Thruster Battery Charging Considerations (??)

[Wotname]

With reference to the diagram, which is the better place to connect the 200A externally regulated alternator, the blue or the red and why?

Also is there significant a advantage in using the Cyrix or the Blue Seas isolator/combiner?

I can see advantages and disadvantages either way of connecting the 200A alternator but I could be missing something basic so what do the CF battery gurus say. I don't know the fine details of the Cyrix ct-230 or the Blue Seas ML-ACR to know which may be better.

The background - the house battery and all the charging sources already exist and there is no shore power available. The thrusters are recent additions and need a decent power source. The Vetus manual calls for a 1000 CCA battery. There is no appetite to add additional charging sources. House loads not shown.

Start battery and charging are totally independent and not part of the discussion.

[smac999]

well if you run the blue you will likly have over 500a through the acr when both thrusters are on. which is over rated on the acr and which will be very hard to fuse and cable.

if you use the red you'll need to put the balmar reg sense on the thruster battery instead of the house battery which may be less then ideal. and you will probably still have 200-300a through the acr.


how are you running a bow and stern thruster off the same battery? do they claim a 1000cca per thruster or for both? I'm guessing each. kinda defeats the point of a thruster bank since you will still have huge cable lengths to atleast one. if the house bank is mid ship i would add a battery in both bow and stern and use 2 acrs with the alt to house bank. so half the current through each acr. or just run both from the house bank and forget the thruster battery. if the house is in the stern I would add bow battery and run the stern thruster off the house bank. 1 acr to bow battery and half the current through acr then your 2 thrusters diagram.


I would also consider figuring out how to connect the SI input on the ACR to activate with the thruster so the acr(s) cut off while the thruster is in use to prevent the high currents in the charge line. this will let you run much smaller cable and fuses. though I don't think you could do that if running both thrusters off 1 battery. you'll need the surport from the house bank.

[Wotname]

Thanks smac999, you have given me plenty of food for thought.

I had figured that both thrusters would not be used together. If the owner wants to operate them simultaneously , I think he would need two seperate batteries etc.

You wrote "if you use the red you'll need to put the balmar reg sense on the thruster battery instead of the house battery which may be less then ideal. and you will probably still have 200-300a through the acr.".

In the ideal world, the sense of the balmar would be on the house battery but I am thinking it wouldn't be too bad if the balmar sensed off the thruster battery as the engine charging (200A alternator) is only used to bulk charge the house battery as required. Absorption charging of the house is mostly done by solar / wind / Honda (as appropriate).

Additionally (and please correct me if I am wrong in my thinking), when using the red option, the thruster will be drawing 400+ A, the alternator will be maxed out, the thruster battery supplying 200+ A with a terminal voltage of <13V so the ACR will be open.

[GreenWave]

Two comments - you will need more battery power... at least one per thruster for sure. I have similar bowthruster and use two batteries to get more juice to the motor. Also, you want the batts as close as possible to the thrusters.

[Wotname]

Originally Posted by GreenWave

Two comments - you will need more battery power... at least one per thruster for sure. I have similar bowthruster and use two batteries to get more juice to the motor. Also, you want the batts as close as possible to the thrusters.

Thanks for your input GreenWave. I'm curious as to what batteries you are using if you need two.

How do you charge your thruster battery or do you have good access to shore power and/or a permanent generator on board.

I understand your logic about keeping the battery close to the thruster however with sufficiently sized cabling, distance shouldn't be an issue. It becomes a trade off between convenience of battery location and price/weight/routing of heavy cable.

[smac999]

Originally Posted by Wotname

Additionally (and please correct me if I am wrong in my thinking), when using the red option, the thruster will be drawing 400+ A, the alternator will be maxed out, the thruster battery supplying 200+ A with a terminal voltage of <13V so the ACR will be open.

the acr has a 30 sec delay to connect or disconnect so it will be closed unless you hold the thruster for more then 30 secs then it would probably open. and because the house bank is much bigger then the thruster battery the house bank will supply a bunch of the curent to the thruster. depentant on cable length and size. so maybe 200 from alt, 100 from thruster batt and 100 from house battery.

but with both thrusters now you're 200 from alt, ~300 from bow and 300 from house.

and it definatlly needs to be able to handle running both thrusters at once. because somebody will do it at some point. you can't have fuses blowing and things failing "because you were not supposed to run both"

[smac999]

Originally Posted by Wotname

I understand your logic about keeping the battery close to the thruster however with sufficiently sized cabling, distance shouldn't be an issue. It becomes a trade off between convenience of battery location and price/weight/routing of heavy cable.

if you are not going to put the batteries near the thruster you may as well just run them off the house battery. add another battery to the house instead of adding another bank and making things more complicated.

is there also an engine battery?

[GreenWave]

Originally Posted by Wotname

Thanks for your input GreenWave. I'm curious as to what batteries you are using if you need two.

How do you charge your thruster battery or do you have good access to shore power and/or a permanent generator on board.

I understand your logic about keeping the battery close to the thruster however with sufficiently sized cabling, distance shouldn't be an issue. It becomes a trade off between convenience of battery location and price/weight/routing of heavy cable.

I will have to look up the info as I didn’t do the setup and don’t have it committed to memory. Will look for a wiring diagram as well. But for charging they are connected to the house charging system through an isolator so can charge from solar, shore or engine. My batts are in the forward cabin under the bunk and are about 6-7 feet from the thruster. It is a lot easier to run a charging cable 30 feet than heavy cable. They are AGMs but not as large as my house bank.

[Jammer]

Get rid of the ACR, they fail and create hard to troubleshoot problems that can leave you stranded.


Connect your engine alternator to the charge bus for the house bank just like you have the other charge sources


Use two thruster batteries, one as close as possible to each thruster

Use 12v-to-12v battery chargers for each thruster battery, like this: https://www.victronenergy.com/dc-dc-...t-non-isolated. Set them up so that they only operate when a charge source is available (genset/propulsion engine alternator/wind/solar in your case)

You will save money by avoiding expensive copper cable runs

You will be able to operate both thrusters at once

You will not melt your alternator because of a current hungry thruster

You will not have to oversize your house battery cables to deal with a current hungry thruster

You will not have to change much existing wiring

[Wotname]

Originally Posted by Jammer

Get rid of the ACR, they fail and create hard to troubleshoot problems that can leave you stranded.


Connect your engine alternator to the charge bus for the house bank just like you have the other charge sources


Use two thruster batteries, one as close as possible to each thruster

Use 12v-to-12v battery chargers for each thruster battery, like this: https://www.victronenergy.com/dc-dc-...t-non-isolated. Set them up so that they only operate when a charge source is available (genset/propulsion engine alternator/wind/solar in your case)

You will save money by avoiding expensive copper cable runs

You will be able to operate both thrusters at once

You will not melt your alternator because of a current hungry thruster

You will not have to oversize your house battery cables to deal with a current hungry thruster

You will not have to change much existing wiring

After much thought about all the various arrangements and their pros and cons, Jammer's advice appears to be the best electrically advantageous option and I will most likely follow this advice.

A big thank you to all thread respondents, each one helped to clarify my thoughts.

[Jammer]

Cool, post up after you've used it for a while and let us know how it worked out

[Wotname]

OK, the thruster batteries are installed (one at the bow and one at the stern) with a Victron DC-DC smart charger (12-12-18) for each.
They work very well and way better than previously.

But...

I have not been able decide on how best the program the DC-DC charger with respect to the 'engine shutdown detection' parameters.

Refer to this thread
https://www.cruisersforum.com/forums...ml#post3513508