Charging Both Ways

[VerMonsterRV]

Well, it has been a while for this project to be completed but it is now finished. There was a shipping delay right before we headed to Baja last fall so I was missing the Victron 12v to 24v DC to DC charger. Well we just arrived in Idaho and it was here waiting for us. So now we have 2 Victron 24v to 12v chargers in parallel that will charge the house bank from the alternator while driving. Then we have a 3rd charger, this time 12v to 24v for charging the start batteries while parked. To make sure only charging was happening in only one direction I utilized Victron's remote start wire. Essentially if you leave this bridged then the chargers use voltage to know when to start charging. They will not charge unless it is bridged, so I wired 2 relays to a single switch. One relay is NO, the other is NC. I have the alternator to house chargers set to NC. Once the switch is flipped the truck chargers is open and the house to truck is closed. I only plan on charging from house to start if we park a while or need to recharge the start batteries if I do something dumb, like run out of fuel and drain the batteries trying to bleed the air out.

Oh, I also plan on installing a 24v lift pump to help with the bleeding. Really don't want a repeat of our night along side the road. Just got to knock off a few other projects first.

 

[DiploStrat]

More to come, but I wired my boost/lift/prime pump to the camper battery as it was easier.

 

[VerMonsterRV]

More to come, but I wired my boost/lift/prime pump to the camper battery as it was easier.

Yup, I have thought of doing the same. Still on the fence though on which way to go but I am considering a waterproof switch next to the remote engine start button. Also saw on the newer LN2's there is a remote engine stop switch next to the start switch. Wonder how difficult it would be to retrofit that to our truck.

 

[DiploStrat]

In my case, the switch is a simple toggle located inside the cover door that covers the fuel tank. Only use the pump when the truck has been sitting and then for about 30 seconds. Didn't want the switch under the cab - too much work.

But it certainly works, should solve priming problems and does not appear to restrict fuel flow when driving. (Or, if it does, it restricts less than a few paper towels! )

 

[DiploStrat]

Sounds like you wired up the manual equivalent to what my Twisted Sister (tm) does automagically.

N.B. As warned by REDARC, the 12v to 24v charger never turns off off as its trigger voltage is the lead acid appropriate 13.2v and my lithium camper battery rests at over 13.3v. Not really a problem as the REDARC drops to float and I never come near killing 800Ah of battery. Sill, I suppose that a manual kill switch would not be unreasonable.

 

[VerMonsterRV]

Sounds like you wired up the manual equivalent to what my Twisted Sister (tm) does automagically.

N.B. As warned by REDARC, the 12v to 24v charger never turns off off as its trigger voltage is the lead acid appropriate 13.2v and my lithium camper battery rests at over 13.3v. Not really a problem as the REDARC drops to float and I never come near killing 800Ah of battery. Sill, I suppose that a manual kill switch would not be unreasonable.

My planned use of the habitat to starter charger is only occasional (for the start battery I have a remote battery cutoff switch so if we are parked for a bit I disconnect so the parasitic drain/discharge on the batteries is very small). It is more if we leave the truck unattended or need a boost if I drain the batteries trying to bleed the engine (been there done that and don't want it to happen again). I could have let the voltage cutoffs take care of the switch as the Victron chargers are completely programmable, but I prefer just flipping a dedicated switch. Just felt a bit more in control. And we don't have a honking big 800 amp house bank (though as you know, I wish we did).

 

[DiploStrat]

Rob Pickering installed a battery isolation switch for the starter. I actually removed it, mostly because I needed the room in the battery box.

As we are not full time, our truck tends to sit a lot - it is nice to have the starter batteries coddled and they certainly seem to be in very good shape. (Whether that is because of or in spite of the float, who knows? )

Having adjustable on/off voltages is a nice feature.

I actually have to turn off the charge side of the BMS most of the time as the actual camper drain when just sitting with heat off, refrigerator off, toilet off, is next to nil. Bit of a brain melt to keep telling myself that I WANT the batteries to drop to about 50%.

 

[Geo.Lander]

Oh, I also plan on installing a 24v lift pump to help with the bleeding. Really don't want a repeat of our night along side the road. Just got to knock off a few other projects first.

Can someone please explain this to me? what is a lift pump?

 

[DiploStrat]

Can someone please explain this to me? what is a lift pump?

A small pump mounted very close to the fuel tank. Used to lift fuel when the lines are empty and the normal fuel pump may not be able to pull enough fuel to prime the system. Basically, it pushes fuel to the vehicle's regular fuel pump - which is normally mounted near or on the engine.

See post number 7 in this thread.

 

[RoamIt]

Is that need to do or a nice to do? If I understand correctly, in this case, its for when the truck has been sitting for awhile and you might kill the batteries trying to get the engine primed enough to start?

I did read elsewhere about someone installing such a pump that they could also use to transfer fuel between tanks.

 

[VerMonsterRV]

Is that need to do or a nice to do? If I understand correctly, in this case, its for when the truck has been sitting for awhile and you might kill the batteries trying to get the engine primed enough to start?

I did read elsewhere about someone installing such a pump that they could also use to transfer fuel between tanks.

I would classify it sort of like recovery gear. You hope to never have to use it but glad it is there if you do.

You are correct, my main goal would be to help prime the engine if it ever becomes air bound. On the sailboat we used to travel on I had a system with a large lift pump with dual inline filters that could be swapped with the engine running by flipping valves. It also had a vacuum gauge so I could see when the filters were starting to go. It was also setup to pump from one tank to the other while filtering the fuel. It was very handy with poor quality fuel we occasionally picked up while in developing nations. I would like something like this on the truck, but not sure where to put it. I wouldn't want all the components out in the elements, bad enough the filter housings are exposed. Pretty sure though I will be adding a Facet pump at some point.

 

[TwinStick]

Manual and automatic systems both have their pros and cons. On the system in our 19' ZR2 Colorado diesel, it is manual and can jump start myself. I have the truck battery and aux battery each on their own on/off switch, then to a off, battery 1, battery 2, or both, then to hd power block for both + & - , then to a 2000/4000 watt pure sine wave inverter. I have run our 700 watt microwave on 2 batteries and 1 battery with no noticeable difference but just for a minute or two, to heat up a plate of food.

 

[VerMonsterRV]

Is that need to do or a nice to do? If I understand correctly, in this case, its for when the truck has been sitting for awhile and you might kill the batteries trying to get the engine primed enough to start?

I did read elsewhere about someone installing such a pump that they could also use to transfer fuel between tanks.

It could also happen if you have a fuel issue while driving potentially leaving you roadside. Once run out of fuel these trucks take a bit to get things re-primed (well at least ours does). Cranking the starter for long periods to get things to prime is not too great for the starter (we carry a spare). I have yet to install the 24v priming pump, but have it on my long term todo list.

Although not a serious problem yet, our manual priming pump is now leaking. It is before the injectors/pump. I just found a new pump locally and will install it soon once we get to a spot that I can work on the truck.

 

[DiploStrat]

The pump is a cheap nice-to-have for all the reasons that Jon mentioned. Ours is simply powered from the 12v camper battery. We had considered one of the sexy FAAS systems, but the dealer noted that it simply was not needed.

And our injector pump is leaking a bit and dripping oil on a radiator hose - which hose is, naturally, not available in the US.

 

[VerMonsterRV]

The pump is a cheap nice-to-have for all the reasons that Jon mentioned. Ours is simply powered from the 12v camper battery. We had considered one of the sexy FAAS systems, but the dealer noted that it simply was not needed.

And our injector pump is leaking a bit and dripping oil on a radiator hose - which hose is, naturally, not available in the US.

We've got the same problem, but it is out manual priming pump that's leaking. Covers the side of the engine and drips down onto the radiator hose. The little priming pump is cheap, especially in Europe.