Replaced house battery- alternator won't charge house batt

[DerPo]

So just got to camp at Zion, plugged in my hand Amazon battery checker and saw that my new Trojan agm was down to 12.04v. I left the tester on and turned on the engine, and the Volt's stayed the same. Fortunately there is a 30a hookup and that is charging my battery.

The alternator was charging my engine batt.

The alternator was charging my house battery before I swapped it.



Any thoughts?

[rallypanam]

Here's what I would do, but others may have more knowledge.

1. Check all the wire connections. I had a loose connection on the wire going to house battery.

2. Check voltage to starting battery with engine running. The isolator will not open unless voltage is over about 13.2-13.4 or so. So if the van is putting out low power, or if the starting battery is particularly weak, then the isolator won't open.

3. Then check the battery isolator.. Probably a SurePower 1600 based on your vintage, but you never know. Likely under hood. You can jump over the SurePower if you can find it, and prove if it's working or not.

[DerPo]

Originally Posted by rallypanam

Here's what I would do, but others may have more knowledge.

1. Check all the wire connections. I had a loose connection on the wire going to house battery.

2. Check voltage to starting battery with engine running. The isolator will not open unless voltage is over about 13.2-13.4 or so. So if the van is putting out low power, or if the starting battery is particularly weak, then the isolator won't open.

3. Then check the battery isolator.. Probably a SurePower 1600 based on your vintage, but you never know. Likely under hood. You can jump over the SurePower if you can find it, and prove if it's working or not.

Connections are good


Starter bat is at 14

I have the hood open and no idea where or what the isolator looks like

[DerPo]

Ok found the isolator! Under the coolant res.

I opened the power distributor box and found 2 blown fuses. But from what I'm seeing online it looks like they are for the radio and instrument cluster. Both are working fine

[DerPo]

Fuses 22 and 14
http://ww2.justanswer.com/uploads/EC/Eclayton4/2013-05-16_192225_ford_99_e250_power_distro_box..gif


Woud that be it?

[rallypanam]

Originally Posted by DerPo

Ok found the isolator! Under the coolant res.

Yup. Blue thing? I think they generally installed a circuit breaker between that and the house battery, but I don't recall ever hearing of one tripping. But you should be able to check voltage on the output side and confirm it is functioning, then follow the wire to the house battery (and maybe through a circuit breaker).

Originally Posted by DerPo

I opened the power distributor box

Stock or SMB? It shouldn't matter, the power to the battery isn't going through a small fusebox either way.

[DerPo]

Originally Posted by rallypanam

Yup. Blue thing? I think they generally installed a circuit breaker between that and the house battery, but I don't recall ever hearing of one tripping. But you should be able to check voltage on the output side and confirm it is functioning, then follow the wire to the house battery (and maybe through a circuit breaker).



Stock or SMB? It shouldn't matter, the power to the battery isn't going through a small fusebox either way.

My smb owners manual says there's an auto breaker that resets it's self. Since by new bat was almost to 25%, I'm assuming it never switched it self back ( if it did switch)


The two fuses are a 30a and 40a

[rallypanam]

Maybe the breaker is shot.

The 30 and 40a fuses are in Ford panel or SMB accessory panel?

[DerPo]

Originally Posted by rallypanam

Maybe the breaker is shot.

The 30 and 40a fuses are in Ford panel or SMB accessory panel?

Ford. The link says it's for trailer accessories

[rallypanam]

Originally Posted by DerPo

Ford. The link says it's for trailer accessories

I've never seen SMB wire anything into the stock harness or fuse panels.