article: a heretic nitpicks Maine Sail

Maine Sail, writing at marinehowto and various forums, is one of the best resources on the ‘net on matters related to batteries and their charging. He has real experience and performs valuable and well-designed experiments on our behalf. I will take my reputation in my own hands and push back on one of his statements.

backchannel: Why don’t we get more from 800w of panel?

From this thread on diysolarforum.com which I’ve really been enjoying lately. Lots of good discussions there, many clueful and experienced posters. First off, this is OP’s (original poster, the originator of the thread) first post. This often ends up in a “walk-off” (my term, no response to comments or questions, and never heard from again).

backchannel: isolator and dc-dc

from a comment on this YT video: What if your RV already has an isolator? Should I install DC to DC after the isolator? I think this is worth talking about. in parallel Most people wouldn’t need both an isolator and DC-DC charger. I can’t think of many good use cases for this setup. Maybe

backchannel: killing boat batteries

Saillors/cruisers typically have a pretty good handle on power, as their life may depend on it. This thread, though, reminds us that power fails come in boat form, too. we have 4x125w solar panels fed in pairs to 2 x mppt controllers. Not related to the issue, but an explanation may be in order. Van folk would likely run

the cake is a lie, charge controller edition

Note:  we are discussing charrging 2x 125Ah AGM in parallel, so C==250Ah.   Dealing in general principles here — the battery mfg should be able to provide more precise info.  If they don’t provide it then they probably aren’t making real deep cycle batteries. I’ve tried to get enough to ensure I end up floating charge

backchannel: [not] camping with Bob

The video thumbnail says “Camp with Bob!” …but folks with any passing familiarity with Bob know he doesn’t like to do that. He typically camps far away and “commutes” in. I have no problem with that, btw, but the crushing flocks of clueless newbies are his own fault. He sowed that field when he started

backchannel: “how long would [a 100Ah battery] work?”

From this thread in /r/urbancardwellers .   How long will that thing work? Depends on what you mean. Typical 12v AGM one finds on Amazon, for example, are rated for  400-600 duty cycles if charged correctly.. Under those conditions the thing would work for ~1.5 years.  In the more likely case of insufficient charging I’d expect the

backchannel: why would a 120w panel make only 15w at noon?

Why is a 120w panel tilted toward the sun only making 15w at local noon?  Here is 100% of the information you need to answer the  question with reasonable certainty:   answer sheet Short answer:  because only 15w is needed.    Longer answer:  We know the controller is restricting power harvest since it’s running the

giving up on /r/vandwellers

I’ve mentioned a couple of times that the /r/vandwellers subreddit has bloated beyond recognition, and beyond usability. This is largely a function of youtube and instagram influencers <spit> pushing hashtag-#vanlife. Here are the immediate problems as I see them:

backchannel: isolator confusion

My claim:  “When the batteries are deeply discharged a plain solenoid will typically provide as much current as a 225Ah bank can accept (much more than 300w of solar can make at solar noon). And it does it for 1/10th the cost of the solar.” I mentioned the 300w:225Ah and solenoid configuration because that’s what s/he has on