Wrong manual for Zamp Solar Charger

[jcurtisis]

The Owner’s Manual Supplement for my 2018 Navion 24D had WRONG information on the Zamp Solar controller. I discovered this when I replaced my Lead-Acid batteries with Lithium batteries (Battle Borne 10012; 100 Amp Hour 12 volt). The manual said the Zamp controller supported 4 battery types: Gel, AGM, WET (lead-acid) and calcium. Upon making the change, I tried to change the battery type by holding down the “Battery Type” button for 3 seconds and than selecting the type I needed (the Battle Borne help desk said I should use “AGM”). Unfortunately when I held the button down to change the type, the controller didn’t show any battery types at all- it just had a voltage showing; and each time I pressed the same button to select a battery type it just cycled through 6 different voltage numbers (consistently). This made it look like there were 6 choices (vice 4), but the types weren’t being displayed.
I called Winnebago Customer service ((800) 537-1885) - only had to wait about 2 min (!!) - I explained the issue and was told to call Zamp (541-728-0924). For some reason the phone demons were napping and I got a knowledgeable person in about 2 more min (!!!). He said that the Zamp ZS-30A underwent a software change around the time I bought my rig- the older ones with 4 battery options were updated to six (to accommodate the new lithium batteries which were becoming more popular) and added LiFePO4 and LTO options. Apparently I had the newer version hardware but the older version manual (wonderful....as in “not”).
He also told me I had to do a “hard reboot” as the system didn’t re-set property upon changing batteries. He sent me a document with the steps (involved unscrewing the controller, disconnecting the power leads fro both battery and solar, waiting 5 min, and then re-connecting them). It worked like a champ!
I’ve attached the instructions and photos of the procedure. Not hard at all- just a bit nerve wracking as I’m just not used to working with live wires (I know, I know, it is DC power and not AC...just a bit paranoid about shorting out something with my screwdriver). I made liberal use of electrical tape to ensure no shorting occurred.

[jcurtisis]

These show the back of the unit- easy to unscrew the “+” terminals from solar and from the battery; last one is the CORRECT display showing battery charge at the top, and LiFePO4 battery type at the bottom.

[Winterbagoal]

Interesting dilemma. I've not encountered anything similar, and I have the same year, and theoretically the same charge controller. I swapped in a pair of Relions a couple of months ago, and found (was told by Relion vendor) that either the AGM or LiFePO4 settings are capable of charging the lithiums (as per Battle Born, as well) because the charging numbers for them are the same if you look at the page titled "Specifications".

[Morich]

Interesting how many problems we are now getting where things are "improved" but the directions are not! I have a $400 drone which now has been improved to the point that it will soon be obsolete as they have changed the app!
Can't add anything on the mod you are doing except to share a bit of thinking on how to save some stress when dealing with the wiring.
While it isn't all that much of a killer, it is still a really good idea to cut off the battery power when we get into moving/ changing the wiring. We probably have no danger at all of electrocution but a really big flash and burn is easy to do with 12VDC . Just not worth the risk, just to avoid pulling the ground off the battery or flipping breakers or fuses. Flip it off to do the wire moves and back on to test.

[creativepart]

I have a 2017 WBGO that also came with the Zamp controller. But I removed it and replaced it with a $200 Victron SmartSolar charge controller. It was a direct swap but the result is I got smarter more efficient changing (it's a MPPT controller, the Zamp is a PWM) and BlueTooth monitoring as well.

I feel switching from PWM to MPPT increased efficiency enough that it was almost like adding a 4th 100w panel.

It's hard to tell if that's so, but I see much higher voltages and Watts being generated by my 3-100w panels. Every time I looked at my Zamp controller I was disappointed in the number of Amps being delivered. With the Victron I'm usually surprised by the number of amps coming in.

[jcurtisis]

Not sure what PWM and MPPT are- need to do some reading it seems.

[creativepart]

Originally Posted by jcurtisis

Not sure what PWM and MPPT are- need to do some reading it seems.

I'm sure many with more knowledge will do a better job in answering this... But let me try anyway.

In general, PWM (Pulse Width Modulation) limits the voltage from the solar panels to battery voltage (~12.6v} and then then turns the chargesr on and off as needed. During Bulk charging it could be on 100$ of the time. As the batteries get closer to full charge the PWM charger simply spends more and more time off. When your batteries are fully charged your solar charger may be all the way off.

The MPPT (Maximum Power Point Tracking) work at a higher voltage. And, it is able to convert higher voltages into more amps delivered, plus the chargers are "smart" with actual Bulk, Absorption and Float profiles.

MPPT controllers are usually discribed as 25% to 30% more efficient at charging.

Most 100W panels put out 18 to 20 volts. With a PWM controller it operates at battery voltage. So, with 12v batteries you get 12v from your panels. With MPPT the full 18v to 20v is used by the smart charger in the controller.

The PWM costs less, sometimes 1/2 of the cost of a MPPT. Also, most PWM controllers are limited to smaller amperage and 30-amp controllers are common. This generally limits PWM controlled systems to 400w or less.

For 100w to 200w systems a PWM is a fine, inexpensive choice for a charge controller. As you get closer to or over 400w the MPPT may be a more efficient choice. They really give higher benefit if you run some of your solar panels in series rather than parallel. In series your voltages are higher and the MPPT controller can turn that into high charging amps. The PWM can only operate at close to battery bank voltages.

I have 300w of solar. the PWM charge controller was no doubt fine on my system. But I plan on adding more panels and I decided to make the switch to MPPT now.

As I said. I "feel" like I'm getting more amps from my panels - but it could be mostly related to the better reporting I see from Victron's BlueTooth app.

[jcurtisis]

Creativepart: thanks for the background. Do you know how what one needs to get to measure the actual output of the solar panels?
It is interesting that the “12v” batteries are actually getting charged up to 13.6v on a normal day.

[creativepart]

If you put a volt meter on your solar panel's output wires in full sun you'll see the voltage and it should be between 18v and 22v for a 100w panel.

Your PWM controller takes in the 18v and reduces it to your approximate battery voltage. Your batteries are fully charged at ~12.6v. Your charger, alternator and even solar will apply voltages higher than 12.6v. So, during absorption you'll likely see 13.6v but that's the charge voltage (or, if you've just stopped charging a residue "skin" voltage) not the battery voltage.

Within a few minutes of stopping all charging (15 mins or so), especially if the battery is in use at the time, it will show it's true voltage - around 12.6v if fully charged.

This is why battery voltage is difficult to use to gauge State of Charge. Fully charged is 12.6v and 50% discharged is 12.1v. It's not a very fine scale.