Hello All,
so the draw on the units is causing an issue with running down the cranking battery. i run an interstate 24 for cranking. both onix units and rest of electronics including livewell run on it. got caught with not enough power to crank on a fishing trip. small lake so i wasn't stranded, trolled back to ramp. what i'm thinking of doing is running a separate battery for the onix units, but i don't know what type of battery to get? and how do i tell how long it would run?

would running a higher number cranking solve to issue? like a 27 or 31.

if i run a separate battery is there a way to have the engine alternator wired to the separate so it charges when i run around?

thanks for the help


additional info:
units wired direct to battery
amp draw on onix is 2.5 amp per unit - 2 units
running 3 27 series interstate for trolling motor should i run onix units on the trolling batteries? but these don't charge while running engine. also need to learn how to calculate how long batteries would last.

boat info:
2000 champion 191DC 2000 mercury 2.5L efi

Higher number like 27 and 31 don't mean much. Reserve Capacity is the important number for how long a battery will keep something running. CCA is cold cranking amps and tells how much cranking power you have to start your engine.
5 amp draw is not much. A good cranking battery well charged ought to keep you going all day. How old is your cranking battery? What is the Reserve Capacity? How many CCAs does it have?

I would move up to at least a 27 series, these generally have more reserve cap as mentioned above. Also try to get a battery with the most MCA�s for the money. Do NOT get an AGM battery for that motor. I�ve heard that they will cause some issues with the efi�s such as burning up some electrical parts. A lot of people don�t think about it but I actually replaced my weak starting battery with a Napa Commercial 31 series after lots of research and haven�t had a bit of trouble out of it. Also, you might consider wiring the Onix�s directly to the starting battery, as they are apparently sensitive to voltage variations from running through the wiring through the boats control panel. Just my Good Luck! Let us know what you decide to do and how it works out.

To lessen confusion for you since we used CCA and MCA which you may not understand, CCA is figured at 0� and MCA is figured at 32� so if the battery doesn't say both know that CCA x 1.3 = MCA..

Yes, you can add a battery for the graphs if you wish, and configure it to charge when running, and automatically separate when not running. A Blue Sea Add a Battery Switch will accomadate that.

Reply to Dayne:

cold cranking amps 800
cranking amps 1000
RC is 135 at 25 amps
battery is 1 year old

Odyssey 31-PC2150S Heavy Duty Commercial Battery

This is the battery i run. With a Solix 15 and a Solix 12,

Your reserve amps are very low.

thanks Dayne, probable going to move to a 31 that has 195 reserve amps and 100 or so AH.

That sounds more like something that will go all day and crank that EFI.

Putting the one unit you are not currently viewing in standby mode will help a lot in conserving battery.