lithium Battery and vehicle alternator
- Thread starter Jmarch
- Start date
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Isaac-1
Well-known member
The solution is a DC-DC Charger such as https://www.amazon.com/Victron-Energy-Orion-Tr-Non-Isolated-Bluetooth/dp/B086Q8YNJZ/ or https://www.amazon.com/Renogy-Bluetooth-Compatible-Traditional-Alternators/dp/B0B4JXWLD7/
DonTom
Well-known member
As long as your lith battery is charged full or near full and the lith batt voltage is above, at, or very near the voltage supplied by the alternator, they will be no harm done. I did this for thousands of miles with my Y2K RV with problems at all.
But I finally put in the DC to DC Converter much like mentioned in the above post. It will have one disadvantage; you won't be able to use your switch to add the house battery current to the engine battery for starting when your engine battery is too weak to start. No path back that way. But the DC2DCC will limit the current to a safe amount to the lith battery at all times and has a max charge current (30 amps, IIRC). It's probably the best way to do it. The big advantage is when the lith battery needs a big charge and would otherwise draw a lot of current. The DC2DCC prevents that from happening but still charges at a safe rate.
-Don- Reno, NV
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Lou Schneider
Site Team
- Joined
- Mar 14, 2005
- Posts
- 13,350
I have (2) 100 amp-hour lithium batteries in my Safari Trek motorhome. Without a DC to DC converter they draw about 20 amps each, or 40 amps total from the vehicle alternator, pretty much regardless of their state of charge. And they'll easily start the Chevy 7.5L engine via the Boost relay as I found out when my starting battery decided to disconnect itself in the middle of a trip (internal connection failure).
200 a/h or less doesn't need a DC to DC converter, IMO. But I would put one in to limit the current drawn from the alternator on a bank larger than that.
If you have a trailer a DC to DC converter installed near the trailer batteries will boost the bulk charging rate which is otherwise limited by the long charging wire coming from the tow vehicle's alternator. This is regardless if you have lithium or lead acid batteries. Just make sure the charging wire and any fuses are large enough to handle the converter's rated current.
200 a/h or less doesn't need a DC to DC converter, IMO. But I would put one in to limit the current drawn from the alternator on a bank larger than that.
If you have a trailer a DC to DC converter installed near the trailer batteries will boost the bulk charging rate which is otherwise limited by the long charging wire coming from the tow vehicle's alternator. This is regardless if you have lithium or lead acid batteries. Just make sure the charging wire and any fuses are large enough to handle the converter's rated current.
How would one connect it, orI should say wire it in. Would it be in the tow rig wiring schematic or trailer plug/rig schematic?
DonTom
Well-known member
You need to find the wire that provides the charging from your alternator to the house battery and wire that to the input of the of the DC2DCC and the DC2DCC output to your house battery.
This is the one I use in my Y2K RV.
-Don- Reno, NV
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My trailer hitch cable runs into the camper then there is only the red black cables to the battery box im assuming I need to tap into the power line in that cable or someplace in the camper which would lead me into the underbelly?
Gary RV_Wizard
Site Team
Since the alternator is in the tow vehicle and the lithium battery in the trailer, the DC2DC unit should be inserted between the trailer plug aux power pin and the aux cable to the battery positive. Usually that Aux pin goes direct to the battery. Are you sure it runs into the camper and only reaches the battery thru some other cable?
I suppose you could also install the DC2DC in the truck where it feeds the Auzx 12v pin on the trailer connector, but then your trailer battery benefits only when towed by your truck. That's probbaly 99.9%, so maybe no worry?
I suppose you could also install the DC2DC in the truck where it feeds the Auzx 12v pin on the trailer connector, but then your trailer battery benefits only when towed by your truck. That's probbaly 99.9%, so maybe no worry?
