Merging house batteries with the alternator

[David Anderson]

I have always had a problem with merging my house bank with my 350 amp Neihoff alternator. I use a 500 amp solenoid that I control from the cockpit. It is not continuous duty but it is heavy duty.  So if I use it for eight hours on a road trip that is beyond its ability.   I think I have bought at least three of these during my bus ownership. The one I have now is not really working right anymore. I'm not getting the voltage through the switch as my voltmeter on the dash is showing about 12.5 vdc and the inverter shows the same. It should be close to 14.2 vdc alternator output.
Has anyone had good success with some type of switching device?   I'm open for ideas.
David

[luvrbus]

David, Texas Industrial Electric should have a high amp cross over, if they are not rated for the amps, they go bad, I replaced mine twice before I bit the bullet and paid the price, they are not cheap @ almost 300 bucks, the 500 amp could be just the surge rating lol took me 2 to figure that out, you do need a continuous duty you are wasting money buying a momentary solenoid. My Country Coach has 2 of the $75.00 continuous duty solenoids wired together in parallel for the load when they go bad, I going to replace those with one then I only have 1/2 the problem maybe.    

[RichardEntrekin]

And use a continuous duty solenoid. Replace once per year.

[dtcerrato]

I have always had a problem with merging my house bank with my 350 amp Neihoff alternator. I use a 500 amp solenoid that I control from the cockpit. It is not continuous duty but it is heavy duty.  So if I use it for eight hours on a road trip that is beyond its ability.   I think I have bought at least three of these during my bus ownership. The one I have now is not really working right anymore. I'm not getting the voltage through the switch as my voltmeter on the dash is showing about 12.5 vdc and the inverter shows the same. It should be close to 14.2 vdc alternator output.
Has anyone had good success with some type of switching device?   I'm open for ideas.
David

We use the Blue Sea Remote Battery Switches. Cont. Rating is 500A. It is a latching relay that only needs power to latch in either direction then sits static. They have been issue free working great for several years now. We have one on each the house & chassis battery banks for bringing into or out of circuit for our Magnum converter and/or engine alternator. Ebay & Amazon sells them.

[sledhead]

somthing like this will work just not sure on the quality

https://www.amazon.com/dp/B082HMDMLG/ref=sspa_dk_detail_1?pd_rd_i=B082HMDMLG&pd_rd_w=KqFgC&content-id=amzn1.sym.88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_p=88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_r=CHEFF0QBPY4SSGWG09KX&pd_rd_wg=AMR7F&pd_rd_r=01b9c076-7684-42b4-8368-71a8a24126ce&s=car&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFPNDRFT0VITFRNMFMmZW5jcnlwdGVkSWQ9QTA2MTUxNDAzN1VMVFMzOVRLMFdQJmVuY3J5cHRlZEFkSWQ9QTA3ODE1NzRWV0VSOUpJUUM2RlMmd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl&th=1

[David Anderson]

We use the Blue Sea Remote Battery Switches. Cont. Rating is 500A. It is a latching relay that only needs power to latch in either direction then sits static. They have been issue free working great for several years now. We have one on each the house & chassis battery banks for bringing into or out of circuit for our Magnum converter and/or engine alternator. Ebay & Amazon sells them.

This has my interest. What is the difference between the 7700 momentary and the 7713 continuous?
I'm not clear on that spec.
I don't find any difference in the wiring instructions.
The reason I ask is that I would like to keep the dash switch I have because it matches my switch array on my dash. It is off/on with a light when on. That would be wired as 12v+ 12v-
12v load.
David

[luvrbus]

They wire the same the coil inside are different. A momentary solenoid will get hot as hell under a constant load

[David Anderson]

David, Texas Industrial Electric should have a high amp cross over

This is the 2nd one I've bought from them. He told me on the phone last Friday that 8 hours of continuous coil power is too long. Damaging heat buildup.  I need to change my engineering.
David

[David Anderson]

They wire the same the coil inside are different. A momentary solenoid will get hot as hell under a constant load

Yes but if you look at their specs all model numbers have a continuous rating of 500 amps whether it is a momentary or continuous coil

[dtcerrato]

This has my interest. What is the difference between the 7700 momentary and the 7713 continuous?
I'm not clear on that spec.
I don't find any difference in the wiring instructions.
The reason I ask is that I would like to keep the dash switch I have because it matches my switch array on my dash. It is off/on with a light when on. That would be wired as 12v+ 12v-
12v load.
David

We have the 7700s I think the continuous & momentary mention pertains to the operation, not the coil spec. These are NOT conventional solenoids but latching relays. They only need power to latch. These are once & done... They are in the $100 range, you get what you pay for. We have used solenoids successfully for many decades but when it came to high amperage (500 continuous) and low voltage (12VDC) these latching relays are superior and have the dependability & longevity expected. You could maintain your current switch configuration to power the 7700 & it's needed switch. I'm not particularly versed in the difference between the 7700 & 7713. Go to the Blue Sea website as they give good full descriptions & specs better to understand than 3rd party advertisers.

[buswarrior]

words, they make trouble...

For the silently watching learners, there are two uses of the word "continuous" for these solenoid switches.

The rating of the electrical contacts, the amount of amperage that it should "continuously" carry, without failing, versus a momentary or surge rating.

Then there is the solenoid that draws the electrical contacts together, which may be a "momentary" solenoid, intended for a short connection, like a starter, or a "continuous" solenoid, which is intended to hold the contacts together for a long time.

So, a busnut, for tying a house bank to the alternator for charging purposes, wants a continuous amperage rating higher than the alternator output, and a continuous rated solenoid in that switch. Wired up with the correct size of cables, of course...

The latching feature mentioned earlier is a nice way to go, as there is energizing of the solenoid coil only to move the contacts, not to hold them together.

Fancier they are, the more they co$t...

happy coaching!
buswarrior

[luvrbus]

Yes but if you look at their specs all model numbers have a continuous rating of 500 amps whether it is a momentary or continuous coil

All I can say is someone has the specs screwed up,500 amps is close to what a starter would draw,they use a momentary to tie the banks together for a boost in power for starting all RV's with 2 battery banks have that feature and use another solenoid or isolator to charge the house bank,All continuous service solenoid are not a latching type ones with latching usually have a L in the model number .BlueSea buys their solenoids from Cole/Hersee even the manual rotary switch they sell is a Cole/Hersee lol put it in Blue Sea packing for boat owners and the price goes up.I had a Blue Sea electrical panel 12v and 115 V in one panel only took 2 trips to marine place to find out who made the breakers for the panel 
       

[David Anderson]

words, they make trouble...

For the silently watching learners, there are two uses of the word "continuous" for these solenoid switches.

The rating of the electrical contacts, the amount of amperage that it should "continuously" carry, without failing, versus a momentary or surge rating.

Then there is the solenoid that draws the electrical contacts together, which may be a "momentary" solenoid, intended for a short connection, like a starter, or a "continuous" solenoid, which is intended to hold the contacts together for a long time.

So, a busnut, for tying a house bank to the alternator for charging purposes, wants a continuous amperage rating higher than the alternator output, and a continuous rated solenoid in that switch. Wired up with the correct size of cables, of course...

The latching feature mentioned earlier is a nice way to go, as there is energizing of the solenoid coil only to move the contacts, not to hold them together.

Fancier they are, the more they co$t...

happy coaching!
buswarrior

Well said.

Then the 7713 is the one for me.  I have 4 aught wire and 300 amps is the fuse rating on my line which is sufficient for my uses.
https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/sales_sheets/6834-007-ML-RBS-web.pdf

[olebusman]

    I use a Bigboy latching relay. Been working for 23 years

[TomC]

Check out this smart switch over through Battle Born. https://battlebornbatteries.com/product/lifepo4-battery-isolation-manager/