Bowthruster and 24 v charger

[tonyiiiafl]

I pushed the button on the side shifter bow thruster. Even though the SS340 was rated for my 390CPMY, upon many discussions here and with the vendor I went with the 24V SS350 for 7 HP versus 4HP. With that big sail I have it won’t hurt.

Now I will be putting in 2 12V batteries in series to make the 24. They caution against deep cycle and to use starting batteries of a combined total of 800 CCA. I am hoping to fing AGM or Gel batteries, as the only place I can place them is either under the forward bilge in the galley, or under the forward berth. However, the forwards bert will have challenges as also the forward bilge, as I will need to make a platform for mounting.

ANYWAY, I am now looking for a battery charger. Since it is a 24V system, I would need a 24V single bank charger to install. However, in one of their installations, they had a small 12V 2 bank charger. Each bank was connected to each 12V battery. So on one battery was POS/NEG, and some on other. I am confused as on the middle connection, there is the jumper from neg to positive to enable 24V combined. Thi sounds like disaster waiting to happen to me.

Any thoughts or advice? Not sure how or where is sam going to wire the charger up. May have to run up the side with 14/3 tinned and pony up to an outlet that is seldom used or not used. Like the one in the galley. I had even thought of putting the batteries under the sink area, tucked in the rear. That may be a better location?

Thoughts please.

Side Shifter was $4765.00 ++ $125.00 shipping. No tax/duty. Bot show pricing of $550.00 off. ob griffin, the ceo responded to my emails promptly. I asked him about getting the dual joystick swapped out for the single, s if this works I will add the stern thruster next season. With the new canvas enclosure ($12,500.00) new fridge ($1750.00) and now the bow thruster ($5300.00 including batteries and cables) I have spent enough boat bucks for the session.

Please give me your thoughts. I will update my journey with the thruster. Plan is to install while on the hard storage lot. then when I get back to my slip take a weekend or whatever and wire it up. Looks pretty simple.

This boat saga continues.

best,

Tony

[km1125]

With the two bank charger, you just need to make sure they outputs are ISOLATED. If this is the case, then you really have two separate one bank charger in the same case, and that either of the cables on either charger ("negative" and "positive") can be grounded. That is why you can connect the positive of one of the chargers to the "negative" of the other charger when batteries are joined in series. This is very common in trolling motor setups. This also means if you have a "20A" two bank charger that neither output will actually deliver 20A... each is limited to 10A. This is not so important in YOUR application or a trolling motor application, but important when someone is using one of these kind of chargers for a dual battery start and house situation. The start battery rarely requires much of the current, but the house can certainly, especially if you're sitting at the dock with a bunch of equipment turned on.

You want the batteries as close to the thruster as possible, to minimize those high-current cable lengths and sizes.

I'm not a big fan of gel batteries, and especially not in high-current roles. They do require a much different charge profile than any lead-acid battery (FLA, SLA, or AGM). They are VERY sensitive to a high float voltage. You could get SLA or AGM batteries that fit high-current situations. Do not go with a deep-cycle, as that is NOT what you want for a thruster.

[tonyiiiafl]

Thank you. I knew about not using a deep cycle. Batteries may be 9 to 10’ away from unit unless I can find a way of putting them under the forward berth. I had also thought of placing under the galley sink cabinet. Need to engineer this a bit more. I would need to use 1/0 or 0 cables to minimize current loss. I do not see how there would be long continuous use of thruster, more like a burst or 2. I have a lot to learn about these.

However, looking forward to having more bow control when backing into the slip.

[tonyiiiafl]

Saw one of these on Amazon…

[tonyiiiafl]

https://www.victronenergy.com/upload/do ... VAC-EN.pdf

here is one, single bank 24v

[tonyiiiafl]

ANy suggestions on 12V AGM batteries for the side shifter? Manual says minimum 850CCA. NO deep cycle.

[km1125]

Source of the post ANy suggestions on 12V AGM batteries for the side shifter? Manual says minimum 850CCA. NO deep cycle.

I re-read one of your earlier posts, and you mention " They caution against deep cycle and to use starting batteries of a combined total of 800 CCA".

Sounds like that's a quote from somebody at the company. Do you know what they meant by the "combined total"?? If the batteries are in series, then the CCA would be the minimum of the two in series. If you had two 800CCA batteries in series, then the total CCA would be 800. If, for some reason, you had one 600 CCA and one 800CCA in series, the total CCA available to you is 600 CCA.

I'm surprised they spec 800CCA for a 24V system. (on a 12V system it would make more sense). On a 7HP unit, the current draw should be somewhere around 250A at 24VDC.

[tonyiiiafl]

Yes. Pretty confusing for sure.

[bud37]

Source of the post Yes. Pretty confusing for sure.

Are you looking for a specific brand, I would just use a couple of 1000cca no maintenance start batteries in series for 24 volts. Costco has kirkland which used to be johnson control batteries....good stuff, at least they were a few years back.

Is there a reason you want the agm type?......

[tonyiiiafl]

I was looking for AGM due to less news for ventilation. I will be putting them in the forward bilge or possibly under the c berth. Just thinking of not having to vent the off gas.