Which model Max Power bow thruster on a 44i?

[pipemma]

Does anyone know the exact model of the Max Power bow thruster fitted on the SO 44i? Cloud Nine is a 2009 yacht.
The only bit of paper we have about it is marked "duo 100" - could it be the CT100?

Basically I'm after knowing the power rating of the bow thruster and - above all - what Ah batteries to buy. We replaced them 2 years ago like-for-like (after the old ones nearly caught fire) - I think it's currently 2 x 65 Ah, given the small amount of space available and the terrible access. However, after just 2 years, they are dead again already (CCA rather than V, it seems) and causing battery alarms almost constantly.

Any recommendations for Ah on bow thrusters?
I'm also considering going for something a bit better than bog standard lead acid ones this time so as not to have to change them again in a hurry - again, any recommendations?

As ever, thanks a million in advance!

ETA: in case anyone is a whizz with these things, the plate on the bow thruster lists:
P/N JCM4673AA00-M and
Code MP203102/2

[pipemma]

An update for 44i owners:

Our bow thruster model is the MaxPower CT100. Here are the battery specs recommended by MaxPower in an email:

The battery specs required for 10minutes operation of the thruster per day are the following for either of the two cases:

Battery Bank Capacity

Av. motor	Connection	Providing	Providing
Current (A)	Type	CCA	Ah
680 A	Parallel	2400 CCA	150 Ah
430 A	Series/parallel	1200 CCA	100 Ah

As we're on a 12V circuit, our batteries are connected in parallel, so we need to be looking at 2400 CCA and 150 Ah.

Since the batteries overheated yesterday morning (despite the breaker being off) and we had to get them off the boat PDQ, we need to replace them soon. So now I'm off to read up on some battery threads. As this is the second time in 2.5 years that this has happened, I would appreciate any recommendations for types (avoiding lead acid I think!). MaxPower suggested something like the Exide Maxxima 900

[NZL50505]

I have same CT100 bowthruster and replaced like-for-like after taking advice that these are great batteries for thrusters:

2x Optima 8002 AGM

As you will see they are spiralcell AGM and deliver a very helpful 800A CCA each so plenty enough to drive the CT100.

[GrahamT]

Our 2004 SO 49 has 2 Optima Redtop 34R AGM batteries for the thruster. We replaced these last year after declining thruster performance and heavy corrosion on the terminals. Charging is from the alternator plus a mains trickle charger.

Batteries are 50Ah and 800 CCA each. 10 minutes sounds like a very long time to be running a thruster!

[pipemma]

Thanks both. Mind if ask why the red top, not the yellow top Optimas? (I hear very good things about the Optimas)

Also, your config is only 2/3 of what MaxPower recommend - do you find that enough and do the batteries hold their charge well enough? I can’t seem to find a way to get 2400CCA with fewer than 3 batteries, but there is only wiring for 2

I was considering 2 x 75Ah/900CCA yellow tops - any opinions?

[NZL50505]

Sorry not sure about red vs yellow top. I went with red simply because that’s what was already there (and I suspected original from factory).

Power never seems lacking. If anything at times the props seem close to point of cavitation so I don’t think the motor would benefit from much more power. And for typical 5-10s burst no problem either. So only benefit I could see of adding more capacity (in parallel) would be too increases burst time if berthing in a tight spot that regular requires 30s+ sustained bowthruster interventions to overcome prevailing wind or tide etc.

[pipemma]

Morning all,

Bumping this as it's time to order the new bow thruster batteries. Would appreciate your thoughts/advice as I'm in a dilemma, having narrowed the choice down to two:

2 x Optima blue top DC 75 Ah/975 CCA

+ Available locally and now
+ Only ever hear good reports of Optima batteries
+ Explicitly say up to 3x service life of "conventional" batteries (unclear whether they mean lead acid or other AGMs)
+ Explicitly resistant to vibration and different angles

- A bit more expensive
- Larger and much heavier (26.5 kg each), bearing in mind access is difficult

2 x Exide Maxxima EM1000 50 Ah/800-900 CCA, depending which site you look at (successor to the 900)

+ Successor to the model recommended by Max Power support
+ Smaller and much lighter (10 kg - is that really possible?!)
+ A bit cheaper

- Have to come from Germany via Amazon, but also available in Greece at similar price to the Optimas
- Further away from MaxPower's specifications above - unless they're suggesting 3x (which would obv add 50% to cost, and require interesting installation)

What would you do?!

(Bearing in mind I'm also going to need 4 x domestic batteries now, and also a new engine battery very soon )

ETA I'm inclining towards the Optimas; and if they do mean 3 x the Exide, I'd say the Optima is a no-brainer?

[loredo]

Yes, Optima for the thruster is a no brainer, just keep in mind that the blue tops are bigger than the red.

Will the blue tops fit?

[pipemma]

Mar 28, 2022 10:33:52 GMT loredo said:

Yes, Optima for the thruster is a no brainer, just keep in mind that the blue tops are bigger than the red.

Will the blue tops fit?

Yes, plenty of space, probably the biggest battery compartment of all, just trickiest access (ahead and down, under the shelves ahead of the V berth - but poss accessible from under the V berth).

[loredo]

....trickiest access.....

I a boat? Nahhhh, that can't be!