Using LFP to Power Bow Thruster

[Nicholson58]

Originally Posted by Paul Allen

Is anyone actually using LFP batteries to power their bow thruster? If so, what is your set up - specifically, how were you able to accommodate the in rush current?

We have Blue Heron LFP 710 AH at 24 volts. The package includes two ‘mixed use’ 12 volt LFP (series 24 volts) with internal BMS in parallel with the LFP house bank. The combo is designed to start our Westerbeke 115 horse 6 cylinder. Max inrush 180 amps. Not a bow thruster but I think the same concept could work.

Contact Hank George, Blue Heron rep. Tell him Roxy sent you.
hank@starboardlanding.com

[ikebartlett]

Manufacturers like LiTime have produced lithium starter batteries, I have one on my 6 cylinder Perkins diesel. I might look in that direction for your situation. I did the lead acid to lithium upgrade for my house load, but, then I had 2 different charging profiles. With the lithium starter battery that issue is resolved. Charging, whether solar, engine alternator or battery charger while hooked up to shore power are all done with lithium charge profiles.

[dougkimmerly]

I run the bow thruster off of the lithium bank and have done so for about five years now. Large bank 24kwh 6kw bow thruster. All Victron I have the Victron VEBus BMS and Victron batteries. The only issue I’ve had is early on blowing the fuse to the thruster, put in a bigger fuse and I try to remember to parallel the AGM starter battery before using the thruster but most of the time I forget.

Really no issues at all.

[Sjoerd02]

The bow truster was already on the 2x160ah lead service battery using 90mm2 cables from aft cabine.
We switched to LFP 2 year ago and choose own build using 2p4s EVE 230 cells and Daly 750A BMS
So far working flawless measuring 350A on the BMS
Bowtruster is a 5KW sleipner.


Had initial bought 2x 200 JK BmS but it could be possible most power will go through a single BMS instead of spreading the load equally. So switch to the 750A single one.

[Fuss]

Originally Posted by Sjoerd02

The bow truster was already on the 2x160ah lead service battery using 90mm2 cables from aft cabine.
We switched to LFP 2 year ago and choose own build using 2p4s EVE 230 cells and Daly 750A BMS
So far working flawless measuring 350A on the BMS
Bowtruster is a 5KW sleipner.


Had initial bought 2x 200 JK BmS but it could be possible most power will go through a single BMS instead of spreading the load equally. So switch to the 750A single one.

Yep, those Daly BMS’s… they are the business… you can’t beat them!!!!

Dockhead… make the one phonecall to Sleipner… all will be clear and you can connect your bow thruster to your new lifepo4 housbank…

[Loredo]

Jedi,a pic tells everything I think.

[ranger58sb]

Has anyone looked closer at the Solid State products?

https://solidstatemarine.com/

-Chris

[CaptainRivet]

Originally Posted by Loredo

I have a 10 KW bow thruster which is powered by a (dedicated) 80Ah @ 24V LTO battery. NO BMS but a 4A Neey balancer. Charged through a DC-DC from the LFP house bank. The 6KW stern thruster has a 40AH @ 24V LTO instead. Both work wonderfully with the LTO's.
Using the house bank would've been possible since I've got 1700Ah @ 24V but the cables would've need to be massive since the house bank is about 35 feet from the bow thruster. Twas easier to build the LTO bank...

That’s the perfect solution for a bowtruster/windlass bank.
Lifepo4 also works but you need either a contactor BMS like Electrodacus, REC, Victron lynx… or several 300A JK BMS in parallel so the possible worst case inrush when eg the truster is blocked by a fishing line is covered.

Be aware that not all thrusters work with lithium as several especially older ones use eg the peukert effect of lead as limiter and if you use these with lithium you burn their windings. So ask your manufacturer before you run them on lithium, some need rewinding and some have an external limiter to make it lithium compatible and some just work.

[CaptainRivet]

Originally Posted by Sjoerd02

The bow truster was already on the 2x160ah lead service battery using 90mm2 cables from aft cabine.
We switched to LFP 2 year ago and choose own build using 2p4s EVE 230 cells and Daly 750A BMS
So far working flawless measuring 350A on the BMS
Bowtruster is a 5KW sleipner.


Had initial bought 2x 200 JK BmS but it could be possible most power will go through a single BMS instead of spreading the load equally. So switch to the 750A single one.

Well 5kw will be around 800-1000A surge current for milliseconds or seconds if a fishing line blocks the truster.

Wrong call, 2x300A JK would have been the right one. That Daly will fail….1000% sooner then later.

[CaptainRivet]

Originally Posted by Loredo

Jedi,a pic tells everything I think.

Good Yinglong LTO, we tortured these cells in car audio like there is no tomorrow. No other chemistry survived that what these cells power flawlessly and reliably.
That’s the right call and the neey active balancer is also your cell voltage supervising device.
You can get the Toshiba scib for a steal at the moment at battery hookup, 40AH 27.8V or 24 cells easily reconfigured to 80AH 14V for 200$ that can easily power a 7kw truster. Cheaper then lead…

[CaptainRivet]

Originally Posted by Nicholson58

We have Blue Heron LFP 710 AH at 24 volts. The package includes two ‘mixed use’ 12 volt LFP (series 24 volts) with internal BMS in parallel with the LFP house bank. The combo is designed to start our Westerbeke 115 horse 6 cylinder. Max inrush 180 amps. Not a bow thruster but I think the same concept could work.

Contact Hank George, Blue Heron rep. Tell him Roxy sent you.
hank@starboardlanding.com

Wrong, a 6 cyclinder will have never 180A inrush, that’s the permanent current of the starter. In best case you are somewhere between 600 and 800A for the first milliseconds. 180A sounds like a 2000W starter and that’s what you can expect. To measure that inrush you need either an expensive fluke meter or an oscilloscope, a normal meter or BMS won’t be able to capture that.
Be happy your BMS supports that.

[Sjoerd02]

Originally Posted by CaptainRivet

Well 5kw will be around 800-1000A surge current for milliseconds or seconds if a fishing line blocks the truster.

Wrong call, 2x300A JK would have been the right one. That Daly will fail….1000% sooner then later.

Based on what both statements?
- how is it guaranteed both BMS take the current equally, resistance diff and voltage drop would be extremely small so could be 80-20% as well !?

I could not find the max inrush current specs for the JK


- have the Daly running now 2nd season including morning line in the thruster blocking it completely but freeing is by short bursts reversed and survived so far.
The continuous max current is at least twice compared to the JK.


When I was building the LFP the largest JK was 200Amps (according to my reseller).

[Wandering1]

Originally Posted by Sjoerd02

Based on what both statements?
- how is it guaranteed both BMS take the current equally, resistance diff and voltage drop would be extremely small so could be 80-20% as well !?

I could not find the max inrush current specs for the JK


- have the Daly running now 2nd season including morning line in the thruster blocking it completely but freeing is by short bursts reversed and survived so far.
The continuous max current is at least twice compared to the JK.


When I was building the LFP the largest JK was 200Amps (according to my reseller).

You will never see 80/20 split on current from two identical lithium batteries.
Jk do 300A continous load bms now. You can still buy the 200A version.
The JK B2A8S30P 300A BMS can handle 500A for 2 minutes.

[GordMay]

Originally Posted by rslifkin

Even then, the nature of a variable speed drive should have a dramatically smaller inrush. It would effectively be a very quick ramp up to full power, rather than starting the motor from a stop by just dumping full voltage to it instantly.

A variable speed drive [VSD], also known as a variable frequency drive [VFD], controls the acceleration, and deceleration, of a motor by adjusting the time it takes to reach a target speed [ramp-up] or return to a stop [ramp-down].
The time for ramp-up is configurable, and can be adjusted to suit the specific application, typically ranging from a few seconds to over 120 seconds.

“Variable frequency drive Ramping” ➥ Variable frequency drive Ramping.

[s/v Jedi]

Yes, VSD / VFD is the bees knees and in the future everything will use that, but the marine industry is severely lagging for this. Look at marine A/C where still the majority of cruisers doesn’t realize the difference while ashore every split unit has used this for years.

There is no inrush anymore.