Non-bluetooth lifepo battery for trolling motor

[webcraft]

After yesterday's fantasy of suddenly and mysteriously being able to afford a Temo, I am looking seriously at a trolling motor powered by a 50AH LiFePo battery.

My good friend SeaChange tells me I must have a smart Bluetooth battery or I will never know how much range I have left.

But BT batteries are 3 times the price.

Most trolling motors have some kind of charge/range display, are these useless?

Or - could a Victron smart shunt or similar be permanently attached? Maybe in a battery box?

— W

 

[Sea Change]

After yesterday's fantasy of suddenly and mysteriously being able to afford a Temo, I am looking seriously at a trolling motor powered by a 50AH LiFePo battery.

My good friend SeaChange tells me I must have a smart Bluetooth battery or I will never know how much range I have left.

But BT batteries are 3 times the price.

Most trolling motors have some kind of charge/range display, are these useless?

Or - could a Victron smart shunt or similar be permanently attached? Maybe in a battery box?

— W

The range/voltage meter on the trolling motor is designed for a lead acid battery, which operates over a fairly wide voltage range.
Lithium has a very flat voltage range, and will sit at 13.2v whether it's at 20% or 80% charge. So you can't use voltage to tell you how much is left in the tank. The meter on the trolling motor will think that a battery at 13v is full, when a lithium is nearly empty at that point.

You can buy super cheap battery monitors off eBay or Amazon. My one on the yacht was £50 but that's got a 500A shunt. Basic 100A versions should be less than £30.

The meter needs to be attached to the battery, not the motor, because all of the charging and discharging has to go through the meter.

 

[webcraft]

The range/voltage meter on the trolling motor is designed for a lead acid battery, which operates over a fairly wide voltage range.
Lithium has a very flat voltage range, and will sit at 13.2v whether it's at 20% or 80% charge. So you can't use voltage to tell you how much is left in the tank. The meter on the trolling motor will think that a battery at 13v is full, when a lithium is nearly empty at that point.

You can buy super cheap battery monitors off eBay or Amazon. My one on the yacht was £50 but that's got a 500A shunt. Basic 100A versions should be less than £30.

The meter needs to be attached to the battery, not the motor, because all of the charging and discharging has to go through the meter.

Methinks the meter needs to be waterproof - and how to semi-permanently mount to battery? On the outside of the battery box, perhaps?

- W

 

[geem]

Methinks the meter needs to be waterproof - and how to semi-permanently mount to battery? On the outside of the battery box, perhaps?

- W

If you 'splashed' out on a victron smart shunt you could fit the shunt inside a battery box to keep it waterproof. The smart shunt will bluetooth to your phone so you will know how much juice you have left

 

[Sea Change]

Methinks the meter needs to be waterproof - and how to semi-permanently mount to battery? On the outside of the battery box, perhaps?

- W

Either use a Bluetooth enabled meter, or fit a window on the box using a scrap of perspex and some sika.

 

[webcraft]

If you 'splashed' out on a victron smart shunt you could fit the shunt inside a battery box to keep it waterproof. The smart shunt will bluetooth to your phone so you will know how much juice you have left

I have gone mad and done just this. The new Victron shunt is IP65 rated anyway.

- W

 

[Neeves]

Like Sea Change I have a cheap shunt and monitor. The monitor is said to be waterproof but for some reason I have never been compelled to throw buckets of water at it to check the waterproof claims. However the display of the monitor looks water proof as it has a touch screen and no joints (to allow water ingress). The monitor is 'about 50mm diameter and fits tightly into a hole I cut with an appropriate hole saw. I'm sure the mon might be water proof but I'm not sure if the connections are (in fact I'm, sure they are not 'waterproof') - so my thought is treat the display with caution and the innards with great care.

Build yourself a box within which you can house the shunt and the wires from the battery (one of those click clack lunch boxes or boxes for the fridge might suit). Ensure the box is water tight, once you have connected the wires you can seal them into the box. Treat the monitor display with some caution and you should be good to go. For my mon you need to access the display as the screen allows you to scroll through amps, volts and amps available, etc - simply by pressing the mon screen with one finger.

The Victron mon must be better, well it has BT and an impressive array of data, but for your application the Victron/BT seems a bit OTT.

I'm not sure if the cheap shunt mons are 'small' enough for your application.

As Seachange has said cheap shunts and mons (they are commonly sold as a package) are 2 a penny - Amazon, eBay, Temu, Aliexpress. I've not seen a cheap BT version yet. There are reputable sources other than Victor, Xantrex is but one - whether they are cheaper - I have no idea.

This one comes from an Oz 4x4 retailer (who source everything from China) - it looks similar to ours (different colours etc), which came from Timu (but I could not find one like ours) and ours was cheaper. I would think you could find something similar in the UK or Europe. Sea change seems happy with his....?

Home Page - Adventure Kings

Jonathan

 

[Neeves]

Just a thought

The limitations, or one of them, is the size of the battery. I don't know what the range of a 50ah Lithium battery might be - but a bigger battery will be longer, or better, and make the motor a bit more useful.

The idea of buying anything from Victron for a trawling motor powered by a 50a/h battery seems to lack any justification - but having a larger battery and it might start to make sense.

Jonathan

 

[geem]

Just a thought

The limitations, or one of them, is the size of the battery. I don't know what the range of a 50ah Lithium battery might be - but a bigger battery will be longer, or better, and make the motor a bit more useful.

The idea of buying anything from Victron for a trawling motor powered by a 50a/h battery seems to lack any justification - but having a larger battery and it might start to make sense.

Jonathan

I don't agree. You have an aversion to Victron but the reality is it is the best stuff out there. It also comes with a 5 year warranty with an after sales services that really works.

 

[fredrussell]

I agree Victron is the best stuff but in a weird way that’s exactly why I wouldn’t want it knocking around in a tender. It’s one thing to drop an el cheapo LiFePo battery in the water, it’s quite another thing to lose, say, the best part of a grands worth of the quality stuff.

I think the Fogstar batteries are ok aren’t they? Better than the budget ones, but still a lot cheaper than premium batteries.

 

[geem]

I agree Victron is the best stuff but in a weird way that’s exactly why I wouldn’t want it knocking around in a tender. It’s one thing to drop an el cheapo LiFePo battery in the water, it’s quite another thing to lose, say, the best part of a grands worth of the quality stuff.

I think the Fogstar batteries are ok aren’t they? Better than the budget ones, but still a lot cheaper than premium batteries.

A smart shunt is £100. Where does the £1000 come from?
Interested to know what you consider a premium battery? Lots of 'premium' batteries now come with features we don't necessarily need onboard. Premium could mean feature rich. For me, premium mean top quality cells and a good reliable BMS with Bluetooth and an active balancer. I dont need a battery that will talk to my external alternator regulator as I don't have one. I don't need the battery to talk to my inverter either.

 

[fredrussell]

Apologies - I hadn’t realised you were talking about smart shunts. I thought you were referring to Victron LiFePo batteries when you defended Victron’s stuff.

 

[geem]

Apologies - I hadn’t realised you were talking about smart shunts. I thought you were referring to Victron LiFePo batteries when you defended Victron’s stuff.

I am not a fan of Victron batteries. Expensive but no longer anything special. They now use cells that nobody has ever heard of. The data sheet for it could be for any other good cell on the market. It doesn't set itself above the rest. The price is far too high for what you get. Lithium cell cost have dropped a lot. This doesn't get reflected in the 'premium' battery costs. They are still crazy expensive.
Last year 280Ah EVE cells were $145US each. This year the same cell is $105US. These are Grade A cells.

 

[Sea Change]

Webby is choosing the smart shunt because it has Bluetooth, which is sensible for this application. The other option would be a more expensive battery which has Bluetooth already built in.

I agree that Victron doesn't seem worth it when it comes to the batteries themselves. A friend recently installed a Victron lithium battery and it cost nearly six times what mine did, per Ah. And my battery wasn't even a particularly good deal.

 

[B27]

There are some cheap 'coulomb counting' battery meters on the bay of e which might help?
I have not tried them myself, but I built one with an arduino FWIW.

 

[Neeves]

There are some cheap 'coulomb counting' battery meters on the bay of e which might help?
I have not tried them myself, but I built one with an arduino FWIW.

That was my point, I don't have anything against Victon (other than price and no-one considers any other supplier) but in this specific application I don't believe the costs of a Victron smart shunt are justified. Its to monitor a small Lithium battery in a dinghy not a 600a/hr installation in a million dollar yacht. If there are doubts about the battery the smart shunt is not going to make it better - buying a better battery would be a better investment. A cheaper coulomb counter should be more than adequate. The Victron smart shunt will cost almost more than the battery.

Sea Change says he is using a cheap coulomb counter in a large LFP bank on a large cruising yacht - he seems to find it adequate.

The Victron smart shunt is undoubtedly an excellent product, we have seen the data it can provide, I really don't think that degree of sophistication is demanded on a 50ah battery for a trawling motor.

If Webcraft is unlucky - the worst that will happen is - he has to row or his phone runs out of battery or he drops it in the bilges (and its not waterproof) and he panics.

Jonathan

 

[Sea Change]

That was my point, I don't have anything against Victon (other than price and no-one considers any other supplier) but in this specific application I don't believe the costs of a Victron smart shunt are justified. Its to monitor a small Lithium battery in a dinghy not a 600a/hr installation in a million dollar yacht. If there are doubts about the battery the smart shunt is not going to make it better - buying a better battery would be a better investment. A cheaper coulomb counter should be more than adequate. The Victron smart shunt will cost more than the battery and might cost more than 2 batteries.

Sea Change says he is using a cheap coulomb counter in a large LFP bank on a large cruising yacht - he seems to find it adequate.

The Victron smart shunt is undoubtedly an excellent product, we have seen the data it can provide, I really don't think that degree of sophistication is demanded on a 50ah battery for a trawling motor.

If Webcraft is unlucky - the worst that will happen is - he has to row or his phone runs out of battery and he panics.

Jonathan

The Victron is Bluetooth, so it can be tucked away inside the waterproof battery box.
The cheap monitors are not waterproof, and do not have Bluetooth. So you'd need to either open the box to check it, or fit a perspex window to be able to see it. That's probably what I would do but we're all free to make our own decisions.

 

[geem]

That was my point, I don't have anything against Victon (other than price and no-one considers any other supplier) but in this specific application I don't believe the costs of a Victron smart shunt are justified. Its to monitor a small Lithium battery in a dinghy not a 600a/hr installation in a million dollar yacht. If there are doubts about the battery the smart shunt is not going to make it better - buying a better battery would be a better investment. A cheaper coulomb counter should be more than adequate. The Victron smart shunt will cost more than the battery and might cost more than 2 batteries.

Sea Change says he is using a cheap coulomb counter in a large LFP bank on a large cruising yacht - he seems to find it adequate.

The Victron smart shunt is undoubtedly an excellent product, we have seen the data it can provide, I really don't think that degree of sophistication is demanded on a 50ah battery for a trawling motor.

If Webcraft is unlucky - the worst that will happen is - he has to row or his phone runs out of battery and he panics.

Jonathan

The Victron Smart shunt is £100. Where are you going to get a lithium battery for £50?
If you are motoring around in a dinghy with an electric outboard and a small lithium battery, I would want a very accurate battery monitor to make sure I didn't run out of juice halfway home

 

[Trident]

Renogy do a nice 50AH battery - about 6 kg and runs my 85lb electric motor on the dinghy for about 2 hours

I paid £249 in 2023 and just bought a second last week for £179 as prices have dropped. Its waterproof, light, very well made and cheap - what more can you ask

 

[webcraft]

The Victron Smart shunt is £100. Where are you going to get a lithium battery for £50?
If you are motoring around in a dinghy with an electric outboard and a small lithium battery, I would want a very accurate battery monitor to make sure I didn't run out of juice halfway home

Indeed. And the cheapest battery with BT is over £100 more than one without the BT facility.

And if all else fails I can repurpose the Victron to monitor the house batteries.

My biggest problem so far is finding a suitable fully waterproof box. Loads on Aliwotsit, but none nearer than Shenzen!

- W