One Charger to Rule Them all?

[1der]

Awesome thread. Some thoughts from my non-engineering/technical brain:

Seems in my experience that relying solely on solar to finish the charging is sketchy. For the past week my batteries have been at 87% SOC because the 300w panel is getting about 1.5 hours of sun a day. During that time it drags in about 25 amps towards a 480 watt battery bank but only a part of that is going to the batteries because of the fridge but also where the batteries are on the charging profile.

The Samlex EVO 2212, not the solution being looked for, but the manual may be worth reading. This is one very sophisticated charger/inverter/transfer switch with multiple managed inputs including External DC which is usually used for input from a Solar charge controller but seems like it could be from something else as long as the parameters are not exceeded. There may be some interesting knowledge in the charts/explanations, etc.

Lastly, I thought forum member Brent Haywood did some type of tricky alternator/charged setup on his van??? Maybe that was an AC alternator..... not sure...

[Noeta]

I am also interested in a complete system redesign and am grateful for this thread. The gold standard for sailboats, which have similar electrical needs, is Mastervolt. They are quite expensive, but solid offer equipment. They have recently diversified into Lithium batteries. And for years they have offered separate chargers and inverters so that quite specific needs could be met. In any case, worth a look: Mastervolt - Innovative power systems<br>for autonomous use. Has anyone installed their stuff?

[Flux]

So I talked with my solar guy today and told him about my plan to separate the battery from the alternator with a switch and he warned me that there could be some issues. A severely drained battery opened up to the alternator could cause a massive current inrush and literally smoke large gauge cords. He also confirmed that repeated charging by an "dumb" alternator will trash a nice AGM. He has a unit that will limit current from the alternator to the battery to 20 Amps, so I will be trying that out.

He also echoed handybob's premise that most wiring is undersized. One solution he had instead of using large gauge that is very difficult to install was to double up smaller gauge cables.

I am gonna put him on to these threads so he can read some of the sentiments here.

[Scalf77]

Flux,
I'ii jump in, but I expect we don't have the full context of the discussion. Most of us have some form of relay that connects the house and starting vans in parallel, while equalization does happen, I would not expect it to be a inrush problem that damages cables. If you installed a high-output alternator and did not upgrade your originally alternator to battery cable, this could be a issue, depending on how high the output was.

Also, a dumb alternator does not trash a AGM battery, many members here run AGM's in both their House and Starting Batteries. I agree you will never get the full potential out of your house battery if you only rely on your alternator to charge it.

I also don't see why limiting the charge to 20 amps would provide any protection from charging from the alternator, what would be the technical reason for that?

I agree that we need to use voltage drop in our calculations for running solar and other appliances. In voltage drop allowance will most certainly be the driving factor on the size of your wire versus the actual current load. Doubling up smaller wires is certainly one way of making that easier, but you have other things such as insulation and strand count that make that much better. I would usually look into those alternatives before doubling up on smaller sizes.

-greg

[Flux]

Greg, I will inquire about that inrush thing and what exactly the issue is. I was not exactly sure how that could be, but he mentioned depleted batteries suddenly opened up to an alternator. I am not sure how the alternator could actually send more amps than it's rated for causing such a big inrush. I was just relaying some of his thinking the guy has a lot of experience with electronics and solar systems.

What I mean by trashing AGM is depleting it and only getting an alternator on it to charge it back up.

I still have a lot to learn and a lot of thinking to on all this.

[Wanderlust Bus]

Bringing this thread back.

I found the CTEK system that was discussed in this thread here:
https://smartercharger.com/products/...ystem-package/

And aside from the issue of not being able to charge from AC shore power, do any of you use this system?

I would like to be able to charge from shore power, so that's a big issue.

[Econoliner]

I've had a D-250S for atleast a couple years and I'm still happy! More importantly, my Lifeline AGM is happy (which makes me happy).

I use a CTEK smart charger when I've got AC shore power. With the included inline connectors it's quick and easy to hook-up to the house battery. Easy enough to hard-wire if you're so-inclined.

[kevman]

What about the Redarc BCDC1240D (or it's smaller brother BCDC1225D)?

It seems to do the same thing as the CTEK (DC-DC charger, Solar MPPT, Start Isolator) but has a 40A max charge (vs. 20A) and includes a Li-Ion battery setting. It seems like a great option but there isn't much information around here on that unit. Am I missing something?

[Machinemman]

I have been contemplating using a mastervolt combi ultra 12 volt , I think does everything but very pricey , I would really like some informed opinions on this product please.
http://www.marinewarehouse.net/image...ra_3foldEN.pdf

[boywonder]

....A couple of additional thoughts....

My solar controller (and most other RV sized controllers) are rated for 30 amps.....so perhaps having the alternator (130A) or my Progressive dynamics 60A charger connected to the controller may be too much....

There are certainly larger sized solar controllers that are rated for higher amperage for cabins, etc...thinking of some of Midnite Solar's offerings.

https://www.midnitesolar.com/product...20-%20Classics

However, setting aside an all-in-one solution for a minute, if the shore power smart chargers and/or alternators tend to undercharge on float, even with our present setups whenever the sun is shining the batteries should be topped up with the smarts of the solar controller, so is the added smarts from the alternator or shore power really that meaningful?

I've had some thoughts on cable sizing ...this thread is probably a good place to talk about them as well.....

We regularly talk about proper wire sizes for charging the batteries from solar, shore power, alternator, etc.......if the conductors happen to be undersized, by the time the battery gets charged enough to be in float charge mode, the current required is tiny.....so why big cables??

...I suppose that the voltage drop due to undersized conductors in bulk charging may have some effect but I'm not sure what that is....perhaps charging time.....again, as the battery charges, it's drawing less current all the way to float where it's drawing a mouse-fart's worth of current....

...the above thoughts are considering slightly undersized conductors...not about using lamp cord to charge batteries.