LFP and Alternator settings

[CaptainRivet]

Originally Posted by sailorboy1

Ok so where can I find accepted “best practices”?

What alternator do you have, what is its real continuous amp capability?
Is it your primary charge source? How many amps do you need on passage at Night to cover your load (chartplotter, lights, fridge…)?
Still have a lead onboard, eg starter, bowtruster…?

[fxykty]

Originally Posted by sailorboy1

Ok so where can I find accepted “best practices”?

Nordkyn Design and Marine How To - the links have been posted many, many times before.

[Nauticatarcher]

We have two alternators, a Bosch 120 amp alternator with Mastervolt Alpha Pro regulator for bulk charging, it also has a switch in field wire so I can turn it off. Also have original Hitachi alternator charging start Batterry with two 15 amp DCDC chargers, gives us a lot of flexibility charging whilst motoring and also redundancy

[CarlF]

You should charge to the battery manufacturers recommendations. They are not all the same. I have Kilovault batteries (recommended by Mainsail). They are conservative. Bulk/absorption 14.1v, 10 min absorption, 13.5v float. One reason for the low Bulk is that that their BMS starts to balance at 14.0v. Some BMS don’t balance until 14.4v.

I follow the earlier suggestion of using the solar panel controller to top the batteries up to full charge. The alternator regulator and Victron Multi charger are set to charge only to 13.9v which is over 90%.

[lateral]

Originally Posted by Networker

Just get a wakespeed, it monitors volts, currents and temp, and stops charging if batteries are full. If batteries need to be filled, it tells regulator to charge. If it’s hot, it backs it off.. It’s dead simple and you can also add a switch to change the field % to something lower than 100% if you want, but so far I’ve found I’ve never used it.

I had the Balmar mc-618 and it worked too, but I had to keep the field manager to 50% to keep the heat down when motoring. But it’s a pain to program as it needed a magnetic pen. The wakespeed can be programmed with an android phone and usb cable.

I thought the MC618 could be programmed with your phone or SG200? have one but not yet installed. Have the 614 as well but didn't fancy the magnetic pen in a seaway.
Edit:

https://www.youtube.com/watch?v=3NyA8U70OcE

I guess you don't have BT gateway.

[Networker]

Originally Posted by lateral

I thought the MC618 could be programmed with your phone or SG200? have one but not yet installed. Have the 614 as well but didn't fancy the magnetic pen in a seaway.
Edit:

I guess you don't have BT gateway.

Correct, I didn’t get the Bluetooth gateway. I would have bit went to the Wakespeed instead, which DOES NOT have Bluetooth config options! I bought two of the esoteric USB cables it requires, labeled and put them in a bag, and cast my lines for my circumnavigation, and now can’t find them when I checked this AM :/ I wish it had Bluetooth config like the mc618 can do.

[hjohnson]

Originally Posted by sailorboy1

How are people preventing their alternators from overcharging their LFP batteries during a long motor? I assume it is in the regulator programing and not hoping the BMS does it. What settings have you programmed in?

I have a Wakespeed WS500 regulator driving my alternator. It just takes direction from my BMS via CANBus just like any other charging source. With the new firmware it also nicely reports into my Victron setup, and varies the Max power based on RPM. Below around 1000rpm it pulls the alternator down to idle so I don’t have the drag while doing close quarters maneuvering in the marina.

[newhaul]

Originally Posted by sailorboy1

How are people preventing their alternators from overcharging their LFP batteries during a long motor? I assume it is in the regulator programing and not hoping the BMS does it. What settings have you programmed in?

40 amp dc dc charger set to my lifepo4 profile .
130 usd from renogy. https://www.renogy.com/12v-40a-dc-to...gaAvfvEALw_wcB

[SOLAR SUPPORT]

Over time, there is a balance problem between the series-connected cells that make up the LFP battery. There are many reasons for this and sometimes the bms can't fix these imbalances.

These batteries that we use on boats are not used as in a telephone or electric vehicle. On our boats, the batteries can be charged and discharged at the same time. Different charge sources such as mppt, ac-dc, alternator, generator are used without very precise control of the charge parameters of charge sources. In a phone or EV, the situation is very different and orderly.

It is not always possible for BMS to provide cell balance by passive balancing under these variable conditions. Accordingly, as the size of the imbalance between cells increases, the bms has to cut off the charge in order to protect the battery in accordance with the cell voltage at the top. A cell whose level gradually decreases can receive less and less charge from other cells in the long run. If the LFP battery applies a gradually decreasing HVC voltage such as 0.1 volts every month over the months, this is because the bms cannot compensate the charge of the cell with the lower charge in order to protect the cell with the highest charge voltage, and the low charge problem in this cell gradually increases over time.

To fix this problem, I cut the drop-in battery from the top and opened it. There was a bms in the battery that had no communication with the external environment. I connected the smart active balancer to the cells. With an active equalization charge lasting approximately 24 hours, the charge level of a cell that was out of balance was restored. Battery HVC was 13.7V, after active balancing, HVC became 14.5V.

As you can see, the sensitive charging cut-off settings, which are made considering that the HVC in the batteries will remain constant, need to change over time. As a result, two options emerge. Frequently checking the balance of the cells in your batteries or the charging cut-off settings of the chargers. I think it's better to check both. It seems more logical to choose a large battery pack and deal with a single cell array.

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

Over time, there is a balance problem between the series-connected cells that make up the LFP battery. There are many reasons for this and sometimes the bms can't fix these imbalances.

These batteries that we use on boats are not used as in a telephone or electric vehicle. On our boats, the batteries can be charged and discharged at the same time. Different charge sources such as mppt, ac-dc, alternator, generator are used without very precise control of the charge parameters of charge sources. In a phone or EV, the situation is very different and orderly.

It is not always possible for BMS to provide cell balance by passive balancing under these variable conditions. Accordingly, as the size of the imbalance between cells increases, the bms has to cut off the charge in order to protect the battery in accordance with the cell voltage at the top. A cell whose level gradually decreases can receive less and less charge from other cells in the long run. If the LFP battery applies a gradually decreasing HVC voltage such as 0.1 volts every month over the months, this is because the bms cannot compensate the charge of the cell with the lower charge in order to protect the cell with the highest charge voltage, and the low charge problem in this cell gradually increases over time.

To fix this problem, I cut the drop-in battery from the top and opened it. There was a bms in the battery that had no communication with the external environment. I connected the smart active balancer to the cells. With an active equalization charge lasting approximately 24 hours, the charge level of a cell that was out of balance was restored. Battery HVC was 13.7V, after active balancing, HVC became 14.5V.

As you can see, the sensitive charging cut-off settings, which are made considering that the HVC in the batteries will remain constant, need to change over time. As a result, two options emerge. Frequently checking the balance of the cells in your batteries or the charging cut-off settings of the chargers. I think it's better to check both. It seems more logical to choose a large battery pack and deal with a single cell array.

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.

[tanglewood]

Originally Posted by SOLAR SUPPORT

Over time, there is a balance problem between the series-connected cells that make up the LFP battery. There are many reasons for this and sometimes the bms can't fix these imbalances.

These batteries that we use on boats are not used as in a telephone or electric vehicle. On our boats, the batteries can be charged and discharged at the same time. Different charge sources such as mppt, ac-dc, alternator, generator are used without very precise control of the charge parameters of charge sources. In a phone or EV, the situation is very different and orderly.

It is not always possible for BMS to provide cell balance by passive balancing under these variable conditions. Accordingly, as the size of the imbalance between cells increases, the bms has to cut off the charge in order to protect the battery in accordance with the cell voltage at the top. A cell whose level gradually decreases can receive less and less charge from other cells in the long run. If the LFP battery applies a gradually decreasing HVC voltage such as 0.1 volts every month over the months, this is because the bms cannot compensate the charge of the cell with the lower charge in order to protect the cell with the highest charge voltage, and the low charge problem in this cell gradually increases over time.

To fix this problem, I cut the drop-in battery from the top and opened it. There was a bms in the battery that had no communication with the external environment. I connected the smart active balancer to the cells. With an active equalization charge lasting approximately 24 hours, the charge level of a cell that was out of balance was restored. Battery HVC was 13.7V, after active balancing, HVC became 14.5V.

As you can see, the sensitive charging cut-off settings, which are made considering that the HVC in the batteries will remain constant, need to change over time. As a result, two options emerge. Frequently checking the balance of the cells in your batteries or the charging cut-off settings of the chargers. I think it's better to check both. It seems more logical to choose a large battery pack and deal with a single cell array.

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?

[tanglewood]

I don't think the research supports a lot of what you are saying.

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.

Yes, this is certainly true, especially with respect to balancers that only run at elevated voltages.

Originally Posted by CaptainRivet

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.

This only makes sense to the extent that it provides more run time for a balancer. Otherwise there is nothing to suggest that cells need "time to settle" or to charge slowly.

Originally Posted by CaptainRivet

3)Discharge max. 0.3C, above cells start to differ strongly

Again, I don't think the research supports this.

Originally Posted by CaptainRivet

4)longer absobtion phase, this helps the cells balancing and also reduces delta voltage between cells

only to the extend that it allows a balancer to do a better job. For teh cells themselves I don't think it makes any difference at all.

Originally Posted by CaptainRivet

5)make sure your charge sources can deliver the voltage for HVC

Why? Isn't charging to HVC is exactly what you are NOT supposed to do?

Originally Posted by CaptainRivet

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.

If you are going to buy crap batteries, cut them open, then apply electronics to make them work correctly, why not start with bare cells in the first place?

[wholybee]

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?

IMHO, the need for active balancing is largely a myth that stems from DIY builds using cells from Alixxx that are factory rejects and quickly go far out of balance. You can buy a stack of reject grade B cells ultra cheap, and add an active balancer to make them work. Add to this that many of these people think they bought grade A cells, and the myth is born that new grade A cells need an active balancer.

The passive balancer built into the cheapest BMS is plenty enough if you have good cells to begin with.

[wholybee]

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.

Following his issue in another thread, I believe it was caused by long-term undercharging the battery. His bulk/absorption voltage was quite low. It never charged into the knee, and thus never balanced.

[wholybee]

Originally Posted by lateral

I thought the MC618 could be programmed with your phone or SG200? have one but not yet installed. Have the 614 as well but didn't fancy the magnetic pen in a seaway.
Edit:

I guess you don't have BT gateway.

The MC618 can be programmed with your phone only if you also have the SG200 and the Bluetooth thingy. If you prefer the Victron BVM, then you are stuck with the magnetic pen. And having to buy all three just to avoid the 30 year old magnetic pen trick is really expensive.