Electrical Question: Is This Normal???

Sharphooks

Sharphooks

Well-Known Member
So I picked up a kicker for my new ride. I sort of assumed (ha ha) that the marine installer would wire it to the house battery. No, why do something logical like that? My quiet suspicion is they wired it to the starter battery to save on having to make a 4 AWG wire run. So yesterday I picked up some 4 AWG, did a nice clean swage job on the connectors, and got it all zip tied in nice and purty.

Unfortunately, I wasn’t thinking clearly and I wired it into a house power bus that was on the wrong side of the power shut off switch so it basically got wired “hot” direct to the house bank

So I had the hot end of the wire in my hand and while trying to decide where I would install the power pole so the 4 AWG wire could shake hands with the positive wire from the kicker I happened to brush the flange up against that aluminum flange below in the picture covering the bilge hose ( I believe it’s a bracket for a diesel tank that feeds the webasto).

48902368-CB76-40BE-94FD-1D97D8ADA795.jpeg


Instant spark. I didn’t get shocked but I might as well have brushed the positive up against a negative bus bar.

Today, a bit spooked, I hooked up a multimeter to the hot end of that 4 AWG flange and wow, any piece of aluminum I touched on the transom (through-bolts for the outboard bracket etc) I got 12.50 V on the multimeter

What the heck——On a fiberglass boat? How can those flanges and bolts be grounded enough to register 12.5 V???

This afternoon I was sufficiently spooked to re-wire the kicker so now that cable will only be hot when the house switch is in the “on” position

Am I missing something? Is that normal to see 12V, especially on a fiberglass boat??? If I connected the multimeter to the outside of my 150 gallon gas tanks would it have registered 12.5V???

I’d appreciate any comments
 
What is the aluminum piece in the picture and is it the flange your said you touched? Your fuel tank should be grounded and show a voltage. As for engine bolts...it finds away like mike mentioned.
Meters are also super sensitive and it does not take much for them to read a voltage...a dirty trick that sometimes makes people run in circles. Do you have a test light? Be interesting to see if it lights up. Its possible to see voltage and not be able to pass any useful amount of current.
 
Kicker should be wired up to the start battery. ACR charges the house.
fuel tank should be bonded which would eventually be connected to battery-
Pod will be grounded through the bolts on the engine
 
I rewired so that 4AWG it’s now charge-protected on the proper side of a house battery shut-off solenoid. That aluminum flange that sparked is a bracket for a diesel tank that feeds a heater. I can now see that as it’s bolted into the transom, it’s part of the outboard bonding/negative ground and now understand why it sparked the way it did.....I just never expected to see that on a fiberglass boat without a specific grounding plate
 
Installer was right to wire kicker to start battery/ies. Not a cheapout. House loads should be isolated from start batteries except when charging current is present.
 
I also think it should go to the start battery which will keep that battery topped up and then the acr will allow the house to charge . But I am not 100%.
 
Don't have a kicker and next to zero electrical knowledge so this may be a stupid question. Can the kicker be wired so that it draws current from the start battery to fire up but have the output go to the house battery so that it keeps it topped up when trolling without the use of an ACR?

A little off topic but I know that some don't like to use the house as a start battery. On mine little 30HP diesel I started from the house battery for 5 years and all other electrical draws came from the start battery because they were installed incorrectly. Swapped them around to how they were supposed to be and still going 4 years later.
 
wire it to the house battery. use a spring loaded resettable fuse you can buy off amazon for cheap (look at my latest post for my catmaran and you can see pictures of what they look like) in the trolling motor max amp+20% range. you can wire it up without an ACR. its 2023 and sterling have introduced reversible battery chargers this year. i just bought a bunch - they allow bidirectional flow and are far superior to an ACR. not advertised on their website but you can call them directly if interested and they will ship it to you.
 
I have twin DF300’s recharging the starter batteries. I also just installed a pair of dual purpose Group31’s with lots of amp hours.

I’ve also learned that when having a pile of electronics, HP Scotty’s and a marine refrigerator on a boat, the house battery gets severely beaten up on a long boat camping trips—I no longer call kicker motors trolling motors—-they’re gensets with propellers

I didn’t know about those Sterling reversible battery chargers, Zurk—I will def look into them but I’m not sure what the difference is between these and an ACR —-maybe they’re a bit more sophisticated with charge settings but aren’t they accomplishing the same thing as an ACR?
 
Last edited:
Properly sized DC to DC chargers protect your alternator from overload, and allow you to charge different natures of batteries without the risk of boiling, undercharging or overcharging the house batteries.
 
Captain PartyMarty said:
I asked Bluesea where I should connect the kicker motor output. Here is the tech supports answerView attachment 91991
Click to expand...
Sharphooks said:
So I picked up a kicker for my new ride. I sort of assumed (ha ha) that the marine installer would wire it to the house battery. No, why do something logical like that? My quiet suspicion is they wired it to the starter battery to save on having to make a 4 AWG wire run. So yesterday I picked up some 4 AWG, did a nice clean swage job on the connectors, and got it all zip tied in nice and purty.

Unfortunately, I wasn’t thinking clearly and I wired it into a house power bus that was on the wrong side of the power shut off switch so it basically got wired “hot” direct to the house bank

So I had the hot end of the wire in my hand and while trying to decide where I would install the power pole so the 4 AWG wire could shake hands with the positive wire from the kicker I happened to brush the flange up against that aluminum flange below in the picture covering the bilge hose ( I believe it’s a bracket for a diesel tank that feeds the webasto).

View attachment 91971


Instant spark. I didn’t get shocked but I might as well have brushed the positive up against a negative bus bar.

Today, a bit spooked, I hooked up a multimeter to the hot end of that 4 AWG flange and wow, any piece of aluminum I touched on the transom (through-bolts for the outboard bracket etc) I got 12.50 V on the multimeter

What the heck——On a fiberglass boat? How can those flanges and bolts be grounded enough to register 12.5 V???

This afternoon I was sufficiently spooked to re-wire the kicker so now that cable will only be hot when the house switch is in the “on” position

Am I missing something? Is that normal to see 12V, especially on a fiberglass boat??? If I connected the multimeter to the outside of my 150 gallon gas tanks would it have registered 12.5V???

I’d appreciate any comments
Click to expand...
gunnerlove said:
Properly sized DC to DC chargers protect your alternator from overload, and allow you to charge different natures of batteries without the risk of boiling, undercharging or overcharging the house batteries.
Click to expand...
From reviewing this post the other big piece of the puzzle that is missing is the current chemistries of the batteries.

Most of the Blue sea information for their recommended installations assumes you are using x2 start batteries in their diagrams. I am guilty of running mixed chemistry batteries where I have both a start battery and a deep cycle AGM for my house battery. Deep Cycle AGM's are not designed for the high AMP discharge that is required for a start. They also do not like the recovery starting battery charging schedule used by most store bought chargers.

I have a blue sea add a battery kit on my boat. I use the recommended ACR disconnect switch they show in their diagram for the ACR so that I can charge my batteries using 2 different charging schedules with a dual battery marine charger. Two sets of charging leads, 2 different selected charging rates. In the beginning before adding the ACR disconnect switch the batteries would connect and send my smart charger into a shutdown and a fault code. I mention this because some analog chargers or different brands will not! And then charge the crap out of your deep cycle batteries as if they were flooded starting batteries which beats the hell out of them!

My Kicker is connected to my starting battery because my house battery is a deep cycle AGM for running the house and 24HR circuits for the bilge pumps.

Also I hope you have figured out why other metallic objects on your fiberglass boat show common ground.

Hope this helps
 
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