Solar battery maintainer recommendations

I'm interested in purchasing a solar battery maintainer and adding it to two machines that sit more than they work. Both are 24v systems. Can anyone give me recommendations for maintainer systems that they've seen work well?

Having the 24v system limits options on these charger/maintainers. I do recognize that I could use two 12v systems and wire them to each battery independently. Is this a good plan or am I overlooking something?

Lastly, one system I saw said to disconnect the machine before use. The company said that starting the machine with the charger installed may damage the charger. Is this true for many of these systems? I'd like to wire it in and be done with it.

I bought a 12V unit from pulsetech for my trailer. Its worked well for 3 years now, but not very demanding. I have a couple of 24V machines I am considering solar maintainers, but I think I'll use separate 12V units, one for each battery.

I have a half a dozen of the cheap harbor freight ones, and they work well. I have 2 of them (one on each battery) on a Cat 215c with a weak alternator that sits a lot and it has worked great for 3-4 years.

Just pick a solar panel up and a cheap charge controller like one from Renogy a PWM pulse width modulator one and about 100W monocrystaline panel.
Panel puts about 6 amps on full sunlight, point it to the south at about 30 to 40 degrees, run a 10 gauge wire from it to PWM then from PWM to the battery with same size wire or 8 AWG and watch the batteries (once a week) as to not let it dry out. Closer all the components are the more efficient the system, unless you go with larger wire. Here is one to start with, they sell panels and I am running 1200 watts of their panels right now for powering my home/camper. Need help just PM I can walk you through it.
https://www.renogy.com/wanderer-10a-pwm-charge-controller/

All good info and thanks.

Mitch504 do you leave those HF units mounted outside? Some of the less expensive ones I've seen advertised say leave inside on the dash. Are they OK in the rain?

Spud, I'm some familiar with solar panels having them on our shop. So do I understand from you that those charge controllers will still charge enough to dry a battery out? The ones on my excavator are not in the most convenient place to be refilling often.

A

Evening Digger said:

All good info and thanks.

Mitch504 do you leave those HF units mounted outside? Some of the less expensive ones I've seen advertised say leave inside on the dash. Are they OK in the rain?

Spud, I'm some familiar with solar panels having them on our shop. So do I understand from you that those charge controllers will still charge enough to dry a battery out? The ones on my excavator are not in the most convenient place to be refilling often.

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Any charge controller would do it with time, also they do sell a waterproof charge controller there too for leaving outside.

A note on charge controllers. Older solar panels would work fine without a charge controller as long as it was a small one (like 10 watts for one battery). Most of the new solar panels are made to require a charge controller. If it says anything about MPPT, it needs a charge controller.

Yep, all of mine stay outside all the time.

Amazon has a lot of these.
https://www.amazon.com/solar-battery-charger-12-volt/s?k=solar+battery+charger+12+volt

I bought four solar chargers about six years ago for the small machines in the used yard at the local Cat dealer. Cat mini excavators and skid steers are notorious for dead batteries if they sit for a month or longer. The ones I bought back then would actually charge a dead battery and not just maintain a charge. The only problem I had with them is people stealing them or the yard hand not pulling them off the machine when it was shipped out.

The little dinky harbor freight ones will charge a dead 4d in about a week. It's just a half amp charge.

Solar system that runs my home is so powerful on my camper that it actually keeps the batteries charged on the semi it sits on. There is no ground to the ground on the charge controller so it flows into the frame of the semi back into the batteries. It's like having a float charger without getting one. I can see the pulse on my meter it's about 12 volts when I ground to the ground, thankfully there is no sensitive electronics it's all mechanical engine so nothing is hurt there.

rickermilers said:

I am new to this solar power and I have no idea how billing works. So my 1900sq ft house construction will start next month. The solar company offers a contract of $22,335 of panels +installation with a $93.06/mo lease. Is that $93.06 is separate from the charges you have to pay for your electrical usage or that's a fixed amount you will pay regardless of your usage?

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Since this is a Heavy Equipment forums I can redirect you to a forum where you can find that answer better.
https://www.solarpaneltalk.com/

OP, I think a lot of people get voltage and amperage confused for this discussion. Voltage is what you need to watch, and you certainly BETTER ensure you get a proper charge controller! I have seen this WAY too many times where someone buys a cheap battery device, then it proceeds to take the battery(s) to 15V and beyond!

There is some controversy but I am in this business but I will try to just offer more canned advice. It is very important that batteries (assuming lead acid, FLA, SLA, etc) be "topped" on the regular to inhibit sulfation. For a 12V battery, that is between 14.5-14.7V typically. You most certain 'can' push beyond that, especially for desulfate work, but for a low maint gig, I usually recommend something where you can program your charge cycle a bit. Maybe that over complicates it but what is most important is the battery achieves the target 14.5-14.7V topping charge, and it held there for say 1-2hrs, then allowed to roll back to a maint voltage of no more than 13.8V I can guarantee you, if you get a maintainer and it holds the batteries at 13.8 and never tops, you will lose some capacity in them!

It is also important not to stay at the top too long, but consider that most cars today hold the battery at 14.2-14.7 while driving, but they know the majority of the time will be short drives. Long holds at that voltage will cause water loss, gassing, etc.

I was looking for an actual charge controller and I think the reality is you probably don't want to spend much so I stopped searching. The cheapest one I can recommend is $85. I can offer other other simple solution and that is to incorporate a timer to simply disconnect from the battery after a period of time. It is not ideal, especially if actually trying to charge, but you really need to monitor voltage. This is probably the route I would take on my own stuff.

Do NOT buy the cheap China controllers all over online. The ones that are like $10 and say MPPT. They are NOT. They are a scam and I have raised hell about them. They are certain to melt down and immediately pull a high voltage panel down to 12V, which is NOT how a charge controller should work.

I have some milsurp stuff that came with plusetech solar maintainers. They work really well and are capable of desulfating batteries. I just looked up prices on them and... they are priced like the military buys a lot of them.