[morey]

Electrical System Feedback

I'm planning an all electric conversion and would appreciate any feedback you may have on my system level diagram, see attached.

DC Loads:

• TruckFridge Refrigerator TF65
• Various fans including MAXXFAN Deluxe
• Various LED lights
• Water pump x 2 (galley and outside shower)

AC Loads:

• 1800W Induction Cooktop
• DIY water heater ~600W
• Laptop charging
• Camera charging

Main System Components:

• AMSolar 400Ah LiFePO4 Battery Bank and BMS
• Magnum MS2000 Transfer/Inverter/Charger 2000W
• Magnum CSW1012 Inverter 1000W

Eventually I will add solar but that will be after I decided what I'm going to put on my roof.

Basic idea is to run everything through the Magnum MS2000 since all voltages and currents can be adjusted to fit the lithium battery bank needs.

Thoughts?

 

[tthrsn]

I'm planning an all electric conversion and would appreciate any feedback you may have on my system level diagram ...

Looks fine though:

I would replace the relay and the small inverter with a battery to battery charger, between the starter and house batteries. Then you can eliminate the transfer switch and connect shore power directly to the large inverter. If you want to heat water while driving, use a 12V heating element instead of a 120V one. This should be slightly more efficient and might provide better protection for your starter battery.

I will purchase a 12V brick for my laptop so that I don't have to turn on the inverter just for computer charging. This is a little bit more efficient with less inverter usage (wear and tear, heat and noise). Likewise for the camera?

I think that the engine run signal on the Transit is ground switching and only 250 mA. You need to activate a little relay to get a positive signal. See the BEMM.

But follow this advice at your own peril, I am no expert at this. My van still hasn't arrived yet and I am just in the planning stage myself.

 

[orton]

No need for the transfer switch. Use a manual selector switch to select either shore power or vehicle powered inverter "shore power".


Is the vehicle powered inverter pure sine? It should be.


The induction cooktop forces you have the 2000 watt house inverter. Other loads would not require that large an inverter. Portable propane two burner stove instead of induction cooktop? Less money and can be used outside on picnic table.


Further info:


http://www.ortontransit.info/electric.php

 

[skagitstan]

My question is if you expect to regularly use shore power? Otherwise, I'd suspect that you might have trouble keeping up with your loads.

Stan

 

[morey]

Looks fine though:
I would replace the relay and the small inverter with a battery to battery charger, between the starter and house batteries. Then you can eliminate the transfer switch and connect shore power directly to the large inverter.

I really wanted to use the Sterling B2B 120A charger but it's lithium charge profile is not adjustable and doesn't quite fit my cells. At least according to AMSolar's recommended charging profile.

                            Absorb   Float   
Sterling B2B                13.8V     13.8V
AMSolar Recommendation      14.0V     13.3V

Also, I considered just connecting through a BlueSea ML-ACR or similar engine-on enabled solenoid/relay but during extended drives holding the battery bank at a greater than 14.0V is probably not very good for the pack. If I did go with something like the ML-ACR I could put a switch on the dash and just disconnect the batteries during long drives.

By forcing all charging through the MS2000 I have complete control over the voltages and currents sent to the battery pack. The Sterling B2B doesn't provide this flexibility nor does any other B2B charger that I know off. And obviously a relay/solenoid such as the ML-ACR doesn't allow changing the voltage/current seen by the house battery.

But then I also question is this really that big of an issue. If I just connect the house bank to the vehicle battery and I never disconnect it on long drives how much actual damage will it do? How long will it actually shorten my house battery's life?

There is not much data out there to answer this type of question which motivates me to just follow a cautious and approved approach of charging only via chargers that have programmable charging curves.

If you want to heat water while driving, use a 12V heating element instead of a 120V one. This should be slightly more efficient and might provide better protection for your starter battery.

I'm planning on a 120V due to the ease of availability, for example a quick search on Amazon finds this one. Correct me if I'm wrong but wouldn't a 12V heating element require some significant wires? 1000W / 12V = 83.3 Amps. Also, how would a 12V element provide protection for my starter battery? Heating element is planned to be powered by the lithium pack.

I will purchase a 12V brick for my laptop so that I don't have to turn on the inverter just for computer charging. This is a little bit more efficient with less inverter usage (wear and tear, heat and noise). Likewise for the camera?

A 12V brick would be ideal but the only ones I have seen for the Apple line of laptops do not look well made nor have many reviews.

I think that the engine run signal on the Transit is ground switching and only 300 mA. You need to activate a little relay to get a positive signal. See the BEMM.

You are correct, here is the relevant text from the BEMM:

Pin 3 - Engine Run signal will only support a sense line or relay control.
This engine run signal is ground switching (max current sink 250mA), it provides no positive output (open circuit) and is only active when the engine is running.
The signal will not be present when:
• Key states - OFF (0), Accessory (1), Run but Engine OFF (2), Crank (3).
• Engine running but load is greater than 250mA (driving two or more relays in error).
The fitment of the Auxiliary Fuse Panel will provide a power +12V side for the relay (although connection to the engine run pin is still required). See Auxiliary Fuse Panel circuit diagram later in this section.
If a positive (+12V) engine run signal is required, it can be done by using the switched ground to control an ignition fed relay, to give this output.

But follow this advice at your own peril, I am no expert at this. My van still hasn't arrived yet and I am just in the planning stage myself.

We're in the same boat. Thanks for the taking the time to offer your thoughts.

No need for the transfer switch. Use a manual selector switch to select either shore power or vehicle powered inverter "shore power".

I was thinking if it was automatic that would be nice, that's why I put the auto transfer switch in there. But I don't plan on being plugged in very often so maybe a BlueSea rotator switch would be a better option. Any reason why you prefer to manually have to switch it over?

Is the vehicle powered inverter pure sine? It should be.

Yes. Although I still need to find an inverter that automatically turns on when 12V is applied. Or do all inverters behave like that?

The induction cooktop forces you have the 2000 watt house inverter. Other loads would not require that large an inverter. Portable propane two burner stove instead of induction cooktop? Less money and can be used outside on picnic table.

I don't have a desire to store propane inside the van. That was the main motivation for going all electric. Induction cooktop can still be used outside although it would need to be via an extension cord.

Further info:
http://www.ortontransit.info/electric.php

Thanks.

My question is if you expect to regularly use shore power? Otherwise, I'd suspect that you might have trouble keeping up with your loads.
Stan

I don't plan on regularly using shore power but I do tend to drive a lot. My hope is that with at least 100W of solar on the roof and driving a couple of hours every other day I will be okay. I suppose I should do some more calculations to verify this.

 

[tthrsn]

... Correct me if I'm wrong but wouldn't a 12V heating element require some significant wires? 1000W / 12V = 83.3 Amps ...

Yes, the dual inverter setup does have the advantage of replacing some heavy DC wiring and switches with lighter, less expensive AC ones.

... Also, how would a 12V element provide protection for my starter battery? Heating element is planned to be powered by the lithium pack ...

Sorry, two ideas in the same paragraph. It's the battery to battery charger that might provide better protection for the starter battery.

You have obviously thought everything through very carefully. Good luck with your build.

 

[orton]

I almost never connect to shore power so the Blue Sea switch is normally in the position to connect the vehicle inverter to the Magnum inverter. Switch is simpler.

The Samlex 1000 watt inverter I bought has a remote that will turn it on when 12 volt power applied. I have not installed the vehicle powered inverter yet but believe that will turn it on automatically. I had the vehicle powered inverter system in my Sprinter and did find it a pain restarting the inverter after every engine stop.

Would recommend at least 200 watts of solar. My first panel on the Sprinter was 135 watts. The output about matched the power requirements for my largest power user which was a 80 liter refrigerator. No ability to catch up. Changed that to a 205 watt panel which easily covered the refrigerator. Never connected to shore power after the change. The Transit has the same physical size panel but is a 300 watt panel.

Do recommend a hole in the floor combined with a roof vent to keep inside temperatures close to the exterior temperatures. The other item that appears to make a major difference is building the refrigerator cabinet oversize so refrigerator exterior can be surrounded with 1 1/2" rigid insulation. If you look at the refrigerators, they have thin walls with limited insulation.

Depending on the climate where you drive, with at least 200 watts of solar, you will not have any difficulty with power capacity without the induction cooktop. With cooktop?

I will store the 1# propane containers in a plastic Cabela's ammo box mounted under the van on left side.

 

[skagitstan]

I don't plan on regularly using shore power but I do tend to drive a lot. My hope is that with at least 100W of solar on the roof and driving a couple of hours every other day I will be okay. I suppose I should do some more calculations to verify this.

It sounds iffy to me.
I'm just going to stay with watts here. Converting to AH just factors in one more step that gets factored out anyways.

Assume that the charging system was 100% efficient
Driving a couple of hours every other day is the same as 1 hour/ day. So you can charge 1000W every day.
The cooktop is 1800W. So just using the cooktop, for that hour's worth of drive based charge, you can cook for just about .5 hours each day without slowly depleting your battery.

However, the charge system is far from 100% efficient (inverter losses, charger losses).
If we guestimate 50% efficiency, you can charge about 900W/day with your drive. So, you are down to about 15 minutes cooktop run time per day...not counting any of your other loads.

A 100W panel in the best of sunny conditions could add back maybe 800W for that day. So even then, you are still running a deficit.

Add in any other high current loads, like the H2O heater, and you are even further in the hole.

So the questions are:
How long to you need to run from battery before a FULL recharge event?
Will the expected depletion from full charge at your likely worst case still remain within the battery specs for that time?

Stan

 

[tthrsn]

... Eventually I will add solar but that will be after I decided what I'm going to put on my roof ...

I am delaying my decision on solar until I have had my alternator charging system up and running for a while. Once I get some data on my daily driving hours, my daily battery usage, days between plugins etc. I can decide if I want to add solar and how much (but I don't really want to be cleaning snow and ice off solar panels on a high roof van).

I would actually prefer a dual alternator setup over solar. And maybe I'll manage by just adding a little portable propane burner for frying and heating water sometimes. But hopefully I can balance everything and get by with a basic (single) alternator charging system. We'll see.

If you have the heavy duty alternator, you might consider upsizing the little inverter from 1000W to 1500W. This is the draw of the 120A Sterling battery to battery charger (that other people seem to be using successfully). This might give you more flexibility.

I wonder how much you can actually draw (for house battery charging) from the heavy duty (3000W) alternator, while driving. Could it easily manage a 2000W load? Maybe you could test this with your Magnum inverter before deciding on the size of your smaller inverter.

 

[tthrsn]

If you have user defined upfitter switches, ORTON SUGGESTS using one of them for an engine run signal. This looks simpler than the method outlined in the BEMM (which works for all Transits, not just those with upfitter switches). I think I'll use his suggestion (especially since I haven't found any other use for them yet).

 

[jethaden]

If you have user defined upfitter switches, ORTON SUGGESTS using one of them for an engine run signal.

Only issue with this is that the switches power on with key on but also engine off, so inverter could/will start before engine starts. So you could have an extra high current draw while trying to start the engine. Not so good if you leave upfitter switch on by accident (or intent).

Per page 415 of my 2015 owners manual (PDF version):
"The switches only operate while the ignition is in the on position, whether the engine is running or not."

 

[tthrsn]

Only issue with this is that the switches power on with key on but also engine off, so inverter could/will start before engine starts ...

Thanks. It looks like I'm back to the BEMM method.

 

[orton]

Only issue with this is that the switches power on with key on but also engine off, so inverter could/will start before engine starts. So you could have an extra high current draw while trying to start the engine. Not so good if you leave upfitter switch on by accident (or intent).

Per page 415 of my 2015 owners manual (PDF version):
"The switches only operate while the ignition is in the on position, whether the engine is running or not."

Correct. You do have to remember to turn off the inverter with the user defined switch or not leave the key on with engine not running. With two batteries I suspect the inverter starting for a short period of time before the engine starts will not be a problem. I do not live in a cold climate so that will help.

The other thing to remember is on cold starts to be sure the temperature dial is not turned fully clockwise. The full clockwise position will turn on the Transit electric air heater. I do not want both the inverter and the air heater running at the same time.

One advantage of using the user defined switch is the ability decide if you want the inverter to start/stop automatically. If using the BEMM method a switch could be installed to allow the choice of inverter start or not start automatically.

With either method it might be smart to add a time delay relay in the circuit to delay the inverter start for a fixed time after the engine is running. I will use the user defined switch without the delay relay but will change if there is a problem.

 

[tthrsn]

With either method it might be smart to add a time delay relay in the circuit to delay the inverter start for a fixed time after the engine is running.

I think the BEMM method doesn't provide a signal until the cranking is finished. The Sterling battery to battery charger (in ignition mode) provides an additional 10 second delay.

 

[tthrsn]

... One advantage of using the user defined switch is the ability decide if you want the inverter to start/stop automatically. If using the BEMM method a switch could be installed to allow the choice of inverter start or not start automatically ...

The BEMM method needs a +12V source for the little relay that will provide the engine run signal. If this is taken from one of the upfitter switches then you can turn the alternator charging system on or off while driving.

Thanks, I was looking for a use for those switches.

 

[bicyclist]

The other thing to remember is on cold starts to be sure the temperature dial is not turned fully clockwise. The full clockwise position will turn on the Transit electric air heater.

Dave, are you saying that the cabin heater is electric and not heated by engine coolant or that it is heated by engine coolant but supplemented by electricity when turned up fully?

 

[orton]

Dave, are you saying that the cabin heater is electric and not heated by engine coolant or that it is heated by engine coolant but supplemented by electricity when turned up fully?

That is my understanding. If you turn the temperature dial fully clockwise and then start a cold engine, the Transit has a electrical heating element that warms the air out of the dash vents before the engine coolant is up to temperature. Once the coolant reaches a set temperature the electric air heater turns off.

My sold 08 Sprinter had the same system. The Sprinter voltage on the Scan gauge was normally be at 13.9-14.1 volts. With a cold engine start the voltage would drop to 13.5 volts until the coolant reached 155 degrees. Then the voltage would go back up to 13.9-14.1 volts when the electric air heater turned off.

 

[morey]

It sounds iffy to me.
I'm just going to stay with watts here. Converting to AH just factors in one more step that gets factored out anyways.

Assume that the charging system was 100% efficient
Driving a couple of hours every other day is the same as 1 hour/ day. So you can charge 1000W every day.
The cooktop is 1800W. So just using the cooktop, for that hour's worth of drive based charge, you can cook for just about .5 hours each day without slowly depleting your battery.

However, the charge system is far from 100% efficient (inverter losses, charger losses).
If we guestimate 50% efficiency, you can charge about 900W/day with your drive. So, you are down to about 15 minutes cooktop run time per day...not counting any of your other loads.

A 100W panel in the best of sunny conditions could add back maybe 800W for that day. So even then, you are still running a deficit.

Add in any other high current loads, like the H2O heater, and you are even further in the hole.

So the questions are:
How long to you need to run from battery before a FULL recharge event?
Will the expected depletion from full charge at your likely worst case still remain within the battery specs for that time?

Stan

Thanks guys for making me look at the hard numbers. I'm now planning on bringing propane back into the equation at least until I have my system setup and can gets some real world usage stats. The system I described in the first post of this tread will stay the same I'm just removing the water heating and induction cooktop loads.

I am delaying my decision on solar until I have had my alternator charging system up and running for a while. Once I get some data on my daily driving hours, my daily battery usage, days between plugins etc. I can decide if I want to add solar and how much (but I don't really want to be cleaning snow and ice off solar panels on a high roof van).

I would actually prefer a dual alternator setup over solar. And maybe I'll manage by just adding a little portable propane burner for frying and heating water sometimes. But hopefully I can balance everything and get by with a basic (single) alternator charging system. We'll see.

If you have the heavy duty alternator, you might consider upsizing the little inverter from 1000W to 1500W. This is the draw of the 120A Sterling battery to battery charger (that other people seem to be using successfully). This might give you more flexibility.

I wonder how much you can actually draw (for house battery charging) from the heavy duty (3000W) alternator, while driving. Could it easily manage a 2000W load? Maybe you could test this with your Magnum inverter before deciding on the size of your smaller inverter.

1000w vs 1500w "vehicle shore power" inverter is what I'm currently going back and forth on.

Heavy Duty Alternator: 230A
Current needed for 1500W inverter: 1500W / 12V = 125A DC
CCP available current: 60A * 3 = 180A DC

My concern is what happens at low idle. According to the BEMM its no where near the 230A rating during idle, see attached graph. So I guess during idle the vehicle batteries will fill in what the alternator can't keep up with ¯\(°_o)/¯ . And then once underway the alternator will be able to handle it.

I believe a 1500W "vehicle shore power" inverter would work but the more cautious approach would be the 1000W inverter.

The BEMM method needs a +12V source for the little relay that will provide the engine run signal. If this is taken from one of the upfitter switches then you can turn the alternator charging system on or off while driving.

Thanks, I was looking for a use for those switches.

I plan on using the engine run signal plus a switch. I haven't decided on if it will be an up-fitter switch or a switch in the living quarters next to the Magnum Remote panel.

 

[tthrsn]

...My concern is what happens at low idle. According to the BEMM its no where near the 230A rating during idle, see attached graph. So I guess during idle the vehicle batteries will fill in what the alternator can't keep up with ¯\(°_o)/¯ . And then once underway the alternator will be able to handle it ...

There are high idle controllers available for the Transit. THIS ONE is about $100.

 

[tthrsn]

I really wanted to use the Sterling B2B 120A charger but it's lithium charge profile is not adjustable and doesn't quite fit my cells. ...

I just picked up my Sterling Power BBW12120 120amp Battery to Battery Charger for charging from the alternator. I noticed that (by using the optional remote control) the bulk, absorption, and float voltages are fully customizable in .1 volt increments. This should meet your needs. Here's the link: Custom Battery Type Setting.

The manual that came with my unit (revised December 2015) is more recent than the online version. Here are two other items that don't seem to be online:

1. Using the (optional) remote control one can limit the current the Sterling unit draws to 90%, 80%, 70%, down to 30% of its usual load. This means that you can purchase a larger unit without worrying about it overloading your system.

2. The 180 amp version is due out July 2016. This availability date has slipped from March 2015.

While I have purchased some of the components, it will be a while until I get my house battery system installed. Best wishes with your build.

By the way, Sterling USA in Maine was very helpful.