I bought a new to me truck that replaces my S10..Astounded to find dual batterys under the hood..I have RPO code 8bo.From what I can find this is for the camper. There is a relay that seperates the one batt from the starting batt.Upon testing, the spare batt read 9 volts so I removed it. Also during my tests all 7 pin connections work normal without this battery. All this battery does is it acts like an additional battery on top of the two that I have for the camper. So I assume this will allow me to have a third battery..Im thinking to put a 12 volt duracell deep cylcle 75 AH batt like the camper has.. Does this sound right?I should be able to boon dock with added power longer and get through the fall night with heater going, without waking up to batts that are under 50% discharge..Ill have 225 AH then if I do this..They had an AC delco 600 CCA batt in there. Funny the starting batt is the same but a 770 cca batt. Both these batts state 63 ah on the label which is weird...

What is the new truck? Years back I've seen trucks with a dual battery option, usually as part of snow plow package. I think the extra battery helps run the electric hydraulic pump and extra safety lights, rather than bog down the alternator. I had an 06 1500 Sierra with room for two batteries, but only wiring for one.

GordonThree wrote:What is the new truck? Years back I've seen trucks with a dual battery option, usually as part of snow plow package. I think the extra battery helps run the electric hydraulic pump and extra safety lights, rather than bog down the alternator. I had an 06 1500 Sierra with room for two batteries, but only wiring for one.Its an 06 silverado 1500 as the pic below shows..There is a terminal block that I can hook accessories to..Ill take pics and post back in a few...

Here is tha batt I took out.. And pics of the other batt tray and the starting batt..Extra battStarting battExtra batt tray on passenger side truck near firewall.Overview..

I'd check fuses and wiring to find out why that second battery wasn't charging. 9v is ruined.As far as adding to your power reserve for camping, it's possible but you'll need extra wiring. The factory wiring isn't setup for powering much of a load on the 7way connector.I'd go this route:A 4 gauge wire running from that accessory terminal back to the hitch will help move that extra power. A similar wire on the trailer into the batteries will link them together. Use a heavy duty connector like the Anderson power pole. Use a 4 gauge wire for ground on both sides too, doesn't need to be long, any easy to get to screw or bolt you can put a wiring terminal under.

GordonThree wrote:I'd check fuses and wiring to find out why that second battery wasn't charging. 9v is ruined.As far as adding to your power reserve for camping, it's possible but you'll need extra wiring. The factory wiring isn't setup for powering much of a load on the 7way connector.I'd go this route:A 4 gauge wire running from that accessory terminal back to the hitch will help move that extra power. A similar wire on the trailer into the batteries will link them together. Use a heavy duty connector like the Anderson power pole. Use a 4 gauge wire for ground on both sides too, doesn't need to be long, any easy to get to screw or bolt you can put a wiring terminal under.The battery was charging... Before I removed the batt it was charging and showing 14 volts or so. but with ignition off it was 9 volts... starting batt showed the same but with ign off stayed at 12.7...I understand the 7 way has a small wire to the charging circuit. Thats no worries.

RPO 8BO Duel Batterys on silverado | Good Sam Community

17 Replies

lawrosa
Explorer
Aug 27, 2016
The factory setup is -was-and will temain- a joke. The RV batteey will discharge the 2nd battery will yawn and you'll wonder what went wrong.

What do you mean??? The + at the 7 pin supplys the TT from the aux batt.

Your post dont make sense
MEXICOWANDERER
Explorer
Aug 27, 2016
Pollack and Cole Hersee make connectors with lids for transportation applications. 4-gauge will allow the 3rd battery to charge

BUT!

You must add a 4 gauge terminal and cable to the alternator output stud. Then to a 60-amp breaker then to the charge divider (solenoid) and back to the plug and socket. Wrap the cable running beneath the truck with nylon spiral wrap. Then you'll have something that will work for a living. The factory setup is -was-and will temain- a joke. The RV batteey will discharge the 2nd battery will yawn and you'll wonder what went wrong.
lawrosa
Explorer
Aug 27, 2016
GordonThree wrote:
I'd check fuses and wiring to find out why that second battery wasn't charging. 9v is ruined.

As far as adding to your power reserve for camping, it's possible but you'll need extra wiring. The factory wiring isn't setup for powering much of a load on the 7way connector.

I'd go this route:

A 4 gauge wire running from that accessory terminal back to the hitch will help move that extra power. A similar wire on the trailer into the batteries will link them together.

Use a heavy duty connector like the Anderson power pole. Use a 4 gauge wire for ground on both sides too, doesn't need to be long, any easy to get to screw or bolt you can put a wiring terminal under.

The battery was charging... Before I removed the batt it was charging and showing 14 volts or so. but with ignition off it was 9 volts... starting batt showed the same but with ign off stayed at 12.7...

I understand the 7 way has a small wire to the charging circuit. Thats no worries.
GordonThree
Explorer
Aug 27, 2016
I'd check fuses and wiring to find out why that second battery wasn't charging. 9v is ruined.

As far as adding to your power reserve for camping, it's possible but you'll need extra wiring. The factory wiring isn't setup for powering much of a load on the 7way connector.

I'd go this route:

A 4 gauge wire running from that accessory terminal back to the hitch will help move that extra power. A similar wire on the trailer into the batteries will link them together.

Use a heavy duty connector like the Anderson power pole. Use a 4 gauge wire for ground on both sides too, doesn't need to be long, any easy to get to screw or bolt you can put a wiring terminal under.
lawrosa
Explorer
Aug 27, 2016
Here is tha batt I took out.. And pics of the other batt tray and the starting batt..

Extra batt

Starting batt

Extra batt tray on passenger side truck near firewall.

Overview..
lawrosa
Explorer
Aug 27, 2016
GordonThree wrote:
What is the new truck? Years back I've seen trucks with a dual battery option, usually as part of snow plow package.

I think the extra battery helps run the electric hydraulic pump and extra safety lights, rather than bog down the alternator. I had an 06 1500 Sierra with room for two batteries, but only wiring for one.

Its an 06 silverado 1500 as the pic below shows..

There is a terminal block that I can hook accessories to..

Ill take pics and post back in a few...
GordonThree
Explorer
Aug 27, 2016
What is the new truck? Years back I've seen trucks with a dual battery option, usually as part of snow plow package.

I think the extra battery helps run the electric hydraulic pump and extra safety lights, rather than bog down the alternator. I had an 06 1500 Sierra with room for two batteries, but only wiring for one.

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RPO 8BO Duel Batterys on silverado

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