Should my batteries and solar have a load ?

[OldManMirage]

Yes, mistake on my part, float voltage is 13.7.

Unfortunately it is not adjustable on this controller. Next one will be.

[thomm225]

Originally Posted by OldManMirage

Yes, mistake on my part, float voltage is 13.7.

Unfortunately it is not adjustable on this controller. Next one will be.

You may want to pick up one of these $15 controllers that are adjustable in the mean time.

https://www.amazon.com/WERCHTAY-Cont...5326292&sr=8-4

[senormechanico]

Originally Posted by OldManMirage

I have 230 amps of battery power using 2 Duracell flooded golf cart batteries in series with 200 watts of solar panels running through a Renogy Duo controller. The boat is in her slip in Jacksonville Florida so good sunshine most days this time of year, batteries staying well charged. The only thing running is a Hella Turbo fan I leave going.

Should I have more of a load ? I have a 12 volt portable refrigerator I could set up that would give the batteries something to do.

I guess I'm concerned that they will simply sit there and "cook" even with the controller managing things. The batteries are new, I just finished getting them set up. I will of course keep up with checking battery water level.


Or am I just over thinking this ?

No need whatsoever.

[OldManMirage]

Originally Posted by thomm225

You may want to pick up one of these $15 controllers that are adjustable in the mean time.

https://www.amazon.com/WERCHTAY-Cont...5326292&sr=8-4

Wow, that is ridiculously cheap. I may just do that.

[thomm225]

Originally Posted by OldManMirage

Wow, that is ridiculously cheap. I may just do that.

I've been running on two of the cheaper PWM's since my Victron failed. (just bought a Victron 75/15 (Bluetooth) but have yet to install)

I'm about to clean up the mess I have that is my solar system but here is how it has been for years. One controller to each panel ( a 65 watt and a 50 watt) I unplug the 50 at the panel during the week when not sailing.

It's a Renogy and has a plug right there. My two 20 watt panels I hook up directly to the batteries if need but so far with these two 220 ah Golf Cart batteries I haven't need them.

The 50 watt panel is usually connected to the black controller but is unhooked in photo. You can see there is no charge arrow displayed.

https://www.amazon.com/Controller-In...b-3bb461a9a5a6

[goboatingnow]

Originally Posted by OldManMirage

Wow, that is ridiculously cheap. I may just do that.

These are very cheap low quality Chinese pwm units

[thomm225]

Originally Posted by goboatingnow

These are very cheap low quality Chinese pwm units

They may be cheap, but they work great!

I haven't taken one apart to look at the circuit board, but I'm guessing its your standard circuit card with a few components soldered on it. What sort of quality were you looking for?

I believe this one is maybe 6-7 years old at a cost of $12 or so.

You can see the age on it. (there's rust on the USB Sockets!) Also, it gets knocked around when it's rough enough while sailing.

I had a Victron 75/15 MPPT fail in the mean time.

The first Chinese controllers I had in 2012 would simply clamp the voltage at 14.4 volts so I would unhook them from the batteries after charging, but these have a Float setting and are much better

You can spend a lot or spend a little and still have a good system. It's up to you the owner.

I got another Victron 75/15 for the Bluetooth mainly ......

[noelex 77]

It is amazing what they do for the price.

This type of low cost regulator can be a good solution, especially as this model apparently includes user adjustable infinitely variable voltage set points. There are still limitations and these compromises need to be understood before purchasing.

It is PWM. This means it will only work with “low voltage” panels (so called 12v panels if you have a 12v battery). It also means it misses out on the higher efficiency of the MPPT controllers that incorporate voltage conversion. Expect around 10-15% less solar yield in average conditions.

Finally, while the voltage set points are adjustable, it appears the absorption time is not. There are some work arounds, but in storage mode (the subject of this thread) a very short absorption time is preferable.

Unfortunately, these limitations can impact on battery life. Cruising boats often have large expensive battery banks so you need to be careful saving money on the controller, but spending more on batteries.

However, there is not one size fits all. These cheap PWM controllers can sometimes be a good solution and this particular model looks better than most, judging from the recommendations on the forum.

[thomm225]

I was thinking any cheap or low priced controller would be better than the OP's which he mentioned is set at 14.6 volts Float!? (and unadjustable)

Also I believe the PO is still using those used batteries he got out of his mother-in-law's Golf Cart so no worries about damaging newly bought expensive batteries.

As for as the limitations, I have used these controllers for many years with my batteries which until recently were two 12 volt so-called Deep Cycle Batteries bought at the auto parts store for around $88 each.

They were 90 ah and in parallel. They usually lasted 5-6 years, but they would read 12 volts or less in the am after running the fan all night.

Late last season I bought two (2) Season All 220 ah 6 volt Golf Cart batteries for about $335 total including the $7 caring handles.

These read about 12.3 -12.4 volts in the am after running the fan and depth finder all night.

These Golf Cart Batteries are true deep cycle batteries so the 220 ah is much more than just the 40 ah more than the old style 12 volt "deep cycle" batteries I had before.

So still not a lot invested in the batteries

In my case I'll be connecting my Victron soon enough but I want to mount in this time and hook up the battery wire/cables securely.

At times now I'll adjust the Float voltage to 14.6 and let the batteries charge to that level periodically then drop it back to 13.5 before I leave for the day

[Baronkrak]

Originally Posted by OldManMirage

I have 230 amps of battery power

There is nothing wrong with that statement.
I for instance have 120A of Victron lithium battery power for a capacity off 90Ah.
In comparison the battery power of my 100Ah VRLA is only 5A.

Originally Posted by StuM

..If the power source is providing sufficient power to supply the load there is no current flow out of the batteries. If the load is greater than the input then the batteries will supply the additional power that the laods need. ..

?

Originally Posted by goboatingnow

..until a certain amount of power is drained out of the batteries…
.

?

[StuM]

Originally Posted by Baronkrak

There is nothing wrong with that statement.
I for instance have 120A of Victron lithium battery power for a capacity off 90Ah.
In comparison the battery power of my 100Ah VRLA is only 5A.

You clearly have no idea what those numbers represent and have little or no understanding of the whole concept of power and energy and how batteries work.

Those numbers are certainly not battery capacity, which is what we are discussing.Where do you get them from?
Batteries don't have a fixed "power". (Drop a spanner across the terminals of either your lithium or your VRLA battery and you will get a lot more than 120A or 5A from the battery.) And you can certainly power a device consuming a lot more than 60W (5A @ 12V) with it for a considerable length of time.


Possibly you are talking about "C rates". 5A is indeed the C20 rate for a 100Ah battery. The C20 rate is often quoted for batteries. What that means is that if you discharge over 20 hours (i.e. at 5A), you will get the full 100Ah if you flatten a fully charged battery. Discharge at a lower rate and you will get more Ah, discharge at a faster rate and you will get less Ah before flatteing the battery.
Similary if you discharge your lithium at 120A, you will get the full 90Ah.

But the bottom line is your VRLA does not have a specific power. It can certainly provide a lot more than 5A of power to a connected device.

The only common power ratings for batteries are "cranking amps" which are an indication of the maximum discharge rate that the battery can sustain for a standard length of time in specified conditions before reaching a specified low voltage. For your VRLA, that is likely to be in the hundreds of Amps

[goboatingnow]

What happens very much on what your battery charger is set to

In some cases the charger will not start a charge cycle until a certain amount of power is drained out of the batteries. Hence the load is supplied initially from the battery , in some cases the charger will act as a “ power supply “ and simply maintain a constant fixed voltage typically just above battery float point

If you model the resistances involved some charger current may flow into the battery and sometimes it may ( for all intents and purposes ) flow to the load.

There I’ve put the selective quote you posted back in its context

[goboatingnow]

Originally Posted by OldManMirage

I have 230 amps of battery power using 2 Duracell flooded golf cart batteries in series with 200 watts of solar panels running through a Renogy Duo controller. The boat is in her slip in Jacksonville Florida so good sunshine most days this time of year, batteries staying well charged. The only thing running is a Hella Turbo fan I leave going.

Should I have more of a load ? I have a 12 volt portable refrigerator I could set up that would give the batteries something to do.

I guess I'm concerned that they will simply sit there and "cook" even with the controller managing things. The batteries are new, I just finished getting them set up. I will of course keep up with checking battery water level.

Or am I just over thinking this ?

Not only are you overthinking it , you are very confused as to battery terminology


Your solar is not in series with your batteries and I presume you mean you have 230AH of battery “ capacity “. 230A of battery power is meaningless and incorrect

[PaulCrawhorn]

Originally Posted by Baronkrak

I for instance have 120A of Victron lithium battery power for a capacity off 90Ah.


In comparison the battery power of my 100Ah VRLA is only 5A.

I am very curious, as to what you think those statements mean.

You think the 100Ah batt is only capable of delivering 5A of current to a load? So at 12V, only 60W? What do you observe happening when a load tries to pull more than that?

And the 90Ah pack can only deliver 1.3C? Have you tried to pull more?

Something there is wrong, and nothing to do with the cells themselves, some other circuitry, or faulty connections...

[Uncle Bob]

Originally Posted by PaulCrawhorn

I am very curious, as to what you think those statements mean.

You think the 100Ah batt is only capable of delivering 5A of current to a load? So at 12V, only 60W? What do you observe happening when a load tries to pull more than that?

And the 90Ah pack can only deliver 1.3C? Have you tried to pull more?

Something there is wrong, and nothing to do with the cells themselves, some other circuitry, or faulty connections...

......or lack of comprehension.