[RE-wrenches] FullRiver battery question

[Ray]

Hi Jay,

Thanks for that info on AGM behavior.  I've advocated for years that 
charge controller temp sensors should also be used to sense over temp 
and shut down or reduce charge current.  Midnite added this feature to 
their Classic charge controllers. Its a bit hard to find, but you can 
set the temp to shut off at the battery manufacturer's  highest 
recommended temperature.  Besides catastrophic melt downs,  high temps 
can greatly reduce a battery's cycle life.

Ray Walters
Remote Solar
303 505-8760

On 11/29/18 6:57 PM, jay wrote:
> Hi All,
>
> My 2 cents.
>
> I’ve recently had to do some research for someone who had 16 Full 
> River 400/6v melt down.  ( 48v bank, 2-3 yrs old). Both banks, all 16 
> melted.
> In talking with a battery company expert, what I was given is the 
> following:  AGM if not charged correctly, especially if they are 
> allowed to sulfate ( under charge), and then charged heavily during 
> hot conditions can melt down. When  flooded get sulfated they won’t 
> accept a large charge, current is low.   AGM appear to have the 
> opposite reaction which is that they create high resistance but accept 
> current creating lots of heat.  They can’t vent the heat ( no caps 
>  and if there isn’t enough room around them they can’t expel the heat 
> either.  In a sense if they can melt together, they are too close 
> together ) and if there is external heat to contribute then once they 
> get to 40-50C internal they can melt down.  I mentioned in a previous 
> post that Full River has an EQ type cycle for batteries that are 
> showing lowered capacity which is a form of sulfation and this EQ is 
> to try and prevent this exact situation.
>
> As to MK, I don’t use them as they have very low cycle life.  Those MK 
> 8D AGM are around 700 cycles to 50%, vs Full River or Rolls AGM at 
> around 1300 cycles to 50%.
>
> VRLA  are a pretty tricky compared to flooded.
>
> jay
> peltz power
>
>
>> On Nov 29, 2018, at 8:33 AM, Starlight Solar Power Systems 
>> <larry at starlightsolar.com <mailto:larry at starlightsolar.com>> wrote:
>>
>> Let me confirm what William has shared about Deka/MK 8D AGM 
>> batteries; they have a very high failure rate. We saw over 40% fail 
>> within 2-3 years of installation. Deka would not own up to the 
>> problem and offered no compensation.
>>
>> Fullriver has been the finest AGM we have ever sold. All DC models 
>> are excellent. We especially like the 2 volt L-16’s for high capacity 
>> systems. We had one failure, and I know of one other, where L16 
>> batteries went into thermal runaway. The cases welded together. After 
>> fully testing the power system that we designed and installed, we 
>> found no problem. Fullriver would not offer any help or replacement.
>>
>> Our installations are 100% battery based. When I do see failures I 
>> have many other identical power systems to compare with (in the 
>> thousands, we do 5-8 per week) and this helps me make sound 
>> judgements about our findings.
>>
>> Larry Crutcher
>>
>> *3 year old Deka 8D*
>> <Deka 8D AGM failure_ (2).jpeg>
>>
>> *1.5 year old Fullriver L-16*
>> <IMG_0629 (1).jpeg>
>>
>>
>> On Nov 28, 2018, at 11:43 PM, William Miller <william at millersolar.com 
>> <mailto:william at millersolar.com>> wrote:
>>
>> Allan:
>>
>> We have had poor luck with the 8D AGM batteries (MK/Deka).  Many of 
>> them have had short life spans along with swelling, heating and even 
>> exploding. Your point about the inefficient footprint is right on.
>>
>> I have minimal experience with Full River.  I have seen a set fail, 
>> but heck, anyone can do that in a hurry.
>>
>> When footprint is an issue, we have gone to racked AGMs, like the 
>> Deka Unigy.  Now to get higher voltages might require custom racking, 
>> but the cells come in lots of sizes and shapes, physically and in 
>> capacity.  It may be worth checking into the size of a 400 AH Unigy 
>> cell and see how they rack up.  I don’t have but a smattering of 
>> drawings for the models we have purchased, but my cursory look 
>> indicates you won’t save on volume or dollars,  but you may gain a 
>> smaller footprint with some Unigy racks in series.
>>
>> William
>>
>> <image002.jpg>
>> Lic 773985
>> millersolar.com <http://www.millersolar.com/>
>> 805-438-5600
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