I've just bought 2.3m inflatable as a tender for my 31ft yacht that I also bought recently. I'm contemplating powering it with an inflatable trolling motor - like a Watersnake T24 which can be powered by something like this: itechworld.com.au/collections/lithium-batteries/products/itech024-12v-24ah-lithium-ion-battery-lifepo4-deep-cycle-recycle-camping-rv-solar-golf-buggyDoes anybody have any experience relating to this? I'm not sure whether the power will be suitable or even any better than rowing the inflatable.

I've been using an electric trolling motor on my 2.4m inflatable for the last 3 yrs, mated to a 40ah AGM. Works great! With 200m each way from shore to mooring, and trips ashore/exploring over a weekend away, at the end of a weekend the battery will still be fine- perhaps getting a little slower depending how much the kids have been mucking around in it.
Flat out in optimal conditions i reckon it's equivalent to about a 2-2.5hp outboard, and of course no fuel, no mixing oil etc.
Dont go too light on the thrust though- 24lbs may not be much better than slow rowing - I went for a 55lbs thrust model, ok in most conditions, but into a decent or gusty headwind with a dinghy full of kids and gear - you'll need every bit of it, and you'll be glad you don't have to row.
If you're only going back and forth to the mooring, a 24ah battery would be fine.

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alanfw said..
I've just bought 2.3m inflatable as a tender for my 31ft yacht that I also bought recently. I'm contemplating powering it with an inflatable trolling motor - like a Watersnake T24 which can be powered by something like this: itechworld.com.au/collections/lithium-batteries/products/itech024-12v-24ah-lithium-ion-battery-lifepo4-deep-cycle-recycle-camping-rv-solar-golf-buggyDoes anybody have any experience relating to this? I'm not sure whether the power will be suitable or even any better than rowing the inflatable.

Hi alanfw - by coincidence I just bought a Watersnake 34ftlb unit. When I researched batteries I found two LiFePo batteries at my local electronics shop on special at 50% off. So although the batteries are small - 2 x 18Ah - I'm hoping there will be enough energy in one for getting to my moored boat, with the second one left on the boat on trickle charge so I can swap them over when needed (or take both when I'm doing a dive or fishing trip in the dinghy). I've made connections using 4mm cable and Anderson plugs and bought some cheap flexible lunch-box-style bags from the supermarket to hold them. It's all un-tested, but if it works as desired I will be able to walk from my car to the water with my dinghy slung over one shoulder (Bombard 2.3m inflatable) and outboard AND battery in the other hand. When I get to my 30' yacht, lifting the outboard and battery aboard will be easy as it's very light. Pics below ... Also, for those who think this is ridiculously under-specified, keep in mind how amazing LiFePo batteries are - my electric bike battery, which stores approximately the same amount of energy as the two batteries I've just bought, can carry me (100kg) over at least 20km without me having to pedal. I'm hoping, therefore, that this new dinghy set-up will give me enough power to get safely to and from my vessel when it's windy and tides are running. There is one caveat - the batteries have a maximum extended discharge current of 18A, while the motor's five power settings draw between 7.5A and 34A - what this means is I will only be able to use the first two or three power settings safely, though according to the battery manufacturer I can draw 30A for up to 5 seconds. I'm in lock-down in Melbourne right now, so won't be able to test for a few days or possibly weeks. One more thing, the outboard cost AUD$200, batteries $100 each, cabling and plus $50, and lunch bags $10 for two. Total cost: $460

I have been using a Watersnake with a 7AH AGM battery for a few years on 2.4m soft bottom inflatable. It gets me out to my mooring and back (400m each way) provided that there is little current and wind, and the battery has a few hours to recover while I am out sailing, and I have no passengers.
Although the motor is a TM34 (34 lb thrust) I use it on low speed to restrict its current draw to 10A which suits the small battery. I am probably getting about 10 lb thrust which pushes me along at about the same speed I can row, maybe 3 knots.
If there is significant adverse wind or tide, or I have a passenger, the speed is initially adequate but by halfway through the return journey the battery voltage has dropped so much that I have to row. After the battery has had a few hours to recover, I find that it is still 50% charged but was unable to deliver 10A for long enough without resting.
I think Bluewater's suggested battery size of 18 AH would be more than adequate for my purposes, and that your proposed T24 would be more than adequate for a 2.4m boat if you are happy to travel at 3 or 4 knots. It is important to get the manufacturer's charts showing how long the battery you are considering will deliver various currents, and compare that with the current drawn at various speed settings. Only then will you know how long your battery will last and whether it will take you whatever distance you need to travel. A battery will only deliver its rated AH if the current is low - as soon as you draw off a high current the available AH drops drastically.

I don't have an electric outboard or an inflatable but on my hard dinghy I have a solar panel and battery to power the depth sounder. With the really cheap solar panels about now would not a flexible or fold up panel be handy to charge the battery while your out sailing?

OP, Anaconda has these on sale now...
www.anacondastores.com/fishing/marine/motors-fuel/petrol-electric-motors/watersnake-venom-sxw-transom-mount-elec-motor-34lb/BP90128634?utm_source=sfmc&utm_campaign=A200226_A02_EDM_MEGA_DEALS_WK07&utm_medium=email&utm_content=ANACONDA-FISH-MARINE-3

Buy now, think later?

A mate has an electric outboard. Not sure what type. It has failed to start or to keep going every time we have been out to his boat. About as reliable as a 2 stroke outboard but harder to troubleshoot.

I have a second hand ($120.00 Gumtree) Minn Kota M34 and using a very second hand golf trolley battery from my neighbours garage 12V 24 AH lead acid battery (3.5kg).
This is on the back of a heavy old 14 ft glass row boat.
Works a treat! Motor is super light 6kg, batt lasts about 45 to 50 mins ( bought an eBay 12 volt solar charger $24.00 which lies on the seat and re charges the batt during the day) so we can go over to coffee shop at Clareville in the morning. Super good around Pittwater, if you need to travel more than a few km perhaps an outboard.
Best of all I can pop it in the car anyway I want, it just sits in there for a week or two, no oil or fuel leak ever, always starts first go :) , dead quiet running.

cheers
H.

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SoloCMV said..
I have a second hand ($120.00 Gumtree) Minn Kota M34 and using a very second hand golf trolley battery from my neighbours garage 12V 24 AH lead acid battery (3.5kg).
This is on the back of a heavy old 14 ft glass row boat.
Works a treat! Motor is super light 6kg, batt lasts about 45 to 50 mins ( bought an eBay 12 volt solar charger $24.00 which lies on the seat and re charges the batt during the day) so we can go over to coffee shop at Clareville in the morning. Super good around Pittwater, if you need to travel more than a few km perhaps an outboard.
Best of all I can pop it in the car anyway I want, it just sits in there for a week or two, no oil or fuel leak ever, always starts first go :) , dead quiet running.

cheers
H.

Hi SoloCMV ... yes, that's one of the reasons I got the electric unit - so I can store it anywhere without oil or fuel leaks. Also, lifting it from the tender into the cockpit will be easy. With the lithium battery I bought, I'll be able to lift the motor and battery one handed without any trouble. (Still haven't tested mine on the boat, as we're still in lockdown in Melbourne - argh!)

Hello Bluewater,

I also have a 12V 110AH AGM which lasts about 4 hours, but it's 20kg. I have used it to go down to the Newport Arms or over to Church Point which is fine but it's heavy to lug around. So this also gives me options.

Dinga is having a sale on Watersnake motors. The T24 is $147 plus $30 shipping, or free shipping for Dinga Club members. It's free to join so well worth it. The T24 is great and much lighter than my old 3HP Mercury. I use a 12AH AGM battery ($40 from Amazon) and store it in a Sistema lunchbox. The battery lasts about 20 minutes which is ok for very short trips. I could row but I'm lazy.

www.dinga.com.au/collections/boat-accessories-kayak-motors/products/watersnake-asp-electric-kayak-motors
www.amazon.com.au/ATEM-POWER-VABY001A-Battery-Fridge/dp/B083Y3VTZM/

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SoloCMV said..
Hello Bluewater,

I also have a 12V 110AH AGM which lasts about 4 hours, but it's 20kg. I have used it to go down to the Newport Arms or over to Church Point which is fine but it's heavy to lug around. So this also gives me options.

I might be looking at bigger batteries in the longer term for all-day fishing trips etc. One thing to remember is that LiFePO4 batteries can absorb charge current more quickly, and can be discharged more fully, than the older style batteries. The latter point is important - your 110AH battery would give useable power of about about 55AH. That amount of energy could be delivered by an 80AH lithium battery (the 'full discharge' levels are about 50% and 70% respectively I think). There is a big cost difference - I found a typical 100AH unit for $800, but it is also a lot lighter that what you've got - 12.6kg.

Thanks for all the comments. They pretty much confirm what I was hoping for, except that you seem to be managing with batteries much smaller than I expected!

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alanfw said..
Thanks for all the comments. They pretty much confirm what I was hoping for, except that you seem to be managing with batteries much smaller than I expected!

Hi Alanfw

As an update on what I've written above, I've now had a chance to test my Watersnake outboard, but only in my garden water-tank (we're still in lock-down in Melbourne). I bought a really handy inline power meter from Jaycar in Melbourne (AU$49) www.jaycar.com.au/200a-dc-power-meter-with-anderson-connectors/p/MS6192 which can very accurately tell me what power is being used by the outboard at each setting.

The big issue I mentioned above is the maximum current it draws, as the relatively small battery is only rated for 18A for continuous use (and up to 30A in short bursts of less than 5s).

I'm pretty pleased with the results - see attached table - as it shows me the motor can be used on power setting 4, which is 55% of its full thrust power. If I want to use it at full power, I just need to connect the two lithium batteries I have in parallel and I can use it on full power.

What the test confirms, then, is that this battery and motor will suit my needs well. The next test will be to see what speed my dinghy travels at, and how it performs with a headwind.

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SteveTH said..
I have been using a Watersnake with a 7AH AGM battery for a few years on 2.4m soft bottom inflatable. It gets me out to my mooring and back (400m each way) provided that there is little current and wind, and the battery has a few hours to recover while I am out sailing, and I have no passengers.
Although the motor is a TM34 (34 lb thrust) I use it on low speed to restrict its current draw to 10A which suits the small battery. I am probably getting about 10 lb thrust which pushes me along at about the same speed I can row, maybe 3 knots.
If there is significant adverse wind or tide, or I have a passenger, the speed is initially adequate but by halfway through the return journey the battery voltage has dropped so much that I have to row. After the battery has had a few hours to recover, I find that it is still 50% charged but was unable to deliver 10A for long enough without resting.
I think Bluewater's suggested battery size of 18 AH would be more than adequate for my purposes, and that your proposed T24 would be more than adequate for a 2.4m boat if you are happy to travel at 3 or 4 knots. It is important to get the manufacturer's charts showing how long the battery you are considering will deliver various currents, and compare that with the current drawn at various speed settings. Only then will you know how long your battery will last and whether it will take you whatever distance you need to travel. A battery will only deliver its rated AH if the current is low - as soon as you draw off a high current the available AH drops drastically.

Steve TH, I can now give another real-world update. With my 18AH battery I was only confident to use 4 of the 5 power settings. To get around this, I connected my two 18AH batteries in parallel to make a 36AH battery which I'm guessing can deliver the 32A continuous needed to drive the Watersnake.

Yesterday I spent about 30 minutes pushing my 2.3m inflatable dinghy around a fairly windy patch of water at Williamstown - about 10-15 knots of wind and some chop - and was pretty happy with the result. I was able to travel against the wind at about 2 knots, which is enough to get back to shore with plenty of battery life left.

I guess the moral of the story is use a battery with the correct level of continuous current ability, otherwise you're just not getting the best out of the electric outboard.

I'll stick to my 5hp Yamaha, no issues, very little fuel, 4 on board in 2.7m ducky in wind - all good.
Fun when 1 up and even 2 mid weights it planes.