My thought is that one of the things that goes wrong the most on a boat, and is the most difficult to repair, is the microprocessor board. If all the electronics for a lithium are external, instead of buried under layers of epoxy, then you’d have a more repairable battery system.
I have not looked at all the brands but Battle Born has a 10 year warranty with the first 8 years full replacement. So I would not be too concerned about the circuit board failure.
As a point for discussion, LFP batteries with internal BMS's do not communicate any information outside of their cases. Cell unbalance...nope. High cell temperature...nope. High discharge rate (out of spec)...nope. High charge voltage...nope. Low cell temperature...nope. You get the picture.
All of these conditions are handled internally and the operator does not know anything is amiss until the internal contactor opens and the load connected to the battery goes dead or in the case of charging the charging source takes a back EMF surge. Not the way I would design a critical system on my or a client's boat.
Point well taken. I've been also talking to many RV types that have had Battleborn for many years boondocking, and I find a high level of satisfaction with the product. As mentioned, I haven't found any major concerns with their internal BMS having premature or catastrophic failures.
At this point, I've not found any reason to scare me away.
How many of their batteries will you use in parallel for your house bank? Their spec sheet says 100A continuous, do they recommend using them when paralleled with start batteries for engine starting?
My plan is for 6 Lifepo4 batteries to replace the current bank of 6 Lifeline AGM 6V in the house bank. I figure I'll about double the housebank capacity, with the ability to add more later if desired.
To the best of my knowledge, they can be paralleled to the start bank in an emergency; the Precision Circuits LI-BIM 225 includes a way to do exactly that.
As my thruster bank is wholly separate from the start bank in the current configuration, I plan to add the ability to parallel them to the start back.
Peter,
Excellent choice....keep us posted on how well it works. I have 6 lifeline AGMs now and love them and really have all the power I need for an overnight, but not heavy cooking or AC. Not that the Lifepo4s would give me that, but they could give me several nights on the hook.
Also, leaning toward gas cooking.
My plan is for 6 Lifepo4 batteries to replace the current bank of 6 Lifeline AGM 6V in the house bank. I figure I'll about double the housebank capacity, with the ability to add more later if desired.
To the best of my knowledge, they can be paralleled to the start bank in an emergency; the Precision Circuits LI-BIM 225 includes a way to do exactly that.
As my thruster bank is wholly separate from the start bank in the current configuration, I plan to add the ability to parallel them to the start back.
I just ordered a 120 amp Balmar alternator kit. It comes with the 614 external regulator and 2 temperature sensors, battery and alternator. The list price is about $1200. I found it several places for about $1000. Defender had it for $879 but if you join Defender First for $50 then the cost was $817. So I saved more than the $50 on the one item and the membership is good for the next year. I was concerned about the BMS shutting off the batteries whether for temperature or because they are fully charged. I called Lion Energy asked them about it. They said I could use a DC to DC charger. So I called Balmar. They said that the lithium batteries would definitely shutoff and that it would definitely damage the alternator. They recommended an alternator protection device. It goes across the positive and negative terminals on the alternator. Simple solution that costs about $70. I ordered the Sterling one from marinehowto.com.
Sterling Power 12V or 24V - Alternator Protection Device
The bms will shut off the battery because of over temp? How about the battery temp sensor from the Balmar regulator cant that be set up to a temp less than the BMS shutoff temp? Just wondering I could be missing something.
Bud
I think insulating your battery compartment from the engine room heat is a good idea. Just keep in mind that the batteries themselves will generate little to no heat, assuming you are charging and discharging in the .5C and below range, and that unlikely to be exceeded in a house bank setup. Given the efficiency of LFP (95-98%), the don't heat up the way lead acid does. Ambient heat is what you need to keep them away from, and your insulation should do that nicely.
My batteries (Lion Energy) will shutoff at 111 degrees. Other brands may have a different shutoff temperature but I think that all the lithium batteries have a shutoff temperature. I am going to install them in a cabinet in the salon and put vents both high and low. I am going to insulate under the batteries to keep heat from the engine room from coming up into the cabinet. Also I will put a 50 mAmp fan exhausting hot air out the top vent. I am not sure if the temperature sensor for the batteries is adjustable or not. Balmar said that the 614 regulator will derate the alternator by 20% if you program it for lithium batteries. I was going to derate the alternator anyway so that is taken care of. They recommended the alternator protection device that will stop the alternator from being damaged when the BMS turns the batteries off. So that is a really simple fix. I had imagined a much more complicated fix.
I understand now, the device across the altenator acts as a alternative load for the alternator when and if the battery bms shuts the battery off for full charge or temp.
Bud
Yes, that is my understanding. Marinehowto.com has them.
I am starting out using a dc to dc charger goes between the start batteries and house lithiums so the lithiums could shut off for temp but the start batteries will still be a load for the alternator, so not a problem. Good to know though because I am sure my system will evolve.
Bud
Yes, that is my plan along with active venting. Hopefully they will not get too hot.