Single LiFePo4 Battery or Two LiFePo4 Batteries in Hawk?

[rando]

BattleBorn Li batteries: Bulk 14.4-14.6V and float 13.6V....so I assume our IOTA DLS-30 w/IQ4 is "good to go"?

No, the bulk of 14.8 is too high, it may trip the BMS over voltage shutdown. If you leave your camper plugged in while not in storage, then the float of 13.6v is also higher than you want.

 

[Wallowa]

Rando...

Help me understand...I do not grasp the significance of the difference of .2V in bulk [14.8 IOTA-14.6 BB] and that BB recommends a float of 13.6V which is what the IOTA has...I wonder how other FWC owners have converted to Li with IOTA chargers?

My knowledge is limited in this.

Also can't the BMS voltage shutdown be adjusted?

Any insights would be appreciated...thanks.

Phil

 

[rando]

The 14.6V bulk for battleborn is the maximum charging voltage, not the ideal charging voltage. If the voltage goes much above this (14.7V), the BMS will stop charging to protect the battery. This is like a safety fuse and not something you want to rely on in regular operation. Ideally you want a bulk around 14V. Similarly, 13.6V is the maximum float voltage, and at 13.6V you are actually charging a LiFePO4 battery. Ideally you want a 'float' around 13.3 - 13.4V, so instead of charging the battery, you are just carrying the loads.

I still have my Iota with built in IQ4 in my 2016, but I almost never use it, so I haven't worried about replacing or adjusting it. If you have solar and park outside, you probably don't really need to use it either.

There is no ability to either monitor or adjust anything with battleborn, it is a black (or rather blue) box. If you haven't placed an order yet, I would strongly consider looking into some of the other drop in LiFePO4 offerings that are more competitively priced and include some sort of user interface (either blue tooth or a display) so you have some idea what is going on with your batteries.

 

[Jon R]

I chose a 202 Ah battery from bigbattery.com. It has a power switch and a voltage display, and is sized and shaped such that it fits well in the Grandby battery compartment with room to spare for chargers and bus bars. It had a stainless steel case, and all parts are replaceable. There are reviews and teardown videos on youtube. There’s a 10% off coupon code, so I paid 1179 with shipping. They were backordered for a month or so, but it came earlier than they said it would. They have a person who answers the phone and happily responds to technical questions.

 

[rando]

I don’t think the overvoltage protection is a fuse, I believe it is built into the BMS just like the low voltage protection is.

You are correct, the high voltage protection is not a fuse but is a software limit controlled by the BMS. My point was that the BMS limits should be thought of like fuses - they are there to protect the battery if something goes wrong, and should not be relied on control every day charging.

 

[Mthomas]

My bad, deleted comment before I saw your response. You are correct, built as a safe guard, not as a controller.

I do wonder how to evaluate these batteries in terms of durability when used in an off-road vehicle. I know that Battleborn lists marine application as acceptable. Not sure if that means water tight only or vibration and shock resistant. I am thinking about the hours of time I spent on washboard roads a few weeks ago in DVNP.

 

[Wallowa]

My bad, deleted comment before I saw your response. You are correct, built as a safe guard, not as a controller.

I do wonder how to evaluate these batteries in terms of durability when used in an off-road vehicle. I know that Battleborn lists marine application as acceptable. Not sure if that means water tight only or vibration and shock resistant. I am thinking about the hours of time I spent on washboard roads a few weeks ago in DVNP.


Well Li batteries in marine or off road motorcycles take a beating [getting pounded to your knees on the ocean as the boat slams chop or dropping a dirt bike-repeatedly- is tougher than any washboard in my Tundra/Hawk]...so I believe the Li batteries are sturdy enough to survive.

 

[rando]

I have been using a DIY LiFePO4 pack using cylindrical cells for about 4 years FWC, and prior to that I used one using prismatic cells for about 5 years in my land cruiser, both off road vehicles with plenty of rough and washboard roads. No issues with either construction, and I would hope that commercial batteries would be better constructed than my DIY pack,

My bad, deleted comment before I saw your response. You are correct, built as a safe guard, not as a controller.

I do wonder how to evaluate these batteries in terms of durability when used in an off-road vehicle. I know that Battleborn lists marine application as acceptable. Not sure if that means water tight only or vibration and shock resistant. I am thinking about the hours of time I spent on washboard roads a few weeks ago in DVNP.

 

[Wallowa]

For what it is worth...after digging into the function of chargers/converters used and BMS with a BB battery here is what I found out from talking to BB:

BMS Controls..

Charge shut-off 25 degrees F and 134 degrees F...............& @14.7V +
Discharge shut-off -4 degrees F and 140 degrees F............& @ 10 V -

Other Recommendations/limiters..

Max charge rate recommended 50amps per 100ah capacity
Best charging range for life of battery 20-95% SOC
Loss per month from 100% SOC when stored 2-3%
Maintaining over winter on charger not recommended as it unnecessarily cycles battery and reduces life cycles; disconnect to store is best
Charging at lower temps lessens battery life; optimal 70 degrees F
100% SOC @ 14.2V and when cell modules passively balance the level of charge between cells

As stated by others on this forum 14.4V and 13.6V are MAX voltages from charger to battery and less is safer and prolongs battery life

================
When I store my camper in shop, I will disconnect and not leave on converter 110V like I did my AGMs; but disconnect at 95% SOC

I intend to use 'VictronConnect' w/Blue Tooth to program and limit the 110V and solar charging of my heated Battle Born 100ah...Victron Converter, Controller and BMV 712 monitor.

Just me and I am learning so take all this with a grain of salt! I could be wrong...

Phil

Ps...Heating BB , which is controlled automatically between 24-45 degrees F, assures that discharge and charge is possible and not stopped by BMS

 

[steve whiteside]

I would say it depends on your use. As R&R says above, one battery works for him with the main draw being the fridge. But if you are running the fridge, heater, charging phones, and using a plugged in laptop, that might be enough.
We are having a new rig built right now. We went with two lithium batteries and 400 watts of solar on the roof. I don't want to ever have to worry about enough battery charge.

That is what I have. I run a drip coffee maker for 1100w for 13 minutes each day, misc lights/fans/phones with no issue. When I need to charge my ebike for 5 hours pulling 230 watts I need the 2 batteries. If you get a string of 2-3 cloudy days where you dont run your truck - 1 battery is not enough (for me).

 

[Jon R]

Being a Pacific Northwest person, the string of cloudy days scenario is what led me to go with 200Ah of LiFePO and 400 watts of solar panels.

 

[BlueSky]

I have a single 100AH LifePo4 battery, 110w solar panel, and a Victron solar controller. It runs my Dometic 53 qt fridge, furnace, occasional stereo, and charges my phone. I live in CO. No issues with running out of charge. I can stay out in the boonies until I run out of food and water. I also have a Victron DC-DC charger installed (just in case my solar set-up fails for whatever reason) that I can turn on and charge the LifePo4 battery from the running truck in a pinch. In essence I have a primary solar power source and a secondary/backup truck/alternator power source.

NOTE: If you have a newer truck you probably have a "smart" alternator that puts out only about 12.4v max (check this at the battery terminals while your truck is running at idle to confirm). Your LifePo4 battery charge must fall below this for the DC-DC charger to start charging. So, if you leave the DC-DC charger on along with the Solar charger, and you are cruising down the road on a sunny day, the DC-DC charger probably won't be doing anything because your solar charger will be putting out a lot more voltage than the 12.4v coming from the truck's alternator. I just leave the DC-DC charger off until I really need it. Also, if you use only the DC-DC charger and have a smart alternator, you will not get up to that 13v-14v that a LifePo4 battery is capable of. There may be a setting in the Victron DC-DC charger that allows it to increase the voltage output, but I have not looked into it.

CAVEAT: I am really just a novice at this stuff and there may be more to it than I just said.

 

[Vic Harder]

The whole point of the dcdc charger is to compensate for the low input voltage. It will gladly take the 12.4 and bump it up to what you lipo battery needs

 

[BlueSky]

I don't know if that is the "whole" point of DC-DC charging, but I figured that it was possible to adjust the output voltage. I need to spend more time on the DC-DC charger settings.

 

[fuzzymarindave]

For my lithium battery install I replaced the Iota and Surepower with a combo unit:

https://www.renogy.com/dcc30s-12v-30a-dual-input-dc-dc-on-board-battery-charger-with-mppt/

 

[Vic Harder]

I don't know if that is the "whole" point of DC-DC charging, but I figured that it was possible to adjust the output voltage. I need to spend more time on the DC-DC charger settings.

Agreed. I use mine to protect the alternator from burnout, as it could push it's full capacity for too long over the 2g wire I have in place.

 

[JimBow]

I have a single 100AH LifePo4 battery, 110w solar panel, and a Victron solar controller. It runs my Dometic 53 qt fridge, furnace, occasional stereo, and charges my phone. I live in CO. No issues with running out of charge. I can stay out in the boonies until I run out of food and water. I also have a Victron DC-DC charger installed (just in case my solar set-up fails for whatever reason) that I can turn on and charge the LifePo4 battery from the running truck in a pinch. In essence I have a primary solar power source and a secondary/backup truck/alternator power source.

NOTE: If you have a newer truck you probably have a "smart" alternator that puts out only about 12.4v max (check this at the battery terminals while your truck is running at idle to confirm). Your LifePo4 battery charge must fall below this for the DC-DC charger to start charging. So, if you leave the DC-DC charger on along with the Solar charger, and you are cruising down the road on a sunny day, the DC-DC charger probably won't be doing anything because your solar charger will be putting out a lot more voltage than the 12.4v coming from the truck's alternator. I just leave the DC-DC charger off until I really need it. Also, if you use only the DC-DC charger and have a smart alternator, you will not get up to that 13v-14v that a LifePo4 battery is capable of. There may be a setting in the Victron DC-DC charger that allows it to increase the voltage output, but I have not looked into it.

CAVEAT: I am really just a novice at this stuff and there may be more to it than I just said.

I recently installed a 100 Ah BB and a Victron DC-DC charger. I have a 160 Watt solar panel as well. With the camper battery down 20% and the truck (2020 Ford Ranger) running, I'm getting 35 amps of charging according to my Victron battery monitor. I'm assuming that's 30 amps from the charger and 5 amps from the solar panel. The battery charges up fast. I'm pretty happy with this set up so far.

 

[BlueSky]

I recently installed a 100 Ah BB and a Victron DC-DC charger. I have a 160 Watt solar panel as well. With the camper battery down 20% and the truck (2020 Ford Ranger) running, I'm getting 35 amps of charging according to my Victron battery monitor. I'm assuming that's 30 amps from the charger and 5 amps from the solar panel. The battery charges up fast. I'm pretty happy with this set up so far.

30 amps from the DC-DC charger seems kinda high and might be taxing your alternator too much. My Victron DC-DC charger is the 20 amp model, so it will deliver 20 amp or less, and my assumption is that this will not tax my 150 amp alternator too heavily. I am of course guessing at this level of how much my alternator can handle, and others on this board may have far more experience and understanding in this area.

The Victron app should tell you what the charger is providing to the battery in terms of amps and voltage.

 

[JimBow]

My alternator puts out 105 amps at 750 rpm and 170 amps at 2250 rpm. I ran 6 gauge welding cable from the truck battery to the charger and the charger to the camper battery, and used 60 amp circuit breakers like Victron recommends. I think the Victron Smart 12/12/30 DC-DC charger will be OK with this set up. We'll see!

 

[Vic Harder]

I would hope that 30A out of a 150A alternator is "loafing along" and not stressing it at all. You could stop after an hour and check to see it if is hot?