FWC Electrical basics and upgrading to lithium!

[Vic Harder]

First? Get a shunt based monitor if you don't have one already. I recommend the Victron SmartShunt - LINK to canadian amazon.

After that, what JonR said.

 

[BBZ]

Thx.. today it is not charging at all.. hmm. Suggestions? Bumpy roads.. loose connection??

 

[Vic Harder]

Not charging. Does it need to? If the batteries are full, the MPPT will not add more to them.

 

[Herbie]

1. Older IOTA chargers have an option to plug in an external module to adjust it’s parameters to better charge lithium batteries, newer ones do not. In my experience, the IOTA charger is typically not able to charge a battleborn battery more than 80-90%. Do you NEED lithium?

As far as I can tell, IOTA still sells the DLS- series that accept the IQ4 module (non-"X" suffix). Moreover, they added a Lithium-specific IQ4 module to the lineup a few years back. I'm wondering if your experience is with the "IQ4-LifePo", or just the original battery module?

Switching IQ4 modules from the base IQ4 to the AGM version definitely improved longevity and performance on my current setup, so I had always planned on just swapping to the Lithium version when the time came to replace/upgrade the battery.

 

[BillTheHiker]

Just learning about lithium batteries for campers and have a couple questions about the original post.

Is it OK and safe to have a 4 or 6 gauge wire from alternator to camper lifepo4 battery without a dc-dc charger? Original poster seemed to imply a significant boost to the house batteru with a heavy wire alone. I thought it is critical to control the current into a lithium battery.

Also, if the alternator to camper lifepo4 wire is thin, like 12 or 14 gauge, could that thin wire melt when the truck is running, especially if the lifepo4 SOC is low so it wants to be bulk charged?

 

[Vic Harder]

The stock FWC installation uses 10g wire and 30A thermal fuses. The thermal fuse will prevent the wire from melting.

If you use heavier gauge wire, the fuse/breaker needs to be upgraded as well. I use 2g wire in my setup with 100A breakers.

Before I went lithium, I could see 90A going to my camper batteries, but only for a short time (like 10 minutes) before it dropped down to a steady 40A or so for up to 2 hours at a time before the batteries were recharged. I had 225AH of batteries at that time.

Without the DCDC, a single 100A totally discharged lithium battery could conceivably suck up 100A for a whole hour before being fully recharged. That may or may not damage your alternator. I have 200AH of lithium, and preferred not to test that, so use a 30A DCDC now.

 

[BillTheHiker]

<<That may or may not damage your alternator.>>
But could it damapge the lithium battery?, which I thought is fussy about how it gets charged. I thought the reason a programmable mppt controller is used is to make sure the solar panel feeds the right amount of current at each stage of charging

 

[Vic Harder]

Ironically, lithium is less fussy than AGM. All or nothing is what lithium wants. AND, it it doesn’t like what it is getting, the built in BMS will deal with it.

ALL batteries need a solar controller to convert the output of the PV panels into what the connected batteries need. MPPT is better than the older PWM style of solar controllers, because they are more efficient.

All batteries also have ideal charging parameters, including their max charge rate, and if that ideal is not used, there are compromises in battery life. For Battleborn batteries, that is .5C, or 50A. So if the alternator can put out 200A, the BMS will limited that to 100A and yes, you will shorten the battery’s life expectancy.

 

[BBZ]

Not charging. Does it need to? If the batteries are full, the MPPT will not add more to them.

its at 94.9 %.. does not need to charge for my purposes as we have a rental for a month.. but don't recall it ever doing that before... is there a certain discharge needed before it starts recharging?

 

[Vic Harder]

its at 94.9 %.. does not need to charge for my purposes as we have a rental for a month.. but don't recall it ever doing that before... is there a certain discharge needed before it starts recharging?

well, no. It should be charging if the batteries are at 94.9%. Where are you seeing that number? Based on a previous comment you made "My charge controller only has a gel mode, but not lithium, how much of a difference will that make to get a better charging monitor" I wonder if we need to clarify what you have, since there are really 4 major components to the solar charging system:

1) MPPT - this is your solar charge controller (could be PWM, but those are getting rare). It converts 20+VDC to something closer to the 12V the batteries need. Sometimes these have displays that convey what the controller is putting into the batteries. It can't tell you anything about your battery's state of charge (SOC). It can guess though.
2) Battery Monitor - such as the Victron SmartShunt I linked above. It measures the state of the batteries, regardless of what the controller is putting in.
3 & 4) PV panels and batteries... but we are not talking about those right now.

If your display is from the charge controller (if you have a factory setup with the Overland MPPT, it came with a round display with several buttons on it) and it says 94.9% charged (a guess) AND the PV Voltage is higher than 20V or so, it should be charging. At night, for example, the PV Volts will be zero, and thus no charge can happen. If the sun is shining brightly on your panels, and the display says the PV voltage is 20+V, and you still see zero amps, then the batteries must be fully charged. (or not connected). You can also see the battery voltage on that display, which should be 12.6V (for AGM) or more if fully charged and no load is on them. For lithium, that is more like 13.3V

 

[BillTheHiker]

Will the low voltage cutoff feature of my IndelB/Truckfridge work effectively with a lithium battery? Maybe this is not important since the BMS will prevent discharge below an unsafe level.

 

[Vic Harder]

A lithium battery has a higher resting voltage, and under load the voltage stays higher for much longer too. So, your low voltage cutoff is likely less of a concern than it would be with an AGM battery.

 

[Mighty Dodge Ram]

I’ll second what Vic just wrote. Dometic CFX75D fridge+freezer connected to an ArkPak. With a SLA 105ah marine battery the fridge would frequently shut off. With my newer Renogy LifePo4 100ah battery, it ran down to 5% capacity and the fridge was still running. Yes, I know…I wasn’t paying attention. But unlike the SLA, I’m not too worried that I’ve ruined the battery.

 

[tstumpfig]

1. Shore Power- When you’re plugged into an external AC source, like at a campground or an outlet into your garage, the IOTA AC to DC battery charger inside your camper takes the 110v alternating current and turns it into 12v DC power, then sends it to your batteries to provide a charge. Older IOTA chargers have an option to plug in an external module to adjust it’s parameters to better charge lithium batteries, newer ones do not. In my experience, the IOTA charger is typically not able to charge a battleborn battery more than 80-90%. Will this hurt the battery? Well, technically, yes. If used this way long term with no other charging sources, you could see a drop in battery life since it’s not being fully cycled. So, technically YES, but effectively.. NO. Almost NO FWC users plug in on a regular basis. Even if you do plug in regularly, you also more than likely have a second or third charge source that IS capable of charging the battery fully, so the IOTA really becomes a non-issue. So maybe it can only charge 80%. No big deal, solar or the alternator (through a DCDC charger) can take care of the rest, and realistically will be your main charge sources anyway

I'm guessing this is the external module you're talking about?

https://www.iotaengineering.com/products/detail/1195178/iota/iq4-lifepo-smart-charge-controller/2-stage-smart-charge-controller-for-the-iota-dls-to-use-with-lithium-ion-batteries-with-bms

I have a 2005 hawk with the DLS 30 converter/charger so I'm assuming that it's "old" enough. Will this charge to 100%? Or will we still be at the 80-90% range?

 

[Vic Harder]

Yes, that's the one. This is the manual for that module - 1013590079spec-en.pdf (worldbatteries.net)

The voltages are a bit high for Lithium, so will definitely get you to 100%.

 

[tstumpfig]

I'm guessing this is the external module you're talking about?

https://www.iotaengineering.com/products/detail/1195178/iota/iq4-lifepo-smart-charge-controller/2-stage-smart-charge-controller-for-the-iota-dls-to-use-with-lithium-ion-batteries-with-bms

I have a 2005 hawk with the DLS 30 converter/charger so I'm assuming that it's "old" enough. Will this charge to 100%? Or will we still be at the 80-90% range?

Thanks, good to know, that would be the last piece of the puzzle for me. This thread caused me to go down a rabbit hole and am installing my battery and DCDC charger later in the week.

 

[Herbie]

Yes, that's the one. This is the manual for that module - 1013590079spec-en.pdf (worldbatteries.net)

The voltages are a bit high for Lithium, so will definitely get you to 100%.

That's the spec sheet for the non-LIFEPO version of the IQ4.

The LifePo version has slightly different voltage (14.7v bulk) and no Absorption stage.

These are in the manual here:
https://www.donrowe.com/v/vspfiles/pdf/iq-lifepo_owners_guide.pdf

 

[Vic Harder]

Even better. Thanks for that correction!

 

[bike4mee]

This is awesome info! So if I have my plan right. I can run a 6awg wire from the battery to the truck/camper disconnect plug. Then replace the camper wire with 6awg wire to the breaker. Then I have to put a 100amp breaker in (I hope the IOTA can take a new breaker.)
Then run 6awg to the Sure power ACR. Then run 6awg to the battery.
Do i have my steps correct?

2009 kestral camper with 1-12volt agm battery + 1-120 kv solar panel + portable solar panel as needed

 

[Vic Harder]

I'd add a short length of 6awg to a 50A breaker. I'd consider this one: Blue Sea Surface Mount 285-Series Circuit Breakers (pkys.com)

And only 50A because of the current carrying capacity limits of 6g wire - Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

then use another 50A breaker where you indicated you would use it above, and from there to the ACR as you said.

The breakers go into the +ve wire. The negative wire does not need breakers (you are running two wires, yes? Chassis ground is not a good idea)

What IOTA are you referring to? The IOTA shore power charger does not factor into this at all.