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Opinions on LiFePO4 battery in a mostly hydroelectrically charged system

Darkstar

Rain Wrangler
Joined
Dec 31, 2019
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I have a 1000AH flooded lead acid rolls battery that is charged by a hydroelectric generator during the rainy season (Oct-Jun). It is charged by 800 watts of Renogy panels and an honda inverter generator for the rest of the year. I was wondering if a LiFePO4 battery would be appropriate under this charging regime? Some issues I see:

1. The hydro generator is similar to a wind turbine in that it always needs to be connected to a load (Battery bank). The charge controllers that are appropriate are PWM dump load controllers that dump excess power to a heating element when the battery gets full. So a normal charge controller or BMS system that just disconnects the solar panels/charging source would not work correctly as they would cause the Hydro to overspeed and blow bearings and such if ever disconnected from the battery.

2. During most of the year our battery does not cycle at all. The hydro puts out enough power 24/7 to keep it full for 8 months out of the year. Would a LiFePO4 battery work without issue without many cycles? Would I want to keep the LiFePO4 battery at a lower than full charge state to help extend it's life?
 
Look at you showing off with your endless hydro power.......I want some! Id stick to lead for the buffer to the hydro and just bleed off excess to a better battery bank if you needed the extended storage/fast charge. maybe do a portable bank you can use around your place to power tools and what not? plug it back into the lead pack to trickle charge from the hydro.

I have high flow but only 5-10' drop over 3/4 mile long property, I think a water wheel is in my future.
 
I have high flow but only 5-10' drop over 3/4 mile long property, I think a water wheel is in my future.
Look at low head stream/river diversion hydro. You only need 1.5m head and a swirl pot for good power.



PS yeah your suggestion to OP makes sense to me too. Or have lithium for summer, extra panels and ditch the genny but keep FLA for winter.
 
I believe you would do well with LFP for a number of reasons, most obviously, they charge faster, have more capacity per kg and a deeper DOD (quite safe at 80% for long life) and of course no maintenance, watering and testing Gravity. Ohh that can be such a pain in the ..... ;) Quite a few similarities to the issues with Wind but with one advantage (generally) is that waterflow is consistent, unlike wind which varies all the time & brings it's own set of problems.

The BMS and a Load Diversion mechanism would be pretty important because once the battery is full you'd want to make use of the excess so your not wasting it or damaging the batteries with over charging. I've been reading up on the Electrodacus BMS which has the abilities for DC diversion and more... While it is an "upstart" meaning reasonably new & not a big corporation of unknown origin it certainly does look promising and the feedback is pretty positive.
 
Load diversion on a BMS? That sounds interesting. Thanks for the link.

I'm thinking diverting excess power to a LiFePo4 pack that is charged additionally by solar for summer use is worth looking into. The flat voltage curve is appealing.

Had not thought about mobile battery charging for jobs around the property. Perhaps swap an FLA pack for LiFePo4 and an inverter in an electric side by side so I would have transportation and a mobile power station all in one...

Energy systems and design makes a functional low head high flow unit too. Could be more efficient than a water wheel. Have never looked too close at it as we have 300-400 feet of fall with 3 different water sources on our property.
https://microhydropower.com/our-products/low-head-stream-engine/

Also, youtube low head system:
 
I've got hydro planned as a future add on. My inverter has a smart load option. Once the battery hits a predetermined soc it Will divert power to an optional load panel, this could be a large hot water tank. Another issue with hydro is the open circuit voltage can be 3x the loaded voltage. Have to consider that when spec'ing the turbine.
 
I've got hydro planned as a future add on. My inverter has a smart load option. Once the battery hits a predetermined soc it Will divert power to an optional load panel, this could be a large hot water tank. Another issue with hydro is the open circuit voltage can be 3x the loaded voltage. Have to consider that when spec'ing the turbine.

What brand/model of inverter do you have?
 
What brand/model of inverter do you have?
My Main inverter is a Solark 8K, I picked up a second hand ginlong 3KW for the hydro as it has a 600v max input for the open circuit. So the ginlong will be AC coupled to the Solark.
 
So the ginlong has an MPPT charge controller built in? I am assuing you have the hydro wild AC going into a three phase bridge rectifier and the DC output from the rectifier to the charge controller? Do you have a buying source or link for me to look at further details?
 
Correct. https://www.powerspout.com/ These are the guys. They have some local dealers, though I ordered from NZ. Their onsite calc is great, they will wind the motor based on your site evaluation.
I ended up with a TRG config with a 200v loaded target.
 
I have a 1000AH flooded lead acid rolls battery that is charged by a hydroelectric generator during the rainy season (Oct-Jun). It is charged by 800 watts of Renogy panels and an honda inverter generator for the rest of the year. I was wondering if a LiFePO4 battery would be appropriate under this charging regime? Some issues I see:

1. The hydro generator is similar to a wind turbine in that it always needs to be connected to a load (Battery bank). The charge controllers that are appropriate are PWM dump load controllers that dump excess power to a heating element when the battery gets full. So a normal charge controller or BMS system that just disconnects the solar panels/charging source would not work correctly as they would cause the Hydro to overspeed and blow bearings and such if ever disconnected from the battery.

2. During most of the year our battery does not cycle at all. The hydro puts out enough power 24/7 to keep it full for 8 months out of the year. Would a LiFePO4 battery work without issue without many cycles? Would I want to keep the LiFePO4 battery at a lower than full charge state to help extend it's life?
Did you end up going LiFePo4? Curious how its working for you, Im also on hydro and FLA and thinking of an eventual upgrade
 
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