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dbush31 avatar image
dbush31 asked

Smart Controller 75/10 Charging modes

I have a 100w Solar Panel on our NuCamp Teardrop to which it was never really explained to us how the Victron Smart Controller Works. I have done some research of my own and have received the setting from the manufacturer of the battery. We have two 6v Interstate batteries. Since doing so I have never seen our battery come out of "Bulk" charging. When not in use we plug the camper into home. We recently camped where it was in complete Sun for 4 days and again never went out of "Bulk" mode and I am seeing 0% Consumption. I am affraid something is wrong am I just not reading this correctly.

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MPPT ControllersMultiPlus Quattro Inverter Charger
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JohnC avatar image
JohnC answered ·

Hi @dbush31

You don't say how big (or what type) your batteries are, but let me take a wild stab and say 200Ah (@12V) of fla's. And you're feeding them at best ~4A. They are unlikely to reach Absorb V (in a reasonable time) at that sort of charge rate, and may be destined to never reach it. That doesn't mean they're not charging, but just not fast enough to reach the first setpoint.

I suspect your panel might be sick too, with just a tad over 17V registering each day. I'd expect more like 22V with a healthy '12V' panel, though it might home-in on ~17V under production as it tracks Vmp. Bear in mind too that the mppt needs to see a 5V difference between panel and batts before it will even start.

Note the Consumption registered is only that measured via the Load terminals on the mppt. A load taken direct from the batts won't be seen.

You may need to consider replacing the panel, maybe even with a '24V' unit, the 24V will work better overall into a mppt controller.


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dbush31 avatar image dbush31 commented ·

We have two Interstate GC2 6 volt batteries. Below is what Interstate said the Max Amps I should be getting. Sorry I am new to all of this so just trying to figure out what more I need to do to make sure we are good boondocking.

Since you have 2) 6v batteries connected in series to make 12v’s the ampere-hour capacity will stay the same at 225. The charging ampere can be defined now by the C/10 (“C” = ampere-hour ÷ “10”) which will be 225 ÷ 10 = 22.5 amps.

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JohnC avatar image JohnC ♦ dbush31 commented ·
@dbush31

Yeh, and that 22.5A is 270W at nominal 12V, and much more at 14.4V Absorb. GC2 (a form pattern) are quite reactive batts, and can accept a lot of charge without being limited by reaching V setpoints.

I actually use them myself (different brand, 48V too, 225Ah), and finish Abs at 7A. By then they're 99% charged, and they're fully charged at ~1.3A at 13.5V (equiv).

You really need more panel to see them reach Abs, and without that they'll still charge but take far longer. If you can get them to reach 13.5V at less than 2A (say) going in, then they're pretty much full.

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