Firefly Oasis carbon foam AGM battery

[Alloy]

As mentioned flexible panel are not ideal. The biggest issue would be the heat transfer into the sleeping area.

With rigid panels you'll want a min. 3" air gap under the panel(s) .

When I was looking Panaisonic were #3 in efficiency (19.5%) and the price was better compared to others with less efficiency.

Check if there is a maximum amount of weight that can be added to the top......the gas springs and connections many need upgrading.

 

[shade]

As mentioned flexible panel are not ideal. The biggest issue would be the heat transfer into the sleeping area.

With rigid panels you'll want a min. 3" air gap under the panel(s) .

When I was looking Panaisonic were #3 in efficiency (19.5%) and the price was better compared to others with less efficiency.

Check if there is a maximum amount of weight that can be added to the top......the gas springs and connections many need upgrading.

Weight won't be a problem. The top is designed to open with 100 lbs on it, and can carry much more. I can swap out the struts, if needed.

I knew an air gap was required, but I wasn't aware it was 3" minimum. Not ideal, but I can make it work.

 

[luthj]

I think 3" is more than is strictly needed for a single panel type install. I would aim for 1" between the frame and the roof. A vehicle has drag considerations which tend to be higher priority than max PV output, especially given the low cost of PV.

 

[shade]

I think 3" is more than is strictly needed for a single panel type install. I would aim for 1" between the frame and the roof. A vehicle has drag considerations which tend to be higher priority than max PV output, especially given the low cost of PV.

That's more what I'm after. I may even angle the leading edge down if that works better with the front deflector panel, if needed. My truck gets bad enough fuel economy as it is.

 

[Billoftt]

Their spec sheet says the operating temperature is -4° to 104°. I would definitely avoid putting it under my hood.

 

[shade]

Their spec sheet says the operating temperature is -4° to 104°. I would definitely avoid putting it under my hood.

The Firefly battery? It operates over a wider range that that.

Firefly Oasis Battery - Carbon Foam AGM

The only Carbon-foam AGM battery is the Firefly Oasis Battery. Now available for marine applications, it is capable of deeper discharges and longer life

oceanplanetenergy.com

Strong Performance in Extreme Cold and Heat– performance range is -20° C to 50° C

I still have to look for a spot, but if I buy anything but a low cost battery, it won't go under the hood. There's just too much money & battery life wasted going that route.

 

[Alloy]

Weight won't be a problem. The top is designed to open with 100 lbs on it, and can carry much more. I can swap out the struts, if needed.

I knew an air gap was required, but I wasn't aware it was 3" minimum. Not ideal, but I can make it work.

There is no minimum air gap. The bigger it is the more efficent the panels are and there is less heat transfer into the roof.

I have 4" under mine. When I put my hand under the panels when it is a 100F it feels like an oven.

 

[shade]

Ok, makes sense. The large white composite panel that makes the camper roof also insulates. I've seen a few of the same camper with rigid panels on top, so I'll check on how those setups are working.

 

[SBDuller]

That's more what I'm after. I may even angle the leading edge down if that works better with the front deflector panel, if needed. My truck gets bad enough fuel economy as it is.

since you've mentioned PV mounted as deflector on cab roof, this is my recent hard-mounting. unfortunately, one panel is all i can mount permanetly. plan is at least one portable panel in addition.

 

[r27d]

I picked up a pair of Firefly Oasis at their location in Peoria this week. The batteries are made in India now but are each fully tested and conditioned at their lab in Peoria. What should I get for a charger from the alternator? I was considering a KISAE DMT1250 is there something that will work better? From their user guide:

"For a complete charge cycle, charge the G31 to 14.4V/L15+ to 4.8V with temperature compensation (bulk phase) and continue charging until the charging current drops to 1.5A for the G31 or 6A for the L15+ (absorption phase time will vary). You DO NOT need to fully charge the batteries each cycle in order to maintain the capacity, however, we recommend doing a complete charge cycle at least once a month when cycling once per day or every 30 cycles if running a couple cycles a day. Ideally, if the battery is under heavy use, we recommend doing a full charge cycle at least every 2 weeks.

For charging sources that may be charging the battery for an extended period of time (solar, or an alternator if motoring for a while); set the float voltage to 13.4V or 13.5V for the G31 and 4.5V for the L15. Firefly batteries do not require a float charge. But, if you are float charging, due to the their longer projected lifespan, it is important to keep the float voltage at 13.4V or 13.5V (4.5V for L15+) to ensure the battery lasts for as many cycles as possible. Reset to bulk phase: for programmable charging sources, adjust the “reset to bulk phase” to occur if the battery voltage drops below 12.0V for >1 minute for the G31 or 4.0V for >1 minute for the L15+."

 

[john61ct]

Kisae DCDC needs a VSR or off switch, not automatic.

But is user adjustable voltage, I believe only one other than Sterling BB series.

Charge the FF to 14.4V with temperature compensation (bulk phase) and continue charging until the charging current drops to 1.5A (absorption phase, time will vary).

You DO NOT need to fully charge the Oasis every cycle in order to maintain the capacity and only need to perform a complete charge cycle when you want to maximize the capacity for the following discharge cycle.

For charging sources that may be charging the battery for an extended period of time (solar, or an alternator if motoring for a while); set the float voltage to 13.2V or less.

The Oasis does not require a float charge, ideal is none like LFP.

But, if float charging, due to the Oasis’s longer projected lifespan, it is important to keep the float voltage at or below 13.2V to ensure the battery lasts for as many cycles as possible.

Reset to bulk phase: for programmable charging sources, adjust the “reset to bulk phase” to occur if the battery voltage drops below 12.0V for >1 minute.

 

[ADVdreams]

Thought I would share my experience. I am using a single G31 as a house battery for light loads (fridge, lights, espar heaters, device charging). I tried to keep the house system as simple as possible using a bluesea ACR (7622) and monitoring of house and starting batteries via a Merlin (Balmar) smartgauge battery monitor.

I chose the G31 for a few reasons
1) high sulphate resistance
2) good low temperature performance vs Li-ion
3) ability to safely install inside living space
4) charging simplicity - already had lead acid alternator and solar charging

Various competing priorities prevent me from getting away as much as I would like so the batteries don’t get used much (hence the priority on sulphate resistance)

After 1 year of use I tested the G31 and found that it was well below rated capacity. I attributed the loss of capacity to sulphation, however recently I am not so sure. During the year in service I routinely charged the battery when at home and all attempts to de-sulphate (equalization charging) have resulted in further capacity loss. I am now wondering if the battery is actually suffering (dryout or grid corrosion?) from having floated at alternator voltage during a few longish driving legs (4-6 hrs) when charged.

Resting OCV when charged appear to be normal, where as I have read a common symptom of sulphation is lower OCV. Based on at least one source I read normal OCV and low capacity can be caused by AGM electrolyte dryout.

The initial design intentionally avoided the complexity, cost and reduced amperage output of a DC-DC charger vs. alternator charging based on perceived advantage (4) above, documented ability to cycle at PSOC without damage.

At a minimum I think I will be manually opening the ACR contacts for long drives when the battery is at or above 80% capacity.

The G31 seems like the ideal battery for my application, perhaps it’s even more sensitive to floating than I thought. I’m curious what service life others are seeing.

 

[dwh]

I doubt a few hours here and there at elevated voltage will have a harmful effect.

I think I'd try an actual desulfator rather than EQing an AGM.

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Might take a few weeks or months to see any significant improvement.

 

[luthj]

Improper charging can cause electrolyte loss. We need more details. Battery type, charger, etc.

 

[ADVdreams]

Thanks for the questions!

Charger is programable 24A. Parameters are 24A CC with a ~2A transition to 14.4V CV, float is 13.4V but I don’t really let it float, unplug as soon as I notice it’s done.

Vehicle charging is primarily alternator with some sporadic solar top up.

Battery is an Oasis G31 AGM 116AH capacity