home. I'll try that to see if it gives a more accurate state of charge reading.

[Riggerdood]

Is it a Renogy battery Tom? I would find it odd if Renogy controllers only worked with Renogy batteries and vice versa. I saw the DC Home app, but decided to stay with Renogy BT because it works fine with my Optima AGM. If/when I upgrade to LiFePO4 I'll probably switch.

[tjspiel]

Is it a Renogy battery Tom? I would find it odd if Renogy controllers only worked with Renogy batteries and vice versa. I saw the DC Home app, but decided to stay with Renogy BT because it works fine with my Optima AGM. If/when I upgrade to LiFePO4 I'll probably switch.

No. It's an "LiTime" (formerly "Ampere Time"). They're fairly reputable, - though basically the same battery is sold by multiple companies. The same is true of Renogy too. Their controllers are made by SVN and Renogy is just one of the companies that sells them.

Tried the DC Home app today. It was able to discover the Wanderer controller and added it to its list of devices. But it was greyed out on the display and wouldn't show any data for it. Not sure why. DC Home is updated fairly frequently but doesn't get the best reviews.

The boat comes out of the water in a couple of weeks and it will be easier to troubleshoot in the backyard. Though I'm staring to like the idea of using a Raspberry Pi instead.

[Quantico Frank]

Tom, I didn't get out yesterday, unfortunately. I had to finish a project on the deck of my house before this big storm we're having right now arrived, and it went longer than I planned. I looked up Raspberry Pi, and it's the most intriguing thing I've seen in a while. I'm sending you a DM.

[tjspiel]

Tom, I didn't get out yesterday, unfortunately. I had to finish a project on the deck of my house before this big storm we're having right now arrived, and it went longer than I planned. I looked up Raspberry Pi, and it's the most intriguing thing I've seen in a while. I'm sending you a DM.

Raspberry Pi computers are a lot of fun if you're into that kind of thing. So far I haven't done anything boat related with them. Here's the closest thing:

You cannot view this attachment.You cannot view this attachment. 

The first picture is the front of my weather station display. The second is of the back. The white thing is one of the smaller versions of a Raspberry Pi. It's smaller than two packs of gum and is typically powered by USB.

It sends weather data from my weather station to weather underground so I can view it remotely. I wanted to do that because there would be many times I'd be sitting at the office in the late afternoon wondering if there was enough wind to make it worthwhile for me to rush home to take the boat out.

Wind varies a lot here even within a small area and period of time. I wanted to have up to the minute info.

So something like that with a USB cell modem attached would replace the iPhone I keep on the boat now to monitor the solar system and battery. It would be a lot more flexible in what it could do vs the Renogy apps.