Replace 190ah AGM with 100ah Lithium???

[GeorgiaBill]

Sean (Battle Born COO) has at least 2 videos stating I can remove the AGM and drop in the Lithium. Do I need to let our charger know the battery type is being changed or will it be detected automatically?

[Vermilye]

If you have an inverter, check the maximum current draw of the 100 amp hour lithium. Many are limited to 100 amps, which might not be enough for a 1500 watt inverter at a heavy load. Battleborn recommended 2 100 amp hour batteries to allow the inverter to be used at its maximum power.

As to the converter, if you have the stock WFCO converter Escape provided in 2014 it probably will not fully charge the lithium battery which requires an output of 14.4 - 14.6 volts. Undercharging lithium batteries won't hurt them, if fact it will make them last longer, but you will only get about 80% of the capacity charging at 13.6V, the maximum that the WFCO usually produces.

If you have solar, using the AGM settings may get you a higher voltage that will top off the lithium batteries.

[alanmalk]

Originally Posted by Vermilye

...
If you have solar, using the AGM settings may get you a higher voltage that will top off the lithium batteries.

To elaborate a bit...
Lithium batteries also like to be charged at 14.4-14.6 vdc so that the internal BMS system "balances" the individual cells. This doesn't have to happen every charge cycle, but perhaps (guessing) once every few dozen charge cycles might be useful.

I tricked my 2015 GoPower solar charger into providing 14.6 vdc by putting a diode in the ground lead and doing some creative rewiring. Not for the faint of heart...

[John in Santa Cruz]

a 190AH AGM must be huge, like double the size of a large car battery, and well over 100 lbs ? I would probably replace that with a 200AH lithium, or 2 100AH

[GeorgiaBill]

Originally Posted by Vermilye

If you have an inverter, check the maximum current draw of the 100 amp hour lithium. Many are limited to 100 amps, which might not be enough for a 1500 watt inverter at a heavy load. Battleborn recommended 2 100 amp hour batteries to allow the inverter to be used at its maximum power.

As to the converter, if you have the stock WFCO converter Escape provided in 2014 it probably will not fully charge the lithium battery which requires an output of 14.4 - 14.6 volts. Undercharging lithium batteries won't hurt them, if fact it will make them last longer, but you will only get about 80% of the capacity charging at 13.6V, the maximum that the WFCO usually produces.

If you have solar, using the AGM settings may get you a higher voltage that will top off the lithium batteries.

No inverter. The AGM battery is 22 months old and had always shown around 190 AH on shore power when fully charged. Recently peaked at 178.8 and I figured it was perhaps failing. Lithium seemed cheaper if it would last longer.

Half of 178.8 is slightly more than 80% of 100 so perhaps I wait and see.

Thanks, Jon

[GeorgiaBill]

[QUOTE=alanmalk;436855]To elaborate a bit...
Lithium batteries also like to be charged at 14.4-14.6 vdc so that the internal BMS system "balances" the individual cells. This doesn't have to happen every charge cycle, but perhaps (guessing) once every few dozen charge cycles might be useful.

Alan, I just walked out to the trailer, and the volts were registering 13.72 volts. Maybe that's tops for my charger. Live and learn. Thanks
/QUOTE]

[GeorgiaBill]

Originally Posted by John in Santa Cruz

a 190AH AGM must be huge, like double the size of a large car battery, and well over 100 lbs ? I would probably replace that with a 200AH lithium, or 2 100AH

John, I have 2 Duracell 6 volt golf cart batteries, from Sams, 95ah each. Thanks.

[John in Santa Cruz]

Originally Posted by GeorgiaBill

John, I have 2 Duracell 6 volt golf cart batteries, from Sams, 95ah each. Thanks.

batteries in series add their voltages, the current capacity is the same as either one (you add the current capacity when the batteries are in parallel)... but, standard golf cart batteries are generally around 200-225 AH.

either way, I would replace a pair of GC batteries with one of these...
https://www.currentconnected.com/product/sok-sk12v206/

I've had two of these in parallel for a year now, they have performed very well. very nicely made. if you live where its regularly well below freezing, I would get the upgraded version with the internal pre-charge heater and bluetooth monitoring.

[Perry Butler]

Originally Posted by John in Santa Cruz

I've had two of these in parallel for a year now, they have performed very well. very nicely made. if you live where its regularly well below freezing, I would get the upgraded version with the internal pre-charge heater and bluetooth monitoring.

In one of Will Prowse's videos he talks about why a heater is not what most people think. Most heaters only heat when connected to another power source, either a charger hooked to the grid or a solar controller.

On SOK's 206 ah battery with bluetooth and heater web page they state,

"Can safely charge at temperatures down to -20°C (-4°F) by a standard charger or solar charger. The heater pads which draws power from the charger itself,battery cells no power lost."

The heater won't work when boondocking at night, because there is no power source and that's when I need a heater.

I'd just buy SOK's 206 ah battery with bluetooth.

Enjoy,

Perry

[John in Santa Cruz]

indeed, the heater is for charging, as you can NOT charge a LFP battery that is below 32F, most good ones have a BMS that will disable charging at any temp colder than that. the battery can be discharged as low as -4F. Note also, that if you're pulling a steady current off the battery, it warms itself up,

I'm not real worried about this on my 21C as the batteries are inside the trailer, under the dinette bench, but I could see it being a problem with tongue mounted batteries.

note lead acid batteries also have issues at very low temps, the charging voltages should be temperature compensated, and at temps like 0F, they might have only 50% or less of their nominal capacity.

[alanmalk]

Originally Posted by John in Santa Cruz

...


I'm not real worried about this on my 21C as the batteries are inside the trailer, under the dinette bench, but I could see it being a problem with tongue mounted batteries.

note lead acid batteries also have issues at very low temps, the charging voltages should be temperature compensated, and at temps like 0F, they might have only 50% or less of their nominal capacity.

I will second that. If I am using the trailer in outside temperatures below 32F/0C, I expect the battery to be reasonably warm under my seat so there should be no issues when charging. If the trailer is unattended in winter then I switch the solar charger off to protect the batteries. What does concern me is that here in Denver we occasionally approach the temperatures that damage Lithium, -20F is the number my manufacture uses. I don't want to pull the batteries for winter but I am taking my chances. -14F is the forecast for Thursday morning. Yikes!

And yes, one of the big problems with lead-acid batteries is the low temperature performance is the pits. I've given a lot of jump starts to campers who expect their battery to behave in mid-winter, but are rudely reminded in the morning that cold batteries just don't have what it takes.

[alanmalk]

Originally Posted by Perry Butler

In one of Will Prowse's videos he talks about why a heater is not what most people think. Most heaters only heat when connected to another power source, either a charger hooked to the grid or a solar controller.

...

Maybe I'm missing something but shouldn't 2 Lithium batteries in parallel emulate a power source for each other?

[splitting_lanes]

Originally Posted by alanmalk

Maybe I'm missing something but shouldn't 2 Lithium batteries in parallel emulate a power source for each other?

If they were connected in parallel, they’d be sitting at the same voltage. So , no, they wouldn’t power each others heaters.

But, if something tried to charge the batteries, that energy would be diverted to the heater(s) in the batteries to raise the internal temperature until it was high enough that they could be charged. At least, that’s how it should work.

[GeorgiaBill]

Thanks to all who responded. I think the most helpful response for me was the one from Jon ===>>>I can replace the battery but the WFCO won't fully charge.

I wonder about the alternator, 220 amp in the max tow configuration. Would that top off the battery or is the WFCO charger involved?

I do have a Renogy 200w solar suitcase and a Bluetti AC200MAX which allows more time off grid.

John, the SOC battery looks interesting, I'll search your posts for more info.

For now I'm going to run more discharge/charge cycles and see if the battery continues to decline. And continue lithium research.

Thanks all.

[Vermilye]

Unless you add a DC to DC converter to raise the tow vehicle charge line to 14.4V - 14.6V, the tow vehicle alternator will probably not peak the batteries. There is too much voltage loss in the typical vehicle & trailer wiring.

If you add a DC to DC converter, it is a one way device, ie the trailer battery will no longer power the breakaway switch or, if you have one, power tongue jack (which are powered by the trailer charge wire). I added a #6 wire from my batteries to the tongue area to power both.

Again, setting the solar controller to AGM may provide the voltage necessary to peak & balance the lithium batteries. Check the voltage specifications on your controller.

[GeorgiaBill]

Thanks, again, Jon.

[alanmalk]

Originally Posted by GeorgiaBill

I do have a Renogy 200w solar suitcase and a Bluetti AC200MAX which allows more time off grid.
...
For now I'm going to run more discharge/charge cycles and see if the battery continues to decline. And continue lithium research.
...

Considering the relatively young age of your AGM, using it up and waiting a couple of years might be the best alternative. In a couple of years the advancement in Lithium battery technology might make the wait worth it.

But if your credit card is burning a hole in your pocket, the Renogy panel could easily be modified to charge and top-off your new Lithium's.

[GeorgiaBill]

Good idea, Alan. I'm going to Quartzsite in February and don't want a dead battery on the trip. I'll continue the partial discharge/charge cycle, and just realized I can discharge the Escape battery more quickly by using it to charge the Bluetti battery.

The Renogy products don't detect the Bluetti lithium battery, and I'm trying to get some level of customer support. I'll start a Bluetti thread in case others are interested or have advice.

[BobG]

Bill,

I think a battery warranty gives a view of what life expectancy can be expected. Trojan says an AGM battery is still good if above 60% of listed capacity during the 2 year free replacement warranty. The published life cycle of these batteries is 1000 cycles of 50% depth of discharge.

I think you can expect significant capacity loss in lead acid batteries is normal and may become a problem after 5 years or after the warranty expires.

For comparison, the warranty of some lithium batteries is 10 years with a measured capacity loss of 20%. That leaves 80% of original capacity after 10 years.

I think between now and when the batteries let you down, you can plan out a replacement system of lithium batteries. Lithium batteries offer opportunity for a different life style.

This article says capacity of lead acid batteries starts declining after 100 to 200 cycles. https://batteryuniversity.com/articl...acid-batteries

[GeorgiaBill]

Bob, thanks for the article. My warranty was only one year and I still have 90% capacity remaining, so I guess it's within Duracell expectations.