Lithium Iron battery test

[trailertrawlerkismet]

Over the last 2 days we were able to give the Lithium Iron house battery option we added to our R25OB build its first real field test. We went to a favorite anchorage in Florida for a 2 day/night stay. During this time we started with the Lithium batteries 100% charged. During the 48 hours we ran the hot water heater for 1 hour, used an electric skillet for 40 minutes, the stove top burner for 20 minutes, 2 pots of coffee from our electric percolator, tv for 2 hours, radio for an hour, anchor light for 2 nights, various interior lights, went for a one hour boat ride, house and spare refrigerator always had power when needed and all the other little things that take power. In the end we had a 44% state of charge with 27 hours of charge remaining. More information will be learned as we use them more but I’d have to say that I’m happy with the initial results.

Jim F

 

[BB marine]

That is quite impressive. I did receive some information about the install from Andrew for my electrical presentation at the SWF rendezvous. Based on the drawing there is a 600 AH lithium battery bank used for the house battery bank. At 44% charge you used 396 AH of battery capacity + the solar input for two days and 1 hour of engine charging. This leaves you with about 200 Ah to total discharge which from what I read will not damage the battery's if done occasional . Dakota does recommend that you do not discharge below 80% to maintain battery life. I looked at the Ranger install and it looks well thought out. A larger solar charging panel would be a great addition but with limited room the set up seems to be sufficient for a boat of this size. Did you record how much solar power input you received and how much engine charging amps increased the stored capacity?

Seems like this is the future in battery power. I'm still on the fence because of my lack of knowledge to this technology.The more I research it and the more information available and use of Lithium batteries in the marine and RV industries it seems to be the direction to go.

 

[trailertrawlerkismet]

Unfortunately Brian I did not record the numbers from the solar or engine, next time. I was on the fence about the Lithium package but the more I read and understand how they work the more confident I’m becoming. More data as my learning curve improves.

Jim F

 

[baz]

Brian: Several years ago I purchased a 50 Ah Lithium battery that weighed in at around 10 lbs. I bench tested it against a varying load to see what voltage it provided all the way down to around 10% charge level from its starting 12.4v. It bottomed out with just under 11v displaying, and during the whole test provided a solid power output to my test trolling motor that was dunked into a large trash bin full of water. The test from full charge down to 10% was a good 12 hrs as I recall, or may have been longer.

I'm certainly a fan of the Lithium battery and from all the chat about optimizing Lithium batteries in computer laptops the rule is to not overly charge above 80% unless needed.

In July 2022 I will be welcoming my new 2023 model R25/OB NW Edition (identical in many ways to Jim & Lisa's R25/OB) that unfortunately RT does not offer the Lithium package for at this time.

However, I note that the stock 4x AGM batteries in the port side cockpit locker leave plenty of space to add a couple of Lithium-ion batteries.

A Dakota LITHIUM 12V 100AH DEEP CYCLE LIFEPO4 BATTERY (weighs 32 lb) can be obtained today for around $900, and can be associated with a DAKOTA LITHIUM MULTI FUNCTION 300W POWER INVERTER DC 12V TO 110V AC CONVERTER for $139, and an ULTRA FAST 12V 20 AMP LITHIUM LIFEPO4 BATTERY CHARGER for $199.

"DL LiFePO4 batteries have a flat voltage curve, which means they have a steady power output as the battery discharges. The power output will not dramatically drop like similar sized SLA batteries. You get all the juice down to the last drop."

These batteries have a whooping 2,000 life time full charge cycles.

I'm thinking I might get two of these to aid with the R25/OB's house 2x AGM house batteries, but as independent batteries to remove any complication taping into the stock AGM circuitry, and that get charged up at dockside before casting off, and that can be used to power lights and low power consuming 'gadgets'.

 

[baz]

Jim: Lithium batteries typically have a limited number of full charging cycles, much like for computer laptop batteries. Does your setup have a meter display that shows the number of full charge cycles the batteries have been subject to, and what their full output is as the cycle counts climb? The Dakota Lithium batteries I mention in my post to Brian claim to have a life-time 2,000 cycle rating.

 

[Submariner]

Jim: Lithium batteries typically have a limited number of full charging cycles, much like for computer laptop batteries. Does your setup have a meter display that shows the number of full charge cycles the batteries have been subject to, and what their full output is as the cycle counts climb? The Dakota Lithium batteries I mention in my post to Brian claim to have a life-time 2,000 cycle rating.

2,000 cycles... is a lot of boating. If I cycled the batteries 100 times a year, that'd be 100 outings a year, then there's 20 years worth of batteries. I suspect the batteries would wear out due to age before they run out of cycles. The Victron BMV-712 battery monitor does keep track of cycles. I don't know if the Balmar that comes with the boat does or doesn't.

 

[trailertrawlerkismet]

Barry, there is no number of cycles registered on the display gauge however there is a SOH (State of Health) that is displayed as a % of the remaining battery banks life….this would be for the long term life vs the SOC (State of Charge) which is a display of the the cycle the battery bank is in currently, or short term as you are using them.

Jim

 

[CruisingElvinRay]

BattleBorn has some great batteries, too. I’m looking at 1 or 2 of their Game Changer 3 batteries. 270Ah each in a form factor that would allow 2 side-by-side in the port locker. And the height of the battery almost fully utilizes the space (about an inch to spare)

I’ve already replaced the 20A Kisae charger with the 60A model. I stayed with Kisae mainly because it fit right where the 20A charger was. I now have 60A into the my existing house bank and 20A to the Engine and Thruster batteries.


Sent from my iPad using Tapatalk

 

[trailertrawlerkismet]

I reached out to customer support at Dakota Lithium in order to better understand how I can discharge my 6 house Lifepo4 100AH, 1,280 WH batteries while away from shore power. Specifically I wanted to know my discharge limits, what I could safely let the volts drop down to without harming the batteries and before the the BMS (Battery Monitoring System) would cut power to protect the batteries. Rather then explain I’ll quote what I received from Richard at Dakota.

“If you have the batteries in parallel, then the voltage is firm at 10V for the low voltage cutoff. You want to avoid draining down to 10V because then the BMS will cut power to protect the batteries. Here is an actual discharge graph of a 12V 100ah battery under a 66a load discharge. (I’m not familiar how to add this graph, so if anyone would like it please PM your email address for me to email it to you)

As you can see….the battery voltage stays the same until the cells are drained, then sharply drops to 10V when the battery pack is about 90% discharged.

This also shows you the voltage sag effect of the load. So under the above 66a load, the battery reads above 11V for the majority of the curve, then drops when capacity runs out.

So, moving forward, it’s best to recharge your batteries when they are reading below 12V.

A simple solution would be a monitor that shows you the state of charge”.

I hope this helps others who have or are planning to look into the Lithium house battery package. Lastly the monitor that was suggested…..there is one that is installed and it does measure current Volts, time left in battery bank under current load, State of Charge (SOC), State of Health (SOH)…this is the long term battery condition, and current amp draw.

Jim F