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 > Lifepo4 battery in 1990 Lance?

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BFL13

Victoria, BC

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Posted: 01/12/21 01:23pm Link  |  Quote  |  Print  |  Notify Moderator

"I don't quite follow. Isn't this exactly the point you were trying to make? That SiO2 has higher capacity because it has more cycles at a given SOC?"

It can do many cycles down to a LOW SOC. And that many cycles can be enough. An LFP can do many more of those than an SiO2 (if you live long enough to use them!)

Try that with a regular AGM or FLA and it will not be enough cycles for how many times you have to buy new batteries. So 50% is recommended as the low SOC point for them.

I don't know what the OP would think is "worth it". If it is an option, he could get the extra AH by putting FLAs in the truck bed ahead of the wheel wells as mentioned earlier.


1. 1991 Oakland 28DB Class C
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2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
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jaycocreek

Idaho

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Posted: 01/12/21 01:50pm Link  |  Quote  |  Print  |  Notify Moderator

I have extra batteries in the wheel wells but there not wired into the system..Each one serves a purpose for things like the TV /DVD /Compressor fridge and odds and ends...When I had two group 27 batteries in my last rv,I didn't really have any issues but one just isn't enough for my uses...I rely on generator assistance to keep my one group 27 above the 50% just for normal use..it came with a group 24 but a 27 fits..I use a Noco 10 and another smart charger to charge my external batteries,so when the gen is running,most batteries are charging...I have 200 watts of portable solar but I need a controller to use it to charge my 12v batteries..

Just thinking if I had a 100ah lifepo4 it would theoretically be like two group 27 batteries if I ran it to 0% which I would never do..I doubt my Les Schwab battery is a 100ah battery anyway,but it was my only choice at the time...There are a couple lifepo4 in the $500 range that are getting good reviews I have been thinking about and why this post asking....

Another issue is I am not sure I want to put any more money into the camper itself like upgrading the power center ,I can take the lifepo4 out when and if I sell it and my solar is portable..


1994 F-350 DRW /460/k&n intake /415# torque/lance 9.6/Engel compressor fridge/3 gr 27 batteries/Honda 2k/Honda 3K/WH Camo 2250/Reese solid bar extension/Buddy heater/3 inverters//Happi Jack tie downs /Firestone bags/Yamaha Rhino/Winch and Lockers

3 tons

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Posted: 01/12/21 02:57pm Link  |  Quote  |  Print  |  Notify Moderator

I might definitely lean more in the direction of SiO2 where (in the following order):

1) If weather conditions might include ‘extended excursions’ at or below 32F while having no provisions for keeping battery above 32F (e.g. heated compartment or batt. blanket - note, Li safely discharges to about -4’ish F). For some this criteria could be paramount..

2) Initial cost...However, this issue is often mitigated by the long cycle life of LiFePo4, while LiFePo4 entry-fees seem to be slowly dropping...

3) Ultra high amperage discharge rating of SiO2’s well exceeds all other competing Battery types - depends on one’s amperage requirements?

4) Where Recharge ‘C rate’ is not a critical parameter - this more in terms of off-grid (32F +) solar peak-period harvesting windows.

5) Where ‘required-usable’ DOD (depth of discharge) and voltage-sag (vs LiFePo4 alternative) can be offset by having more a/hr capacity - assumes no space or weight restrictions....Much depends on other variables surrounding one’s own particular camping style - not always of primary consideration or limitation.

6) Where unattended self-discharge rate can be mitigated by an active charging device - something to consider when off grid...

FWIW, My camping style is mostly off-grid desert (40th’ish parallel north) with solar harvesting - for ultra low battery internal resistance, limited truck camper space and other camping style reasons I opted to go the Li route, but that’s just me (“actual user experience may vary” - lol!)..

JMHO,

3 tons

BFL13

Victoria, BC

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Posted: 01/12/21 03:41pm Link  |  Quote  |  Print  |  Notify Moderator

Since the OP actually has three 27s and his set-up indicates he can do wiring for inverters etc, one thing to get more AH is just parallel all three batts. Peukert (sp?) then gives you more running time for the same amps draw right there

Another advantage over a split bank is that you might be low on the regular Rv bank but there is still some left in the "inverter" bank, but you can't get at that to run the furnace. If they are all in parallel they all can be used for everything.

I drill holes in my old TC for wires and don't care. If the next guy doesn't like that, too bad! [emoticon]

Yes, you can leave the whole 6300 in place and use portable chargers. I found you can make a portable charger from a deck mount converter by using a cut off set of jumper cables with the clamps, in the DC output terminals. This can give you higher amps and a proper charging profile compared with the usual portable charger.

There is room for a pair of 6s ahead of each wheel well in our truck, which is better than a 27 or two, which might be another opportunity for the OP. I used to carry a pair of T-1275s up on the left side there, which also fit same as 6s. That pair of T-1275s was rated for 300AH when new (mine were used ex-golf cart but still in good shape)

StirCrazy

Kamloops, BC, Canada

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Posted: 01/13/21 06:06am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

StirCrazy wrote:

BFL13 wrote:

Understand the "density" point. BUT--we are talking about "space" for one battery in the battery compartment. The SiO2 27 is a 27. You can run it down to a low SOC no problems so you can have more AH in the same 27 space, which is what the OP wants.

I don't know the true story about Li charging, but I suspect others will want to comment on using a 6300 converter for that. Should be interesting! [emoticon]


and the same ah in LiFeO4 is about 1/3 the size. so for a limited battery space the Li is the better choice. also a lot lighter for the same AH capacity.

Steve


Must be a typo or something there?

A Walmart G27 is 12.65 x 6.9 x 8.94 inches and 49 lbs
A Relion 100AH LFP is 13 x 6.8 x 8.9 and 32 lbs
A Trillium 111AH LFP is 12.07 x 6.57 x 8.63 and 30lbs
A Stark 105AH AGM is 12.9 x 6.8 x 8.7 and 66 lbs
An SiO2 100AH is 12.28 x 6.72 x 8.6 and 60 lbs

Another thing about battery compartments in RVs is their odd shapes and any pipes or whatever in them, so battery orientation could determine how many you can get in. Some you can put end up or not, or just on their sides, but none upside down

Allowance for wiring needed too--stiff wires can't be bent in much--it all depends.

LFP "roll your own" needs a box and keep the cells tight so no vibration, lots of wires and a BMS. I dont know what that takes for volume or shape as to what would fit in the OP's battery compartment--he would have to figure that out.

Also he needs room for the heat pads and whatever wiring they take with LFP.

On that 6300--I would toss that whatever kind of battery. In the MH I kept the 6300 panels and swapped out the charger for a PowerMax modern type. The TC original charger was gone and the prev. owner used a portable charger. I tossed that and use a deck mount PowerMax converter in there.

The OP has a 32 amper for the TC which is ok for a 100AH batt, but if he gets more AH, more amps of a charger would be good. Depends on the battery charging spec. 30% charging rate is max for AGMs and SiO2s, eg.
LFP can take way more.

You have to juggle the charger size in amps with the size of the portable gen you can take along to run the charger. That is my limit in the Class C. Can't carry a 3000w gen, but can carry a 2200, so 75 amps is my limit for a charger. The OP has to figure that all out for his own rig as to what is possible.


ya, its kinda hard to use "standard" battery sizes and 100ah li. they build the box for a standard look. when you look at a bigger cell say I put one togeatyher that was 280 or 300 ah. they will be almost the same size and only 2-5lbs more in weight. give or take as I am just pulling the numbers out of my &^% this morning in a hurry. so when your talking about 280-300 ah thats about 240 available so now your looking at a comparison to four 235ah 6V batteries at around 68-80ish lbs each so going from 240 lbs to about say 50 lbs is a huge difference and about the footprint of one of thoes 6V instead of 4. buying premade Li doesnt offer you the saize savings realy but does cut the weight a lot. and making your own boc and adding a BMS is something that from what I see quite a few people on here are quite capable of.

Steve

Steve


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wintersun

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Posted: 01/13/21 04:08pm Link  |  Quote  |  Print  |  Notify Moderator

I built a metal frame to hold a second AGM Group 31 battery under the floor of my Lance camper and I would have had more capacity with a single lithium phosphate battery and had a much simple installation. Lithionics makes a 125HA battery for 25% more charge capacity than a 100AH from Battle Born and others.
What is not understood or appreciated that instead of getting 80-90 percent of 125AH versus 50% of 100AH with a lead acid battery, the lithium phosphate batteries will recharge 4 times as fast as the lead acid ones.

With my current RV the two Lithionics 125AH can be at 50% SOC and brought back to 100% SOC in an hour with the Onan generator running versus 3-4 hours with the lead acid batteries at the same SOC level.

Saying one does not need lithium phosphate batteries makes as much sense as saying you do not need an air conditioner when you can always simply open the windows.

Going to a lithium phosphate battery is the single easiest and most beneficial upgrade to any RV one can make.

BFL13

Victoria, BC

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Posted: 01/13/21 05:41pm Link  |  Quote  |  Print  |  Notify Moderator

"With my current RV the two Lithionics 125AH can be at 50% SOC and brought back to 100% SOC in an hour with the Onan generator running versus 3-4 hours with the lead acid batteries at the same SOC level."

Some numbers to play with! [emoticon]

That means you can restore 125AH in an hour which means you have a 125 amp charger. Also that the batts get to 100 with no tapering. The Onan gen can run the 125 amp charger.

You would be charging at a 50% charging rate, per LFP specs.

Actually the lead acid batts would take much longer to reach 100% than 3-4 hours. 250AH bank of FLA batts will take a 30% charging rate, so more like 75 amps. In that case from 50% it would take about 30 minutes to get to 65% SOC at 75 amps when amps would then taper for about a 100 minutes to reach 90% SOC

So call it two hours to restore 100 AH (40% of 250) vs an hour to do 125
( about 2 x not 4 x+ in this case.)

It will take maybe 12 hours more to get the FLAs from 90 to 100% so not done on generator.

The claim that LFP are faster charging is true if you have a charger that can do the high amps and a gen with enough VA to run that big charger.

Itinerant1

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Posted: 01/13/21 06:17pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

"With my current RV the two Lithionics 125AH can be at 50% SOC and brought back to 100% SOC in an hour with the Onan generator running versus 3-4 hours with the lead acid batteries at the same SOC level."

Some numbers to play with! [emoticon]

That means you can restore 125AH in an hour which means you have a 125 amp charger. Also that the batts get to 100 with no tapering. The Onan gen can run the 125 amp charger.

You would be charging at a 50% charging rate, per LFP specs.

Actually the lead acid batts would take much longer to reach 100% than 3-4 hours. 250AH bank of FLA batts will take a 30% charging rate, so more like 75 amps. In that case from 50% it would take about 30 minutes to get to 65% SOC at 75 amps when amps would then taper for about a 100 minutes to reach 90% SOC

So call it two hours to restore 100 AH (40% of 250) vs an hour to do 125
( about 2 x not 4 x+ in this case.)

It will take maybe 12 hours more to get the FLAs from 90 to 100% so not done on generator.

The claim that LFP are faster charging is true if you have a charger that can do the high amps and a gen with enough VA to run that big charger.


Uhmmm.... this conversation is like ground hog day. I always like when you go into the math of charging lead batteries, it seems it takes aloooonnnngggg time. [emoticon]

I almost believe I could deplete my batteries and charge them twice by the time you had yours done once just using my 2200w generator.


12v 500ah (5,120Wh usable), 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 1,600+ cycles.

3 tons

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Posted: 01/13/21 06:29pm Link  |  Quote  |  Print  |  Notify Moderator

“ That means you can restore 125AH in an hour which means you have a 125 amp charger. Also that the batts get to 100 with no tapering. The Onan gen can run the 125 amp charger.”

So with SiO2, sounds like there’s no chemical soup resistance?...Not sure what you mean here but I must say that that is pretty dang impressive, outpacing even LiFePo4 !!...

Either way, for uber efficient off-grid solar harvesting (within peak harvest window), internal resistance is a factor worth considering...

3 tons

BFL13

Victoria, BC

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Posted: 01/13/21 07:04pm Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

“ That means you can restore 125AH in an hour which means you have a 125 amp charger. Also that the batts get to 100 with no tapering. The Onan gen can run the 125 amp charger.”

So with SiO2, sounds like there’s no chemical soup resistance?...Not sure what you mean here but I must say that that is pretty dang impressive, outpacing even LiFePo4 !!...

Either way, for uber efficient off-grid solar harvesting (within peak harvest window), internal resistance is a factor worth considering...

3 tons


No! That was in reply to the guy with 250AH worth of LFPs.

SiO2 are limited to about 30% charging rate, same as regular AGMs. Some gen time advantage with SiO2 over regular AGMs is between 80-90 % where they stay constant amps before tapering around 90%, and that you can start the high rate constant amps from 20% instead of 50% (LFP can do that too) so no wasted gen time while amps taper if doing a "20-90"

I covered that in my SiO2 testing in that long thread a couple months ago.

-----------
"I almost believe I could deplete my batteries and charge them twice by the time you had yours done once just using my 2200w generator."

As in the example above, you could do 125AH in half the time it takes the same size bank of FLAs to do that many AH doing a "50-90". All you need is a big enough amp charger and a gen big enough to run it.

Gets harder to compare 500AH banks with RV size chargers and gens! Have to be very specific what the two things are being compared.

* This post was edited 01/13/21 07:11pm by BFL13 *

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