Charging Both Ways

VerMonsterRV

Gotta Be Nuts
Jon, what engine is that? The OM366 should not need bleeding, pump the manual lift pump(right beside the fuel filter) till it gets hard and it should start very quickly.
The injectors are not easy to access.
As for the 24 V battery issue, we carry a 230V 24V battery charger, hook it up to the inverter in just such an emergency, run the generator if necessary.
OM366LA, the injector pump has check valves before the fuel hard lines. The hand pump can not pump pass these valves leaving the hardlines empty (if you ran the lines dry like I did). You can also hear a slight squeak when the air is removed from the injector pump when using the had primer (just for others reading this that did not know it, I didn't). So the only way remove the air in the hardlines is cranking the starter (got this directly from a retired Mercedes truck mechanic). Granted I probably fumbled with it too much and caused more trouble than needed, but this was my first time bleeding the engine along a highway, after dark in below freezing temps. I ended up using a spray bottle with gasoline to mist in the intake to get the engine to fire, which worked perfectly.

I'd think along a different and more mechanical route...

I have a Facet in line electric fuel pump on our engine fuel supply line, which will have a push button hidden in the gas locker. This pump will get it's power from the Hab Box batteries (once I have them). Our fuel filters are located at the back of the engine (accessable from the Hab Box floor hatch)... We can bleed the fuel system using the electric pump (Wifetec operated) while I bleed the air at the filters without having to tip the cab. No cranking involved until the last moment when in theory the engine should burst back into life.

Why have I done this...? Because I've been caught out several times (like you) with blocked filters, a blocked fuel pick up line, and a broken return line (meaning air could get into the system and the truck needs bleeding if it was left more than 2 weeks)...
Nice, on our sailboat we had something similar but instead of the Facet cube pumps I had a much larger one (still flow through). I had it setup so I could polish the fuel between tanks(why the bigger pump), swap tanks, bleed the engine with it and have a inline second filter that could be switched to while the engine was running. It was a pretty nice setup but I am not sure where I would fit it on the truck. I might just need to follow your lead with the smaller Facet pump.

Totally disconnect your house bank, rewire with sufficient jump leads to connect to your truck pair to start. You might just need a short length between two 12v house batteries, then two longer ones to reach the starters/chassis?
Fortunately/unfortunately our house bank is made up of 3.2v LifePO4 cells. Splitting them up is a bit of a pain so I want something a bit more user friendly, though I have to admit I considered it.

You dont need an external relays, there are 2 ways to activate house -> start circuit charging, either using the program engine detection with your custom voltages on the alternator line into the DCDC line or a combination of the L-pin override. you do not even need an isolator as you can use the voltage detection metrics to program your own start and stop parameters and use the L-pin integrated switch on the Alternator->House bank circuit (although that would need a simple relay). Plenty of ways to do this once you dig into the docs on the Orion units :D
Thanks for this, I did get the isolated units and will look into the docs. There might be a better way than what I came up with while hiking in the Redwoods today. For the house to start charger I am thinking I will have it triggered off one of our electrical panel switches. I want to be able to control when/if it charges (more often will be in the off position). If this switch is used, then the start to house chargers would not start, only when the switch is in the off position. If I can not do this with the built in Orion features, I think I can do it with a relay (but that would be second to using a built in Orion feature if available).
 

Geo.Lander

Active member
Thanks for this, I did get the isolated units and will look into the docs. There might be a better way than what I came up with while hiking in the Redwoods today. For the house to start charger I am thinking I will have it triggered off one of our electrical panel switches. I want to be able to control when/if it charges (more often will be in the off position). If this switch is used, then the start to house chargers would not start, only when the switch is in the off position. If I can not do this with the built in Orion features, I think I can do it with a relay (but that would be second to using a built in Orion feature if available).
As mentioned by @DiploStrat protecting the house bank discharge is key, to only fill the starter bank when you have at least nominal voltage in the house bank using the Vstart/shutdown trigger metrics in the Orion. I suppose you could go as low as 3.0v per cell and the unit charging profile will convert that to lead-acid etc absorption profile.
The L-pin switch is inverted to work with ignitions. So a great idea to close the circuit to start the charge from a panel :D
 

mog

Kodiak Wrangler
Unless I am mistaken (a good possibility) what you want is a way to 'emergency' jump-start (actual emergency charge) your engine batteries (two 12vdc batteries in series for 24vdc) from your house 12vdc LifePO4 cells. So the simpler the better and not a need for constant operations.

It seems to me you could use two simple battery selector switches to do this (black lines are your current wiring without the B2B charger included)

Step one - move switch A from the normal position that ties the positive of one engine battery to the negative of the other battery for 24vdc. As this becomes 'untied' it connects the negative terminal of the 2nd battery to the ground. You now have system-wise two 12 vdc 'engine' batteries. Step two - rotate switch B which is normally in an open/unconnected position to the closed position tieing the 12 vdc from your house batteries to your now '12 vdc' engine batteries. Wait for 1.5 bottles of wine as all the batteries equalize, then return switches A and B to the original positions and start the truck.
EJj.jpg
 

DiploStrat

Expedition Leader
This really needs a thread of its own as the rules are very different when both batteries are the same voltage or the same formulation. Remember. we are talking battery maintenance, NOT self-jumping.

So, assuming:

-- 24v start battery
-- 12v camper battery
-- Camper battery is lithium iron. (This really only impacts the profiles, not the concept.)

THEORETICALLY, you can let each battery to battery charger (B2B) run by its own rules. Practically, the gurus that I spoke with (bunch of folks who talk funny, wear hats with lopsided brims, and actually manufacture B2B's insist that you need a positive control to avoid any danger of a runaway loop, or feedback. So.

Step One, B2B from 24v start to 12v camper/house/etc. This is fairly simple. Sterling and REDARC both make models that can do this and, I understand, so does Victron.

If you are traveling, this is all you need, as you will probably run the truck engine at least once a week and that will keep the start battery happy.

Park for a few weeks between trips, or put the truck into winter storage, etc., and now you have to worry about both battery banks. For this argument, we will assume that your solar or shore is adequate for the camper, we just want to share with the starter. One, easy option is a small, clip on shore or solar charger of the appropriate type.

But we want to do more and make it auto magic. So,

Step Two, another B2B, 12v camper to 24v starter. Again, Sterling, REDARC, and, I assume, Victron will sell you this.

The danger comes if the camper battery is above the turn on voltage of the B2B pointed at the starter battery while, at the same time, the starter battery is above the turn on voltage of the B2B from the start to the camper. Now you can have a loop with each charger trying to satisfy the other. How much of a practical danger this is, I don't know. I would imagine that it can be made a bit worse with a much larger camper battery. It seems that if your shore or solar charger added enough power, then eventually each battery would hit "full" (as per the profile of each charger, and each would turn off.)

How do I deal with this? (And this has worked for years.)

-- There is a brick wall relay between the starter battery and the input to the primary (starter to camper) B2B. This relay only turns on when the ignition is on. (It is controlled by the switch, not the actual state of the engine.) If the relay is closed, then the B2B turns on of off, depending on its profile. This is easy.

-- There is another, normally closed relay that controls the second B2B. In my case, it is wired on an ignition trigger wire, but that is unique to the particular model of REDARC I am using. You could also wire this relay to simply shut of the connection to the camper battery. When the ignition turns on, the relay opens and this B2B is thus turned off. At this point, the starter battery is charged by the alternator.

The relay that I am using is a 24v "crossover" relay. So, when it is energized, the input contact moves to the other output and, because there is nothing there, it has the effect of opening the circuit.

Possible point of failure? The turn on voltage for the 12v>24v charger is 13.2v (classic lead acid) and the lithium battery is typically at 13.3v+. With an 800Ah camper battery, this has not been a real issue, especially as the starter battery is almost always only floating, but it does probably add about 1A to my background load.
 

grizzlyj

Tea pot tester
I would have thought mains charging big lead acid starters would not be a get out of jail solution at the side of the road? 24 hours to fully recharge? So if possible I would look at splitting them so you can jump yourself?
Or, spend lotsa cash and buy a pair of Victrom Buck boosters that can be set as master and slave. I think this might even allow spare solar to head to the starters.
Or, in your scenario have a mains powered 12v charger you can run off the house batteries to charge the starters when nothing else is running? You could also use that with a third party who has mains power, take the starters with you to a house etc?
 

Geo.Lander

Active member
Unless I am mistaken (a good possibility) what you want is a way to 'emergency' jump-start (actual emergency charge) your engine batteries (two 12vdc batteries in series for 24vdc) from your house 12vdc LifePO4 cells. So the simpler the better and not a need for constant operations.

It seems to me you could use two simple battery selector switches to do this (black lines are your current wiring without the B2B charger included)

Step one - move switch A from the normal position that ties the positive of one engine battery to the negative of the other battery for 24vdc. As this becomes 'untied' it connects the negative terminal of the 2nd battery to the ground. You now have system-wise two 12 vdc 'engine' batteries. Step two - rotate switch B which is normally in an open/unconnected position to the closed position tieing the 12 vdc from your house batteries to your now '12 vdc' engine batteries. Wait for 1.5 bottles of wine as all the batteries equalize, then return switches A and B to the original positions and start the truck.
View attachment 688378
This is a really dangerous approach IMO. Those lithium cells will push as much current as they can, you need a charge regulator.
 

VerMonsterRV

Gotta Be Nuts
This is why I went with the fuel pump! I'm lost already when it comes to the smoke and mirrors of fancy electrickery! :LOL:
Although I still plan on adding the house to start charger (using a simple automotive relay and on/off distribution panel switch) I am also planning on the Facet pump. Strange thing is our truck is "finished" yet my TODO list seems to be growing ;).

This is a really dangerous approach IMO. Those lithium cells will push as much current as they can, you need a charge regulator.
And I agree, lithium cells are fantastic if controlled (they can charge/discharge at the rated capacity). I actually jump started a full sized Dodge pickup once using a small 16ah 12v lithium battery I had for our portable water pump/filter (he was in a no cell service remote area). The guy was a bit skeptical when I attached his jumper cables to the small terminals, but when his engine rumbled to life I think he became a believer.
 

DiploStrat

Expedition Leader
Facet pump and filter in hand. Hopefully will install next week. May be overkill, but seems very reasonable insurance.
 

Geo.Lander

Active member
And I agree, lithium cells are fantastic if controlled (they can charge/discharge at the rated capacity). I actually jump started a full sized Dodge pickup once using a small 16ah 12v lithium battery I had for our portable water pump/filter (he was in a no cell service remote area). The guy was a bit skeptical when I attached his jumper cables to the small terminals, but when his engine rumbled to life I think he became a believer.
A 1C discharge from the cells themselves sure. But most BMS´s can't and don't do 1C discharge rate.
The most problematic issue with the direct wiring approach would be charging curve of the nominal voltage. The voltage curves for the different chemistries are totally different, not to mention the charging current would most probably fry the lead acid start batteries as the absorption currents need to be max 25% of capacity to avoid thermal runaway.
If you need to charge mixed battery chemistry you need a charge controller with the applicable charging profile applied to the target batteries. Any any other approach is just not a good Idea.
 
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Alloy

Well-known member
Hi DiploStrait.

It's a small Facet Cube pump. These can be bought in 12 or 24v. The cube pumps don't have an anti syphon valve in them, so can be used as a primer pump to bleed the system,but then just sit quietly in the fuel line (between the fuel tank and first filter) doing nothing until such a time as it's needed as it will let fuel pass when not in use. I'll only use it to bleed the system if I run the truck out of fuel, change filters etc. Re pulling a bockage through, no it won't do that, but it will indicate to you that there is a blockage prior to the pump when using it to try and bleed the system as no fuel will flow out at the filter bleed points. This is where the fuel pump can be disconnected on the suction side, and an air line used to blow air back into the tank (fuel cap off) to reverse the blockage. With the fuel line clear, the fuel lines can be reconected and the Facet used to bleed the system. The main reason for having this is so we don't have to crank the engine to prime it, or tip the cab to get to the hand primer.
We used Carter fuel pumps plumbed in parallel (ball valve on each side) to prime filters and fill day tanks. They move allot of fuel (8psi) and take allot of (water/sluge) abuse. The 3 nuts come off and the steel vanes/impeller can be serviced.

Edit: Forgot to include a link.

 
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Alloy

Well-known member
For the number of times this may happen with a set of jumper cables you can jump from the 12V Lithium to one of the 12V (24V bank) batteries at a time. To speed things up 2 set of jumper cable can be used.

The 24V lead acid will self regulate.
 

Geo.Lander

Active member
Jon, I was thinking, why not just use your MPPT controller to charge the starter whenever you need a bump? I suppose it already has the charging profile and the wiring would be simple enough..
Alternator charging is such a hassle in general, I want to forgo it completely if possible on the house bank too..
 

VerMonsterRV

Gotta Be Nuts
Jon, I was thinking, why not just use your MPPT controller to charge the starter whenever you need a bump? I suppose it already has the charging profile and the wiring would be simple enough..
Alternator charging is such a hassle in general, I want to forgo it completely if possible on the house bank too..
If you're talking about our solar charge controller I did think of that. What I decided is if I needed to charge when there was no sun it wouldn't work (or if you're talking about utilizing the charge controller directly from the batteries as a charging source, then it seems a bit more complicated). The 2 Victron start/house and 1 Victron house/start chargers have arrived at my friend's sisters house (hey, when on the road you get any mailing address you can :cool: ). Once we pick them up, in about a week, I will collect all the other bits needed for the install. Then once we get a project day I will do the install. With our less than sunny weather here in northern California we are looking forward to the 60 amps of charging (instead of our half working Sterling at 35).

Here is my take on charging your house bank. Have as many charging sources as possible. For us I consider both the alternator and solar panels necessary for charging the house bank. Compared to the boat, this setup is pretty basic. On the boat, wind, towable water, diesel generator, engine alternator and solar charging sources.
 
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