House battery charging

[Marino24FE]

Hi all, I am new to this forum and looking forward to this community. I need help on setting up my auxiliary battery set up. My main goal is to run a load of 700-1000 watts continuously while driving and ideally having a battery discharge and charging set up that would have close to zero battery depletion as I can get after 8 hours of driving. I need help sizing the inverter, dc to dc charger, best AGM batteries at what amp size. Also I need to I figure out the output of my alternator. I have a 2019 Thor 24FE Mercedes chassis, 6 cylinder diesel.

Thanks in advance for your help…Mike

[DavidEM]

I have read over on iRV2 that the Mercedes Sprinter recommends limiting external loads on the alternator (those not required for routine driving) to 40 amps. Another person said that they hit 60 amps with no problem, but who knows how long that will hold up.

Your 1000 watt load is roughly 80 amps which is twice Mercedes recommendation, so I would rethink your plan.

David

[Marino24FE]

Thank you David for your reply! The actual load is a oxygen concentrator (medical) that runs on 120VAC and 6 amps. So if my math is correct, I have load of 720 watts, 100Ah lead acid battery of 1250 watts and a charge input from my alternator of 500 watts. That leaves me with a net discharge of 220 watts and for each LA battery based on 0.5 depth of discharge, I can get 2.84 hrs of driving time, with two 100 Ah batteries I can get 6.68 hours of driving before I have to strop discharging. Do you think this is correct?

Thanks in advance!

[Marino24FE]

I realize at the end of the day my driving time with be regulated by my house battery bank capacity and my alternator capacity. So assuming 40 amps from my alternator, can you recommend a DC to DC charger and a 1000 watt inventor for my system?

[Hooligan2]

Concentrator will require a Pure Sine Wave inverter to operate.
Check with concentrator manufacturer to see if they offer a 12 volt adapter unit.

[Marino24FE]

Thanks. I was thinking on getting the Renology 2000 W Pure sine wave inverter, would I still need the 12 volt adapter from the concentrator manufacture? I was planning on just plugging in the 120 VAC concentrator into the inverter, is this correct?

[16ACE27]

Originally Posted by Marino24FE

Thanks. I was thinking on getting the Renology 2000 W Pure sine wave inverter, would I still need the 12 volt adapter from the concentrator manufacture? I was planning on just plugging in the 120 VAC concentrator into the inverter, is this correct?

One or the other. Inverter with 120 VAC brick or 12 volt adapter for the concentrator. It it truly needs 120 watts I doubt there is a 12 VDC adapter for it.

[Marino24FE]

Hi all, I have a 2019 class C Thor Freedom Elite 24 FE and I want to install an inverter and dc to dc charger System either a combination unit or separate devices. My goal is to use a 120 VAC unit while driving, therefore I wanna charge from my chassis alternator. Renogy makes these devices separately and I know Victron has some combo units but I’m not able to identify exactly what I may need. Does anybody have any advice on installation of these and or wiring diagrams they can share?

Thanks in advance, Mike

[BASSMAN]

I have the Renogy 60 amp dc to dc charger, the charger is powered by your engine battery and not your alternator an will draw 90 amps to put out the 60 amp charge, its going to impact your alternator, I replaced the engine battery with a bigger Durcell to help handle the load, I also have 4, 100 watt panels on the roof so they help out during the day driving, I priced out a new alternator to see in the event it fails and they want over $450.00 for a new one, they list several different ones depending on amp rating

[16ACE27]

Originally Posted by BASSMAN

I have the Renogy 60 amp dc to dc charger, the charger is powered by your engine battery and not your alternator an will draw 90 amps to put out the 60 amp charge, its going to impact your alternator, I replaced the engine battery with a bigger Durcell to help handle the load, I also have 4, 100 watt panels on the roof so they help out during the day driving, I priced out a new alternator to see in the event it fails and they want over $450.00 for a new one, they list several different ones depending on amp rating

How do you figure that? That can only happen if the engine is not running or the alternator is overloaded.
Otherwise, your engine battery is a 12.6 VDC source in parallel with the alternator as a 14.5 VDC source. Not only is the alternator supplying all electrical loads connected to the DC circuit (including the DC-to-DC converter), it is charging the engine battery as well.

[BASSMAN]

The dc to dc charger hooks directly to your batteries an not your alternator, you have an ignition wire that hooks to the dc to dc battery charger and only allows it to charge when the engine is running, they have several warnings in the owners manual to not hook to the alternator

[16ACE27]

Originally Posted by BASSMAN

The dc to dc charger hooks directly to your batteries an not your alternator, you have an ignition wire that hooks to the dc to dc battery charger and only allows it to charge when the engine is running, they have several warnings in the owners manual to not hook to the alternator

You realize there is a single, high current capable wire connected directly between the positive post of the engine battery and the positive output post of the alternator? They are electrically the same point as is the connection directly to the starter.

[BASSMAN]

I have worked as a mechanic for all my working life so yes the alternator charges through the dc to dc charger to charge the house batteries but the connection from the dc to dc charger does not hook directly to the alternator, the connection between the engine battery and the alternator is usually a 6 or 4 gauge wire depending on the amp out put of the alternator. I talked to the service rep at Renogy about the install an told him there was some incorrect information on the install manual, he told me they had problems with people wiring the dc to dc directly to the alternator. wile it is the same connection the cable size is bigger depending on where you hook the unit up to, its a good unit and I have had mine for a few years, I am charging 4, 100 amp hour gel cells