So I will try to keep this short, I upgraded to lithium batteries, but from extra research I could see an issue with hurting my alternator so I added the Renogy 40 amp DC to DC charger to limit how much the alternator can push to the house batteries. So not thinking it through this also isolates the starting battereies from the inverter/charger that is used when plugged in. What did I do wrong, how do I get the starter batteries charged since it is no longer tied to the inverter/charger? Thanks for the help, thinking it has to be something simple I am missing but can't figure it out.

that appears it will solve my issue,Thank you for the help.

You don’t say how new your vehicle is -not familiar with Renogy but iyour vehicle may have a ‘Smart’ alternator, that requires a compatible dc to dc converter.3 tons

3 tons wrote:You don’t say how new your vehicle is -not familiar with Renogy but iyour vehicle may have a ‘Smart’ alternator, that requires a compatible dc to dc converter.3 tonsI have a 2004 Coachmen 40 ft, caterpillar 3126 diesel, freightliner chassis and a magnum charger inverter. When I added the dc to dc charger it isolated the starting batteries too, which I didn't catch during install, I found out when my starting batteries were dead and then I realized I was missing something in the design, which the device above should take care of that for me.

Leonandlisa wrote:that appears it will solve my issue,Thank you for the help.As long as the Renogy sensing wire is not activated by the TLS voltage.

Added DC to DC charger, starting batteries don't charge

Bobbo
Explorer II
Mar 16, 2021
Amp-L-Start
Leonandlisa
Explorer
Mar 16, 2021
that appears it will solve my issue,

Thank you for the help.
3_tons
Explorer III
Mar 16, 2021
You don’t say how new your vehicle is -not familiar with Renogy but iyour vehicle may have a ‘Smart’ alternator, that requires a compatible dc to dc converter.

3 tons
Leonandlisa
Explorer
Mar 16, 2021
3 tons wrote:
You don’t say how new your vehicle is -not familiar with Renogy but iyour vehicle may have a ‘Smart’ alternator, that requires a compatible dc to dc converter.

3 tons

I have a 2004 Coachmen 40 ft, caterpillar 3126 diesel, freightliner chassis and a magnum charger inverter.

When I added the dc to dc charger it isolated the starting batteries too, which I didn't catch during install, I found out when my starting batteries were dead and then I realized I was missing something in the design, which the device above should take care of that for me.
time2roll
Nomad
Mar 16, 2021
Leonandlisa wrote:
that appears it will solve my issue,

Thank you for the help.
As long as the Renogy sensing wire is not activated by the TLS voltage.
noteven
Explorer III
Mar 16, 2021
You might want to discover what is drawing on your starting batteries when the engine is shut down?
MEXICOWANDERER
Explorer
Mar 16, 2021
Just to cover all bases...

David Smead and Ample Power are out of business.

Sure Power and Blue Seas offer proven excellent units.

I prefer the 200 amp models as they use a better design relay.
theoldwizard1
Explorer II
Mar 17, 2021
Why do you need to charge the starting battery ? My E150 sits for several weeks and still starts up !
stevenal
Nomad II
Mar 17, 2021
The DC-DC units I'm familiar with route alternator charging to house and starter batteries. The one I have has an input for solar as well. I know of no unit that has an input for converter power.
stevenal
Nomad II
Mar 18, 2021
See page 9, installation diagram 6 for an installation that claims to do what you wish. Lots of parts needed.

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Added DC to DC charger, starting batteries don't charge

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