20 amp regulated alternator charging batteries?

seewll · 03-05-2007, 11:04 PM

I have a Johnson 115 and it has a 20 amp regulated alternator. If I want to hook up two 875 MCA batteries, using a ACR relay will this motors alternator charge them with out causing damage to anything in the electrical system of the motor. Will the alternator handle this? The min MCA is 465 for the motor, I know it is overKill but wanted to have plenty. Am I going in the wrong direction? If this needs to be asked in another forum please let me know. THanks, I am confused, I searched for an answer on the old posts but no information showed a match. Thanks.

A1 Outboard · 03-06-2007, 10:06 PM

It's a lot cheaper and easier just to add a 1-2-ALL battery switch so you can always have one charged up. Just alternate the battery switch so #1 for going out and #2 battery for coming back.

Another way is to get the battery isolator and charging wire kit from BRP and wire it in, assuming that you have the 60 degree 115, 1995 or newer.

seewll · 03-07-2007, 06:12 PM

A1, I have a blue seas ACR on order, and a Perko switch, my motor is a 2000, Ocean Pro J115VLSSS.
Can you have a battery too big?

A1 Outboard · 03-08-2007, 01:19 AM

Quote:

seewll - 3/7/2007 6:12 PM

Can you have a battery too big?

nope, just be sure to use stainless steel nuts on the terminals, never wing nuts.

seewll · 03-08-2007, 08:28 PM

A1, THANKS for answering my question, How do I decide what size battery cable to use as far as connecting the common ground or negative between the two batteries. I do not have a large load, GPS, VHF Radio, maybe a CD player later and maybe a trolling motor next year, other than that I do not see any other adds. I looked at a wire drop calculater from BEP and not sure what amp draw to go with. How do I calculate this, based off the size of the battery or the load. THANKS again for the information, If i lived close YOU would work on my boat!

A1 Outboard · 03-09-2007, 07:14 AM

For a ground cable between the 2 batteries, use at least the same size as the other battery cables, but no less than 4 ga. Everything is related to the load thru the cables, not the size of the battery.

snoopy · 03-09-2007, 01:49 PM

Why do you recommend 'NO WINGNUTS '?

A1 Outboard · 03-09-2007, 03:07 PM

Quote:

snoopy - 3/9/2007 1:49 PM

Why do you recommend 'NO WINGNUTS '?

Read the service manual, talk to a factory trained technician, later owners manuals mention it as well as the installation manuals. Most folks use their fingers on a wing nut. Lockwashers and hexnuts keep the smoke inside the electronic items on the motor.

seewll · 03-09-2007, 10:03 PM

Quote:

A1 Outboard - 3/9/2007 3:07 PM

Quote:

snoopy - 3/9/2007 1:49 PM

Why do you recommend 'NO WINGNUTS '?

Read the service manual, talk to a factory trained technician, later owners manuals mention it as well as the installation manuals. Most folks use their fingers on a wing nut. Lockwashers and hexnuts keep the smoke inside the electronic items on the motor.

YEP my Johnson manual says NO wing nuts! the old one sure had them, I will go find some lock washers and nuts.