LFP and Alternator settings

[sailorboy1]

Well I programmed my ARS-5 regulator today for installing my LFP batteries next week. I went conservative because charging with the engine is not a norm and I think it best to not have that burn up my alternator or over charge my batteries.

[SOLAR SUPPORT]

Originally Posted by CaptainRivet

to not get into this problem, I highly advice to follow this points for drop ins (especially the cheap ones):
1)use the parameters the manufacturer gives you, they know what's inside especially HVC as this has a correlation to passive balancing.
2) Charge with max. 0.15C, that gives the cells time to settle and charge slowly, especially towards end of charge. charging with more cells start to differ and one cell hits HVC earlier causing more imbalance.
3)Discharge max. 0.3C, above cells start to differ strongly
4)longer absobtion phase, this helps the cells balancing and also reduces delta voltage between cells
5)make sure your charge sources can deliver the voltage for HVC
6)if it must be drop ins get one which you can open, SOK batteries come first to my mind. you can reach individual cells, balance manually and swap parts out if they break.

Approaching a problem with a material with a "cheapness" point of view does not show that your point of view and thesis about the problem with that material is correct.
Our boats have alternators of the same brand and capacity. I continue to use my own alternator. Your alternator burned out so you had to replace it. How does the alternator, which has a thermal protection circuit in it, and which many people say that they have been using directly for Lifepo4 charging on their boats for years, lights up on your boat? Maybe it was a cheap one.

During active cell balancing, directing the cells with high energy to the cells with low energy gives very effective results. The superior features of this technique are that energy is preserved during the balancing of the cells, and that it concludes the balancing in a much shorter time and effectively compared to passive balancing. If your drop-in battery does not have a smart bms, it will be difficult to follow the balance of the cells.

Opening the drop-in battery box with a sealed box is not an easy task, but; When you open the box carefully and add a smart active balancer, it becomes possible to constantly monitor the health of the energy levels of the battery cells. In order to minimize this work, it will make your job easier to prefer large-capacity batteries and batteries with easily opened sealed boxes rather than small-capacity drop-in batteries.

New generation bms, which do not have passive balancer but integrated active balancer, started to be produced.

[SOLAR SUPPORT]

Originally Posted by tanglewood

I really don't get your point. You seem to be saying that most built-in cell balancing isn't up to the task, and you need to add an external balancing circuit of some sort for it to really work? Exactly which batteries have inadequate cell balancers?

My aim is to provide the cell balance of my drop-in batteries, whose HvCutoff voltage drops every month and has recently been 3.4 vpc. I don't know how long the batteries were in the warehouse when I first bought them. I realized that I needed to solve the cell balance problem, which I predicted to deteriorate more and more in the long run, without delay.

I did not have a thesis that this problem that I have experienced is experienced in all drop-in batteries. However, similarly, a drop-in battery with a decreasing HvCutoff voltage may experience capacity problems in the future if the cell balance problem that increases over time is not resolved. How do I know which drop-in batteries will experience such stability problems?

[justinfinity]

Start with your BMS. Understand how your BMS works on your LiFePO4 batteries. Then work your way back from the BMS to your charge sources. You can't fiddle with charge sources until you know how your BMS operates, what voltages it expects, and what its various thresholds and protection settings are.

If you have assembled your own LiFePO4 battery, then you should have chosen a BMS and know the settings. If you have purchased something like a drop-in, then the quality and sophistication of the BMS will vary according to what you purchased.

Once you have done all that, plan to have a load dump to protect your alternator from a sudden disconnection. A simple solution is to have a conventional lead acid battery on the circuit (isolated during discharge) that can take the load once the LiFePO4 BMS disconnects from the charge source. There are some other non-battery semi-intelligent solutions out there for load dump protection as well.

[Nicholson58]

Originally Posted by Networker

Use the external regulator and tell it to stop when voltage hits 14.4v. I use wakespeed.

Proper advice!

We have Balmar external alternator regulators on both alternators. These and the Victron, solar were reprogrammed for our new Blue Heron lithium system.

[donradcliffe]

Originally Posted by tanglewood

I really don't get your point. You seem to be saying that most built-in cell balancing isn't up to the task, and you need to add an external balancing circuit of some sort for it to really work? Exactly which batteries have inadequate cell balancers?

That is exactly his point. After a month of trying to get the balancer in the BMS to balance my cells, I bought a $10 active balancer on Ebay. It took less than 24 hours to get the cells balanced, so I unplugged it 2 years ago and have not had to use it since. The BMS balancers move milliamps around, and only when you are overcharging the batteries. The active balancers move amps around and work at any SOC.

[goat]

Keep it simple.

Alternator charges LA start battery. Solar, wind, shore for lithium house bank. DC-DC from house to start for multi-week sails so you don't need to start your motor to charge start battery. I ended up removing my alternator belt as it wasn't really needed.

Of course this only works if you've balanced your solar and battery sizes with power consumption.

Be very careful with Lithium; I started out with a 200 ah bank and had so much reserve power I started looking for ways to burn it. I ended up with a 48v 180ah bank. now looking at an electric galley on a 27 foot boat. Very addictive.

Something that's been on my mind that the people here with actual useful brains can school my on; it takes a certain amount of work (watts) to say, run your refrigerator. Those watts being supplied with the higher voltage of lithium would require less amps. Less amps doing the same work equals more amp hours available from a similar sized AH bank.

Don't laugh too hard at my math I'm just a

goat

[Pete7]

Originally Posted by goat

Be very careful with Lithium; I started out with a 200 ah bank and had so much reserve power I started looking for ways to burn it. I ended up with a 48v 180ah bank. now looking at an electric galley on a 27 foot boat. Very addictive.

Just do it and then post the pics please. We are half way there.

Pete

[Scott Berg]

Originally Posted by smac999

Float at 13.5v. Same as sitting at the dock 360 days a year which most boats do.

No bms I have seen stops charging. (Victron, mastervolt etc) Maybe some of the home made ones do.

the victron SmartBMS and Lynx both will stop a Victron charger and the Lynx works directly with the WS500 controller. 'drop in' BMS can't communicate which is, in my mind, a problem.

[TPG]

It seems that this topic has taken on the same discussion as the anchoring topic. We all love to joke about the anchor opinions but I'd argue electrical is its twin brother.

I'm always looking for the best practice in everything and will continue to pursue the best option.

[Jetx]

Our setup is dead simple. We have one Nordkyn VRC regulating both OEM Volvo 115A alternators on our cat. The alternators are unmodified, so the factory standard internal regulators still provide alternator over-temperature protection for the alts. Alternators charge the LFP house bank (Kilovault drop-ins) directly, not through any B2B.

The VRC is set to 13.9v bulk, 5 minutes absorption time. This gets me to about 95-97% SOC typically; I’m not concerned about getting all the way to 100. It then drops to 13.35v float (which Nordkyn more properly calls “hold”). At this holding voltage, the alternators will continue to supply DC loads during extended motoring, while the battery SOC declines VERY slowly, so the LFP batteries aren’t floated / kept full.

The VRC operates completely independently. It’s not connected to any other charging equipment, to a BMS, or to a shunt for current measurement (although it is capable of these things). It simply charges to 13.9, and drops to 13.35 for as long as either engines is running.

People will say you “must” have a communicating/networked, all-singing all-dancing, current-sensing setup for LFP. While you can certainly achieve even more granular control and an “academically superior” charging regime that way, it seems to me like a big step up in complexity and expense for very little practical benefit.

The same people will also say you can’t use OEM alternators to charge LFP batteries unless you run through a B2B to limit charge current. But ours have run fine this way for the past 250 hours, and are still putting out about the same charging current (roughly 90 amps continuous when hot). Maybe they’ll burn out eventually, but so far, so good.

[sailorboy1]

Originally Posted by TPG

I'm always looking for the best practice in everything and will continue to pursue the best option.

good luckl

[newhaul]

Originally Posted by Jetx

Our setup is dead simple. We have one Nordkyn VRC regulating both OEM Volvo 115A alternators on our cat. The alternators are unmodified, so the factory standard internal regulators still provide alternator over-temperature protection for the alts. Alternators charge the LFP house bank (Kilovault drop-ins) directly, not through any B2B.

The VRC is set to 13.9v bulk, 5 minutes absorption time. This gets me to about 95-97% SOC typically; I’m not concerned about getting all the way to 100. It then drops to 13.35v float (which Nordkyn more properly calls “hold”). At this holding voltage, the alternators will continue to supply DC loads during extended motoring, while the battery SOC declines VERY slowly, so the LFP batteries aren’t floated / kept full.

The VRC operates completely independently. It’s not connected to any other charging equipment, to a BMS, or to a shunt for current measurement (although it is capable of these things). It simply charges to 13.9, and drops to 13.35 for as long as either engines is running.

People will say you “must” have a communicating/networked, all-singing all-dancing, current-sensing setup for LFP. While you can certainly achieve even more granular control and an “academically superior” charging regime that way, it seems to me like a big step up in complexity and expense for very little practical benefit.

The same people will also say you can’t use OEM alternators to charge LFP batteries unless you run through a B2B to limit charge current. But ours have run fine this way for the past 250 hours, and are still putting out about the same charging current (roughly 90 amps continuous when hot). Maybe they’ll burn out eventually, but so far, so good.

So running external alternator controller that has been discussed on other threads . That is a good option
For others the dc2dc is the option of choice as it does the same thing and cost is about 1/4 .that of the Nordkyn VRC .

[Jetx]

Originally Posted by newhaul

So running external alternator controller that has been discussed on other threads . That is a good option
For others the dc2dc is the option of choice as it does the same thing and cost is about 1/4 .that of the Nordkyn VRC .

Except with a B2B, you’re going to be severely limited on charging current, unless you parallel several of them, which then of course drives up the cost. I’m using a single VRC to control two alternators, and can charge the house bank at 200 amps when both engines are running.

B2B makes sense if you can accept very slow charge rates. Of course some folks view that as a feature, rather than a limitation, since it’s a dead simple way to protect the alternator from overheating.

[newhaul]

Originally Posted by Jetx

Except with a B2B, you’re going to be severely limited on charging current, unless you parallel several of them, which then of course drives up the cost. I’m using a single VRC to control two alternators, and can charge the house bank at 200 amps when both engines are running.

B2B makes sense if you can accept very slow charge rates. Of course some folks view that as a feature, rather than a limitation, since it’s a dead simple way to protect the alternator from overheating.

.??? Well using your own numbers 180 amps and victron and sterling both make dc2dc units from 20 to 200 amps so that is not an issue.
Myself run a 40 amp unit with a 75 amp alternator. As it is just a backup charge source ( as in the #4 source )