Lifepo4 upgrade?

[wholybee]

Originally Posted by Chotu

What is the limit on the hot end? I didn’t even know about that.

My boat is designed really well. I designed All mechanical things out of the interior of the boat. They don’t belong in there offgassing and stinking things up. They have a locker outside. In the aft cockpit area.

LFP are sealed, and only off-gas if something goes very wrong, and the vent/seal breaks. It can and does happen, but it's rare, usually due to extreme overcharging and not setting up a BMS correctly.

For charging below 0c, use a small heat pad. Either have the batteries always power the heat pad to keep them warm, or have the heat pad powered by the charger, and the BMS will prevent the battery from charging until the heat pad heats the battery sufficiently.

[Chotu]

Originally Posted by dlj

Battleborn publishes -4F to 135F. You'd have to see what the specific batteries you're looking into state.

All boat designs have compromises no matter how well they are designed.

Placing your batteries in an aft locker has it's design compromises. There is no such thing as "all good" or "all bad".... (well, there can be exceptions on the bad side I suppose...)

dj

I see no compromise with keeping mechanical systems out of living quarters. All the best and highest quality boats do this.

The battle born ones seem ridiculously overpriced. The ones I looked at said do not charge below freezing.

I’m sure I can figure something out, such as heating the battery compartment.

I35 shouldn’t be too hard to avoid

[PaulCrawhorn]

No LFP should be charged at all below freezing.

In HOT temps they can be fast charged safely at high current

In sweater weather definitely stay under 0.4C

As you approach 40°F stay well under 0.1C.

Being conservative will extend lifespan.

Taking chances can render scrap, and even increase risk of cells shorting out.

There are dropins with internal heating circuits, but silicone heating pads with built in thermostat cutoffs are not expensive.

If you insulate a box, make sure it can be vented when things get hot again

[Chotu]

Originally Posted by PaulCrawhorn

No LFP should be charged at all below freezing.

In HOT temps they can be fast charged safely at high current

In sweater weather definitely stay under 0.4C

As you approach 40°F stay well under 0.1C.

Being conservative will extend lifespan.

Taking chances can render scrap, and even increase risk of cells shorting out.

There are dropins with internal heating circuits, but silicone heating pads with built in thermostat cutoffs are not expensive.

If you insulate a box, make sure it can be vented when things get hot again

Thank you for the post. Wow. These limitations are really having me reconsider the idea of switching to this type of battery.

This is exactly what I’m not looking for. Having my batteries become a chore. Something to look after. I have outback 6DMPPT charge controllers. They deliver whatever they deliver. I don’t think I can adjust them my temperature to say .1 C or .4 C. They are highly configurable, but I’m not sure that they can be configured in this way.

Sounds like quite a headache. In fact, I may just stick with the flooded lead acid batteries. I can buy two more. Stick them in. Deal with the extra weight. And not have to think about all of this stuff.

So many people have converted to these batteries. I can’t believe they’re so difficult to use.

[Chotu]

Originally Posted by wholybee

LFP are sealed, and only off-gas if something goes very wrong, and the vent/seal breaks. It can and does happen, but it's rare, usually due to extreme overcharging and not setting up a BMS correctly.

For charging below 0c, use a small heat pad. Either have the batteries always power the heat pad to keep them warm, or have the heat pad powered by the charger, and the BMS will prevent the battery from charging until the heat pad heats the battery sufficiently.

I suppose this would be a doable solution. But my charging is done by solar. For the most part. Very rarely by any other power source.

I guess that means the batteries would power the heat pad i turn on each morning? This sounds like a lot of extra work.

Is there some kind of premade battery system where you don’t have to do all of this work? And certainly running a heating pad is going to reduce the overall efficiency of the electrical system a bit. As you are wasting energy into that heating pad instead of charging the batteries.

I may not ever see freezing temperatures outdoors at the boat. I hope not. I like to travel with the weather. But there is some potential for it. Should I just not plan for that?

Additionally, I’m not sure what the top end restrictions are.

When is it too hot to charge these batteries? It regularly can be like 105°. Are they just fine at this temperature?

[goboatingnow]

Originally Posted by Chotu

Thank you for the post. Wow. These limitations are really having me reconsider the idea of switching to this type of battery.



This is exactly what I’m not looking for. Having my batteries become a chore. Something to look after. I have outback 6DMPPT charge controllers. They deliver whatever they deliver. I don’t think I can adjust them my temperature to say .1 C or .4 C. They are highly configurable, but I’m not sure that they can be configured in this way.



Sounds like quite a headache. In fact, I may just stick with the flooded lead acid batteries. I can buy two more. Stick them in. Deal with the extra weight. And not have to think about all of this stuff.



So many people have converted to these batteries. I can’t believe they’re so difficult to use.

A very small minority have converted as of yet.

[Chotu]

I looked up the top end temperature restrictions. I found them. They are 113 Fahrenheit. That should be fine.

Certainly, I don’t want to buy a new charge controllers they are very expensive. Is it possible to use my outback 60 MPPT controllers with these types of batteries?

Does everything have to be temperature compensated?

Can these out back controllers provide for the temperature compensation and vary the C rate?

[Chotu]

Originally Posted by goboatingnow

A very small minority have converted as of yet.

They sure are a vocal minority. Ha ha. Just by reading the forum and things online it seems like at least half the people have these now.

There is an incredible weight savings to be had.

But I definitely, definitely don’t need another hobby on the boat. There are enough jobs to work on aside from managing batteries.

[rslifkin]

The cold weather concerns are a big thing in my mind as well. For those of us who store our boats in below freezing weather over the winter, it's a challenge. My boat sits unplugged (and no sun on the solar panels) over the winter when I'm not there, but when I go to work on something, I expect to be able to plug the boat it and have power. Needing to worry about bypassing the house bank (or only being able to discharge it but not charge) would be a definite annoyance.

[goboatingnow]

Originally Posted by Chotu

They sure are a vocal minority. Ha ha. Just by reading the forum and things online it seems like at least half the people have these now.



There is an incredible weight savings to be had.



But I definitely, definitely don’t need another hobby on the boat. There are enough jobs to work on aside from managing batteries.

There is zero maintenance overseeing LFP , much less then lead acid in general.

All the monitoring is automatic etc and requires no particular oversight.

[Chotu]

Originally Posted by goboatingnow

There is zero maintenance overseeing LFP , much less then lead acid in general.

All the monitoring is automatic etc and requires no particular oversight.

With solar, and lead acid, I just set my charge controlling points and forget it. Then I add water when they need water. That’s it. Doesn’t matter what temperature they are at.

I know there are people that really get into it and do all sorts of things to keep the temperature perfect for the charge rate. I don’t do that.

It seems like the lithium batteries require me to do that right? And what about stressing out every time the temperature is dipping below 40F? Or 4C?

It just sounds very stressful to have to worry about your batteries instead of having them just working.

I’d really like to make the switch, But not having batteries when it goes below 32F is a real showstopper for me. I might potentially be in cold weather sometimes.

[emilecantin]

Originally Posted by Chotu

With solar, and lead acid, I just set my charge controlling points and forget it. Then I add water when they need water. That’s it. Doesn’t matter what temperature they are at.

Does it? The spec sheet for my AGM batteries has a lot to say about temperatures, there's even a graph of capacity vs temp.

I wouldn't worry too much about the low-end of temperatures; do you really use your boat when it's freezing inside? If so, you probably already have some form of heating, just make sure the battery also benefits from it.

[Chotu]

Originally Posted by rslifkin

The cold weather concerns are a big thing in my mind as well. For those of us who store our boats in below freezing weather over the winter, it's a challenge. My boat sits unplugged (and no sun on the solar panels) over the winter when I'm not there, but when I go to work on something, I expect to be able to plug the boat it and have power. Needing to worry about bypassing the house bank (or only being able to discharge it but not charge) would be a definite annoyance.

Yeah. I think I’m with you on this one. I really wanted these batteries, but I don’t like the restrictions that are involved with them. It’s unfortunate that I have to put so much weight in the boat to start using an electric refrigerator. But the convenience factor might be worth it.

This was the reason I use the propane refrigerator to begin with. It weighs less. Because it doesn’t require an extensive electrical system.

I was trying to just stick with the propane refrigerator for this little winter test drive. Figured I could reevaluate all of this in the spring after some time on the boat again. However, the part I need for the refrigerator isn’t available for 5 to 8 weeks. And I need a refrigerator in three weeks.

So unbelievably I have to toss a $1500 refrigerator that works perfectly. Making the post, I’m starting to wonder if maybe there’s another type of controller I can get for this thing. Maybe one of the old fashion ones. If they use the same wiring.

[Chotu]

Oooh!!!! Huge amount of work was just lifted from the pre-sailing checklist. I found the board that burnt out!!

There was one in stock. Only one.

Great news. So I don’t have to use as much electricity and won’t need to even upgrade the system. I can keep the weight down this winter and just use what I have on board already.

I’ll look at upgrading some other time.

[rslifkin]

Originally Posted by Chotu

Oooh!!!! Huge amount of work was just lifted from the pre-sailing checklist. I found the board that burnt out!!

There was one in stock. Only one.

Great news. So I don’t have to use as much electricity and won’t need to even upgrade the system. I can keep the weight down this winter and just use what I have on board already.

I’ll look at upgrading some other time.

Perfect! Big upgrades always go better when you have time to figure it out slowly and aren't under the gun to get something working.