1 minute ago, Craig P said:

Just a note on the 50ah batteries for the TM.  That TM is looking for a 60ah input.  Guys on another forum are starting to realize their motors will not run at full speed with consistency while powering at that AH.  I would consider using 60ah for the TM.

I'd like to see the write-ups on that - AH should have nothing to do with how well the TM runs...just how long you can run it.

33 minutes ago, MN Fisher said:

I'd like to see the write-ups on that - AH should have nothing to do with how well the TM runs...just how long you can run it.

Yes and no. While ah is used for a common understanding of how long something can run vs watt need, if a device is expecting a higher flow rate than a battery can provide then performance is going to be hindered.  It’s been proven on the water by people who run TMs on a popular bass boating forum. 

I agree @MN Fisher.  A trolling motor does not have an amp hour requirement.  A LifePo4 battery’s maximum current output amperage is usually very close to its amp hour rating which is why I suggested earlier in this thread to check the max draw of the TM against the maximum output of the battery.  The BMS will shut off the output if this maximum is exceeded for a specified number of seconds.  It should all be defined in the battery’s specifications.   This is only true for batteries with a BMS which is what the OP is asking about.

9 minutes ago, Tennessee Boy said:

I agree @MN Fisher.  A trolling motor does not have an amp hour requirement.  A LifePo4 battery’s maximum current output amperage is usually very close to its amp hour rating which is why I suggested earlier in this thread to check the max draw of the TM against the maximum output of the battery.  The BMS will shut off the output if this maximum is exceeded for a specified number of seconds.  It should all be defined in the battery’s specifications.   This is only true for batteries with a BMS which is what the OP is asking about.

 

I recommend looking at the specifications from the manufacturer.  For this thread's purpose and the OP's desired TM, this is a link to the specifications and the input amperage stated for that TM.

 

https://www8.garmin.com/manuals/webhelp/GUID-B3BCDA2E-E3B8-4864-840E-DA1DB2C5C670/EN-US/GUID-72459CF0-A338-433B-B128-5359C52E18E1.html

1 hour ago, Craig P said:

I recommend looking at the specifications from the manufacturer.

Yes the input rating is 60 amps so the maximum output of the battery should be over 60 amps.   The “amp hour” rating of the battery is different.    The OP does not say what batteries he is looking at.   If we look at Ionic batteries specs,  a 50 ah 12 volt batteries would be a problem because they are rated at 50 amps max discharge.   A Battle Born 50ah 12 volt has a max continuous discharge of 60 amp and a 30 second max discharge of 100 amps.  If these values are exceeded, the BMS will shut off the current.  The Battleborn will reconnect after 5 seconds,  I don’t know about Ionic.

2 minutes ago, Tennessee Boy said:

Yes the input rating is 60 amps so the maximum output of the battery should be over 60 amps.

I just did a little nosing around. Most LiFePo4 batteries are rated at '1C' - that means they can't output more amps than their AH rating...ergo: a 50ah battery can only supply 50amps continuous. There are some exceptions, like the Battleborn you mentioned, but most LiFePo4 batteries are restricted in this manner.

 

Of course, I'd never try to run a 60amp TM off a 50ah battery anyway...heck, I'm running my 42amp max Edge off a 100ah battery....I want the time on the water that gives me.

21 minutes ago, Tennessee Boy said:

Yes the input rating is 60 amps so the maximum output of the battery should be over 60 amps.   The “amp hour” rating is different.    The OP does not say what batteries he is looking at.   If we look at Ionic batteries specs,  a 50 ah 12 volt batteries would be a problem because they are rated at 50 amps max discharge.   A Battle Born 50ah 12 volt has a max continuous discharge of 60 amp and a 30 second max discharge of 100 amps.  If these values are exceeded, the BMS will shut off the current.  The Battleborn will reconnect after 5 seconds,  I don’t know about Ionic.

So it does have an amp hour requirement.  At least the OP has some food for thought and can do his due diligence in available batteries for his needs. 

On 1/15/2024 at 2:45 PM, Craig P said:

So it does have an amp hour requirement.  At least the OP has some food for thought and can do his due diligence in available batteries for his needs. 

No there is no amp hour rating on the trolling motor specifications you linked to.  You can guess at what the max amperage of a battery might be based on the amp hour rating but they are not the same and suggesting they are will confuse people.

Trolling motor amp input power is limited by the circuit breaker rating and the wire size used. Think of amps as pressure too much pressure trips the circuit breaker and over heats the wire if too small circular mill area (CMA) to carry the DC load (Ohms Law).

If you to increase ah increase voltage.

Tom

40 minutes ago, Tennessee Boy said:

No there is no amp hour rating on the trolling motor specifications you linked to.  You can guess at what the max amperage might be based on the amp hour rating but they are not the same and suggesting they are will confuse people.

 

The link shows "Input Amperage" 60 A continuous.

12 minutes ago, Craig P said:

 

The link shows "Input Amperage" 60 A continuous.

That is the maximum amperage that the trolling motor draws on it's highest speed.  A is amperage.  aH is amp hours.

 

A battery stores energy like a gas tank.  The maximum amperage is like the maximum rate that gas can flow out of the gas tank.   Amp Hours is like how much gas the tank can hold.  A lawn mower engine needs a certain amount of gas flow to run properly but has not requirement as far as how big the attached gas tank needs to be to run properly.

 

A 100 amp hour battery can deliver 1 amp for 100 hours or 10 amps for 10 hours etc.

12 minutes ago, Tennessee Boy said:

That is the maximum amperage that the trolling motor draws on it's highest speed.  A is amperage.  aH is amp hours.

I think we’re in the same church, just different pews. Amp draw should be the concern first, use length, second. 

On 1/10/2024 at 12:56 PM, Siebert Outdoors said:

The lowest I've got the batteries for the TM is about 75%.  That was on a long windy day on St Clair.  Now if i fished the Detroit river or a river I'm sure I could drain them fairly quickly.  But for how I normally fish I've never had an issue.   

 

I have a single charger that charges my outboard that I will hook it up and check the battery but it rarely needs charged since the motor charges it.

 

I dont fish many tournaments.

Great topic and I'm going through the same process. We fish St Clair 95% of the time and like you we don't tournament fish but do fish every Saturday and Sunday (weather dependent) . We cruise around but spot hop and don't hit the rivers very often 

 

I originally was going to go 3 50ah 12v for my Ghost but then got some feedback on 2 36V 60ah. I think it might be too much power but its a big investment. Measure twice, cut once if you will. I'm still torn and looking for real world examples.