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Shore and Alternator charging? Easiest way to accomplish this.

14K views 35 replies 12 participants last post by  orton 
#1 · (Edited)
My transit will be my daily driver as well as camper van, so I am curious about having the alternator be the primary source of power. Before I dive into a wiring diagram, can anyone point me in the right direction for the easiest and cheapest way to accomplish the following?

1) The alternator will provide the vast majority of the power. Currently I have just the stock alternator. Can I upgrade this or add an alternator exclusively for the battery bank?
2) Shore power available to provide auxiliary charging power when parked. Can this be done with standard 120V and also an 30A RV hookup? I imagine this being plugged in both while traveling at a campsite, as well as in the driveway of my home.
3) Setting up A/C to run on shore power, but also for short times on battery. Should I connect the A/C to the battery bank, and have the shore power push through the bank? Or wire directly to the shore power? The issue here is that I want to be able to run the A/C for an hour or so on battery power, just to drop humidity in areas like FL to make sleeping bearable.
4) Just to complicate... I also want to charge lithium batteries that I use in my boat (trolling motor) from the van. Two 12V 50AH batteries. How would you wire this - just hook up a standard charger to an inverter, or is there a more efficient solution?

I am planning on about 400AH of lithium.

Thanks!
 
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#3 · (Edited)
Boats are typically 24 volt.

Sterling makes a battery to battery charger specifically for this application. The alternative of using an inverter to a charger also works and ends up costing about the same.

If it were me, I would build the main house bank as a 24 or 48 volt system as well, as it will work out a lot better for feeding the inverter.

As an example, the photo on the left is (internally) a 24 volt based system with 4 each battle borns in the larger case and all of the DC distribution / outlets, including 24 volt, USB, regulated 12 volt, etc. The smaller case contains the inverter and 120 vac power distribution.

We build and ship these to customers routinely. The end customer just loads the batteries and does the final connections.

Based on the BB specs it should run an AC for around 2 hrs plus have some extra over head room.
 
#4 · (Edited)
If you are usually connecting to shore power all you would need is a good battery charger like you would use in the garage. Choose one that does multi-stage and maintenance charging duties, hard-wire it to the battery using a charging connector (instead of the clamps) and mount it permanently in the van (allowing for some airflow) with an outlet nearby that is wired to your shore connection.

As for the lithium, you will need a charger that has a setting for that charging profile. Something else to look for in the charger mentioned above, then, have pigtails for the Lithium batteries that can connect to the charger after flipping the switch from lead-acid charging to the appropriate Lithium profile.

Charging batteries other than the start battery from the alternator would involve a battery to battery charger as mentioned, and one that can switch from Lead-acid to Lithium profiles if you need to charge both types.

Do take the time to read up on wiring an RV for shore power, and especially on how to test the supply connection prior to hooking it to your van. There are significant safety concerns that must be addressed in case the shore power supply outlet is not wired correctly.

Most RV spots I've used offering shore power have a standard 15 Amp 120VAC outlet in addition to the 30A or 50A connection. Still, it might be good to get a 30A male to 15A female adapter to keep on board.

When you aren't using loads that exceed what you would put on an outlet at home, 15A is all you would need.

For AC the 30A connection will probably be necessary, depending upon the rating of the AC unit, as well as wiring in the van to support that current.
 
#5 ·

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#6 ·
Hi Flyfish,

Just a comment - if you are spending the money for 400Ah of lithium, I recommend that you spend a little more to get quality components that make your whole system work well. As with previous posters, I recommend a Victron inverter/charger to provide AC power from your battery bank. The Sterling charger is a smart solution for house battery charging from the alternator. As to the question about an auxiliary alternator, it depends on your power consumption and how quickly you need to recharge. If necessary, you can add a second alternator or install one with larger capacity.

Best of luck on your build!
 
#7 ·
The all in one inverter/charger/shore transfer units look great on paper and definitely have their uses. They also have drawbacks. They are either an inverter running off a battery or they are a charger running off shore power. They can't do both at once.

Another drawback is when the charger or inverter side fails, the whole unit is scrap.

I have all seperate units. A 2000w inverter, powered off the engine alternator, or house battery, or shore power, or genny. A battery charger, powered off the inverter. A standalone 30amp shore power transfer switch.

I have no solar, the house battery will mainly charge from the inverter off the engine alternator powered inverter. At least once a week I'll plug into shore power if I feel I have not driven enough to complete a 3 phase charge to the house battery.
 
#8 · (Edited)
The all in one inverter/charger/shore transfer units look great on paper and definitely have their uses. They also have drawbacks. They are either an inverter running off a battery or they are a charger running off shore power. They can't do both at once.
This combo unit can charge from Solar or Shore and manage providing 120VAC via inverter or Shore connection simultaneously.
https://www.fordtransitusaforum.com...ngoldpower-all-one-mppt-inverter-charger.html

Theoretically, you might could connect the Start battery to the MPPT input on the above to accomplish what you describe, with an inline low voltage cutoff to prevent over discharge of the Start battery.

Come to think of it, I might be able to parallel the Start battery circuit (w/ low voltage cutoff) with the Solar input to do this on mine. Thanks for sending my thoughts in this direction. :D

I'll need to research whether back voltage to the Solar panels could be an issue when the Start battery voltage exceeds the output of the panels while the alternator is running.

If anyone knows of a reason either of these ideas wouldn't work, post up please.
 
#9 ·
The advantage of a inverter/charger/transfer switch is the physical space required and the reduced wiring connections.

My 1000 watt Magnum MMS1012 has worked very well for my application. I have two sources of 120 volt AC power. Either real shore power or 120 volt AC from the vehicle powered 1000 watt pure sine inverter. Do not directly connect the house battery to the vehicle battery for charging.

Have a single 300 watt solar panel with MPPT controller. Both the Magnum and the solar controller provide a proper 3 stage charge profile.
 
#15 ·
Hybrid technology: Most inverters only use one source of energy to power loads, either
from incoming AC power – shore or AC generator – or from the batteries. The MSH-M
Series combines the energy from both sources to power loads. This allows the inverter to
recharge the batteries when there is surplus power or deliver more power to the loads if
they require more than the AC input can supply by itself.


This would be very useful at campgrounds with intermittent low voltage.



https://www.magnum-dimensions.com/m...2987&field_output_power_watts_value[max]=5600
 
#20 ·
I'm not the one with a question. I have my system parameters worked out. I was only offing an option for the OP.

My system will have one vehicle powered inverter (Orton style). It will have the option to be powered from the alternator OR the house battery via a 3 way select switch. The inverter will power a shore battery charger that is connected to house battery. I will be able to charge the house battery when driving AND have 115vac available to recharge electronics. If I don't need to charge house battery, the engine powered inverter will be able to run a roof air conditioner as long as the van engine is running thanks to a 250 amp alternator. My shore power transfer switch will take over all 115vac tasks when plugged in to external ac OR a genny.
 
#22 ·
I will be able to charge the house battery when driving AND have 115vac available to recharge electronics.
I just bought a small foldable 20" electric bike. Fits inside across back of van between the rear door frame posts. So another use for the vehicle powered inverter is charging the bike as I drive.
 
#21 ·
We have used both combo inverter / chargers hybrids (example Victron 3000) and separate component charger + inverters in projects.

While both can work, the big advantage of using separate components is tolerance to poor incoming power, such as generators that are not working quite right. It is pretty common for RV generators to work non ideally, and campgrounds have fairly massive variable loads from people coming and going with 50 amp x 240 vac connections.

Transfer switches remain as a high incident failure component in RVs, and that can completely take out a combo unit since many are not repairable these days.

A build based on a dedicated charger and dedicated inverter is a lot more robust for operation in those fairly terrible incoming power conditions. Not as efficient, but really tolerant.

Our default standard is dedicated components unless really pushed by the customer for something else.
 
#25 ·
Wow, a huge thank you to all who have participated here. Lots of great info - and question essentially answered.

Sportcoupe, your wiring diagram looks very appropriate for my application. Just so I understand, the system here would operate in the following manner...

- The alternator would run, charging either the house battery or the starting batteries.
- The charge direction from the alternator (house or starting) would be manually selected with a three way switch. Only one at a time.
- The batteries (house or alternator) could also be charged by a 110V charger from shore. Only one at a time.
- If connected to shore, the charger could keep the batteries charged but power could pass through to the A/C system, via the inverter. If the charger was disconnected, it would (quickly) drain the batteries, but it would be doable.

Do I have this correct?
 
#26 ·
- The alternator would run, charging the van starting batteries as designed by Ford. To charge house battery in my diagram, you select switch position #2 (van battery to inverter). The inverter will need to be turned on and the charger turned on, then it will charge house batteries.

- The charge direction from the alternator (house or starting) would be manually selected with a three way switch. Only one at a time. Correct.

- The batteries (house or alternator) could also be charged by a 110V charger from shore. Only one at a time. Correct.

- If connected to shore, the charger could keep the batteries charged but power could pass through to the A/C system, via the inverter. If the charger was disconnected, it would (quickly) drain the batteries, but it would be doable. I'll add my shore power transfer switch to the diagram tomorrow. When on shore power (or generator), all 115vac needs are on shore power, the inverter is off.
 
#30 ·
My DC ground is the same point for both batteries. There is no change. What neutral in a DC circuit?


That clarifies, thank you! Without seeing the shore power transfer switch I was speculating a little bit.
Flyfish, attached is an updated diagram showing shore transfer switch and I updated the 3 way switch to see it's action better. Again, this is an untested diagram in work.
 

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