LifePO4 vs AGM Batteries

[cdnred]

When I bought my TD the AGM battery in it was toast. I decided to use a 12v 40ah LifePO4 that I had as the replacement. I'm a CPAP user and my CPAP machine is rated at 6.67a so over a period of 7 hours it would use ~47a. That's more then my 40ah LIfePO4 could put out. The 12v circuit would only be used for running my CPAP plus possibly running a phone charger if needed. I could really run the phone charger off the TV while traveling to save battery usage..

I had planned to get a 100ah LifePO4 down the road but feel that it's needed now. A LifePO4 battery has different requirements when it comes to recharging. My TD came with a 4 pin wiring harness which I had changed over to a 7 pin plug so that I could recharge while traveling. With the LifePO4, the charging wires will need to pass thru a 12v 20a DC-DC charger to prevent over-taxing the TV alternator. The 100ah LifePO4 would run approx $200 plus another $170 for the DC-DC charger and another $20 for a shunt so that comes to approx $390. The 100ah LifePO4 could manage to put out approx 95ah until requiring a recharge..

Going with the 200ah AGM deep cycle battery allows me about 50% usage that would be equal to the 100ah LifePO4 for power output. With the AGM, I wouldn't be required to use a DC-DC charger as I could wire it up directly to the incoming wire from the 7 pin plug. I think that I'd prefer to still use the shunt for monitoring the battery usage. A 200ah AGM would cost approx $350 plus another $20 for the shunt coming to $370 total..

Overall the costs for either system would be about the same. I think the 100ah LIfePO4 would be much lighter to handle and much safer to use plus I could wire in the 40ah LifePO4 I have now into the circuit to increase system output to 140ah right off..

Looking at both systems, I feel the LifePO4 setup to be the better route to take. What's everyone's opinion on which is the better route..?

Helmuth

[Pmullen503]

Of the two options, I'd go with the larger battery. If you frequently boondock without shore power, I'd opt for solar panels rather than try to charge from the TV.

If you haven't already, connect your CPAP and run it on battery to check it's actual consumption.

[Tom&Shelly]

Looking at both systems, I feel the LifePO4 setup to be the better route to take. What's everyone's opinion on which is the better route..?

Helmuth

Looks like you've done your homework. We use an AGM, but I made the decision 5 years ago. The LifePo offerings have advanced and today I would go with the 100ah LifePO4 battery, but I haven't changed yet so can't offer a definitive comparison.

Tom

[cdnred]

I actually have a 2000w Jenny that I could use when there's no shower power or for boondocking. In most campgrounds that don't offer shore power, they have quiet hours that need to be observed. I tend to frequent locations where shore power is available when possible, When on shore power or when using the Jenny, I can run my CPAP from the 110v circuit instead saving battery use. I'm planning to head up to Alaska the end of next spring for 6 week trip and I remember the last time I took this trip, there weren't many campgrounds on that route that had 110v services available. Was just hoping to cover all the bases and be prepared just in case..

[cdnred]

[/quote]Looks like you've done your homework. We use an AGM, but I made the decision 5 years ago. The LifePo offerings have advanced and today I would go with the 100ah LifePO4 battery, but I haven't changed yet so can't offer a definitive comparison.

Tom[/quote]
Last year I was in the market to buy a battery for running my small trolling motor on my inflatable and was looking for something that was very manageable to handle on my boat. My 40ah LifePO4 is so lite and small that it surprises me with output it can deliver. I was surprised at the costs, LifePO4's have become comparable with AGM's as far as price goes. Looking at the AGM's, I would need a 200ah to compare with a 100ah LifePO4 for usage. LifePO4 is the direction I'll likely be going with..

Helmuth

[tony.latham]

I too, use a CPAP. I saved a lot of juice (roughly 20%) by getting rid of the 120-volt cord and going with a 12-volt adapter cord. The other thing, I leave the heated tube at home and have a tube with a fleece sleeve. That saves amps... lots of amps. As in a third the power needs.

I run a group 24 AGM in my teardrop but bought a Weize 50 amp LiPo for my drift boat trolling motor. When I bought the AGM, lithium batteries were too expensive. Financially, it didn't compute. Times have changed, when the AGM dies, I'll stick a LiPo in the 'drop.

Tony

[cdnred]

I too, use a CPAP. I saved a lot of juice (roughly 20%) by getting rid of the 120-volt cord and going with a 12-volt adapter cord. The other thing, I leave the heated tube at home and have a tube with a fleece sleeve. That saves amps... lots of amps. As in a third the power needs.

Tony

The CPAP I've got "DreamStation by Philips" reads DC Power Consumption: 12 VDC, 6.67A but I've never measured to confirm. It never came with a heated tube otherwise the rating would be a lot higher. I run it without a heated tube and use the fleece sleeve but I was under the impression that the amp usage would be the same as stated. I don't use the 120v convertor when hooked up to 12v straight from the battery. When connected to 120v then I use the convertor. CPAP's are real power hogs, I wish I didn't have to use one..

Helmuth

[RJ Howell]

I run LiFePo4 and bought the DC/DC - MPPT Solar charger for ~$160.. I like the unit as its all-in-one for charging either way or any battery. You use twice what I do in a 24hr period (well, overnight) and I find my 120w panel keeps me charged up, you my be looking at doubling up.. I have the Atempower 25a and I find it's harder now to get it, but if you do chase it down, I like this unit!

I look at any style of DC/DC charging should be a whole 'nother set of wires if you wish to get full gain. My old pull behind I rewired from battery to tailgate, and again hitch to battery. Yes it worked without doing so before.. I didn't like the existing conditions..wire size, distance, amp pull, etc..

Easy way around it all is just mount a panel on the TD and have another to deploy once you arrive. LiFePo solar chargers are still affordable!

Just my 2 cents..

[cdnred]

I had been thinking about solar panels for awhile. They seem to be rather expensive right off but I'm sure that with some digging around better bargains can be found. I was considering something like a 200w or even a 300w panel to keep me charged up. The only thing I'd need it for would be for my CPAP usage, For cooking when plugged in, I've got a 2 burner hot plate and when not plugged in I can rely on a butane burner for cooking. Solar panels would be nice for recharging all day even when I'm not around whereas with my Jenny, I wouldn't leave it unattended for fear of it getting stolen..

Perhaps mount 2 100w panels side by side on the roof, out of the way. With the solar panels I'd need to install a separate DC/DC - MPPT Solar charger in addition to the 12v 20a DC-DC charger..? Electrical add-ons can run up in costs very qwikly..

Helmuth

[tony.latham]

The CPAP I've got "DreamStation by Philips" reads DC Power Consumption: 12 VDC, 6.67A but I've never measured to confirm. It never came with a heated tube otherwise the rating would be a lot higher.

That's the CPAP I use. When you plug in the tube, I think you'll see it has an electronic connection.

Solar? I have a 100-watt Renogy flexible on the roof and a 30-watt panel on the tongue box.







I like the no set up or storage issue. If you go with a flexible, don't get one made from PET plastic. It'll not last.

Tony

[cdnred]

That's the CPAP I use. When you plug in the tube, I think you'll see it has an electronic connection.

Solar? I have a 100-watt Renogy flexible on the roof and a 30-watt panel on the tongue box.

I think my DreamStation maybe the older version, it's 6 years old now but was refurbished due to the recall. It has a straight hose nipple on the machine and the tube just slides over it, no electric connection..

Your 100w Renogy plus a 30w on your tongue box, do you find it sufficient to keep your battery charged up..? You mentioned earlier that you were running a group 24 AGM. What's the ah rating on it, 75ah or 100ah..? Those solar panels aren't that cheap for a reliable one..

[tony.latham]

Your 100w Renogy plus a 30w on your tongue box, do you find it sufficient to keep your battery charged up..? You mentioned earlier that you were running a group 24 AGM. What's the ah rating on it, 75ah or 100ah..?

Yes, we can go forever if we get a bit of sun in camp. 4-5 days if we're in the deep shade.



The battery is rated at 70 amps, so it has 35 useable amps.

Tony

[cdnred]

The battery is rated at 70 amps, so it has 35 useable amps

Wow that's not much for running your CPAP all nite. On your DreamStation, what does it read for DC Power Consumption..? Mine reads 12 VDC, 6.67A so I'm thinking yours must be much lower if you can run yours on 70ah battery, 35ah usable all nite. Maybe I'm over rating what I need, my CPAP is barebones with no extras added..? I was thinking that my CPAP rated at 6.67a over a period of 7 hours it would use ~47a..

[lfhoward]

Since this seems to be a CPAP thread, I will chime in too. 156Ah LiFePO4 battery (soon to be 246 with the addition of a second 90Ah battery). My ResMed unit is 24 volt and runs at about 65 watts (about 5 amps at 13.2V) on its 120VAC power brick. I have an inverter that can run it easily, but I am wondering if anyone has any solutions for converting 12 to 24 volts to run a CPAP? There is no car charger for my unit because of the voltage difference. I know DC-DC converters exist, but would they be any more efficient than my Victron Phoenix inverter? I like the idea of getting a non heated hose to save power while camping.

[tony.latham]

Mine reads 12 VDC, 6.67A

Mine is the same, but it uses much less than that (I can't recall how much) when I dump the stock tubing.

Tony