I have the dual battery HD alternator option in our 2016 transit. I know there are lots and lots of threads regarding controllers and chargers already, but almost all of them assume you have a house battery that's separate from the starter battery. I do not. Our electrical needs are relatively modest, and the dual batteries cover our needs without jeopardizing the ability to start the van after a day or two of use. If we wanted to add a fridge, I'd probably simply add a third matching battery to the same bank, as jonsobi did.
Anyway, for those times where we park for more than a day or two, I'd like to have a solar charger, as well as the ability to plug in. Solar would probably satisfy all our needs, but a) a shore charger would be good peace of mind, and b) we don't have a solar panel yet, and probably won't for a while.
I could get two devices: a solar controller/charger, and a traditional plug-in battery charger, and connect them both up. For reasons that I don't fully understand, these two devices can generally coexist, though I'd think that if they weren't designed identically they might want to enter different charging modes at different times. For that reason, as well as for simplicity of installation, and cost, I'd prefer the two devices were in one unit. (Am I way off-base here? Is connecting two chargers in parallel completely worry-free?)
For a while I thought the CTEK D250S was the answer, in combination with a big DC power supply as its second power source. But then I realized the D250S is for charging a house battery -- one of its dual power sources is supposed to be the starter battery (and the other a solar panel). That might be fine, except that apparently it will also attempt to charge the starter battery, and if I'm using a DC power supply in that position, the supply might not like it.
So, am I right about the D250S? Is it inappropriate for my application?
Are there any other combined devices I should look at? Ideally such a device would have two inputs (solar and 110V AC) and would connect to my starter batteries to charge them. Since suitable DC power supplies are easy to find (especially in my basement, not sure about anyone else's), I'd also be happy with two inputs, one solar, the second 12 to 24VDC.
Anyway, for those times where we park for more than a day or two, I'd like to have a solar charger, as well as the ability to plug in. Solar would probably satisfy all our needs, but a) a shore charger would be good peace of mind, and b) we don't have a solar panel yet, and probably won't for a while.
I could get two devices: a solar controller/charger, and a traditional plug-in battery charger, and connect them both up. For reasons that I don't fully understand, these two devices can generally coexist, though I'd think that if they weren't designed identically they might want to enter different charging modes at different times. For that reason, as well as for simplicity of installation, and cost, I'd prefer the two devices were in one unit. (Am I way off-base here? Is connecting two chargers in parallel completely worry-free?)
For a while I thought the CTEK D250S was the answer, in combination with a big DC power supply as its second power source. But then I realized the D250S is for charging a house battery -- one of its dual power sources is supposed to be the starter battery (and the other a solar panel). That might be fine, except that apparently it will also attempt to charge the starter battery, and if I'm using a DC power supply in that position, the supply might not like it.
So, am I right about the D250S? Is it inappropriate for my application?
Are there any other combined devices I should look at? Ideally such a device would have two inputs (solar and 110V AC) and would connect to my starter batteries to charge them. Since suitable DC power supplies are easy to find (especially in my basement, not sure about anyone else's), I'd also be happy with two inputs, one solar, the second 12 to 24VDC.
