As promised, here’s the full rundown of what I discovered (and what I did to fix it!) while checking out the Muddy Manor (MM) solar and systems set up for Jane Morgan a couple of weekends ago in the sunny Hawkes Bay.
There were five primary issues, and I’ve broken those down below.
In Jane’s system, the measuring device [called a shunt. see picture for reference] that sends information to her dashboard meter inside the MM was not the right size for her system (too small).
That was compounded by several devices including the 3000 watt pure sine wave (PSW) inverter (primarily required for making good; no, great; no, outstanding coffee!!), being connected in a way that they were not being measured by the shunt, giving Jane inaccurate readings for the state of her batteries and not accurately telling her the charging and discharging rates.
Living off-grid full time, Jane does place a significant load on her system. That isn’t to say it’s not OK to do that … It just needed to be optimised for her needs. And that included making sure that her meters were accurately telling her what was going in or out of her batteries.
The dashboard meter/display in the MM was not even the tiniest bit accurate. Worse! It was giving Jane false “batteries are 100% charged” readings. That could have had a very bad effect on the life of her batteries. Luckily, Jane was (in her own words!) “obsessed” with wanting to keep her batteries at what she thought was 100% (when they were probably more like 65 – 70%).
Her obsession and running the generator as often as she did likely avoided drastically shortening the life of her batteries. Well played, Jane!
I installed a new 400 amp shunt with an updated display inside the MM, as well as re-configuring the wiring to ensure everything is now being measured by the shunt. Such that her display is now giving Jane a true and correct indication of the state of all parts of her system.
Jane’s 230 volt 40amp smart charger that is used in conjunction with her generator has 2 modes – Power Source and Smart Charger.
Unfortunately, the charger was configured as a power source rather than as a smart charger. Just how that happened is not known.
The smart charger was putting out a constant 13.5 volts and restricted current, approx ½ its rated output as a charger.
I reconfigured the unit from power supply to smart charger, allowing it to operate correctly as a smart charger and in doing so, it’ll now charge the house batteries faster and correctly.
Some of the wiring (e.g. Jane’s full-sized 12-volt fridge/freezer) was not the correct size (too small), some of the wiring (-ve’s) were connected to the bus body/chassis via small M3 bolts.
Some of the crimping of the wires to the connectors was so bad that several came apart in my hand as I was moving them.
The wires used were too small for the load they carried and there was the potential for wires to fall out of the connectors, with possible serious consequences.
I replaced any wiring that was too small and replaced terminations, the negatives were all removed off the bus body and reconfigured back to the shunt using insulated studs with interconnects to the shunt and also installed a new chassis bonding strap off the shunt.
Fortunately, the MM has massive storage space in the bowels of the bus, so it was relatively simple to trace all circuits and check and replace loose connectors.
Jane strongly suspected that her system had what she described as a “parasitic load.” But no amount of detective work enabled her to identify it.
You may recall her questions at times, such as how many amps does 18 USB ports use, etc? These questions were part of her sleuthing activities!
It took me a fair bit of head-scratching and analysing to work out the house batteries were not getting everything they should from the smart charger every time she ran the generator.
It was losing two ways 1/ incorrect setting of the smart charger (described above and 2/ a second charger that was faulty. The faulty unit that had been installed to provide house battery charging when the bus engine is running.
Her house batteries were missing out on a lot of charging whenever the 230-volt smart charger was used.
It was during this head-scratching where the numbers just didn’t add up that I identified the issue with the smart charger being set as a power supply in conjunction with the faulty charge unit.
The faulty unit was a programmable buck boost battery charger. The charger was designed to connect when the bus engine was running and disconnect when not running. That was not happening (not disconnecting) and so I disconnected the unit isolating it from being used.
Jane has since my visit, harassed the supplier (nicely) who have said they will replace it, however that unit is now a discontinued line. So Jane will have the option to change it out for a better quality DC-DC charger in future if she so chooses.
Jane’s battery bank consists of 3 x 260-ampere hour 12-volt batteries wired in parallel giving a 12 volts 780-ampere hour battery bank. There were circuits connected to all three batteries as opposed to being connected to the main positive of the battery bank.
The potential to cause balancing issues causing premature ageing of the batteries!
Reconfigured all positive battery terminations to the appropriate position on the bank.
A Victon Shunt
So, to summarise:
Jane’s set-up was a bit of a “perfect storm” and it may not be normal to find as many issues as I did.
However, what the whole exercise demonstrated is that while you may have the best quality gear – configuration is critically important to ensure it works effectively and to the best of its capacity!
It is also worth pointing out that Jane had several of the “usual” pre-purchase checks done before buying the MM, all of which gave her the thumbs up. I suspect there are many owners around who may also presume that an electrical WOF includes the condition and quality of the solar set-up. IT DOESN’T!
Under current regulations, anyone can work on/install low voltage solar set-up equipment and this has happened in the history of the MM. This is just something to be mindful of.