BZ MPPT 500 charge control

[RCpilot]

Here's a shot of the BZ MPPT 500 charge control I forgot to post in the previous entry. It's reading 6.7 amps, the decimal point didn't show up in the picture.

[Volvo farmer]

Oooh, here's another opportunity for me to bash BZ Products on the 'net!

What you got there is NOT a three stage charger. I had a MPPT200 for about a year till it blew up. I ran mine on a mostly unattended, unused system and it boiled the crap out of my batteries. When I let it go four months with very light loads, I could see the tops of my battery plates, not good.

Look at the specs on that thing, it's factory set for a float voltage of 14.1V. That's way too high for float but if you set it lower, you don't get a nice absorption charge everyday. I guess if you're using a considerable amount of your power, it might work out OK at the preset voltage but I don't like the idea.

I subscribe to the theory that flooded lead acid batteries should be charged in three stages, bulk, absorption and float. A good battery charger should bring a battery up to 14.4V or so, hold it there for 1-3 hours and then throttle back to a sensible float voltage, somewhere around 13V.

Furthermore, there's been some reported problems with that charge controller. See the first review posted here. http://tinyurl.com/yr8s5p

I like it how some guy that works for BZ gets on there and apologizes for bad firmware, and then gives his own product five stars.

The best thing I ever did for my garage batteries was put a regular old Xantrex C35 on them, it was only ninety bucks and works flawlessly. If you must go MPPT, Blue Sky at least has a three stage charger, but at those prices, why not just get the mother of all MPPT controllers, the tried and true MX60? I've got one of those on my house system and really, really like it. The only thing I'd ever give it up for would be a Classic. (Cough cough, get back to work, boB :-)

[henjulfox]

I, too, have had bad luck with the BZ products. My first controller blew up when I first gave it power. I double checked connections before and after the magic smoke got out and it wasn't my fault. BZ promptly and professionally replaced it. The next one worked when powered up. I tested the output with my own amp meter and was showing output of less than what the BZ meter was displaying, on the order of 10% less. Could have been that my meter was not accurate. While I was puzzeling over that, the second unit failed. I gave up and spent the money for an MX-60 and have lived happily ever after.

I hope your luck is better than mine...

-Henry

[boB]

>>(Cough cough, get back to work, boB :-)

OK !!!  I'm working !  I'm working !!

boB

[RCpilot]

So far at least this one is working. I wish I had found this board before purchasing anything but being new to all this and trying to get the most for what money I don't have, the BZ is what I came up with. I wanted to be able to series my panels to limit the wire size I need as I have an 80' run from the panels to the control. And I thought from the little I knew about MPPT that it was the way to go. I'm only running two panels right now but will have a couple more within a month once I get back to building them. The meter on the front is pretty accurate as I have checked against it also with a good Fluke and a digital clamp on ammeter. The voltage that the Xantrex displays for the battery is almost .5 volt different and the AC voltage it shows is about 4 volts from what the line voltage really is. That is, while it's connected to "Shore Power" As long as the BZ works and I learn more about this I will live with it unless like it did for Bob and start boiling the battery. I have a long way to go before reaching that kind of danger with my system. I appreciate all the comments, maybe someone that has a BZ that is happy with it might reply and let us know their story.

Kelly

[RCpilot]

Today I measured the displayed current on the BZ against a clamp on digital ammeter and indeed it was off. Also the displayed voltage was off by .2 volts against a Fluke 26II True RMS Multimeter. Being the tinkerer I am I noticed pots on the BZ and started messing with them. After messing with them I was able to get the displayed current to agree with my ammeter and the Voltage to display properly as well. To adjust the voltage, I had to remove the display board and there was a small ten turn trim pot on it that adjusted the displayed voltage. The current display is adjusted with two single turn pots on the mainboard, one is for the PV Amps and one is for the Battery Amps. Then, there is the float adjust and I turned it down just a bit like Bob said where the float is factory set to 14.1 I believe. So far, the two panels are charging the battery up each day, I am still not doing any loads yet, this weekend will be testing the Battery capacity. Other than that it's working fine.