Balmar 614 vs Li battery BMS cutout

[Britishsea]

Originally Posted by Philtao

Does anyone know how much current is carried by the ignition wire? My BMS relay outputs are fused at 2A (7A for 100ms) and it would be nice to use them directly without an intermediate relay.

Also does disconnecting the ignition has any impact on the tachometer out sender wire? (will I loose the tachometer reading?)

My BMS has a max 50ma internal relays and manages the Balmar brown wire just fine. I have a 12 volt system and use a 500ohm resistor in the above circuit path to protect the BMS's FET based relay from over current. This brings down the current to about 30ma and it still seems to be fine to control the Balmar brown wire. This assumes your red power wire to the Balmar always has power.

[Philtao]

Originally Posted by Britishsea

My BMS has a max 50ma internal relays and manages the Balmar brown wire just fine. I have a 12 volt system and use a 500ohm resistor in the above circuit path to protect the BMS's FET based relay from over current. This brings down the current to about 30ma and it still seems to be fine to control the Balmar brown wire. This assumes your red power wire to the Balmar always has power.

Thanks @Britishsea to confirm that. I actually did some testing yesterday and measured less that 100 mA on the brown ignition wire.

I also confirm that the tachometer does not work when the ignition wire is disconnected. But that is not a big deal as the 'hour meter" still works, and when you know your engine, the ear is a good enough measuring device.

[Philtao]

Originally Posted by Britishsea

This is exactly how I ended up putting my system together - which has been running now without problems for about 3 months. I have a BMS which allows me to disconnect the Balmar ignition sense wire (brown) at 3.55volts and a second master charge bus relay disconnect at 3.65 volts.

For those that do not have the knowledge to put their own system together, this is a standard feature of the TAO BMS used by @Fxykty (20 custom on/off thresholds - cell voltage, cell temperature or SOC - that can each command any of the 6 relay outputs)

[s/v Jedi]

Originally Posted by Philtao

Thanks @Britishsea to confirm that. I actually did some testing yesterday and measured less that 100 mA on the brown ignition wire.

I also confirm that the tachometer does not work when the ignition wire is disconnected. But that is not a big deal as the 'hour meter" still works, and when you know your engine, the ear is a good enough measuring device.

You are disconnecting at the wrong point. If you disconnect between regulator and ignition wire, everything works like normal. It sounds like you disconnect the ignition wire like if you turn the key to off.

[Philtao]

Originally Posted by s/v Jedi

You are disconnecting at the wrong point. If you disconnect between regulator and ignition wire, everything works like normal. It sounds like you disconnect the ignition wire like if you turn the key to off.

I disconnect pin 3 (brown wire) on the regulator so that it is not powered by the ignition key (ignition key still on).
It keep counting running hours, but tachometer stays on zero.

Which other pin number do you suggest I disconnect so that everything works like normal?

[s/v Jedi]

Originally Posted by Philtao

I disconnect pin 3 (brown wire) on the regulator so that it is not powered by the ignition key (ignition key still on).
It keep counting running hours, but tachometer stays on zero.

Which other pin number do you suggest I disconnect so that everything works like normal?

If your tachometer stops working when you disconnect the regulator then you have a tachometer that uses the alternator to count revelations. There’s nothing you can do to make that work with the alternator disabled.

Other engines have a sensor that counts the teeth of a flywheel turning and keep showing tachometer without the alternator… except when ignition key is turned off which disables all gauges and alarm signal lights and sounds.

[tgarrett16]

I have read this entire thread and there is some great (albeit frustrating) information so thanks to all that contributed. I just purchased 2 Renorgy 12V 200AH batteries to replace my LA house bank (sailboat no gen-set) . When I install them I will also instal a new AGM starting battery. I had planed on programing my older MC-614 regulator with a lithium profile but after learning more about the two pronged threat of the BMS shutting down the input charge and the potential damage to the alternator and electronics on the house banks I think I will have the alternator charge the AGM starter and get the largest amp battery to battery charger i can find (so far it is Renorgy's 12V 60amp). I will program the MC-614 with an AGM profile. The advantages of this set up obviously eliminate the two aforementioned threats if the alternator is wired to the Lithium house bank. However I want to make sure I understand the disadvantages of this set up. As I understand it because I will have the MC-614 programed for an AGM set up, the regulator will limit the voltage to a value less than optimum for LiPo4 and therefor a 100% SOC may be more difficult to achieve from alternator charging alone. Is this assumption correct?

The second question I have relates to the solar and wind i am installing. I will have 525W of solar and a wind generator both with their own charge controllers. We intend on going cruising and plan on our primary source of charging will be wind and solar. Because of this I want to utilize the charge controllers LiPo4 charging profiles connected to the LiPo4 House bank. The max combined charge amps from both of these sources is 55 amps with 20-30 being much more common. Do I still have to worry about a voltage spike if the BMS shuts down the battery accepting charge from the solar and wind like we did with a high output alternator. If so, is it advisable to also wire the wind and solar to the starter side and utilize the battery to battery charger to charge the Lithium? The disadvantage being that the charge controllers would also need to be programed for AGM and then not being able to charge the LiPo4 as efficiently. If if is ok to wire the solar and wind charge controllers to the LiPo4 house bank can I install a smaller batter to battery (victon 12/12/18 orion) charger to go from the lithium to the AGM to keep the starter topped up. I assume there are diodes in the dc to dc chargers or will having 2 charge controllers create problems?

Thanks in advance! If anyone has any suggestions for my setup please let me know as the only items I have purchased so far are the LiPo4 batteries. I already have the Balmer regulator. I have a morningstar MPPT controller and a Magnum MagnaSine charger inverter (not sure which side I will wire this to yet)

[Philtao]

Hi, this is Philippe from Tao BMS. Unfortunately you are very much constrained by your choice of drop-in batteries. But you can make it work for the alternator as you suggest.
The DC/DC charger will charge the lithium battery based on the way you program it (lithium). It is independent from the alternator regulator settings (lead-acid). Just make sure the voltages for the selected charger are what you need for input and output.

For the solar and wind, it all depends on your equipment and the way it is protected. for example the notice for the Victron MPPT specifies that the solar panels must be disconnected from the regulator before disconnecting the battery.
So you need to check the recommendations from Morningstar and the manufacturer of the wind regulator.

You could also use the output of a battery monitor (like Victron BMV7xx) to command a relay between solar panels and MPPT regulator (and stop the wind generator) based on a battery voltage (or SOC if you can trust it). That would work if the cells are well balanced across the two batteries and there is some margin between the battery monitor cut-off and the BMS cut-off.

Other way to do it is to always have the AGM battery connected to the lithium and set all regulators for lithium. This way the regulators will always have a battery to charge when the BMS disconnects the lithium, and the AGM will always be trickle charged and stay full. But what you have to worry in that case is when the lithium battery gets fully discharged... it will also discharge the AGM starter battery and you won't be able to start your engine. Maybe in that case use a different lead-acid battery to be in parallel with the lithium and charge the starter battery with a DC/DC charger?

Too ate for you, but for other readers the lesson from that could be to do the planning before buying drop-in batteries and realizing afterward the head hake it can create if you want to do it right (another point to consider if your drop-in batteries do not give advanced warning before shutting down the power, is that could lead to dangerous situations on a boat).

[s/v Jedi]

Originally Posted by tgarrett16

I have read this entire thread and there is some great (albeit frustrating) information so thanks to all that contributed. I just purchased 2 Renorgy 12V 200AH batteries to replace my LA house bank (sailboat no gen-set) . When I install them I will also instal a new AGM starting battery. I had planed on programing my older MC-614 regulator with a lithium profile but after learning more about the two pronged threat of the BMS shutting down the input charge and the potential damage to the alternator and electronics on the house banks I think I will have the alternator charge the AGM starter and get the largest amp battery to battery charger i can find (so far it is Renorgy's 12V 60amp). I will program the MC-614 with an AGM profile. The advantages of this set up obviously eliminate the two aforementioned threats if the alternator is wired to the Lithium house bank. However I want to make sure I understand the disadvantages of this set up. As I understand it because I will have the MC-614 programed for an AGM set up, the regulator will limit the voltage to a value less than optimum for LiPo4 and therefor a 100% SOC may be more difficult to achieve from alternator charging alone. Is this assumption correct?

The second question I have relates to the solar and wind i am installing. I will have 525W of solar and a wind generator both with their own charge controllers. We intend on going cruising and plan on our primary source of charging will be wind and solar. Because of this I want to utilize the charge controllers LiPo4 charging profiles connected to the LiPo4 House bank. The max combined charge amps from both of these sources is 55 amps with 20-30 being much more common. Do I still have to worry about a voltage spike if the BMS shuts down the battery accepting charge from the solar and wind like we did with a high output alternator. If so, is it advisable to also wire the wind and solar to the starter side and utilize the battery to battery charger to charge the Lithium? The disadvantage being that the charge controllers would also need to be programed for AGM and then not being able to charge the LiPo4 as efficiently. If if is ok to wire the solar and wind charge controllers to the LiPo4 house bank can I install a smaller batter to battery (victon 12/12/18 orion) charger to go from the lithium to the AGM to keep the starter topped up. I assume there are diodes in the dc to dc chargers or will having 2 charge controllers create problems?

Thanks in advance! If anyone has any suggestions for my setup please let me know as the only items I have purchased so far are the LiPo4 batteries. I already have the Balmer regulator. I have a morningstar MPPT controller and a Magnum MagnaSine charger inverter (not sure which side I will wire this to yet)

I don’t know the dc-dc converter you plan to use but I do know the Smart Orion from Victron and this will charge your 12V or 24V lithium house bank perfectly from a 12V alternator + starting battery. It will auto detect the alternator spinning and take 30A from it to charge the house bank. If you have 60A available then you can install two in parallel. Make sure ipthey are the smart versions though.
Other dc-dc converters may have the same features, I am simply not familiar with them.

[Britishsea]

Originally Posted by Philtao

Hi,

Other way to do it is to always have the AGM battery connected to the lithium and set all regulators for lithium. This way the regulators will always have a battery to charge when the BMS disconnects the lithium, and the AGM will always be trickle charged and stay full. But what you have to worry in that case is when the lithium battery gets fully discharged... it will also discharge the AGM starter battery and you won't be able to start your engine. Maybe in that case use a different lead-acid battery to be in parallel with the lithium and charge the starter battery with a DC/DC charger?.

All great points above.

Why not install a battery isolator (like a Victron Argofet) and charge the drop-in LFP directly from the Balmar 614? They are relatively cheap. That way you will always have a AGM start battery as load-dump in case your LFP bank were to disconnect, but not risk your LFP bank bringing down your start battery. Much more efficient than a DC-DC charger. Those DC-DC chargers get very hot and tend to work intermittently at idle engine RPM unless sized very conservatively.

All charge sources could go to the battery isolator, but I would consider some logic (relay) with a manual over-ride, so that the AGM battery is only connected to battery isolator when the engine ignition is on, that way you are not constantly charging your full AGM start battery at a highish voltage with solar/ wind.

Philtao, really covet your BMS. Great design and features. It's on the top of my list for a replacement for my current one.

[Philtao]

I am not familiar with the Argofet as I avoid adding hardware, connectors and cables between the chargers and the batteries. But looking at the specs, and if the voltage drop is only 0.1 volt at full load, that sounds like a great idea...

Maybe those who know / use the product can tell us more about it. My concern is about the sentence: "Voltage drop... averages 0,1 Volt at higher currents". It does not give much info on actual resistance / voltage drop of the FET or power dissipation at maximum load. The product looks like a heat sink, so it makes me think it needs to dissipate more than 10W (0.1 v * 100 A). How hot does it gets at 80% of max load, and what is the actual voltage drop?

I see your point about a relay to connect the AGM battery to the isolator so that it gets charged only when the engine runs. But what happens if the BMS disconnects the lithium battery when charging with solar or wind? I guess the regulator will see an open circuit - some regulators may accept it, some may not.
I still think a BMS that commands lathing relays is the best and most flexible answer... but I may not be fully objective ;-)

[Britishsea]

Originally Posted by Philtao

I am not familiar with the Argofet as I avoid adding hardware, connectors and cables between the chargers and the batteries. But looking at the specs, and if the voltage drop is only 0.1 volt at full load, that sounds like a great idea...

Maybe those who know / use the product can tell us more about it. My concern is about the sentence: "Voltage drop... averages 0,1 Volt at higher currents". It does not give much info on actual resistance / voltage drop of the FET or power dissipation at maximum load. The product looks like a heat sink, so it makes me think it needs to dissipate more than 10W (0.1 v * 100 A). How hot does it gets at 80% of max load, and what is the actual voltage drop?

I see your point about a relay to connect the AGM battery to the isolator so that it gets charged only when the engine runs. But what happens if the BMS disconnects the lithium battery when charging with solar or wind? I guess the regulator will see an open circuit - some regulators may accept it, some may not.
I still think a BMS that commands lathing relays is the best and most flexible answer... but I may not be fully objective ;-)

Philtao,

you are right to be sceptical of Victron's vague claims around voltage drop. I find the company lacking in transparent specs for a lot of their products (this in comparison to a company like Blue Sea).

However, i think the FET based battery isolators are at least a significant improvement over their diode based siblings. I deliberately oversized my 220 Amp Agrofet for my 110amp alt for this reason. I have never felt it get warm and voltage drop at 70 amps is around 0.2v. This despite the sub-par lug terminals they use (too small). I can't vouch for its long term durability, as I have only had it for about a year.

I believe Mastervolt also makes a Fet based battery isolator and perhaps there are others.

The Balmar 614 has a dedicated volt sense wire, so any voltage drop across the battery isolator can be compensated for by the regulator. Anyway, it's certainly less heat loss than the 80ish% efficacy of a DC-DC charger.

Would need to also factor the length of your LFP charge wire runs to determine what voltage the AGM start battery would see.

I'm not expert on this subject . Just a hobby for me. Also i have never tried drop-in LFP batteries (i have raw cells) which seem to want a higher charge voltage than raw cells, depending on the BMS being used internally ... so take the all the above with a grain of salt.


I have linked this before, but i like Stan Honey's notes on this topic and stole many ideas from him (battery isolator, thermal cut-off fuses attached to each cells, Balmar settings, etc)

http://honeynav.com/wp-content/uploa...oney-notes.pdf

[Jim Cate]

The evil goblins of the internet closed this thread yesterday and indicated that I did it!

Dunno how this happens, but I'm sorry if it inconvenienced anyone... thread now open for further discussion.

Jim

[Philtao]

Originally Posted by Britishsea

I deliberately oversized my 220 Amp Agrofet for my 110amp alt for this reason. I have never felt it get warm and voltage drop at 70 amps is around 0.2v.

Thank you for the real life experience feedback. That is a reasonable internal resistance of 3 milliOhm and a useful product.

[s/v Jedi]

Originally Posted by Philtao

Thank you for the real life experience feedback. That is a reasonable internal resistance of 3 milliOhm and a useful product.

A power MOSFET has about a 150mOhm drain-source resistance in it’s on-state. A cable crimp connection is about 15mOhm.