Not DC-DC exactly . . . but it looks like this MPPT will:
reverse charge the starter battery @1A,
run lithium,
and have LTD !
*****************************
The Voltronic DUO - https://amzn.to/2Gvj3xH
"The MPP-series controllers feature a second output so that some of the solar power can be used to trickle-charge a starter battery with a current of 1A max."
******************
looks like there is 4x versions goin up in charge current.
Votronic, MPPT 165 Duo Digital charge controller - https://amzn.to/2Gr4g7q
Votronic, MPPT 250 Duo Digital charge controller - https://amzn.to/2sXG6hC
Votronic, MPPT 350 Duo Digital charge controller - https://amzn.to/2t4lGnm
Votronic, MPPT 430 Duo Digital charge controller - https://amzn.to/2O1yGkP
.
.
*****************
https://www.votronic.de/images/Manuals/07. Solar Current Technology/1710_1715_1720_1725_e.pdf
***************
.
.
looks like it has LTD (low temp) too . . .
.
reverse charge the starter battery @1A,
run lithium,
and have LTD !
*****************************
The Voltronic DUO - https://amzn.to/2Gvj3xH
"The MPP-series controllers feature a second output so that some of the solar power can be used to trickle-charge a starter battery with a current of 1A max."
- Nominal operating voltage: 12V DC
- Solar module max. output: 250W
- Solar module max. current: 15A
- Solar module max. open circuit (OC) voltage: 50V DC
- Max. charging current: 17.5A (aux) / 1A (starter)
- Compatible battery types: Lead-acid (flooded, sealed), Gel, AGM, LiFePO4
- Stand-by current consumption: 0.004 A
- Over-charge protection: Yes
- Reverse current protection (back drain at night): Yes
- On-board mains suppression filter: Yes
- Number of charging ports: 2
- Protection against over-load, over-temperature, short-circuit: Yes
- Connection for temperature sensor: Yes
- Compensation for voltage loss on charging cables: Yes
- Connection for remote display panel: Yes
- Operating temperature range: -20 to +45°C
- Overall dims incl. mounting flanges: 131 (W) x 40 (D) x 77 (H) mm
- Weight: 235g
- Manufacturer's article number: 1715
******************
looks like there is 4x versions goin up in charge current.
Votronic, MPPT 165 Duo Digital charge controller - https://amzn.to/2Gr4g7q
Votronic, MPPT 250 Duo Digital charge controller - https://amzn.to/2sXG6hC
Votronic, MPPT 350 Duo Digital charge controller - https://amzn.to/2t4lGnm
Votronic, MPPT 430 Duo Digital charge controller - https://amzn.to/2O1yGkP
.
.
*****************
https://www.votronic.de/images/Manuals/07. Solar Current Technology/1710_1715_1720_1725_e.pdf
***************
.
.
looks like it has LTD (low temp) too . . .
.