Dedicated thruster battery - thoughts?

[DougSea]

Has anyone added a dedicated battery for their bow thruster?

I get a huge voltage drop when using the thruster - and of course usually when I'm using it I really need it.

I've been considering adding a new battery forward to keep the run from the battery to the thruster as short as possible. Installing that's all pretty straight forward. What I'm wondering about is how folks did/didn't use the existing large gauge cables that run from the main batteries. One possibility is to add a 1/2/1+2 battery switch forward and have the ability to tie the forward battery to the existing. (New battery would be #1, cables from house would be #2)

Another possibility is to "abandon" the existing wire and install a dedicated charger and treat the thruster as an independent entity. An advantage with this is I could use an AGM, with its better vibration resistance, forward, while leaving the house as Lead Acid.

A final option is similar to the last one but use an ACR to charge the thruster battery from the house bank.

I'd love to hear what others have done.

[Pitou]

Hey Doug .. This may be a much simpler solution for you:

Try moving your Thruster Feed Wire from the House Bank to the Start Bank.

Three years back I had a different issue when using my Thruster:
My electronics would drop out when the thruster was engaged so I added a Newmar Start Guard. Electronics drop out solved. A lot of this was because of how Albin had wired the boat. The Electronics, Thruster and Windlass were all fed from the House Bank which was 1 - 8D. Adding the Start Guard was the quick fix as opposed to isolating everything at the time.

Fast forward to the following year and isolation. The House Bank was upgraded to 6 golf cart batteries in series and parallel, Start Bank upgraded from 1 – 8D to 2 Grp 31’s in parallel and generator is 1-Grp 31 which could easily be a Grp 28. Batteries are now isolated with the 1-2-Both Switches being replaced with the House now having a simple Off/On (with an ACR) and can be combined with Start Switch, the Start with Off/On/Combine and ACR. The Generator now stands alone with an Off/On and charges by its own alternator or the AC charger.

When I did this isolation project I took the Thruster and Windlass feeds from the House Bank and moved them to the Start Bank since these two loads are only run when the engine is running with its high output alternator charging the Start battery. Just moving the Thruster Feed Wire may resolve your problem and I would give it a try.

Here are some pictures of the new switched and how they are wired:

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[Paddy]

Thanks to the previous owner, I have what I call overkill. He installed 2x 4D interstate house batteries that the thruster is connected to, plus an optima blue top starter battery. The 4Ds were dated 4/11 and finally died last November. I like overkill, so I replaced the 4Ds with new interstate batteries. I rely on the thruster too much not to have the battery backup, so I happy with the current setup.

[RobS]

Kevin,
Drinking rum when rewiring your boat makes for creative labeling !

Doug,
If you do as Kevin says make sure your alt & start battery (or bank) can handle the thruster draw as you do not want to solve one issue and create another... your Volvo's are electronic so you don't want a voltage drop that could result in an ECM drop-out.

[Pitou]

Kevin,
Drinking rum when rewiring your boat makes for creative labeling !

I was wondering who would pick up on that "combine wire" first .. one has to have a sense of humor!

If you do as Kevin says make sure your alt & start battery (or bank) can handle the thruster draw as you do not want to solve one issue and create another... your Volvo's are electronic so you don't want a voltage drop that could result in an ECM drop-out.

No ECM drop-out on the Cummins QSQ.

[RobS]

No ECM drop-out on the Cummins QSQ.

Yup, just not sure what Doug has as to his crank battery(s) and alternator output...

[DougSea]

All good info gents! I'll be taking a look at all of the battery wiring as I'm also replacing my battery charger. For the second time...

I'll post more as I go.

Now...where's the rum?

[RobS]

Why the premature battery charger failure?

And the next topic ----- "Bow thruster with twin screw inboards?"

I've seen twin gassers with baby props need some good throttle to make the boat respond but twin diesels with big props are quite responsive. And thinking about it, it sure seems the thruster would be more of a distraction from working the controls the way they should be worked.

[DougSea]

Why the premature battery charger failure?

Don't know. And it's annoying. I put in a ProMariner ProNautic P 1260 several years ago but it is now putting out no power and showing a fault of "low input voltage". (Interesting spec - it's supposed to handle voltages down to 100vac) Naturally I've checked all connections and AC voltages. It's not the boat.

And the next topic ----- "Bow thruster with twin screw inboards?"

I've seen twin gassers with baby props need some good throttle to make the boat respond but twin diesels with big props are quite responsive. And thinking about it, it sure seems the thruster would be more of a distraction from working the controls the way they should be worked.

Sigh...

Sometimes a timely shove at the bow is a helpful thing. Especially with a First Mate who isn't moving as fast as she used to.

NO SHAME!!

[RobS]

Yup, just like all those bells/whistles in the fancy cars we drive --- not really "needed" but surely nice to have !

And, no fair, you cannot blame your docking woes on Kat when she's not here to provide her defensive .... we shall reconvene on this in late June when all parties are present!

As to the charger, maybe the manufacturer will offer some assistance/replacement even though it's out of warranty but still fairly new. If you end up shopping, I put in a Marinco Charge Pro for my 2 cranks and the genset battery 3 years ago and am quite happy with it.

[Pitou]

Now...where's the rum?

When working with electricity (or firearms) the rum comes out when the day is done!

The ProMariner 1260.P that I put in two years ago when I did that wiring project has been working flawlessly .. expecting that to continue. I also wired a remote display and utilized a temperature shunt to the battery bank. Even though the 1260 can handle three banks, I chose to utilize it as an isolated charger for the House Bank only and kept the original ProNautic to charge the Start Bank and Genset Battery. So far so good. Thankfully my woes are now all squared away. BTW - same company just different generations of the charger. As Rob said, give them a call. When I was setting up my new DC refit they were super helpful over the phone and they're fairly local .. New Hampshire.

If you decide to add another battery for the thruster and decide to go with an Off/1/2/BOTH switch , I've got a Blue Seas part#9001E with your name on it .. it's on me .. I owe you!

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[Pima]

Hi Kevin --

Your solutions to the thruster issue and to the D8 battery issue look real good. I also have a 31TE and have had battery problems for the 3 years that I have owned her, so your solution looks excellent!

I also like the way you have reconfigured the battery switches, as I have never been comfortable with the original Albin arrangement.

A couple of questions concerning your wiring of the ACR:
1. I noticed that you did not wire the ACR directly to the batteries, but to the other sides of the two battery switches. Is this to really isolate the two battery banks when the two switches are off so that one bank would not discharge the other if there was an issue?
2. There's a good article ("Making Sense of Automatic Charging Relays") on the website Marine-How-To that discusses use of the Blue Seas ACRs that suggests that the alternator should be attached to the House bank, not the Engine bank for the reason that the House bank is apt to be discharged more than the Engine bank; if you wire the alternator to the Engine bank, than the ACR may have to carry almost the full alternator current to charge the House bank. If the alternator is wired to the House bank, then the ACR does not need to carry much current to charge the Engine bank. Did you wire to the Engine bank because you connected the Thruster and the Windlass to the Engine bank switch and didn't want to run that extra current through the ACR?

Thanks,

[Pitou]

Hi Kevin --

Your solutions to the thruster issue and to the D8 battery issue look real good. I also have a 31TE and have had battery problems for the 3 years that I have owned her, so your solution looks excellent! I had 3 years of trouble too, thus the the changes.

I also like the way you have reconfigured the battery switches, as I have never been comfortable with the original Albin arrangement. The new switching and Blue Seas SI-ACR totally isolate all batteries. No more unwanted draw leaking from one bank to another.

A couple of questions concerning your wiring of the ACR:
1. I noticed that you did not wire the ACR directly to the batteries, but to the other sides of the two battery switches. Is this to really isolate the two battery banks when the two switches are off so that one bank would not discharge the other if there was an issue? That is part of it and I just followed the directions included with the ACR switch.
2. There's a good article ("Making Sense of Automatic Charging Relays") on the website Marine-How-To that discusses use of the Blue Seas ACRs that suggests that the alternator should be attached to the House bank, not the Engine bank for the reason that the House bank is apt to be discharged more than the Engine bank; if you wire the alternator to the Engine bank, than the ACR may have to carry almost the full alternator current to charge the House bank. If the alternator is wired to the House bank, then the ACR does not need to carry much current to charge the Engine bank. Did you wire to the Engine bank because you connected the Thruster and the Windlass to the Engine bank switch and didn't want to run that extra current through the ACR? The instructions included with the Blue Seas SI-ACR switch allow for connecting the A terminal of the ACR to either bank and yes I chose the Start Bank because of my Windlass and Bow Thruster being drawn from the Starting Bank.

I do respect and often read the Marine-How-To articles and have purchase his butyl bedding tape to use for the mast goes up and the mast comes down project each year .. sure beats caulking!

Thanks,

Ken, I Hope that my answers within your quoted text above are helpful. As always and since you are local, you are welcome to come aboard and have a first hand look.

[Pima]

Thank you, Kevin! See you around Cape Ann this summer!
Ken.