# 2020 Tohatsu 40 hp lithium cranking battery?



## Stonedupwillie56 (Apr 12, 2021)

Is there anybody out there running a lithium battery for a cranking battery for your tohatsu 40 4 stroke. Relion batteries told me that the hp series would work as along as the motors alternator put out enough volts but then I spoke with tohatsu and the said as of now they don’t support lithium batteries. If y’all are running a lithium battery what all do you need to make the system work properly


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## TheAdamsProject (Oct 29, 2007)

Was told through multiple sources the Tohatsu and Lithium do not get along.


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## Stonedupwillie56 (Apr 12, 2021)

TheAdamsProject said:


> Was told through multiple sources the Tohatsu and Lithium do not get along.


Is there anyway to make them play nice with each other or is it just oil and water ?


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## TheAdamsProject (Oct 29, 2007)

Stonedupwillie56 said:


> Is there anyway to make them play nice with each other or is it just oil and water ?


I believe it was due to the voltage output from the tohatsu. I wasn't going that route so I did not dig into a solution but did pose that question at the time. Granted that was 2yrs ago and maybe they have made adjustments in the batteries as I am not aware of any changes made on tohatsu's end. I use a Group U1 AGM which is only 26lbs and been great.


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## mmccull5 (Nov 15, 2012)

May not be the same for tohatsu, but a regulator-rectigier from a higher hp motor seems to be the trick for yamaha.

Lithium pros also said having a power pole charge installed will act as a voltage regulator. After speaking with multiple power pole techs, no one gave me a definite answer on this.

I'd speak it over with Relion, they appear to have a good return policy if it does not work as intended.


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## TheFrequentFlier (Feb 17, 2016)

mmccull5 said:


> May not be the same for tohatsu, but a regulator-rectigier from a higher hp motor seems to be the trick for yamaha.
> 
> Lithium pros also said having a power pole charge installed will act as a voltage regulator. After speaking with multiple power pole techs, no one gave me a definite answer on this.
> 
> I'd speak it over with Relion, they appear to have a good return policy if it does not work as intended.


yeah I was speaking with PP about the same thing. I’m looking for a Lithium solution to crank an F70


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## NVswitch (Jan 25, 2021)

My understanding from reading but untested. Not all lithium batteries are the same when it comes maximum peak amp output. Which is when the starter is turned.
Outboards need 150 peak amps and not all the lithium 12 volt batteries supply this. I am looking at getting a Battle Born 100 amph battery for trolling motor and one of reason for this is that it has a 150 peak output. That is one of the reasons why it is called a “drop in replacement”. I want to be able to use in a pinch as a back up if starting battery goes out. 
But if it doesn’t work, I really got it for trolling motor battery. 
Again my thoughts and totally not tested. I will report once I get the battery in the coming months and can tell if it actually will start my Mercury/ Tohatsu 30.
Mike


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## bryson (Jun 22, 2015)

I'm not sure, but I think Tohatsu sells components (not sure which, exactly) to make the charging system work with lithium batteries. It's worth looking into.


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## mmccull5 (Nov 15, 2012)

NVswitch said:


> My understanding from reading but untested. Not all lithium batteries are the same when it comes maximum peak amp output. Which is when the starter is turned.
> Outboards need 150 peak amps and not all the lithium 12 volt batteries supply this. I am looking at getting a Battle Born 100 amph battery for trolling motor and one of reason for this is that it has a 150 peak output. That is one of the reasons why it is called a “drop in replacement”. I want to be able to use in a pinch as a back up if starting battery goes out.
> But if it doesn’t work, I really got it for trolling motor battery.
> Again my thoughts and totally not tested. I will report once I get the battery in the coming months and can tell if it actually will start my Mercury/ Tohatsu 30.
> Mike


You should have zero problem starting. The motor shutting off above idle is the issue.


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## Chumplz (Mar 23, 2021)

mmccull5 said:


> May not be the same for tohatsu, but a regulator-rectigier from a higher hp motor seems to be the trick for yamaha.
> 
> Lithium pros also said having a power pole charge installed will act as a voltage regulator. After speaking with multiple power pole techs, no one gave me a definite answer on this.
> 
> I'd speak it over with Relion, they appear to have a good return policy if it does not work as intended.


I was just digging around on this and couldnt get a clear response from Yamaha as to why you cant use lithium, asides from it not being supported. I have a new SHO 90 with the Banshee lithium battery and yet to have issues. I spoke with the guy that designed the batteries at Banshee and he said there should be zero issue with the motor over charging then causing a shutoff while underway at higher rpms. 

Where would this regulator-rectifer go if installed?


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## mmccull5 (Nov 15, 2012)

Chumplz said:


> I was just digging around on this and couldnt get a clear response from Yamaha as to why you cant use lithium, asides from it not being supported. I have a new SHO 90 with the Banshee lithium battery and yet to have issues. I spoke with the guy that designed the batteries at Banshee and he said there should be zero issue with the motor over charging then causing a shutoff while underway at higher rpms.
> 
> Where would this regulator-rectifer go if installed?


From my understanding it's all in the battery management system (bms). Appears either (a) banshee has it going on or (b) the 90 has a more robust regulator rectifier than the f70. 

This is the rr on an f70:


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## TheFrequentFlier (Feb 17, 2016)

I would think a PP charge would nullify the issue, but I’m not an electron expert at all.


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## Fishshoot (Oct 26, 2017)

Won't work on Yamaha either. Mine would always start but shut off with no warning. I was told it was because of voltage spikes from battery. My friend ran a tohatsu 50 off a motorcycle battery no problem and it was plenty light weight if that's what you are concerned with.


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## Chumplz (Mar 23, 2021)

Deep Cycle Lithium Iron Marine Battery Group 34 LiFeP04 800CCA


Our new Super lightweight Lithium ion LifePo4 battery is 1/3 the weight and has 3xs the life.



www.bigtimebattery.com





Here is the battery I run.


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## Tomas (Aug 2, 2018)

Don’t use lithium as a cranking battery. May interfere with your Tohatsu warranty and that 40hp won’t keep it charged. Just get a small AGM starting battery and save your $$. Lithium’s are great for trolling motors.


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## TheFrequentFlier (Feb 17, 2016)

Chumplz said:


> Deep Cycle Lithium Iron Marine Battery Group 34 LiFeP04 800CCA
> 
> 
> Our new Super lightweight Lithium ion LifePo4 battery is 1/3 the weight and has 3xs the life.
> ...


Nevermind. Answer is above.


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## TheFrequentFlier (Feb 17, 2016)

From a PP rep:

“The Power-Pole Charge will pull power from the cranking side battery and move it towards the trolling side but it’s not going to be a voltage regulator. We would also recommend to contact his motor company if they recommend a lithium battery on the cranking side because some motor manufacturers don’t.”


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## Matts (Sep 2, 2015)

I have just installed a small lithium as my starter battery and no problems thus far. I keep it charged all the time with on board smart charger. I have a Tohatsu 50hp. Chittum rep runs the same battery. It was around $350 and actually a motorcycle battery, but meets CCA required. It maybe weighs 3 pounds. I've done 3 trips so far with the new battery. Shop installed a lead acid battery, as per Tohatsu 50hp specifications and it leaked all over inside my center console. What a mess to clean up. I'll never let that shop touch my skiff again.


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## Rich11111 (Jun 6, 2018)

Matts said:


> I have just installed a small lithium as my starter battery and no problems thus far. I keep it charged all the time with on board smart charger. I have a Tohatsu 50hp. Chittum rep runs the same battery. It was around $350 and actually a motorcycle battery, but meets CCA required. It maybe weighs 3 pounds. I've done 3 trips so far with the new battery. Shop installed a lead acid battery, as per Tohatsu 50hp specifications and it leaked all over inside my center console. What a mess to clean up. I'll never let that shop touch my skiff again.


Don't need one now but for later reference. which battery do you have?


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## NVswitch (Jan 25, 2021)

I have a question for those using lithium as their main starting battery. I agree that one can get a lithium ion battery with enough of a max peak amp output to start an outboard.
The other side of the issue is if the outboard motor charging system can charge the lithium battery correctly? If not, one is totally relying on self charging the starting battery daily to prevent it from eventually going dead.
Any feedback on this point?
Mike


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## Matts (Sep 2, 2015)

Rich11111 said:


> Don't need one now but for later reference. which battery do you have?


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## Smackdaddy53 (Dec 31, 2012)

Matts said:


> View attachment 186031


That’s not the one Ford showed me. He was installing a black one when I was picking up the 21. Has he changed batteries since then?


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## Matts (Sep 2, 2015)

Smackdaddy53 said:


> That’s not the one Ford showed me. He was installing a black one when I was picking up the 21. Has he changed batteries since then?


No idea.


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