12v battery/ 12./24v MPPT ~ 24v PV Panel

[Old___Slow]

This question troubles the Old and Slow mind. I have a 24v/120w Cynergy PV panel. I would like to use it for duel purpose. For my 24v e/scooter and my 12v RV, not at the same time. The MPPT states (15a 12v/24v), hook battery first, then panel/then load. What will happen with use for the 12v Is it mix and match? Just a novice. Like one fine fellow said, who am I, where am I and why am I here?



Floyd

[BFL13]

I got lost again how the 40amper could do more watts than the 30amper but with 100v limit where the 30 has 150. So picking panels and arranging your strings and parallels must be a tricky business. ?

I see the MPPTs do a "four stage PWM output" which would be like the PWM LandStar charging profile that I have, which is working well on my four 6s.

Prices. The dealer here says he can't beat those Amazon prices at all. Some controllers are selling at less than what he would have to pay for them in small quantities. It seems if you order say 500 of one particular model you can get a really low price from the factory, but then you have to be able to sell them or they are yours. So you need lots of customers.

He says his outfit chose to still make 12v panels where many don't anymore. The big panels need a big laminating machine and the small laminating machines got tossed. Some grid-tie set-ups might have a pair of 480w panels instead of a bunch of small panels.

[mena661]

Looks like the 40 amp can 520W and the 30 amp can do 390W. You could do a bunch of 12V panels in series or series/parallel.

EDIT: Ebay for $200

[BFL13]

Not sure what Old and Slow has, but learned that the MPPT version of the LandStar PWM is called Tracer

http://epsolarpv.com/en/index.php/Product/index/id/95/am_id/134

They all belong to a bigger outfit called epsolarpv it seems

I am trying to figure out the 30amper which has 100 or 150v input limit and the 40amper with only a 100v limit but higher wattage limits, and where that fits in with the MS 45 and its 150v limit and their prices.

No luck finding prices on these things. One place was selling the 40 amper for $178 but that is way high compared with Old and Slow's. another local place is selling MS 45s MPPT for $459.

My local solar dealer does not carry them anyway. He says, "Why would anybody want a 20amp MPPT controller? (instead of PWM)" He is used to the grid-tie market and BIG set-ups

[HiTech]

x2!

Take the solar and try it out on the RV battery 😉

Is this The manual?

When you get back to it, don't worry about the load terminals. You likely won't be using them.

Jim

[mena661]

Have fun camping!

[Old___Slow]

Right in the middle of something intertesing, DW just came in and said. We are leaving to go down to the RV and the beach, get ready and let's go. I shall return Sunday. Thanks to those giving help the O&S, He needs it.

[mena661]

MEXICOWANDERER wrote:
and knee pads.

I still have to keep those even in retirement? LOL!

[MEXICOWANDERER]

Old & Slow,

Let's start from scratch. Go to the auto parts store and get an inline ATC fuse with holder rated for the capacity of your controller. With a 2.5 amo controller a 2.5 ATO fuse will protect the controller no matter what.

Follow the connection diagram and sequence exactly as described in your unit's manual. But stick the fuse inline with the positive lead before you connect.

If the fuse blows, something is bad wrong, return to the forum.

If the fuse does NOT blow, you have a keep an eye on the charging voltage. This is to make sure the Chinese had a clue as to design the charger. For a sealed Lead acid battery 14.8 volts is about it. For AGM, I would not let the battery voltage rise above 14.4. If you encounter a problem return to the forum.

29.6 volts for 24 volt sealed lead acid

28.8 volts for 24 volt AGM.

Yes, it is a pain keeping an eye on the voltage as it rises. But we're retired right? Got time, reading glasses and knee pads.

Take your time and don't get in a rush.

[HiTech]

mena661 wrote:
SLA's are flooded batteries not AGM or GEL.

I've always been a bit confused by the term. This paper of battery terms defines it as:

"sealed lead-acid battery: An incorrect term often used to refer to VRLA batteries"

O&S is there a table in the sheet for your solar charge controller that defines what charging voltages it uses?

Jim

[mena661]

SLA's are flooded batteries not AGM or GEL.

[HiTech]

These are the SUNNYWAY SW12120 batteries:

Hard to find data sheet!

Slightly different charging specs than on the battery. Initial charging current can be 4.8 amps according to the battery data sheet.

Jim

[pianotuna]

Hi,

The existing charger is not much help. Is there a maker's name on the batteries and a model number?

[HiTech]

I am thinking the same thing. If you actually get more than 2-3 amps flowing into them from the controller, you can cover part of the panel (only mid day if you like) to reduce output.

Does the controller have a manual?

Mex or others, any thoughts?

Jim

[time2roll]

I am trying to assume the battery is AGM and will be just fine with the solar.

[Old___Slow]

Jim (HiTech)


HMMM, Your more expert than you know. You sure do know what questions to ask. Here is what I just found. Looking at the battery charger that came with the scooter. "Sealed Lead-Acid Battery charger. Input AC100~240v~1.8A 50/60Hz Output DC24v ---2A Hmm, Hmm.
What to do now?? Am I up the ol' creek?

Floyd