36v to 12v question

[JustinNC]

So the new-to-me boat I bought came with 2 lithium 36v 60ah lithium batteries. I've added brakes (two 30lb MK Enduras) to the back of the boat (crappie fisherman), and not wanting to pony anything else off the starting (12 v 100ah) starting battery. I can either add another 12v dedicated to the brakes, or add a converter to pull off one of the 36V.

Are there any drawbacks or potential dangers/cautions to using a converter? If I go converter route, is there anything in particular I should look for in one?

My bilge/livewell/anchor and running lights and two graphs are on starting battery. Two livescopes and associated head units on another 100ah battery. Hate to add ANOTHER battery, but I will if the converter doesn't seem to be a good option.

[CatFan]

Should be fine. Just make sure you know how much power you need and get one rated for enough.

[JustinNC]

Should be fine. Just make sure you know how much power you need and get one rated for enough.

Dumb question but how would I figure what I need it to be rated for other than 36v to 12v. I see some say 10amp and some say 20amp, etc.

[MTW]

buy one that is well filtered. i wouldnt use anything above 120mvp ripple in the spec.

[CatFan]

Dumb question but how would I figure what I need it to be rated for other than 36v to 12v. I see some say 10amp and some say 20amp, etc.

Add up the max current for everything you want to run off of it and get a unit a little bigger

[BRNut]

Looks like 30amp max draw per trolling motor.

Like CatFan suggested, 60amp plus margin say 80a.

Going to be a reasonably large 36 to 12 converter.

Mean Well SD-1000L-12, 60amp output
Item #: SD-1000L-12

DC/DC Converter
Enclosed Type
Input Range: 19~72vdc
Manufacturer: MEAN WELL

Too be completely honest, 36v powered motors would have been better.

Battery would be my choice with what you have.

Best,

BRNut