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Goal Zero Yeti 1250 – Great platform for drop-in LiFePO4 upgrade

In my opinion, the older generation lead acid Goal Zero generators were and still are somewhat better than their current lithium offerings. Not only were the batteries user replaceable thus allowing for lithium upgrades, the generators were rather bulky so adding stuff like a shunt meter for monitoring a lithium battery and adding extra ports or integrating a QI charger is something you could do.
Looking over Goal Zeros current offerings, especially compared to similar generators from other brands, it doesn't seem like Goal Zero is worth the higher price anymore.
 
Goal Zero works as aspected. If the inverter is specified to give 1000 watts it gives you 1000 watts (and a bit more) until the battery is empty. Same with Jackery.

If someone buy a all in one plug and play system it should be working without issues.

I have here some GZ units, old lead acid and some from the actual Yeti X for mobile use. And two Jackery. All of them are working perfect, no issues about many years.
 
Goal Zero works as aspected. If the inverter is specified to give 1000 watts it gives you 1000 watts (and a bit more) until the battery is empty. Same with Jackery.

If someone buy a all in one plug and play system it should be working without issues.

I have here some GZ units, old lead acid and some from the actual Yeti X for mobile use. And two Jackery. All of them are working perfect, no issues about many years.
i do like the GZ for what they are, i do begrudge the pricetag and have bought both mine as used/openbox. That said i find them good quality. Next purchase will be a 400 unit. Seen alot of people going for lithium upgrades of the older units. previously seen the Bioenno drop in cell and various incarnations of 18650 packs which shed alot of the weight out of the older tech.

Does anyone have voltage specs for the 150/400/1250? GZ weren't overly helpful in sharing those....... whilst we cant remove the SLA/AGM charge circuit we can at least build BMS in-between to stop the lithium's going funky. But also wary we can abuse AGM but Lithiums are cranky when they get too discharged.
 
What’s This Post About?
I got the portable, LiFePO4-based solar generator I wanted by combining an old-school Goal Zero Yeti 1250 with a Lion Energy Safari UT battery.

This is not the best system for everyone, but it fits my requirements almost perfectly. It’s also straightforward to achieve:
  • Buy a used Goal Zero Yeti 1250.
  • Buy a Lion Energy Safari UT LiFePO4 battery.
  • Replace the lead-acid battery with the LiFePO4 battery.
  • Enjoy your full featured, high capacity, portable LiFePO4 solar generator.
For those who want more of the story, read on.


Background

I wanted a portable, relatively large capacity, lithium-based solar generator that had room for expansion. In looking at the full-sized offerings on the market I found I didn’t really love the big Li-NMC systems. My concerns were fewer max capacity cycles, lack of easy expansion, and battery chemistry safety compared to LiFePO4. I looked to see if any vendors offered a LiFePO4-based system but didn’t find anything I liked. I figured I’d have to go the route of others and build my own portable system (I’m amazed at how cool the systems in Show and Tell are). Then I remembered a solar generator I had first looked at way back in 2012 but always dismissed as not truly portable: the lead-acid Goal Zero Yeti 1250.

Go here for Goal Zero Yeti 1250 info


The Conversion to LiFePO4
The Yeti 1250 is a monstrously heavy 103 lbs (46.7 kg) unit with a group 27 100Ah AGM lead-acid battery at its core. The good news is that Goal Zero designed this system to have a user-replaceable battery. The battery accounts for over 60 lbs of the Yeti 1250’s weight, so I thought if I found a LiFePO4 drop-in replacement that was light weight and could fit in the battery compartment I might have something to work with. (The original battery measures 12.9" x 6.8" x 8.7".)

Enter the Lion Energy Safari UT 1200. Coming in at 21 lbs and offering more effective capacity than the lead-acid it would replace, I figured it would make the Yeti 1250 light enough to lift and make it actually portable (where my definition of portable is that I can lift it myself and put it into a vehicle for remote use). The Safari UT physical dimensions of 10.2” x 6.6” x 8.8” seemed workable in theory. In practice, it fits and has worked great so far.

Replacing the battery was straightforward, and Goal Zero even provides a seven-step procedure in the user manual. Here’s a YouTube video of how to replace the battery.

After replacing the battery, the whole system weighs about 60 lbs.


Charging
  • The old Yeti 1250 has a 20A MPPT charge controller built in! And unlike the MPPT module Goal Zero sells now for their Li-NMC models, you can put 12V panels in series because the input is rated at 16-48V (the Yeti Lithium 25A MPPT module input is rated at 15-22V which means you will be putting your 12V panels in parallel).

    There are two types of charging ports, (2) 10A 8mm and a 20A Anderson power pole port for a combined input power rating of 240W.

    [The website (320W) and manual (240W) have conflicting information, so I contacted Goal Zero customer support to confirm what the actual max input wattage is. The answer is max input of 240W, regardless of whether that all comes in through the Anderson power pole input or split between that and the 10mm input ports.]

  • You can also use the chaining port (described below) to jack in whatever charge controller/charger you want. I use this to connect a Samlex 30A grid-power charger. I may also use it for a higher rated MPPT charge controller down the road.

State of Charge Monitoring
Note: I haven’t yet decided what I’m going to do long-term for state of charge monitoring since I assume the built-in monitor is calibrated for lead-acid. Stay tuned.

(Edit: Dec 21, 2019) First attempt at SoC monitoring is to use this Drok meter with hall effect sensor. (More details below.)

(Edit: June 9, 2020) The Drok is a bust as it does not provide accurate SoC. I'll work on a shunt-based solution.

Output Ports
  • 1200W continuous/1500W surge AC inverter (pure sine wave) with three outlets
  • 3 – USB (2.1A)
  • 2 – 6mm 12V DC (6A)
  • 1 – Cigarette lighter style 12V DC (10A)
  • 1 – Anderson power pole 12V DC (33A)

Expandability
The Yeti 1250 has a built-in chaining port (Anderson SB175 connector) on the back that allows users to add additional batteries in parallel. Perfect! I can attach more Safari UTs if I need to get more run-time, and since they only weigh 21 lbs a piece I can still load the whole setup into my SUV in pieces and reconnect at my destination. With the Anderson connector, adding or subtracting the additional batteries is a snap.

(Edit Mar 6, 2020) Example of chaining extra batteries can be seen in this post below.

Availability
  • Yeti 1250 – Find a used one on eBay. Goal Zero customer support told me that they have discontinued the Yeti 1250 (shortly after I bought a refurbished one from them).

  • LiFePO4 Battery – Buy a Lion Energy UT 1300 (or any LiFePO4 battery that fits the dimensions stated above. Or go the DIY LiFePO4 route).

    Note: Lion Energy discontinued the UT 1200 shortly after I bought a couple. Hmm, a pattern. The universe seems to be trying to tell me something. However, they are replacing it with a UT 1300 that is the same physical size, only 23 lbs, and reportedly will be 105 Ah (vs. 90 Ah for the 1200)

The Cost
Your mileage will likely vary from mine, but here it is for reference:

  • Yeti 1250 - $700 for an “open box” Yeti 1250 from Goal Zero. I was able to sell both the lead-acid battery, and the Yeti roll cart (you may want to keep this depending on your situation) which brought my cost down to $550.

    I’ve seen used Yeti 1250s sell on eBay for between $475-$650 recently.

  • Safari UT 1200/1300 – $650 for a UT 1200 from Costco’s recent clearance sale. This is an atypically low price, so you will likely spend closer to $800-900 for a battery that fits into the compartment.

  • Drok meter for SoC monitoring - $29 (Edit: June 9, 2020) Don't buy the Drok.

  • Chaining cable for extra battery capacity - $25 on eBay for a 2’ long 4 AWG cable: eBay chaining cable

Total cost for my base system: $1,200 $1229 (Edit: Dec 21, 2019)

For reference, that is virtually identical to a Goal Zero Lithium (NMC) Yeti 1000 w/MPPT module.
Hi @Bob142, I have a victron blue smart 12v 30a charger and when attached to the chaining port there is no current pushed to the battery, but when I hook it up directly to the battery is only when I get 30a charge. Has anyone come across this? This is with the 100ah agm battery as I didn’t receive a charger with my used yeti 1250 and figured the victron would be able to allow me to monitor the charge via bluetooth. It is just odd the victron only will charge when attached to the battery directly and not by chaining port.
 

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Hi @Bob142, I have a victron blue smart 12v 30a charger and when attached to the chaining port there is no current pushed to the battery, but when I hook it up directly to the battery is only when I get 30a charge. Has anyone come across this? This is with the 100ah agm battery as I didn’t receive a charger with my used yeti 1250 and figured the victron would be able to allow me to monitor the charge via bluetooth. It is just odd the victron only will charge when attached to the battery directly and not by chaining port.
disregard, chain port fuses blown. i will change these and see if it works again.
 
i bought the 1250 used and the fuses external at the chaining port were purple 3a fuses. ah wth, so these are 50a fuses?
LMAO yes the original fuses were 50 amps each, total of 200 amps. Not sure why they went with such a high value, I personally swapped them out for 30 amp fuses as if the internal lifepo were to short on that chaining port, I'd like to limit it to 120 amps
 
LMAO yes the original fuses were 50 amps each, total of 200 amps. Not sure why they went with such a high value, I personally swapped them out for 30 amp fuses as if the internal lifepo were to short on that chaining port, I'd like to limit it to 120 amps
thank you @invento123 for the knowledge! super appreciated.
 
LMAO yes the original fuses were 50 amps each, total of 200 amps. Not sure why they went with such a high value, I personally swapped them out for 30 amp fuses as if the internal lifepo were to short on that chaining port, I'd like to limit it to 120 amps
Unless the fuse size is maxi, blade fuses aren’t made above 40A…
 
Holy cow. I would not trust that. I have a hard time trusting 30A fuses in that size..
HOLY SMOKES HEY WILL!!! Love your videos! I personally had no issues with the fuses in the 6 years I've owned my 1250. Granted the most I ever pulled out of the chaining port was probably around 130 amps when I used it to run a 1.6kw Northern Tools inverter as the 1.2kw inside wasn't enough for a time.
But I agree. Even though in theory Goal Zero tested the 50 amp fuses and they must have performed fine, pushing a combined 200 amps through 4 of those standard fuses probably isn't great, another reason I lowered them to 30 amp fuses when I replaced them.
 
I was happy to see your post on retrofitting a Yeti 1250 with a LiFePO4 battery, as my AGM batteries don't last long :-(

I was curious to see what Goal Zero thought about the upgrade, so I contacted their technical department to see what they thought about it.

What are your thoughts/comments about their reply below?

***** Email Reply from Goal Zero *****
Thanks for sending that article and information over to me. I had a conversation with our engineers, and they confirmed that we do NOT recommend going from Lead Acid to any sort of lithium battery. This can cause damage to the Yeti 1250 itself since these units were originally created for Lead Acid batteries. With our X-line units you can go from Lithium to Lead Acid using what we call the Yeti Link Expansion Module but there is no way to go from Lead Acid to Lithium.

Let me know if you have any questions, thanks!

Best Regards,

Solution Center Representative
***** Email Reply from Goal Zero *****
 
What are your thoughts/comments about their reply below?
Welcome to the forum!

That kind of reply is expected from a vendor that has most likely never tried to retrofit one of their legacy units with an LFP battery. There is really no incentive for them to try it out or to support it in any way. They are more interested in selling their newer units.

Ultimately I trust the facts on the ground of my own upgrade and those of several others.

Bottom line: this DIY upgrade works and I haven't heard of anyone who has a unit that was "damaged" in any way by changing the battery from AGM to LFP.
 
I take the response from GZ with a pinch of salt. Lithium is different technology, however the lithium BMS is key here within the Lithium pack replacement, The SLA charge board within the Yeti's has a cut-off voltage designed for SLA, i agree there. As long as the SLA Yeti board doesnt "brainfart" when the lithium unit is swapped and the charge of the lithium BMS halts at correct lithium voltage i dont see a problem.

There are already SLA replacement Lithium units out there for exactly this solution. I looked at similar for my tiny yeti 150 (bioenno 15ah lithium cell) was a drop in unit and a guy on youtube (link in my other posts) did conversion.
The 150/400/1250 are way out of warranty so there is limited if anything to comeback on GZ, and we are not in kansas anymore dorothy with the amount of modding done in this forum to the units :)
 
I put a LFP in one of my little 150. It runs without issues, the charge status display is a bit crazy because the discharge/charge behavior (voltage) is different from SLA. The cut off is the same and the LFP can be charged with a SLA charger (and any solar charge controller for SLA).
 
I was happy to see your post on retrofitting a Yeti 1250 with a LiFePO4 battery, as my AGM batteries don't last long :-(

I was curious to see what Goal Zero thought about the upgrade, so I contacted their technical department to see what they thought about it.

What are your thoughts/comments about their reply below?

***** Email Reply from Goal Zero *****
Thanks for sending that article and information over to me. I had a conversation with our engineers, and they confirmed that we do NOT recommend going from Lead Acid to any sort of lithium battery. This can cause damage to the Yeti 1250 itself since these units were originally created for Lead Acid batteries. With our X-line units you can go from Lithium to Lead Acid using what we call the Yeti Link Expansion Module but there is no way to go from Lead Acid to Lithium.

Let me know if you have any questions, thanks!

Best Regards,

Solution Center Representative
***** Email Reply from Goal Zero *****
I haven't had any issues either as others have mentioned. Here is the build I have just completed: https://diysolarforum.com/threads/280ah-lifepo4-goal-zero-yeti-1250.36995/
 
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I put a LFP in one of my little 150. It runs without issues, the charge status display is a bit crazy because the discharge/charge behavior (voltage) is different from SLA. The cut off is the same and the LFP can be charged with a SLA charger (and any solar charge controller for SLA).
Thats cool you took the plunge, I did wonder if the increase in capacity makes the (highly inaccurate :p) LCD display go a bit wayward, i had a 14ah from factory, then threw a 15ah in and it seems to hit 60% way sooner than it used to. What brand did you get?
 
Thats cool you took the plunge, I did wonder if the increase in capacity makes the (highly inaccurate :p) LCD display go a bit wayward, i had a 14ah from factory, then threw a 15ah in and it seems to hit 60% way sooner than it used to. What brand did you get?
I got this one (Germany). It‘s very good, a little more Wh as expected.
 

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