Elec help needed to charge house batteries

[LegalEagle82]

tom and gumpy,

could either of you post a picture of your setup. 

I have an eagle, so its 12 volt system for house and start.  I'm trying to understand if you can use 1 solenoid for both the charge connection and to help jump start if start batteries get just a little low on mine.  (Again, since the are both 12 volt)

Gumpy for example, you have a 200 amp solenoid.  Is that plenty enough rating if you have a 270/300 amp alternator?
My bus says the solenoid is a jump start relay.  I was thinking as long as I energize the solenoid while the engine is running it would allow my house batteries to charge.   

I'm not sure how to tell the amp rating of my solenoid.  I did not build my bus just bought it.  You can see my pictures of my solenoid under my posting for Jump Start Relay.  I guess I need to determine if it is a continuous duty solenoid too.

Any thoughts appreciated.   Its a little cold here in Nashville so I'll wait a few days before I have some of my own answers. Just looking for as much input as possible.  I thought if I have some low amp start relay only, I would change it out for a heavy duty solenoid and get all the benefits I was looking for.

Evan in Nashville....if anybody is close by, feel free to stop by and look and ponder...

[John Z]

Richard, i went to a web site for a distributor for the Sure Power isolator. After looking over their info, i don't know if it will work on my bus or not. They mention that whether or not you can use an isolator depends on whether your alternator is externally or internally switched. Hell! I don't even know if my 59 04 has a generator or an alternator! Simply wiring the two banks together with some sort of switch to connect or disconnect, i can understand. I would be comfortable putting that together. I do not have the knowledge to wire in the isolator.

[DrivingMissLazy]

I understand. It definitely will work, but you really need to stop at Grumpy's or someone else to get it hooked up. For the interim, the contactor will work fine.
Richard
BTW, the older 4104's had a generator. The newer ones had an alternator. You can easily tell it you like. If it has a removable band, and under the band are large brushes riding on copper commutator bars, it ia a generator.

Richard, i went to a web site for a distributor for the Sure Power isolator. After looking over their info, i don't know if it will work on my bus or not. They mention that whether or not you can use an isolator depends on whether your alternator is externally or internally switched. Hell! I don't even know if my 59 04 has a generator or an alternator! Simply wiring the two banks together with some sort of switch to connect or disconnect, i can understand. I would be comfortable putting that together. I do not have the knowledge to wire in the isolator.

[Dallas]

Another way to tell if it's an alternator or the original Delco generator is if it has 4 connectors on the side, (1 huge for battery connection and 3 smaller connectors), it's a generator. Also if it has a filter on the back end... it's a generator.

Here's a photo of a generator:

[gumpy]

Gumpy for example, you have a 200 amp solenoid.  Is that plenty enough rating if you have a 270/300 amp alternator?
My bus says the solenoid is a jump start relay.  I was thinking as long as I energize the solenoid while the engine is running it would allow my house batteries to charge.   

That is plenty large. The most I've ever seen going into my batteries off the engine is just over 100 amps @ 24v when the relay is first turned on, and then it drops very quickly to around 50-60 amps, and then drops as the batteries charge through the day of driving.

Trace recommends maximum charge rate at 1/5 the battery capacity. My bank is 440 amp hours @ 24v. That comes out to 88 amps max. This is used to calculate the inverter charger setting. I've never seen a continuous charge off the alternator above that, and again, only a short term (less than 3 minutes) above that when first connected.

If my bus batteries should get discharged and I needed to augment them with the house battery, I'd engage the relay, and let it sit for awhile before trying to start. This gives the coach batteries a chance to come up in charge prior to engaging the starter. That way, you are not drawing huge loads off the house bank during starting.

[jjrbus]

 While relays and solenoids are great, for the people that know how to troubleshoot them. Wouldnt a simple marine type selector switch be better for us non electric types? A 4 position switch rated at 350 amps continuous is less than $50 at marine supply stores.

[Kwajdiver]

John,

If you come to Ark.  I'm at the KOA, North Little Rock.  Should be here at least a couple more weeks.

Bill

[John Z]

Dallas and Richard, thanks to you guys, i am pretty sure i have an alternator! Cool! I checked it and no removeable band, and only three terminals - the large output cable, one marked "relay" and one marked "F", and above the F is marked "Do not ground." Not sure this helps me right now with getting the house bank charged, but it is good info to have in my book.

Bill - unreal! We were just looking at the AAA Arkansas book last night for a camp ground for the second night out. We may just look you up if for no other reason than to say "Hi." If all goes according to our rough plan, we would arrive evening Sun 2/11.

The relay i can understand and wire up,, but was looking at Grainger catalog and sure can't tell which one to buy, but am sure they can help me pick that out. The 12v switch to trigger the relay should not need to be anything special thouigh should it?

Thanks again to all you guys,, sure do appreciate the help.

[Len Silva]

While relays and solenoids are great, for the people that know how to troubleshoot them. Wouldnt a simple marine type selector switch be better for us non electric types? A 4 position switch rated at 350 amps continuous is less than $50 at marine supply stores.

The advantage to a solenoid is location, you can put it close to the batteries. If the batteries are in the rear and you want the switch up front it will take a lot of heavy cable. Another advantage is that the solenoid can be controlled in such a way that you can't forget it (by wiring into the ignition switch for example).

Len

[Homegrowndiesel]

John, I would suggest a fuse at one battery connection and the switch on the other end, both properly sized for the wire used. Easy to cut off the juice in the cable in case of an emergency.

When charging my house bank, or my 2- 8d coach batteries, the current draw routinely exceeds 250amps. But no matter how large a battery bank I have. The main issue is what You intend to do.

If you have an inverter, microwave, a/c unit or any high amp draw appliance, or battery bank the total amp draw will be alot, most likely all the alternator can put out. This will be the total of the batteries being recharged, as well as the total load of the electrical use.

To small  a wire and fuse and you will have more money in blown fuses, and a useless system.

If on the other hand you have really small electrical draws and battery bank that draw no more than a #6, wire can handle, then by all means you COULD use small connections.

We all use our busses differently.

Good luck with your choices.

Bill

[Gary '79 5C]

JohnZ,
I went thru this some time back as the isolation relay whcih connects house and coach batts, while OTR stuck in ( closed ). It was a intermittent duty relay, not intended for use over 3-5 minutes. This would work in a horm application.

I was looking for a 200 Amp Continuious Duty Relay and had one in my 5-C. The coach air cond. had been removed, however the 200 Amp relays were in the front bagg bay.
Sorry I have not been around a 41XX, so my help stops here.
The idea is the bus charges the two coach batts with 24Vdc, you connect an equalizer to derive 12Vdc (equally across the 2 coach batts, if not the weaker batt will take all the load (less internal resistance) The relay connects the this derived 12V to the house batts. Just run the 24V relay coil wire to the voltage regulator. When the coach is running the relay connects the two coach and house batts.

I would short term pull the coach batts out and into the house or heated space. Clean them off. Bring them up to 65 - 70 Deg. It will take 8 - 10 hours due to mass. Heck put them in the bath tub, clean them up right, Your wife will understand,,,, I would be sleeping the bus if I did that..

Charge the batts invividually with a large cap. 12V charger.

Install just before you leave or decide to start up. Clean the cables as well.
I will try to gin up a sketch of this and provide later. I think that Wrico has some wiring digrams, but I might be wrong

Best of Luck and hope this helps.
Gary

[DavidInWilmNC]

I just picked up a 24 volt continuous duty solenoid (relay) for joining the house and start batteries from Gainger.  It was $70, which was the best price I could find it for.  I have a DPDT switch mounted near the parking brake knob.  It'll allow me to connect the battery banks automatically (when the 'not gen' light goes off and the HVAC blowers will come on), manually, for jump starting off the house batteries, or off, to keep the batteries separate. 

This solenoid is also available in a 12 volt version.  If you need the part number, I can get it for you.

The only question I have is where the connection that allows the HVAC blowers to turn on.  I haven't been able to locate anything in the manuals.  Thanks.

David

[H3Jim]

David, what was the Grainger part number?  How many amps can it handle?

[DavidInWilmNC]

It handles 200 amps continuous.  Here's the link http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?ItemId=1611756367, Grainger part number 6C025.  The hardest part of the whole thing was getting an account set up (I'm not a business).  I'm glad I did, though, as there are lots of items that'll be helpful for this project.

David

[John Z]

Thanks David, one of those with a 12v trigger is just what i need. Now i just need to figure out and decide how heavy of wire to use for running between the battery banks. Just to show you how poor i am at electrical theory; until your post, i did not know that a solenoid and relay were the same critter! Thanks again.