Lithium install in my Hawk

[photohc]

I just posted on my website my recent adventure in installing a Lithium LiFePo4 Prismatic cell in my camper. A little different from the recent active post by cdbrow1 as my install involves using solar panels. I kept the IOTA installed for those times I need to recharge if power is available and the sun is hiding behind clouds. I've removed the alternator link from the truck engine as I don't think I'll need that with the 150 watt panel on the roof all the time.
Harv

 

[DrJ]

Harv,
Thanks for taking the time to post that info. It's quite interesting to me. This technology is getting better all of the time and it's likely to be used in future camper set ups.

 

[craig333]

I just received a summit catalog. Open it up and the first thing that jumps out at me are lithium batteries.

http://www.summitracing.com/nv/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=deltran&N=4294925527
Of course they're going for the motorcycle segment.

 

[photohc]

Lithium's a are showing up in various applications more. Those jump starters for cars are amazing for the size and amps it can pump out. I believe Lithium adoption is making a bigger inroads in the boating industry and in the very early stages for RV's.

 

[Happyjax]

Very nice write up! Thanks for the info and pictures

 

[cdbrow1]

I just posted on my website my recent adventure in installing a Lithium LiFePo4 Prismatic cell in my camper. A little different from the recent active post by cdbrow1 as my install involves using solar panels. I kept the IOTA installed for those times I need to recharge if power is available and the sun is hiding behind clouds. I've removed the alternator link from the truck engine as I don't think I'll need that with the 150 watt panel on the roof all the time.
Harv

I thought about cutting the cord to the alternator myself and going solar. I will probably add panels in the near future.

 

[photohc]

I thought about cutting the cord to the alternator myself and going solar. I will probably add panels in the near future.

I think the problem with using the alternator is managing the current from it. Too high a current can be problems to the battery. I don't have a way to manage that so, I chose to keep the alternator disconnected. The Morningstar controller will cut off the charge current once it hits 14.2v thus preventing any damage to the lithium. Some manufacturers list a higher voltage tolerance but I think their being too optimistic. Elite Power Solutions technical support suggested keeping the battery between 12v-14.2v. Lithiums don't like full charges and discharges. Unlike other batteries, memory problems don't exist here. It is perfectly fine to charge to 80% and store it that way.

 

[cdbrow1]

My charge voltage is rated at 14.6V, but I agree the manufacturer might be overoptimistic. They specifically said charging off an alternator was not a problem. Of course I really don't know what they have going on in the BMS. They sell alot of units for motorcycles which have the same charging system - so I hope it's programmed well.

I wonder if there is a programmable charge controller that could be run off the vehicle charging system?

 

[photohc]

My charge voltage is rated at 14.6V, but I agree the manufacturer might be overoptimistic. They specifically said charging off an alternator was not a problem. Of course I really don't know what they have going on in the BMS. They sell alot of units for motorcycles which have the same charging system - so I hope it's programmed well.

I wonder if there is a programmable charge controller that could be run off the vehicle charging system?

Your Stark battery is a self contained unit so it's hard to tell what BMS functions are built in. I would guess, if sold as a drop in unit, it should handle most situations. I looked at the website to see if I could get more information but a technical manual is not there. Might pay some dividends to call and ask if "Maximum Charge Voltage Disconnect" and "Low Voltage Load Disconnect" are built in functions. If so, what are the range of voltages.

As for a programmable charge controller, they do exist as DC-DC charge devices. These are designed to limit the current flow to "X" at a set voltage but the problem is that most of those are designed for lead acid batteries going through bulk, absorption, float, equalization, which a Lithium doesn't need. Some allow a limited amount of program options that allow voltage set points that might work. Here's one made by Xantrex.

 

[Timothy McGowen]

Great write up Harv. I'm anxious to follow your progress.

 

[cdbrow1]

Your Stark battery is a self contained unit so it's hard to tell what BMS functions are built in. I would guess, if sold as a drop in unit, it should handle most situations. I looked at the website to see if I could get more information but a technical manual is not there. Might pay some dividends to call and ask if "Maximum Charge Voltage Disconnect" and "Low Voltage Load Disconnect" are built in functions. If so, what are the range of voltages.

As for a programmable charge controller, they do exist as DC-DC charge devices. These are designed to limit the current flow to "X" at a set voltage but the problem is that most of those are designed for lead acid batteries going through bulk, absorption, float, equalization, which a Lithium doesn't need. Some allow a limited amount of program options that allow voltage set points that might work. Here's one made by Xantrex.

The high voltage disconnect is 16 volts - load disconnect is supposedly at 10 volts, however the battery case says 9.2. Either way I don't plan on running below 11. I have an alarm set up in the Xantrex to go off at 30% and in theory could set up a load disconnect.

 

[photohc]

Great write up Harv. I'm anxious to follow your progress.

Thanks Tim. I go out for a 7 day trip at the end of the month to Lone Pine, Bishop and Death Valley and give it a real test. So far I've been only testing consumption with the Hawk sitting in the garage by running the Dometic 24 hrs/day for the last three days. By the next morning, the battery is usually sitting at 70-75%. I have two solar panels, a 150w sitting on the roof and a 100w portable. I've been stringing the 100w panel outside to catch the sun and the batteries usually charge back up to by 1pm. With both panels out open to the sky, I don't anticipate any issues with getting a full charge before night fall. I probably have an overkill in capacity.