Zamp ZS-15AW Controller in my Hawk

[Advmoto18]

I have been trying to ascertain the state of my 2 month old Optima Blue Top D27M batteries. Quite frankly, impossible with a battery monitor.

But still, I'd like to guesstimate what is going on. Further, I found the Zamp manual somewhat lacking in describing the controller's operation and automatic mode switiching.

According to Optima, the D27M in series should be charged to 14.7V. My Zamp controller displays "FUL" (Full) at 13.6V. I know the D27Ms are not full at 13.6V. I have AGM battery type selected.

My Optima D27M's in series are fully charged at 14.7V. However, the Zamp controller will only charge the batteries to 14.4V before entering Float when AGM is the selected battery type. This will leave the batteries less than fully charged. to what percent less than full? I have no idea without a battery monitor.

While the controller's specs are published on page 8 of the manual, understanding when the specs apply can be difficult to sort out. Thus, a call to Zamp.

After calling and speaking to a Zamp tech rep, I discovered I could select WET bettery on the controller allowing battery charging to 14.7V (as noted on page 8, spec 2-5) then entering Float. However, WET will allow equaization mode and 15.5V charging if the battery charge drops below 10V. 15.5V is far too much charge for the D27M.

I have a Trimetric 2030-RV on order. For the time being I have slected AGM battery type and willing to accept 14.4V max charge before entering Float.

Once the monitor is installed, it will be interesting to see the percent below fully charged the controller with aGM selected and 14.4V cut out is costing me.

It is impossible to get in touch with a human at the Optima customer service phone number. I would like to know what kind of under-voltage protection the D27M has and if the under-charge design will prevent the intiatization of equailzation mode if WET is selected as the battery type on the controller.

 

[Old Crow]

Advmoto...

There are a lot smarter folks than me here on WTW on these issues but let me give you some food for thought....

I believe that 14.7 spec is Optima's recommended charging voltage. But the Zamp manual (page 8) says their charger will, when set to AGM, charge at a slightly lower rate-- 14.4. That's in the absorption stage, after a bulk charge in the 10-14v range (line 2-4).

As the controller charges the battery, the current varies downward and this is how the charger knows when the battery charge is approaching FULL and it's time to switch to Float mode. As the spec chart shows (line 2-6), that's at 0.5 amps. (Or, alternatively, it will change to float if the charger has been charging in the absorption phase for more than four hours, also line 2-6).

At that point the charging voltage drops from 14.4 volts (absorption) to 13.6 volts (float).

So I'm wondering if what's going on is you're seeing the float voltage after the charge is complete. It HAD been charging at 14.4 volts but that stage finished.

The Wet setting is indeed a way to get a 14.7-volt absorption setting. Equalization appears to apply only if the battery drops below 10 volts, i.e., essentially dead. Equalization in this case is part of the process of recovering a deeply-discharged battery. (edited to add- see 6/10 note below)

--OC

I'll just put these here for reference:

http://www.optimabatteries.com/en-us/shop/bluetop/optima-batteries-8027-127-d27m-27-bluetop-marine-deep-cycle-starting/

http://zampsolar.com/newsite/wp-content/uploads/2014/10/User-manual-for-10-or-15A-portable-controller-1.pdf

PS- Please note. I don't have a Zamp (or any solar controller). I'm just reading the manual and assuming the Zamp charging function works like the typical battery charger. And, heck, I could be mis-reading your post.

Edited 6/10/15 to add:

- I missed line 2-7 and 2-9. Though page 6 only describes equalization of a deeply-drained battery, lines 2-7 and 2-9 suggest that every 28 days the controller runs a 2-hour equalization charge at 15.5 volts (assuming 77 degrees F).
- line 2-5 has an intriguing note: "(default setting)" for the 14.4-volt AGM program. Not sure if that means the user could change it, though.
- words

 

[Advmoto18]

OC...

My interpretation is the same as yours after reading the manual and discussing the specs with the Zamp tech rep.

Without an opportunity to talk to a Optima tech rep, I am inclined to think the Optimas are not reaching a fully charged state with the Zamp controller absorption charging to 14.4V then switching to float mode. This assumption is based on the Optima spec of the series charge of 14.7V.

But, without a battery monitor, it is nearly impossible to precisely know battery state. I hope to have the Trimetic 2030-RV installed this weekend. Not being one well versed in electronics, other than I've been told electricity flows like a river which I can grasp, finding all the wires behind the cabinetry and getting them installed on the correct post of the shunt is not going to be an enjoyable task.

I do know from a friend's boat experience, equalization charging (15.5V) will fry most AGM batteries. Fortuantely, the batteries safety valves opened on his AGMs allowing gases to escape. Further, the boat was in his driveway allowing the gases to dissipate greatly reducing risk of fire and/or explosion. And, he caught (actually smelled) his mistake before the HOT batteries melted his boat's battery compartment and inner hull. LUCKY.

Given his experience, I'm not going to select WET battery type on my Zamp controller to achieve a 14.7 absorption charge without knowing the Optima's Blue Top circuity would protect and prevent the battery discharging to something less than 10.5V. I do not want to get anywhere near 10V where equalization mode engages. If I have to take a percentage less than fully charged by accepting the Zamp's 14.4V AGM absorption charge before float engages, then so be it.

The Morningstar SunSaver controller charges to 14.1V (sealed) and 14.4V (wet) before engaging float charge. So the Zamp is actually going to charge the D27M's to higher state. I find it interesting Optima designs batteries for series charging to 14.7V and advertises them suitable for RV use. My thought is Optima does not design their batteries for solar applications since I can't find a controller with an AGM absorption charge specification of 14.7V. Most solar controllers permit 14.4V or less before engaging float mode.

I have had such a good experience with Blue Tops in my boats over the years I assumed they would be the best choice in my FWC Hawk. I had the FWC factory install all the solar components, except the batteries. I seem to recall the factory installs Exide EDGE AGMs. Reading the specs on the Exide web site, the EDGE AGM reaches a fully charged state with an absorption charge between 14.1-14.4V. Right on the spec of the Zamp controller's absorption charge mode. Recommended float charge for the EDGE is 13.6-13.8V; also spot on for the Zamp controller.

It will be interesting to see what the Trimetric battery charger indicates is going on with the Blue Tops. If battery life is less than expected, I may go to Exide EDGE AGMs when the Blue Tops reach the end of their service life.

 

[Old Crow]

Thanks for the thorough explanation. I did indeed mis-read your post.

rerotection against discharging below 10.5. I can't imagine there's any such protection. I can tell you from experience the YellowTop in my van has gone down so low it wouldn't pop the electric locks. If memory serves it read something on the order of 3 volts. Your concern about the 15.5-volt charge seems valid but than again I can't work in Optima's Rapid Recharge instructions which say you can go to 15.6 volts and any amperage so long as the temp doesn't exceed 125 degrees.

I'll be very interested to see what the Trimetric shows on your D27 and whether it meets your expectations.

-OC

 

[deethe]

re: protectiona against discharge below 10.5v

a low voltage disconnect between the batteries and the house would prevent battery discharge below a settable range around 11.7 volts

https://www.bluesea.com/products/7635/m-LVD_Low_Voltage_Disconnect

 

[Advmoto18]

Deethe

The BS LVD is certainly an option. Lowest voltage setting is 11.1V. The Optima Blue Tops (deep cycle) have a lot of stored power availalble below 11.1V I have never had an issue taking them down to 10.5V and re-charging.

The LVD is mainly designed for crank batteries. I have used LVDs on bay boats running around Biscayne Bay south of Miami.