diy solar

diy solar

Newbie - +ve terminal is toast - what could have caused this

F

fakdaddy

New Member
Joined
Jan 1, 2022
Messages
20
Hey guys - not a solar question on this one - lifepo4 specific Q.

Have a 50aH battery. Using for a trolling motor (max draw 45A per spec FWIW).
Was charging with a NICO 5A charger ..... but only ever got to 13.2A before cutoff seemed undercharged.

Switched to a heagstat 2A

Charged for 48 hours straight but never cutoff and went into float/maintenance mode. Battery did get to 13.8.V after 2 hours settled.

Then went fishing ...... and this is what happened.


Im confused as I thought

1) The BMS would prevent over discharge (i.e not allow more than the rated 50A out)
2) 50A wouldnt be enough to do this at 12v.

thoughts ?
 
That’s the pos(+) side?
Not sure on my phone.

A bad connection could create resistance and do that. Even a dirty or poor cable terminal end could transfer heat and once it got hot enough…

What is the ‘thrust’ of your trolling motor?
How long was it running when that happened?
Was the trolling motor on High for 5 minutes?
Do you have a fuse or breaker on the trolling motor cables?

Allowing for a bit of ‘loss,’ roughly 60# of trolling motor thrust is equivalent to one Horsepower which is 768W at full High. At a nominal 12V 768W is 60-64A of current depending on a relatively ’full’ battery’s state of charge. So if your battery is rated at 50 Amp discharge rate, at full throttle with a 55# trolling motor you exceed its discharge capacity by over 10%
If it’s a 40# class that’s around 35A.

That’s leaving the BMS out of it; potentially a separate issue. It also doesn’t consider MinnKota’s older controller that can fail and usually creates Smokey Resistance, or water in the motor brushes which will smoke unfused cables.

fakdaddy said:
2) 50A wouldnt be enough to do this at 12v.
Click to expand...

Varies with application of course but my 120V mig welder can weld sheet steel at surprisingly low volts and 30A

Plastic would easily melt with that heat.
 
Last edited:
Firstly - thanks for jumping in here. Want to learn :)

The trolling motor is 55lb thrust and rated for 45A max (640W).


The motor had been running all day on and off. I didnt notice the smell until towards end of the trip. It was running at full speed.
50A fuse never blew.
The terminals are not super clean as they run on the ocean in kayak - but not super bad either.

Any suggestions on how to salvage this and to ensure battery is ok ? Im still a bit confused on a few points.

1) Why the NOCO charger would always go "green" into maintenance mode but the battery was only at ~13.2v - undercharged
2) Why the new 2A charger even after 48 hours was still charging and never went into maintance/full mode.
3) Why (if the current got above 45A) the fuse didnt blow AND the BMS didnt shutdown above 50A draw.

and finally - where to next ........ on this battery .....

appreciate any and all help
 
fakdaddy said:
Firstly - thanks for jumping in here.
Click to expand...
Glad to
fakdaddy said:
The trolling motor is 55lb thrust and rated for 45A max (640W).
Click to expand...
Which is optimistic marketing at 55# thrust. You said, “The motor had been running all day on and off. I didnt notice the smell until towards end of the trip. It was running at full speed.”
Amps go up as voltage drops in the battery
fakdaddy said:
50A fuse never blew.
The terminals are not super clean as they run on the ocean in kayak - but not super bad either.
Click to expand...
They need to be super clean.
I’d blame that first.

fakdaddy said:
Any suggestions on how to salvage this and to ensure battery is ok ? Im still a bit confused on a few points.
Click to expand...
If a warranty replacement isn’t available, I’d install a stud and run a nut down to the terminal with a big “fender” washer on the damaged side. Tighten the nut to battery mfgrs. specs for the connector bolt. (That’s not best practice in normal circumstances)
That may stabilize the terminal.

Clean those terminals! Once installed dry spritz with FluidFilm to thwart corrosion.
fakdaddy said:
1) Why the NOCO charger would always go "green" into maintenance mode but the battery was only at ~13.2v - undercharged
Click to expand...
It may not be good for lifepo which wants 14.6V
fakdaddy said:
2) Why the new 2A charger even after 48 hours was still charging and never went into maintance/full mode.
Click to expand...
Static voltage on LiFePo is not necessarily an indicator of fully charged. It may take a long time for the BMS to balance the cells.
Plus a 2A charger is not really a charger, it’s a maintainer. You need at least a 10- or 15A charger made for lithium
fakdaddy said:
3) Why (if the current got above 45A) the fuse didnt blow AND the BMS didnt shutdown above 50A draw.
Click to expand...
Which indicates the bad connection from corroded terminals is probably the culprit.
fakdaddy said:
and finally - where to next ........ on this battery ....
Click to expand...
Well I’d see about returning but it may be not a warranty issue- likely the terminal end corrosion.

I can NOT over the internet say that the battery IS SAFE TO USE OR TO ATTEMPT A REPAIR like I suggested above. If you question that or can’t make a determination yourself send it to recycling and buy another one. I’d be comfortable making a determination myself for myself but I cannot say you are- or not- qualified to make that determination. You’re on your own.
 
Should have put the original NOCO charger in there. Its a 5A charger for lifep04 batteries. Charges at 14.6A (supposedly).

Understand what your saying on the battery terminals - but this must be pretty common right ? I mean most guys run trolling motors and am sure most of them probably in worst condition than mine given its only 3 months old. But lets say it was the terminals/connectors ..... are you saying that would cause resistance which would then spike the AMP draw ? In that case wouldnt the BMS still shutdown.

Not questioning from a viewpoint of disagreeing - just to learn. Hope that makes sense.

Understand what your saying about not recommending anything - take that fully on board. Just wanting to know if I can't return the battery what my options are to ensure its just the plastic casing that's damaged - and not the battery itself. I had planned to hook this battery together with another 50aH in series to give me a 100AH. Now worried it might damage my other battery or do this again.

I bought a 200A DC voltage/amp draw/ watt use monitor to hook up inline ........ but anything else I can do on bench prior ?

thx again
 
fakdaddy said:
Should have put the original NOCO charger in there. Its a 5A charger for lifep04 batteries. Charges at 14.6A (supposedly).
Click to expand...
It may not push enough to charge in a reasonable time. At a minimum nominally that’s a ten hour recharge time from empty but something doesn’t compute for me.
fakdaddy said:
Understand what your saying on the battery terminals - but this must be pretty common right ? I mean most guys run trolling motors and am sure most of them probably in worst condition than mine
Click to expand...
That may be true but that’s on them. Some may have issues some not. The condition is a potential risk.
fakdaddy said:
lets say it was the terminals/connectors ..... are you saying that would cause resistance which would then spike the AMP draw ? In that case wouldnt the BMS still shutdown.
Click to expand...
I’m saying resistance causes heat. Throughput and perhaps voltage is reduced and the difference goes away as heat.
People have had car fires from a 5V 2A usb that gets shorted….
fakdaddy said:
Not questioning from a viewpoint of disagreeing - just to learn. Hope that makes sense.

Understand what your saying about not recommending anything - wanting to know if I can't return the battery what my options are to ensure its just the plastic casing that's damaged - and not the battery itself. I had planned to hook this battery together with another 50aH in series to give me a 100AH. Now worried it might damage my other battery or do this again.
Click to expand...
The terminal on that LiFePo is likely not as “solid” in the case as a typical car battery. There’s stuff underneath and you need to know if it’s damaged. BMS wires, one of the cells, etc. Not putting you down- but that you’re asking how makes me think you shouldn’t be doing it. Sounds insulting but that’s not what I mean. It’s like going to the dentist to have a gall bladder removed: competencies and familiarity.
You can learn but I’m not the expert- though I’d do it myself without hesitation.
fakdaddy said:
I bought a 200A DC voltage/amp draw/ watt use monitor to hook up inline ........ but anything else I can do on bench prior ?

thx again
Click to expand...
The thing is you need to look inside imho.
 
12VoltInstalls said:
It may not push enough to charge in a reasonable time. At a minimum nominally that’s a ten hour recharge time from empty but something doesn’t compute for me.

That may be true but that’s on them. Some may have issues some not. The condition is a potential risk.

I’m saying resistance causes heat. Throughput and perhaps voltage is reduced and the difference goes away as heat.
People have had car fires from a 5V 2A usb that gets shorted….

The terminal on that LiFePo is likely not as “solid” in the case as a typical car battery. There’s stuff underneath and you need to know if it’s damaged. BMS wires, one of the cells, etc. Not putting you down- but that you’re asking how makes me think you shouldn’t be doing it. Sounds insulting but that’s not what I mean. It’s like going to the dentist to have a gall bladder removed: competencies and familiarity.
You can learn but I’m not the expert- though I’d do it myself without hesitation.

The thing is you need to look inside imho.
Click to expand...

ok.
looked at few videos on youtube. doesnt seem that complicated in terms of basics.
4 cells in series. Bus bars.
4S BMS.
balance cables

But apart from ripping it out of the ABS plastic ..... what options would there be for testing ..... just seeing if all cells are balanced ?

also if I did that - what are most people using as a DIY casing that could be made somewhat waterproof ........ this sits in the hull of of kayak
 
fakdaddy said:
apart from ripping it out of the ABS plastic ..... what options would there be for testing ..... just seeing if all cells are balanced ?
Click to expand...
Load test it. I’m not that familiar with LiFePo but there’s threads on here that covers it.
But you need to know it’s safe / undamaged inside first.

fakdaddy said:
what are most people using as a DIY casing that could be made somewhat waterproof
Click to expand...
Id search for something ready made? I have no idea. The salt waterproof part is the issue.

How much did that cost?
I’d hate to throw money away but if it’s only $150 that solves all issues…

Otherwise by tonight you’ll know a lot more than I do!

There’s no harm in taking it apart I wouldn’t think. In current status it’s essentially junk so anything you do to get more life out of it isn’t harm- it’s a fix.
 
12VoltInstalls said:
How much did that cost? $280
I’d hate to throw money away but if it’s only $150 that solves all issues…

-- I can live with loss although it hurts ....... more worried about what do do next ........ keep on throwing money at it isn't a great option :)
Click to expand...
 
fakdaddy said:
Understand what your saying about not recommending anything - take that fully on board. Just wanting to know if I can't return the battery what my options are to ensure its just the plastic casing that's damaged - and not the battery itself. I had planned to hook this battery together with another 50aH in series to give me a 100AH. Now worried it might damage my other battery or do this again.

I bought a 200A DC voltage/amp draw/ watt use monitor to hook up inline ........ but anything else I can do on bench prior ?

thx again
Click to expand...
Nope, it is still 50 AH at 24 VDC.
 
fakdaddy said:
Firstly - thanks for jumping in here. Want to learn :)

The trolling motor is 55lb thrust and rated for 45A max (640W).


The motor had been running all day on and off. I didnt notice the smell until towards end of the trip. It was running at full speed.
50A fuse never blew.
The terminals are not super clean as they run on the ocean in kayak - but not super bad either.

Any suggestions on how to salvage this and to ensure battery is ok ? Im still a bit confused on a few points.

1) Why the NOCO charger would always go "green" into maintenance mode but the battery was only at ~13.2v - undercharged
2) Why the new 2A charger even after 48 hours was still charging and never went into maintance/full mode.
3) Why (if the current got above 45A) the fuse didnt blow AND the BMS didnt shutdown above 50A draw.

and finally - where to next ........ on this battery .....

appreciate any and all help
Click to expand...
my thought . dirty connector and vibration from the motor . caused a loose connection . and a arc built up and with that arc . heat built up. fun fact . do you know a arc welder runs on about 48v at 50 amps .. humm look at your numbers
www.instructables.com

Solar Welder

Solar Welder: Once the Golf Cart Welder was working well, the next step was to add solar power.Here's Marko welding a giant sports car rotisserie using the solar welder.These panels charge the cart at about 3 amps. Welding or driving draws up to 150 amps, but onl…
www.instructables.com www.instructables.com
 

Attachments

  • Screenshot 2022-01-01 at 14-04-17 Solar Welder.png
    Screenshot 2022-01-01 at 14-04-17 Solar Welder.png
    2.2 MB · Views: 5
fakdaddy said:
in the hull of of kayak more what do do next ........ keep on throwing money at it isn't a great option
Click to expand...
It sounds like you are exploring the knowledge needed to dissect the battery or not. So you may find it repairable.

If not and either way shine those terminal ends up. Get another battery. Tighten bolts to manufacturers specifications. If it happens again I’d say they owe you a refund on two batteries. I’d contact them about this anyway. As you said it don’t blow the fuse… do it died doing what it is advertised to do.
 
labeeman said:
Agreed but it does say SERIES and he does not know that a bad connection will cause connections to overheat.
Click to expand...
Yep meant the other one.

I actually do a bit with 12v car systems on a DIY restoration basis. Just much simplier.

And this is actually one of the most confusing parts to me .... if you have ever been to a junk yard and seen the condition of the terminals on trucks connected to a battery that supports 5x the cranking amps of this system ....... and even though thats a much shorter duration ..... supports many accessories on various circuits that each draw different amps when running ....... which can be over 50Amps .....

No issues - rusted and corroded terminals to boot. way worse than mine which I would only barley call rusted.
To the point I've seen many where the terminal had to be replaced as any maintenance (disconnecitng) would make it ir-repairable anyway as it was corroded/rusted that bad ....... yet some surface rust is what we think is happening here ?
 
12VoltInstalls said:
It sounds like you are exploring the knowledge needed to dissect the battery or not. So you may find it repairable.

If not and either way shine those terminal ends up. Get another battery. Tighten bolts to manufacturers specifications. If it happens again I’d say they owe you a refund on two batteries. I’d contact them about this anyway. As you said it don’t blow the fuse… do it died doing what it is advertised to do.
Click to expand...
Yes sir.

Thats the plan - have reached out to see what they say. Right now their first two repsonses were ;

1) You didnt have the terminal lugs tightened enough - not the case - was done with a screwdriver to full contact. Had to take off with a screwdriver also.
2) Your trolling motor draws more than 50A for which the battery is rated. Not true (per spec its max rated 45A draw).
 
fakdaddy said:
Yes sir.

Thats the plan - have reached out to see what they say. Right now their first two repsonses were ;

1) You didnt have the terminal lugs tightened enough - not the case - was done with a screwdriver to full contact. Had to take off with a screwdriver also.
2) Your trolling motor draws more than 50A for which the battery is rated. Not true (per spec its max rated 45A draw).
Click to expand...
Suggest that their connection inside the battery was bad.
 
fakdaddy said:
have the terminal lugs tightened enough
Click to expand...
There should be an inch/lb torque specification.
fakdaddy said:
trolling motor draws more than 50A for which the battery is rated
Click to expand...
Except for the trolling motor manufacturers put a big number (55) on their products but apparently can’t do the math. So while they have a point they are wrong.

But I read those responses as having squirming flavor of backing away from supporting the product.
 
12VoltInstalls said:
There should be an inch/lb torque specification.

Except for the trolling motor manufacturers put a big number (55) on their products but apparently can’t do the math. So while they have a point they are wrong.

But I read those responses as having squirming flavor of backing away from supporting the product.
Click to expand...
Well good news and a question.
They are offering a refund.
But this part confused me.

"The continuous output current of your thruster is 45A, and the continuous output current of the battery must be at least 90A to solve the problem. The continuous output current of the 12.8V 50AH lifepo4 battery is 50A, which cannot meet your needs."


Sounds to me like they are not 100% sure either and are just saying I need to upgrade to 100AH with 100A BMS to allow a wider margin of safety.
Or is there some science I don't understand where 45A is larger than 50A :)
 
You must log in or register to reply here.
Back
Top