Help with electric motor battery selection and charging

[Greg P]

Cant speak more highly of the Sterling Pro Charge B for charging your trolling motor batteries on the fly. Very simple to install and works a treat. Initially I had a Mariner Procharger installed on the boat which I had to plug in overnight before heading out but this system with the Sterling works much better for me now given I have a dual circuit charging on the outboard and the dedicated house/start battery set up. The Sterlings are $$$ but worth it and are Lithium compatible for future proofing.

Good watching here in this clip on the dangers of cheap lithium batteries

https://youtu.be/nH7XmprkbOM

[Heliduck]

Great info in this thread, like others I’m researching LiFePO4 batteries for a 36V minnkota. What I’ve been told to date differs a little from what a few other people have done -
- Itech - I spoke with a technician who told me that they only make up to 24V as their BMS displayed cell instability above that voltage. They didn’t consider the 36V market big enough to justify the research & development to resolve this so they didn’t bother. Their internal BMS won’t allow for connecting batteries in series according to him.
- victron don’t make a 36V & don’t recommend connecting multiple batteries in series.
- Enerdrive make a 36V 100Ah , RRP $5600 but their distributors could give a discount on that(Keough’s Marine have them for $4995). Developed specifically for the minn Kota market apparently, looks like a good battery but BIG $$$!!! 2 years warranty + 2 years pro-rata for automotive & marine applications.
- Amptron - I just found this website tonight, they make a 36V 100Ah for $2495, significantly cheaper than Enerdrive With 4 years warranty. I’ll give them a call next week, has anyone had an Amptron LiFePO4 battery?

I was planning on connecting 12V batteries in series to get 36V but what I’ve learnt after a few days of calling manufacturers is that mixing & matching these batteries won’t provide the best result, Buy the battery to suit the application. (have a look at the Enerdrive website as they have a good explanation of why they say that). The price has almost scared me back to AGM batteries, but with a total weight over 100kgs I’ll probably break the piggy bank open.

If anyone has run a 36V 100Ah single battery on a 112lb minnkota I’d be interested to hear how long it lasts in an offshore spot lock situation. The calculations based on the maximum 52amp current draw gives just under 2 hours, but I doubt they draw maximum current very often & therefore should last quite a bit longer in the average operation.

[Heliduck]

Great info in this thread, like others I’m researching LiFePO4 batteries for a 36V minnkota. What I’ve been told to date differs a little from what a few other people have done -
- Itech - I spoke with a technician who told me that they only make up to 24V as their BMS displayed cell instability above that voltage. They didn’t consider the 36V market big enough to justify the research & development to resolve this so they didn’t bother. Their internal BMS won’t allow for connecting batteries in series according to him.
- victron don’t make a 36V & don’t recommend connecting multiple batteries in series.
- Enerdrive make a 36V 100Ah , RRP $5600 but their distributors could give a discount on that(Keough’s Marine have them for $4995). Developed specifically for the minn Kota market apparently, looks like a good battery but BIG $$$!!! 2 years warranty + 2 years pro-rata for automotive & marine applications.
- Amptron - I just found this website tonight, they make a 36V 100Ah for $2495, significantly cheaper than Enerdrive With 4 years warranty. I’ll give them a call next week, has anyone had an Amptron LiFePO4 battery?

I was planning on connecting 12V batteries in series to get 36V but what I’ve learnt after a few days of calling manufacturers is that mixing & matching these batteries won’t provide the best result, Buy the battery to suit the application. (have a look at the Enerdrive website as they have a good explanation of why they say that). The price has almost scared me back to AGM batteries, but with a total weight over 100kgs I’ll probably break the piggy bank open.

If anyone has run a 36V 100Ah single battery on a 112lb minnkota I’d be interested to hear how long it lasts in an offshore spot lock situation. The calculations based on the maximum 52amp current draw gives just under 2 hours, but I doubt they draw maximum current very often & therefore should last quite a bit longer in the average operation.

A bit more info for anyone who is interested -
I spoke to Amptron regarding their battery, it doesn’t have Bluetooth monitoring but they do sell a hard wired battery monitor for $140 which gives you vital data. I reckon this is the way to go, can’t argue with the price of $2495 for the battery. I questioned them on quality as I’m suspicious of a battery which is the same rating but less than half the price of enerdrive, Amptron is a prismatic cell battery made in China (all LiFePO4 batteries for sale in Australia are made in China from what I can find) & the dude I spoke to said he has personally visited several factories in China prior to choosing a supplier who he says is the best they could find. Sounds very similar to enerdrive minus the Bluetooth.
- “Sealed Performance Batteries” sell the Invicta brand of LiFePO4 battery, their 36V 100Ah battery is $4300 quoted through ARB who are a distributor( they buy them from Sealed Performance Batteries). It has blue tooth monitoring & is also a prismatic cell battery.

So far I have 3 clear options - Enerdrive at $4995, Invicta at $4300 & Amptron at $2495 + $140 for a battery monitor.
Big price differences, & from the info I can dig up they’re very similar quality batteries. Watch this space as I haven’t decided yet, my wallet says to buy Amptron but a poor man pays twice. With Amptron’s 4 year warranty it might
be worth the risk.

[Dignity]

On a boat I think I would prefer a hardwired monitor, the preoccupation with bluetooth these days somehow doesn't compute with me as BT devices are power hungry things themselves. All good info above, watching with keen interest on choice of battery.

[Gimme5]

Been 6 months, any updates? Keen to read some reviews.

[chocolatemoose]

id be pretty keen to see what you think as well

Moose

[GAD]

Been trying to get back on for some time , interweb . I have 2 x 120hr V- Giant lithium batteries and have run them for 10 hrs in a heavy current and weather , before the motor stopped and would only stow . came home and charged them up and went out 3 days later and used them all day . I have a victron charger and it does the job , I cut the clips off and put a 50 amp anderson plug and made a extension into two so as to be able to charge one battery at a time or both at the same time . I just split the two batteries with a 50 amp circuit breaker , which I allows me to isolate the batteries for charging .
From the batteries there is a isolator switch and then a 60 amp circuit breaker before the cable to an anderson plug connection to the Minn Kota .

[Toygut]

G'day,

Has anyone purchased these lithiums? They are the cheapest I could find, and curious on people's thoughts for marine application for a Motorguide 105lbs. Cheers

https://outbax.com.au/voltax-12v-100...xoCTx0QAvD_BwE

image.jpg

[disorderly]

G'day,

Has anyone purchased these lithiums? They are the cheapest I could find, and curious on people's thoughts for marine application for a Motorguide 105lbs. Cheers

https://outbax.com.au/voltax-12v-100...xoCTx0QAvD_BwE

image.jpg

They are certainly very cheap..

I know of one member on here that recently bought them for his new 36V Minn kota ..

maybe he will chirp up..

When I was looking for batteries 18 months ago most 100 Ah 12v batteries were in the 12-13 kg range and I was told to be suspicious of batteries that weighed less as they likely contained less lithium and therefore less capacity..and was aware that anyone importing a container load of generic batteries could basically put a sticker onto a battery case that showed whatever they wanted it too...

The Voltax weighs approx only 9.5kg..

Based on what I was told that would suggest a real capacity around 75-80 Ah..

I could well be wrong as I have not looked into them for quite some time and I'm happy to stand corrected if somebody has tested the capacity of them and new technology means they have become lighter and cheaper.....?

Another concern was that I remember some photo's of 12v batteries that had the top removed to demonstrate the difference between the inner workings of established more expensive brand name batteries and the cheap generic ones..the photos may have been biased but they did show the materials used inside and to join the cells together was far more robust in the better brands which may be of concern in a boat that is getting bashed around a bit...

and finally, a warranty and backup service is only as good as the company selling the products...

[Greg P]

Came across this in my feed

https://fb.watch/3Z2ov0Kxzx/

[NAGG]

Came across this in my feed

https://fb.watch/3Z2ov0Kxzx/

What we don't know is how these motors have been used / abused ....... My current boat only sees the motor used to spot lock - my previous boats I would often run 10s moving from one location to the next . ... therefore I would expect to see a difference ( despite my current boat running LiFePO4)

I can tell you now that if you run a leccy out of the water for any length of time , you can get the same result ........ I've seen a couple examples of it over the years .

Another interesting point is that Minn Kota have changed their position on LiFePO4s being used with their motors . They went from an absolute "No" to a it's OK to use a MK with LiFePO4 . Now if anybody was going to see the damage first hand , it would be MK service centers ..... if the damage was so dramatic , then that should have reinforced MKs original stance on the use of LiFePO4 batteries ie: NO!

Chris

[disorderly]

What we don't know is how these motors have been used / abused ....... then that should have reinforced MKs original stance on the use of LiFePO4 batteries ie: NO!

Chris

If you look at the them side by side near the end of the video you can clearly see the huge difference in condition of the propshafts..

The "Lithium" run motor could be 5 yrs old and the other 1 yr..

The "lithium" run motor could have been on a boat that regularly was pushed to full amperage while the other was just used for a bit of spotlock in a lake...

The video just shows the narrative pushed by the guy doing it without any history or any word whether this is reflective of all comparative situations...

How many motors has he pulled apart to arrive at that conclusion...?

It may well be fairly representative of the damage caused by higher initial and running voltage of the lithiums but without more data and history that video itself just shows 2 motor of indeterminate age side by side with one being crappy and old and one seemingly much newer and in good condition...

and to your point, Chris, that if true why havent Minn Kota said "no" to lithiums...

Well I can think of a couple of reasons..

Would they want to push potential customers to their rivals..?.and in a more sinister thought, where short term profit is important, it means they will sell more if the motors have a shorter life and there will be more work for their dealers workshops.....

Nothing would really surprise me with these large corporate run enterprises...

Lets just hope their R@D are working on improving the motors capabilities in being able to handle the lithiums...Does anyone know if that is being looked at ..?..surely it has to be a priority..

[ranmar850]

They are certainly very cheap..

I know of one member on here that recently bought them for his new 36V Minn kota ..

maybe he will chirp up..

When I was looking for batteries 18 months ago most 100 Ah 12v batteries were in the 12-13 kg range and I was told to be suspicious of batteries that weighed less as they likely contained less lithium and therefore less capacity..and was aware that anyone importing a container load of generic batteries could basically put a sticker onto a battery case that showed whatever they wanted it too...

The Voltax weighs approx only 9.5kg..

Based on what I was told that would suggest a real capacity around 75-80 Ah..

I could well be wrong as I have not looked into them for quite some time and I'm happy to stand corrected if somebody has tested the capacity of them and new technology means they have become lighter and cheaper.....?

Another concern was that I remember some photo's of 12v batteries that had the top removed to demonstrate the difference between the inner workings of established more expensive brand name batteries and the cheap generic ones..the photos may have been biased but they did show the materials used inside and to join the cells together was far more robust in the better brands which may be of concern in a boat that is getting bashed around a bit...

and finally, a warranty and backup service is only as good as the company selling the products...

Tearing these things down can reveal some horror stories. Re the minumum weight for a particular AH rating--this is spot on, and some cheapies have been found to actually have "ballast" inside, ie rubbish like ceramic tiles. A young bloke by the name of Will Prowse is on Youtube, he's cutting stuff open all the time, lots of variety in there. My 150ah Amptron is quite heavy at 19kg, but I'd put some of that down to the cells being inside a steel casing, as per their specs. As to the Voltax--if you go to their website, they have a picture of one with the top off, in an effort to prove how "good" their quality is. Well, the BMS is physically very small, and they are using the small tubular cells all spot welded together--this gives you a huge multiple of possible points of failure, compared to using 4 x 3.2 cells on bolted copper bus connection. Maybe not the best thing for batteries exposed to shock and vibration..

I actually gave my Amptron an impromptu load test last night--I hooked up the camper freezer( 150 litre running from a BD50 Danfoss) , and the 45 litre Engel, and, for the hell of it, ran the camp lighting for 2.5 hours as well. Left it running for exactly 12 hours, starting from full charge, then shut it down and connected the 30amp Victron Bluesmart to see what I had used . ( don't have a battery monitor yet). It was still showing 13.0 volts on the Renogy app, all running fine. Imagine my shock to see it needed a full 112ah to re-charge, meaning I had done a 75% discharge of the 150ah rating. Doing some investigating, seems the thermostat on the freezer had failed closed, so it was running flat out all night. Add to that, I realised I hadn't dogged the lid down on the Engel, so it was running full time as well Well, I reckon that proves it likely has the full 150ah capacity claimed.

The point about not simply being able to connect these up any old way is correct, too--look at the manufacturer's specs, and you will see caveats re the limits on series or parallel connections, and they do vary. It's all to do with the type of internal BMS fitted.

[NAGG]

If you look at the them side by side near the end of the video you can clearly see the huge difference in condition of the propshafts..

The "Lithium" run motor could be 5 yrs old and the other 1 yr..

The "lithium" run motor could have been on a boat that regularly was pushed to full amperage while the other was just used for a bit of spotlock in a lake...

The video just shows the narrative pushed by the guy doing it without any history or any word whether this is reflective of all comparative situations...

How many motors has he pulled apart to arrive at that conclusion...?

It may well be fairly representative of the damage caused by higher initial and running voltage of the lithiums but without more data and history that video itself just shows 2 motor of indeterminate age side by side with one being crappy and old and one seemingly much newer and in good condition...

and to your point, Chris, that if true why havent Minn Kota said "no" to lithiums...

Well I can think of a couple of reasons..

Would they want to push potential customers to their rivals..?.and in a more sinister thought, where short term profit is important, it means they will sell more if the motors have a shorter life and there will be more work for their dealers workshops.....

Nothing would really surprise me with these large corporate run enterprises...

Lets just hope their R@D are working on improving the motors capabilities in being able to handle the lithiums...Does anyone know if that is being looked at ..?..surely it has to be a priority..

When it came to LiFePO4s & electric motors - I got peace of mind when I visited a authorised MK seller / repairer to have some repairs done & we got chatting about battery options ...... he showed me his river boat & it was running LiFePO4s . A couple years later when I visited again .... we spoke on the same subject - he was still an advocate for LiFePO4 & said that in the tournament scene many had upgraded to the newer technology .
I've now been running LiFePO4s since Nov 2018 with no issues & I plan to have it serviced in the next month or so ...... I'll ask for some photos to be taken & put them up .

No doubt MK have realised that poo pooing LiFePO4 would cost them sales but ultimately their motors have to be fit for purpose.


Chris

[fishtragic]

An update on my MK and battery setup might interest a few. I run a 112lb Ulterra with 3 x 120Ah Itech world lithiums which produce 41V in series, Victron 30A/3 outlet charger. I burnt out my MK electronics after about 8 mths use, repaired under warranty and asked all over the planet for advice on how to regulate voltage back to a level that would not damage the MK again with little success. One Aust. company could build a voltage reducer for $4k+, twice the size of a shoe box and not marine components, that might last a year or two and generate plenty of heat. Not such a positive solution. So talking to a leco friend about this and he says off the cuff, "I can probably fix that, leave it with me". He turned up the other day, connected his voltage reducer box (half the size of a shoe box and $150 worth of simple bits), took the boat for a work out and it worked perfectly with minimal heat generated. Same batteries,still putting out 41V but output from the reducer is now 36-38V. I'm a pretty happy camper at this stage. Having said all that, BLA and MK are now recommending their own lithium 36V battery for trolling motors. It is a rebadged battery from another brand but their marketting says its output is 38V. I was about to go that way until my mate came up with his VR, hopefully problem solved. I told him to patent it and sell them but he's not interested.