Does anyone have any idea whether it would be possible to adapt a lithium bike battery for (occasional) use to power an electric outboard engine/motor? The electric outboard motors that I have looked at are 12v with, for example, 40lb thrust. These are normally powered by a 85aH or 110aH "leisure" battery. Any advice would be very helpful as it might mean I could use one of my bike Lithium batteries to power such a motor when I want to do a bit of fly fishing on a small local lake.
Alternative Lithium battery use
- Thread starter Wingreen
- Start date
There are 128 topics on this very idea here.
https://endless-sphere.com/forums/viewforum.php?f=39
This one is about a 12 volt outboard on Lithium.
https://endless-sphere.com/forums/viewtopic.php?f=39&t=68245
https://endless-sphere.com/forums/viewforum.php?f=39
This one is about a 12 volt outboard on Lithium.
https://endless-sphere.com/forums/viewtopic.php?f=39&t=68245
If you want a serious motor you can't beat the Torqueedo it runs rings around cheap trolling motors. Unfortunately the battery also contains the GPS. Maybe as a range extender (I haven't Googled to see if anyone has done this yet).
A 4S Multistar Lipoly would work, any 12V motor should work just fine at 14.8 V .
A 4S Multistar Lipoly would work, any 12V motor should work just fine at 14.8 V .
I'm only looking for a "kit" that will chug me out into a small lake then I'd be drifting with the wind and casting for trout. Then a trip back up to the start of the drift etc.. So, I dont think I need anything too powerful (it'll be used on a 10 ft or 12 ft rowing boat). I'm really interested in the Lithium battery option for several reasons. 1. It will be much lighter 2. I have three lithium batteries already which, when not being used on a bike, I could use. The ones I have are two "frog" batteries (each of which is spec'd at 24v 8,5A) and the one I got with my Big Bear (36v 15A). I'm sure one of these could somehow be used but I'm damned if I can make head or tail of the information on the links Kinninvie kindly sent me. Its clearly a very complicated subject!
A cheap step down DC DC converter then. You will generate a bit of heat. 24 to 12 volt are quite common in the automotive world.
Sounds interesting and worth exploring. As you may have gathered, I'm far from knowledgeable about these things but I assume you mean to step down the "frog" battery (which is 24v). I am wondering whether there would be a problem with it being rated 8.5A when the recommended leisure batteries are rated 85Ah or 110Ah (but it may be that, in some way, the "8.5A" is "equivalent" to a much higher "Ah"). I'd also be interested to get an idea of whether the "frog" battery is going to give me comparable power and would last as long per charge.
http://batteryuniversity.com/
Here is some light reading for you
Your frog battery holds 204 Wh you want to know how many Watts the motor uses per hour. That will give you your running time approximately. Many of your Watts will be wasted by going down to 12 V.
Car batteries have huge Ah because when you turn over the starter motor it draws very large amounts of current in a short period. An electric motor draws a set amount continuously once it is up to speed. If you rev up your trolling motor continuously it will draw more current at each acceleration.
Hope that helps
Here is some light reading for you
Your frog battery holds 204 Wh you want to know how many Watts the motor uses per hour. That will give you your running time approximately. Many of your Watts will be wasted by going down to 12 V.
Car batteries have huge Ah because when you turn over the starter motor it draws very large amounts of current in a short period. An electric motor draws a set amount continuously once it is up to speed. If you rev up your trolling motor continuously it will draw more current at each acceleration.
Hope that helps
You're a star! I will certainly study the information in the link - and, hopefully, understand things well enough to come to a (wise!) decision. I was hoping that stepping down the voltage might help a bit but clearly not. (Maybe I need a 24v electric outboard motor - if there is such a thing). I dont intend doing anything much more than chugging out into the (small) lake and back again but I have a feeling that 8.5A (which I think is actually 8.5Ah) is nowhere going to be enough, when compared to the recommended 85Ah "leisure" battery. Although it does seem counter-intuitive - the 24v 8.5A lithium battery will get my bike to go about 18 miles so chugging around a lake for a few hundred metres didnt seem to be anywhere near as challenging.http://batteryuniversity.com/
Here is some light reading for you
Your frog battery holds 204 Wh you want to know how many Watts the motor uses per hour. That will give you your running time approximately. Many of your Watts will be wasted by going down to 12 V.
Car batteries have huge Ah because when you turn over the starter motor it draws very large amounts of current in a short period. An electric motor draws a set amount continuously once it is up to speed. If you rev up your trolling motor continuously it will draw more current at each acceleration.
Hope that helps
It should be plenty for your purpose, forget Ah and think in terms of time and power needed.
The power needed is probably little more than your e-bike needs. Your 18 miles on the e-bike will take about one and a quarter hours at the legal assist speed. Take off the quarter hour to account for the voltage conversion loss and you might get up to an hours gentle running on the lake.
At three knots that's nearly 5000 metres in an hour, so your possible 500 metres won't cause any problems.
.
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D
Deleted member 4366
Guest
Ebike batteries aren't suitable because they can't provide enough current.
Instead, get yourself some 4S lipos from Hobbyking. The voltage is a bit higher than what the motor's designed for, but it'll work OK. You'll need about 40 amp-hours. I bought a balance board, then beefed up the main power tracks on the back of the pcb by adding thick copper wire. That allowed several of the 4S packs to be connected in parallel without a harness. You need 12g wire or thicker for 40 amps.
You'll also need a decent lipo charger, which costs about £50 plus.
http://www.ebay.co.uk/itm/Parallel-Charging-Balance-Board-for-Lipo-LiFe-Li-ion-IMAX-B6-Battery-Charger-S-/261624069224?hash=item3cea027c68:g:h4kAAOSwe~dTxi7q
Instead, get yourself some 4S lipos from Hobbyking. The voltage is a bit higher than what the motor's designed for, but it'll work OK. You'll need about 40 amp-hours. I bought a balance board, then beefed up the main power tracks on the back of the pcb by adding thick copper wire. That allowed several of the 4S packs to be connected in parallel without a harness. You need 12g wire or thicker for 40 amps.
You'll also need a decent lipo charger, which costs about £50 plus.
http://www.ebay.co.uk/itm/Parallel-Charging-Balance-Board-for-Lipo-LiFe-Li-ion-IMAX-B6-Battery-Charger-S-/261624069224?hash=item3cea027c68:g:h4kAAOSwe~dTxi7q
Thanks d8veh - I was hoping you'd pick up on the discussion as I know (believe?!) you have a good handle on these things. I'll look into the overall cost (not such an attractive option if I cant make use of my existing lithium batteries)
My apologies for not noticing this request for info sooner, I don't log in so often at the moment.
Wingreen messaged me, so I thought I'd better reply on here in case anyone else is interested.
I asked the same questions on here a year or two back, and d8veh very kindly gave me all the info to make my own 4s 30 amp battery pack.
I've tinkered with electrics and electronics quite a bit in the past, but I was very green with Lipo technology then. I've since got into radio control models, so that Lipo knowledge has come in very handy since !
I connected six hobbyking 5amp 4s hard case lipos in parallel to create a 30 amp 16v battery for my two 12v outboard motors.
The output from each pack was connected via a fuse, and the 4s balance leads were connected in parallel for charging, and monitoring via the lipo alarm.
The whole lot fitted into a watertight transparent food container, with the output terminals bolted through the casing, so that the outboard croc clips connect just like a standard lead acid battery.
It's almost as bulky as an 85 amp lead acid leisure battery, but it's much lighter (4kg), and all of the 30ah can be used, so it's got almost the same useable capacity of the 85a leisure battery, used to the recommended 50% discharge level.
Wingreen messaged me, so I thought I'd better reply on here in case anyone else is interested.
I asked the same questions on here a year or two back, and d8veh very kindly gave me all the info to make my own 4s 30 amp battery pack.
I've tinkered with electrics and electronics quite a bit in the past, but I was very green with Lipo technology then. I've since got into radio control models, so that Lipo knowledge has come in very handy since !
I connected six hobbyking 5amp 4s hard case lipos in parallel to create a 30 amp 16v battery for my two 12v outboard motors.
The output from each pack was connected via a fuse, and the 4s balance leads were connected in parallel for charging, and monitoring via the lipo alarm.
The whole lot fitted into a watertight transparent food container, with the output terminals bolted through the casing, so that the outboard croc clips connect just like a standard lead acid battery.
It's almost as bulky as an 85 amp lead acid leisure battery, but it's much lighter (4kg), and all of the 30ah can be used, so it's got almost the same useable capacity of the 85a leisure battery, used to the recommended 50% discharge level.
Attachments
The specs of the 2015 Torqueedo battery are:
In 2016 it looks like they have upgraded the 18650 cells because they now have 18 Ah
- 320 Wh
- 29.6 V
- 11 Ah
In 2016 it looks like they have upgraded the 18650 cells because they now have 18 Ah
Thanks. The information you've provided is really useful. I'm certainly going to explore this option as, depending on how the costs add up c/w with the more usual Leisure battery, the saving in weight is really attractive.
Now I'm getting a bit confused. Recent posts I've read say that the 8.5 Amp frog battery (or, indeed, any/most Lithium bike batteries) is a non-starter for use in powering a 12V electric outboard motor. Its clearly a complicated subject! If my frog battery would/could work then it would clearly be the best (cheapest) option - especially as it only gets used very rarely at the moment.
All options to explore (and understand) further - after sleeping on it!
D
Deleted member 4366
Guest
Half of that price being the Li-Ion battery, you already have a battery (or two). If you want a brand new Minn Kota 24 V trolling motor you will be looking at $900+ and the batteries so much of a muchness...
Bison trolling motor on ebay UK:
"Battery choice?
To power your electric outboard you will need a DEEP CYCLE battery, also known as a LEISURE battery in our experience 85Ah is an ideal size for most applications.
As a rough rule of thumb, to calculate the size of battery you need, just take the max amps draw of your desired motor from the table, and times that by the number of hours you wish to use the motor. Then add 20% so you aren't completely draining your battery every time.
So, for the 55LB motor, 52A at max speed, We wish to run it for an hour, so: 52amps x 1hours = 52
52 + 20% = 63 therefore we would require a 65 Amp Hour battery or larger.
Also worth noting is that current consumption at slower speeds is much less, you will draw about a quarter of the charge from your battery at low speed."
Now go over to battery university and read about the difference between lead acid and lithium batteries.
Bison trolling motor on ebay UK:
"Battery choice?
To power your electric outboard you will need a DEEP CYCLE battery, also known as a LEISURE battery in our experience 85Ah is an ideal size for most applications.
As a rough rule of thumb, to calculate the size of battery you need, just take the max amps draw of your desired motor from the table, and times that by the number of hours you wish to use the motor. Then add 20% so you aren't completely draining your battery every time.
So, for the 55LB motor, 52A at max speed, We wish to run it for an hour, so: 52amps x 1hours = 52
52 + 20% = 63 therefore we would require a 65 Amp Hour battery or larger.
Also worth noting is that current consumption at slower speeds is much less, you will draw about a quarter of the charge from your battery at low speed."
Now go over to battery university and read about the difference between lead acid and lithium batteries.
Thanks. Again, very helpful. I'm beginning to think that, especially given my novice status as regards electronics, I will just have to go for the leisure battery option and be prepared to lug the extra weight. I will certainly continue exploring the Battery University website but it is very frustrating - I have three lithium batteries, a 36 hole lead acid golf trolley battery, three lithium battery chargers, one car battery charger and about three golf battery chargers, none of which can be used adapted in any way to solve my "problem" (and the leisure battery chargers arent cheap!). Seems to me that there might be money to be made by some enterprising small electronics company to explore "kits" that can, in some way (if possible), be used to adapt different batteries to carry out different functions.