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diy solar

Using ebike battery to power 12 v trolling motor

G

gouthro2002

New Member
Joined
Feb 17, 2023
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32
Location
nova scotia
Hello everyone
I am new to electrical things and to this forum. Learning a bit from Will’s presentation. Thank you for having me.

Introduction finished let me say that I hope i have the right forum for this. And that there is not already a thread on the subject.
I have a rad electric bike with a 48v battery that i want to use on my 12v trolling motor for a small canoe. I communicated with a guy who did this. But he said that i needed something like this:

Reention bike side battery power input connector​

Image 1
But that it doesn’t work with Rad batteries.

Rad said i could get a replacement cradle which might allow this to work

What would i have to verify on this replacement cradle to see if i could make it work?

Also ehay else would i need? I am assuming the right buck converter. Anything else?

Thankyou very much for any held g

1676916176888.png
KB
 
gouthro2002 said:
Also ehay else would i need? I am assuming the right buck converter. Anything else?
Click to expand...
I don’t think that would last that well with a 55# thrust trolling motor. I think you will kill the battery - there’s a lot of amps even for a 36#. I’d be inclined to buy another higher capacity battery at the correct volts
 
Thanks Murphyguy. It is not q #55 thrust,though, but rather #30 thrust. As i say, i am someone who has two days looking at Will’s instructions and someone who saw electricity as a total mystery. But the buy says that he did actually use it to power his canoe, which was also 30 thrust. I would like to try it but i want to be really careful.
12VoltInstalls said:
I don’t think that would last that well with a 55# thrust trolling motor. I think you will kill the battery - there’s a lot of amps even for a 36#. I’d be inclined to buy another higher capacity battery at the correct volts
Click to expand...
Thanks for the reply. The motor is 30 thrust and not 55. I am totally new to this but i would like to try it with a little caution. The guy says he used it on his 30 thrust. Here is a link to his blog post:
hilleater.ca

Other uses for your e-bike battery!

Power outage, camping, trolling motor, travelling with electronics, running a portable cooler, recharging your drone at the park? All of these things can be done using your existing e-bike battery! All you need is the correct plug to get the power out of the battery, and the equipment to...
hilleater.ca hilleater.ca
G
 
Those are a 500W battery @48v - so a 10Ah battery.

A 30lb thrust minn-kota will draw 30A max - or about 20 minutes to draw your battery down. And I'm not sure what max-draw rating for an ebike battery is, but they are lithium-ion and over drawing or charging will cause shut down, and they have the potential to catch fire.

Minn Kota: https://www.hodgesmarine.com/min1352230-minn-kota-endura-c2-30-12v-30lb-30.html

To power your electric outboard consider a nice lifepo4 100Ah and a decent charger - you'll be MUCH happier with the performance. Prices have come down a lot - you'll spend about $300 for the combo.
 
gouthro2002 said:
am totally new to this but i would like to try it with a little caution.
Click to expand...
wellllll the thing is that a lot of things 'can' be done but often- they are ill advised.
Browneye said:
20 minutes to draw your battery down. And I'm not sure what max-draw rating for an ebike battery is, but they are lithium-ion and over drawing or charging will cause shut down, and they have the potential to catch fire.
Click to expand...
This is what I meant. I can tow my buddy's car hauler with my jeep wrangler. Empty. I could try it with a 4000# car on it... and I know it would do it- for a while. But if I didn't crash it by being too heavy, the vehicle would not survive long mechanically. That is a decent metaphor or an abstract comparison. I just wouldn't do it myself.
 
Browneye said:
Those are a 500W battery @48v - so a 10Ah battery.

A 30lb thrust minn-kota will draw 30A max - or about 20 minutes to draw your battery down. And I'm not sure what max-draw rating for an ebike battery is, but they are lithium-ion and over drawing or charging will cause shut down, and they have the potential to catch fire.

Minn Kota: https://www.hodgesmarine.com/min1352230-minn-kota-endura-c2-30-12v-30lb-30.html

To power your electric outboard consider a nice lifepo4 100Ah and a decent charger - you'll be MUCH happier with the performance. Prices have come down a lot - you'll spend about $300 for the combo.
Click to expand...
Thanks for the suggestions. I am going to use a bigger battery, as well, but i thought it intriguing to be able to use the bicycle battery, too.

To be honest with the guy who gave me the idea, i should add that he connects it to solar panels. That apparently keeps it charged.

I noticed that battery prices have come down. SOK is still a little rich for my uses. But i did see some good reviews from this one at eco worthy. A little bigger than I need but i can use it for other things, as well:
www.eco-worthy.com

12V 100Ah Lifepo4 Lithium Iron Phosphate Battery

Upgrade your power solutions with Eco-Worthy's 12V 100Ah LiFePO4 Lithium Iron Phosphate Battery. Ideal for solar systems, RVs, and off-grid applications. Explore now for reliable, long-lasting energy storage!
www.eco-worthy.com www.eco-worthy.com

Thanks again
G
 
Hey, this is a great discussion. But I didn’t realize that we had gone down a rabbit hole. The original question was would a buck converter , and if so, what kind, would work with a 48 volt ebike battery? Now, remember that we are dealing with a solar panel, then the battery and then. 30 thrust trolling motor.

Would you put one between the solar panel and the motor? Perhaps another one between the battery and the motor? I am having a hard time visualizing it

Thanks g
 
gouthro2002 said:
Thanks for the suggestions. I am going to use a bigger battery, as well, but i thought it intriguing to be able to use the bicycle battery, too.

To be honest with the guy who gave me the idea, i should add that he connects it to solar panels. That apparently keeps it charged.

I noticed that battery prices have come down. SOK is still a little rich for my uses. But i did see some good reviews from this one at eco worthy. A little bigger than I need but i can use it for other things, as well:
www.eco-worthy.com

12V 100Ah Lifepo4 Lithium Iron Phosphate Battery

Upgrade your power solutions with Eco-Worthy's 12V 100Ah LiFePO4 Lithium Iron Phosphate Battery. Ideal for solar systems, RVs, and off-grid applications. Explore now for reliable, long-lasting energy storage!
www.eco-worthy.com www.eco-worthy.com

Thanks again
G
Click to expand...
Solar panels are large - does not dovetail well with a canoe. :)
 
gouthro2002 said:
Hey, this is a great discussion. But I didn’t realize that we had gone down a rabbit hole. The original question was would a buck converter , and if so, what kind, would work with a 48 volt ebike battery? Now, remember that we are dealing with a solar panel, then the battery and then. 30 thrust trolling motor.

Would you put one between the solar panel and the motor? Perhaps another one between the battery and the motor? I am having a hard time visualizing it

Thanks g
Click to expand...
Missing one compnent- charge controller. To use a solar panel you need a charge controller.image.jpg
gouthro2002 said:
The guy in the article uses flexible ones and it seems to work
Click to expand...
flexible is short lifespan and a poor spend.
Of course they’ll work. For a while.

I’ve actually rebuilt a couple minnkota trolling motors, my own has been refreshed a few times. 42# and a lead acid “group 29” deep cycle would go 6-7 hours in my 14’ MFG Niagara closed bow. Killed a lot of batteries with that.

Do I’m not being joik- actually have some experience. But that was??? what, 120Ah labeled? Even at 50% usable that’s over sic times what you’re proposing to do.

Try it if you must but imho it’s poor economy. You’ll spend part of a battery that could be joy just getting this one to work

To each his own
 
12VoltInstalls said:
Missing one compnent- charge controller. To use a solar panel you need a charge controller.View attachment 135930

flexible is short lifespan and a poor spend.
Of course they’ll work. For a while.

I’ve actually rebuilt a couple minnkota trolling motors, my own has been refreshed a few times. 42# and a lead acid “group 29” deep cycle would go 6-7 hours in my 14’ MFG Niagara closed bow. Killed a lot of batteries with that.

Do I’m not being joik- actually have some experience. But that was??? what, 120Ah labeled? Even at 50% usable that’s over sic times what you’re proposing to do.

Try it if you must but imho it’s poor economy. You’ll spend part of a battery that could be joy just getting this one to work

To each his own
Click to expand...
Thanks. That’s getting out of the rabbit hole a bit. So you would use a charge controller between the solar panels rather than a buck converter. And then a buck converter between the battery and the motor. I am not saying i am going to do this. One of the reasons I posted on this forum was to check the feasibility as well as the how to. Thanks once again for your input, it is most appreciated on both those counts.
G
 
gouthro2002 said:
then a buck converter between the battery and the motor.
Click to expand...
Yes- you want the voltage control of the load between the load and the power source.
If you put it straight after the panels and you actually configured them to be capable of charging 48V nominal you’d probably blow out the converter and likely kill the battery. The solar charge controller is a requirement for the battery anyways.

By the time you configure your attempt with the necessary purchases you will spend a lot of the money that would have bought components that would work out of the gate.
 
12VoltInstalls said:
Yes- you want the voltage control of the load between the load and the power source.
If you put it straight after the panels and you actually configured them to be capable of charging 48V nominal you’d probably blow out the converter and likely kill the battery. The solar charge controller is a requirement for the battery anyways.

By the time you configure your attempt with the necessary purchases you will spend a lot of the money that would have bought components that would work out of the gate.
Click to expand...
Thanks once again for the advice. I would have known that if I had thought a bit more carefully. All the terminology can be confusing when you are just starting.

From what you are saying, i will probably steer away from the ebike battery altogether.

Even before getting a solar panel i will probably get the 12 volt 100ah battery mentionned above and hook it up directly to the trolling motor. From my reading, though, i believe i will need a fuse or a current cutter, whatever it is called, between the battery and the motor. If i did use a solar panel with this set up the configuration would be solar panel, charge controller, battery, circuit breaker and then motor. Right?
 
gouthro2002 said:
i did use a solar panel with this set up the configuration would be solar panel, charge controller, battery, circuit breaker and then motor. Right?
Click to expand...
Well I’d use a fuse on the battery 25% higher than the cable amp rating, and wire both the controller and the trolling motor load after the fuse or breaker.
 
I am soon to test a buck on a custom 14S 48V pack to drive a Minn Kota Endura C2, just to satisfy my curiosity. I've successfully run the Endura with boost converters off multiple configurations of power drill packs. I believe I'll have similar success in the other direction. One thing I noticed in this thread is that people are concerned your 48V pack didn't have enough AH. Not necessarily true: at 48V it's 10AH, but you buck it down to 12V and that becomes 40AH - 10% (buck toll), so you'll have about 36AH on a pack like that. That'd give you an hour-ish of runtime on an Endura.
 
eagleray said:
I am soon to test a buck on a custom 14S 48V pack to drive a Minn Kota Endura C2, just to satisfy my curiosity. I've successfully run the Endura with boost converters off multiple configurations of power drill packs. I believe I'll have similar success in the other direction. One thing I noticed in this thread is that people are concerned your 48V pack didn't have enough AH. Not necessarily true: at 48V it's 10AH, but you buck it down to 12V and that becomes 40AH - 10% (buck toll), so you'll have about 36AH on a pack like that. That'd give you an hour-ish of runtime on an Endura.
Click to expand...
Thanks. That's nice to know. If you connected it to a solar panel it could run for a long time, as well.
 
I have plans to put solar on as soon as I know what it can do range-wise. I've got some old recycled 75W panels here and a Renogy 2kw inverter. Just need to pick up an MPPT. I think a lot of people are focused on this holy grail of sailing all day on sun power, but I'm more curious about the nitty gritty details of range extension versus weight when weighing opportunity cost of solar versus adding more batteries.
 
eagleray said:
I have plans to put solar on as soon as I know what it can do range-wise. I've got some old recycled 75W panels here and a Renogy 2kw inverter. Just need to pick up an MPPT. I think a lot of people are focused on this holy grail of sailing all day on sun power, but I'm more curious about the nitty gritty details of range extension versus weight when weighing opportunity cost of solar versus adding more batteries.
Click to expand...
I have a large Greenland 2 double folding kayak, so weight is not too important to me. I just bought a 12v battery and so i am giving up on the ebike battery for the moment. I may come back to it later.

Right now i am thinking of getting the all in one system that Will mentioned on his site. I thought mainly of buying this to create a backup generator for the house. But, it looks like it is small and light enough to take camping and even in the canoe
Joe
 
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