Charger doesn't meet expectations

[Sabatical]

This Go Power GPC 35 max charger came as part of our first solar setup. I had never used it but we've been having alot of grey days here. I could really use a few equalizing charges to bring sg up and figured I would plug it in.
This unit has no external controls. It is labeled as a smart charger. I figured maybe there was some way to trick it into an eq charge. So I called the company monday and was told that in order to get an eq charge I would need to leave it plugged in for 5 days and then it would automatically run a 15v eq for 30 minutes. I laughed at the guy on the phone, I couldn't help it. I asked the "tech guy" if they felt a 30 minute eq was adequate and he replied "well no one has complained". I guess I'm the first.

 

[highdesertranger]

thanks for the info. highdesertranger

 

[SternWake]

http://www.amazon.com/DROK-Converter-Transformer-Regulator-Controller/dp/B00E8D7XYG

Once ~ 200 AH of battery capacity  can no longer accept about 12 amps at 14.4 to 14.8v, one can use this device to bump the voltage up to as high as 16v, and one can also control current.

Not automatic, 16v needs to be monitored and halted once SG no longer rises accounting for increasing temperature, or battery temp begins to rapidly rise, or the Amps required to hold 16v, or any level voltage, start increasing.

Whomever programs these charge algorithms, might have a lawyer looking over their shoulder, making sure the battery never gets anywhere near fully charged in a timely manner.  

Heavily cycled flooded batteries very much enjoy and respond to the occasional EQ charge.

Some might be able to program their solar controller to goto 16v, but they need about 5 amps minimum to get a fully charged 100AH battery to 16v

 

[Sabatical]

I'd love to be able to say I understood that but I cannot. I know so little about how all this electronic gadgetry works. I am extremely thankful to have not damaged anything in our set-up.
I have figured out that this charger is undersized for the battery bank I have it attached to (675ah). I read today (on the Trojan site) that the charger amperage should be 10% of the bank size. We do not use much of our capacity though, so it has been useful.
Also this bank was a mix of 2 one year old and 4 new batteries. Thier state of charge was different when I connected them and the older ones needed water and hadn't been eq'd in several months. Still, somehow, I managed to get an sg reading of 1.27 on every cell today. Either i'm extremely lucky or these Trojan t105s are very tolerant of newbies. I'm happy either way.

 

[Sabatical]

...don't give up on me though SW. Your input is greatly appreciated and I am slowly learning.

 

[SternWake]

The linked product can be hooked between your existing charger and your house battery bank, to bump up voltage up to 16v for a true equalization charge.

Only after the batteries are "fully" charged, and when they cannot accept more than 12 amps of current together, then the linked product can be used to bring the battery upto as much as 16v. It will actually go higher but don't do this to lead acid batteries.

Probably best to just do 1 pair of T-105s at a time with that device.

I do not own that one personally, I have the 150 watt version that lacks current control, not the 600 watt version linked.

 

[Sabatical]

Thank you SW. Now I get it. When I have more time on my hands I'll give this a try.
On a different component... I spent yesterday morning watching videos on the Midnite Solar channel and learned that the Whiz Bang Jr. can be set to stop the absorb cycle with ending amps rather than time. I called Trojan yesterday and they don't have a preference (time vs end amps) and suggested 2% of bank capacity. In my case it's 13.2 amps. I'm hoping that works out to be less time than my current 195 minute setting.

 

[SternWake]

Thank you SW. Now I get it. When I have more time on my hands I'll give this a try.
On a different component... I spent yesterday morning watching videos on the Midnite Solar channel and learned that the Whiz Bang Jr. can be set to stop the absorb cycle with ending amps rather than time. I called Trojan yesterday and they don't have a preference (time vs end amps) and suggested 2% of bank capacity. In my case it's 13.2 amps. I'm hoping that works out to be less time than my current 195 minute setting.

An amperage threshold crossing at absorption voltage is the best way to trigger float voltage.

The precise amount of time needed at absorption voltage is a moving target, affected by battery health, temperature, depth of discharge, accumulated cycles since last EQ charge, and the possible presence of Locusts in the vicinity.

If grid powered smart chargers actually allowed this parameter to be set, I would not talk so much crap about them and their 90% charged is 100% charge when the green light is illuminated mentality.

That last 10% makes a huge difference in cycle life on deep cycle batteries.  Most every grid powered charger drops out of absorption voltage way too early, and that 10% might take another week at 13.2v, if the battery is still healthy.

If it is not healthy then a month of 13.2v will not raise the SG to 1.275 or higher.

My 40 amp MeanWell adjustable voltage power supply will blow away any smart charger for its ability to hold absorption voltage as long as needed, it just can't be set to ABSV, and left unattended.  

Usually my Northstar AGM needs about 3 to 3.5 hours at absv before amps taper to 0.42 when cycled to the 60%  range.  The other day after 4 recharges by low and slow solar only, it took 6 hours for amps to taper to 0.42, and I had to employ my powersupply to finish off the charge.  So Current, rather than time, is a much more precise method, and this ability to adjust  absorption time is really key to getting excellent service life from deep cycle batteries .

 

[Sabatical]

Maybe you'd be willing to show me how your MeanWell is setup at the RTR.
After making the change to end amps this morning, we made it to float today. The dummy lights even told me I'd received a full charge. I hadn't seen them for a while.

 

[SternWake]

I don;t know If I'll be making the RTR, but I did start a thread about the MeanWell rsp-500-15 here:


https://vanlivingforum.com/Thread-My-newest-electrical-toy

 

[Sabatical]

Thanks for the thread link. I'll check it out.