Battery and regulator rectifier for Tohatsu MFS30C

[adamjs16]

I am adding some electronics to my boat. I have two questions:

1) I have determined I need to add a regulator rectifier to the outboard to charge a battery. I have noticed a lot of people on here say you can use a motorbike one to save money. Am I able to use something like this for my outboard:

https://www.amazon.co.uk/dp/B07HQKJ3KP/ref=cm_sw_r_cp_apa_glc_fabc_VBTP2HHKAMP59HTMFCB0

2) I want to use a lithium battery to keep the weight down. Is this battery a suitable battery to hook up to the outboard:

https://www.eco-worthy.com/pages/second-one58bpv

Thanks for your advice.

[Poly]

Originally Posted by adamjs16

I am adding some electronics to my boat. I have two questions:

1) I have determined I need to add a regulator rectifier to the outboard to charge a battery. I have noticed a lot of people on here say you can use a motorbike one to save money. Am I able to use something like this for my outboard:

https://www.amazon.co.uk/dp/B07HQKJ3...HKAMP59HTMFCB0

I'm not an expert but looks like it should work in theory. It doesn't say what charge current its rated at. How confident are you that you can make good connections and keep them dry and immune to vibration? it looks like its meant to fit a specific loom.

2) I want to use a lithium battery to keep the weight down. Is this battery a suitable battery to hook up to the outboard:

https://www.eco-worthy.com/pages/second-one58bpv

Thanks for your advice.

At that size is the weight saving really that useful? The weight saving would be less than the difference between me sitting in shorts and t-shirt and me sitting in full water proofs having just been for a swim! I don't know much about Li batteries but they are almost universally considered a bit sensitive to charging conditions... with bad things happening if you abuse them. My only experience with a regulator issue (which was actually a cable corrosion issue not the regulator) was that the voltage shot up to >20V... that's bad for a Pb-acid but I think might by "lively" on a LiFePO

[adamjs16]

To be honest I'm not that confident fitting it myself. It would be easy to use the official Tohatsu part but it is about 7x the price. I would like to use a cheaper part if possible. Is there any other kind of reg rec you can recommend?

The battery weighs about half a lead acid battery (saves 11-12kg). Do you think that extra weight is not worth worrying about and I should save money instead?

[Poly]

Originally Posted by adamjs16

To be honest I'm not that confident fitting it myself. It would be easy to use the official Tohatsu part but it is about 7x the price. I would like to use a cheaper part if possible. Is there any other kind of reg rec you can recommend?

How do you feel about ordering from China? Does this look like it would plug directly into the loom on the engine?
https://www.aliexpress.com/item/4000875703559.html
I can't recommend any specific - as my engines have always come with it built in - but if I was doing a bodge job I'd be thinking about 1. How to make connections; 2. How to keep it dry; 3. How to ensure keeping it dry doesn't stop the heat getting out; 4. Using a battery that would be reasonably tolerant of any possibly ropey output.

Bear in mind that most tohatsu parts have a mariner direct equivalent.

If I was skimping I might look at something like this - then end up spending the same money again on connectors to make it fit: https://uk.banggood.com/Marine-Outbo...p-1814291.html

The battery weighs about half a lead acid battery (saves 11-12kg). Do you think that extra weight is not worth worrying about and I should save money instead?

12 kg is not much in the grand scheme of things - unless you are really struggling with weight / balance / or have a bad back and find lifting it in / our hard etc (is it really even as much as that - I have a Pb-acid which is 50ish Ah and I'd guess probably weighs <15kg. The only reason I'd go LiFePO on a SIB would be if I wasn't charging when underway - so the deeper cycling would be useful and popping in on a decent charger in the garage would be simple. But I think you'd want a charger designed for the purpose to get the best out of it.

[Pikey Dave]

Originally Posted by adamjs16

I am adding some electronics to my boat. I have two questions:



1) I have determined I need to add a regulator rectifier to the outboard to charge a battery. I have noticed a lot of people on here say you can use a motorbike one to save money. Am I able to use something like this for my outboard:



https://www.amazon.co.uk/dp/B07HQKJ3...HKAMP59HTMFCB0



2) I want to use a lithium battery to keep the weight down. Is this battery a suitable battery to hook up to the outboard:



https://www.eco-worthy.com/pages/second-one58bpv



Thanks for your advice.

What electronics are you fitting? I use a 20Ah Poover Lithium on my SIB. I also fitted a regulator to my manual start Suzi 20hp that gives max 6A. The battery is bag of sugar weight & size & will run my Lowrance Hook5/USB phone charger for a couple of days without trying. 30Ah might be a bit of an overkill, depending on what you’re running.
See my Volaire build thread for more info.

[adamjs16]

Sorry for the slow reply.

I have already seen your post Pikey Dave. It looks a great setup. I liked the ideas for a seat stopper. I had a seat fall off causing a puncture!

I have been talking with the dealer, as the listing on the Tohatsu site says it is including, I have been offered a 50% discount but I feel it should be free. Seems Suzuki and Tohatsu are playing the same trick. Still not heard back.

I have the same problem with the outboard voltage as Pikey Dave. I have been told by the dealer that the voltage outputted by the reg rec can exceed the 14.5v maximum voltage of the battery. I to, will look into get a buck converter.

I ended trying to get a 50Ah but because it was not in stock I got 2 of the 30Ah batteries from the site in my first post. I can see why you went for lead acid as they are cheap but I decided it was worth the extra money.

The elcetronics I'm going to get are:
Coolbox
IP67 LED light strips
360 nav light
Velixar SonarPhone fish finder
Two QC3 USB chargers
12V socket
Electric tyre pump with valve for SIBs
Small bilage pump
VHF receiver
IMU
Raspberry Pi

The raspberry Pi will send data from the outboard, sensors and VHF receiver to the chart plotter app on my phone.

I have quite a lot of stuff so I can camp on the boat. I need to be able to power the electronics, when the engine is off, for extended periods of time.

I'm trying to fit on a boat tent I brought on eBay but I'm having difficulties as the fit seems a bit off. If I sort out the tent, I'm tempted to try heating it with a Chinese diesel heater.

I will make a post dedicated to my mods very soon!

[Limecc]

"I'm tempted to try heating it with a Chinese diesel heater"

I have one of these in suitcase form and although I have yet to fire it up, I know they are 12v power hungry to drive the fan and also to get the catalyst up to temperature. Great for heating a garage but not your tent. I also purchased a silencer for it, they are quite noisy.