Balmar 614 vs Li battery BMS cutout

[Karanga]

I have a pre-2017 Balmar 614 regulator controlling a Balmar 180amp alternator and I am considering swapping my AGM house battery bank with Lithium.
I know I can modify the 614 charging profile, but I do wonder if it is possible for the internal BMS to ever disconnect the battery from the charging, and thereby potentially cause damage to the alternator. The Balmar notes do mention this as a risk, but is it a realistic risk?
If I set the max (absorption and float) charge to 13.8v, would this mean that the batteries are never quite full so the BMS is less likely to disconnect?
Tim

[s/v Jedi]

Originally Posted by Karanga

I have a pre-2017 Balmar 614 regulator controlling a Balmar 180amp alternator and I am considering swapping my AGM house battery bank with Lithium.
I know I can modify the 614 charging profile, but I do wonder if it is possible for the internal BMS to ever disconnect the battery from the charging, and thereby potentially cause damage to the alternator. The Balmar notes do mention this as a risk, but is it a realistic risk?
If I set the max (absorption and float) charge to 13.8v, would this mean that the batteries are never quite full so the BMS is less likely to disconnect?
Tim

No, you need to be able to cope with that event. I recommend an AGM battery as starter battery and to deal with this. You can use a Victron ArgoFET connected to the alternator and the two batteries to it’s outputs. When the BMS disconnects, the alternator keeps charging the AGM.

When you change the regulator settings to Lithium, this would under-charge the AGM. A way around this is to leave it at AGM settings and just connect the AGM battery without the ArgoFET, then use one or more DC-DC converters (Orion-tr Smart) to convert that to Lithium charge profile. Each one can do 30A at 12V.

Also, that last option allows you to change to a 24V house bank because you can use a 12 -> 24 DC-DC converter. Of-course this requires a 24V inverter/charger as well.

[markcouz]

I am sitting with a similar issue, and am considering putting a small 7ah alarm battery in parallel as a permanent (never disconnected) load. I don't think the alternator cares how small the load is, so long as there is something there in the event of a BMS disconnect.

[Karanga]

Wow!
That seems like a remarkable simple (and cheap!) workaround, if it could work.
Do any of the experts have views on the viability of this?
It feels so frustrating to have all this amazing technology and power available, yet it is still so poorly managed. Maybe we haven't got past early adopter stage yet...

Originally Posted by markcouz

I am sitting with a similar issue, and am considering putting a small 7ah alarm battery in parallel as a permanent (never disconnected) load. I don't think the alternator cares how small the load is, so long as there is something there in the event of a BMS disconnect.

[markcouz]

If your BMS cuts off at the very low final charge current then the 7.5ah would comfortably handle being a replacement load.

If the BMS cuts off at a high current (short cct etc) then the small battery may not handle the inrush current while regulator adapts to lower load - if you anticipate this then a small vehicle start battery might better suit your needs.

[smac999]

Internal bms is for cheap jobs. Any good install would have an external bms. And that external bms would cut the ignition power Feed to the balmar reg.

Yes you are right. Lithium is still in devoplent stage. And has a way to go.

The bms only cuts out on a problem. High / low voltage, low temp. Etc. It does not cut out at full batteries. So if you lucky. It will never shut off..,

[Riddle]

Another issue could be very high charging currents with lithium.
Balmar rating maybe 120 amp, but never for prolonged time and not in a warm (hot) engine room. The simplest way to prevent these high currents is to have a very small resistor (rheostat) in the circuit that makes the Balmar think that it is charging voltage is slightly higher then the actual voltage at the battery terminals.

And indeed the "better" but more expensive way is to have a proper DC/DC converter for charging the Lithium bank. For instance the Macplus from Mastervolt

[Cbcruiser]

My BattleBorn Lithium instructions recommend reducing the Balmar charge rate to 50% of max.

[markcouz]

Originally Posted by Riddle

Another issue could be very high charging currents with lithium.
Balmar rating maybe 120 amp, but never for prolonged time and not in a warm (hot) engine room. The simplest way to prevent these high currents is to have a very small resistor (rheostat) in the circuit that makes the Balmar think that it is charging voltage is slightly higher then the actual voltage at the battery terminals.

And indeed the "better" but more expensive way is to have a proper DC/DC converter for charging the Lithium bank. For instance the Macplus from Mastervolt

EISH! (a versatile Saffer word covering amazement, horror confusion etc)


I would guess that the Balmar 614 being a costly piece of kit would have programmable voltages and current limiting to suit LiFePO4 - if it doesn't then find something that does!

[LeaseOnLife]

Also be aware, with the Balmar 614, the target voltage to transition from bulk to absorption charge is a minimum of 14.1V. It will stay in bulk for almost forever, since the LiFePo4 will suck all the power they get and the Voltage won't get to 14.1V until (too) full. I find 14.1V too high for my Lithiums ....

[smac999]

Originally Posted by Riddle

Another issue could be very high charging currents with lithium.
Balmar rating maybe 120 amp, but never for prolonged time and not in a warm (hot) engine room. The simplest way to prevent these high currents is to have a very small resistor (rheostat) in the circuit that makes the Balmar think that it is charging voltage is slightly higher then the actual voltage at the battery terminals.

And indeed the "better" but more expensive way is to have a proper DC/DC converter for charging the Lithium bank. For instance the Macplus from Mastervolt

that is what the belt manager is for. it limits the max current. trying to fake a $500 peice of gear defeats the whole point of buying the best one.

[smac999]

Originally Posted by LeaseOnLife

Also be aware, with the Balmar 614, the target voltage to transition from bulk to absorption charge is a minimum of 14.1V. It will stay in bulk for almost forever, since the LiFePo4 will suck all the power they get and the Voltage won't get to 14.1V until (too) full. I find 14.1V too high for my Lithiums ....

the mastervolt and victron lith batteries both want over 14.1v bulk

interesting it't can't go below that. I have never tried. I wonder if the newer ones do. (2018 manual says 14.1 lowest)

[Karanga]

This borders on the ridiculous.

I have got a large frame, high capacity, good quality alternator - not cheap...
I have got a good quality external regulator - not cheap...
I am considering upgrading from agm to Lithium - certainly not cheap...
But to do this, probably means I have to add in a decent quality (not cheap - cos ya wouldn't want to go low-budget-quality, right?) DC-DC charger!! Sheesh!

It kinda makes it look like running my diesel generator (at about 1 litre per hour) and 120amp charging system for half an hour each morning and evening to top up the existing agm, is by far the cheapest option for a long time yet.

It is so good to have decent experts weigh in on these subjects, with great information, to put things into perspective. Thank you.
Tim

[markcouz]

You don't need the DC-DC charger, the Balmar 614 can be setup to charge your batteries with a lithium profile.

Read your manual and get the temperature sensure which will derate the alternator if it gets too hot - no drama!

Your lithium bank will be over 95% charged at 14V, if it takes some time to reach 14.1V who cares- your batteries will charge very fast to a very high SOC, much faster than your previous lead acid.

The only precaution I would take is to have a directly connected load that can handle an input surge in the unlikely event that the Lithium BMS disconnects at high current - i plan to use a 7.5ah batt, for you i would suggest the smallest vehicle start battery that you can find (in fact i might do the same thing to err on the side of caution).

[Karanga]

Just to follow up on this, FYI.

I have installed 3 x 200 A/hr lithium batteries, plus a 20 A/hr small car starter lead acid battery in parallel. The lead battery circuit has a separate isolation switch, so that it can be disconnected from the rest of the battery bank, if desired.
So far, the system is working very well. Charging via genset at 120amps gets the batteries full. This has temperature sensor monitoring
Charging via Balmar 180amp alternator and 614 regulator is going well and gets to full charge. This also has a battery temperature sensor. Plus I have derated the belt loading to setting of 3 (as per Balmar instructions), but I have left the charging profile the same as it was for the old AGM batteries. (good/bad?).

Discharging is going really well. I haven't gone below about 75% so far, and easily make 2 cups of coffee via the inverter each morning before any solar charging kicks in.
The battery monitoring kit has now become much more important to indicate state of charge, because the voltage sits permanently at 13.25 (not the slow decrease seen with lead batteries).
Importantly, the small lead acid battery appears to make no difference at all to the charging or discharging performance. However, because it can provide approx 400 CCA of starting power, it must be contributing significantly to the anchor windlass, plus the diesel genset starting (off the house bank).
I am assuming that the lead battery is available to serve its primary purpose of creating an emergency amp sink if ever the lithium BMS disconnects the batteries during high rates of charge from the alternator via the 614 regulator. I don't really want to test this...

Tim