I have just purchased an SOK 100ah battery with heat and BT to replace my LA battery in my 5th wheel. First, my converter is LI friendly and I switched it to LI prior to installing the LI battery. The LI battery was at 26% when I installed. My RV is plugged into 110 in my garage. I woke up this morning and my LI battery was not on and no power to my RV from shore power. The 25 amp fuse for battery cable reversal protection was blown. I unhooked the battery from the rig, replaced the fuse and now have shore power to the rig. Why would my fuse blow? does the battery need to be completely charged prior to installation? Can I charge it with my normal LA battery charger? My LA battery is completely gone due to an incident from last year while boondocking, that is why the switch to LI.
Lead acid swap to lithium
- Thread starter VicRider
- Start date
sunshine_eggo
Happy Breffast!
Fuses can wear out if operated at or near their rated current. If the fuse doesn't blow again, I wouldn't worry about it.
LFP batteries typically ship at a low state of charge. This likely demanded the converter charge at max output for an extended period. It might have contributed to the fuse blow. I would deliberately discharge the batter to a low state of charge and then re-charge to confirm it doesn't repeat.
LFP batteries can be charged with most LA chargers provided the bulk/absorption/boost is 14.6V or less and float is 13.8V or less (13.6V preferred).
LFP batteries only need to be floated in a cyclic application. If charging on shore power for extended periods, disable float or drop it to 13.2V.
LFP batteries typically ship at a low state of charge. This likely demanded the converter charge at max output for an extended period. It might have contributed to the fuse blow. I would deliberately discharge the batter to a low state of charge and then re-charge to confirm it doesn't repeat.
LFP batteries can be charged with most LA chargers provided the bulk/absorption/boost is 14.6V or less and float is 13.8V or less (13.6V preferred).
LFP batteries only need to be floated in a cyclic application. If charging on shore power for extended periods, disable float or drop it to 13.2V.
Rbertalotto
Solar Enthusiast
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OK....What damaged your LA battery last year?
What do you have for an onboard Charger/Converter in the trailer? If it outputs more than 25 amps maybe that was the cause.
Are you sure the battery cables were not reversed?
What do you have for an onboard Charger/Converter in the trailer? If it outputs more than 25 amps maybe that was the cause.
Are you sure the battery cables were not reversed?
Last year while boondocking my tow vehicle broke down and I was away from my RV and unable to run my generator to keep the LA battery from completely discharging. I have a progressive dynamics converter charger that has the charge wizard and LA/LI switch. I switched it to LI prior to installing the cables, and yes verified they were not reversed. the battery was at 26% according to the BT app on my phone. This morning, no power to the rig the battery was shut down. I checked the 25 amp fuse and it was blown.
I am currently charging the battery, your last statement was to disable or drop the float to 13.2V. Not sure I understand or know how to do that.
sunshine_eggo
Happy Breffast!
That would depend on your converter's settings/programmability.
joanna_lannie
Maybe sleepwalking now
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- Sep 14, 2021
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To be honest, it is not particularly recommended to use the LA charger to charge the LFP, because it is difficult to guarantee that the voltage of LA and LFP are completely similar, which means that you may not be able to fully charge your LFP battery, which is a pity The news, LiFePO4 battery charging is best to guarantee that the battery can be fully charged safely, and a dedicated LFP battery charger will be better.
sunshine_eggo
Happy Breffast!
This is just not true. The answer is "it depends." Many implementations of "Lithium chargers" leave a lot to be desired.
joanna_lannie
Maybe sleepwalking now
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Do you have some examples? Since I've always thought that LFP chargers are designed to be the most suitable for charging LFP batteries, if you can help me correct my wrong thinking, I'd appreciate it.
sunshine_eggo
Happy Breffast!
Most RV "Lithium" converters force a 4 hour absorption cycle with no float. That may be desirable in some circumstances and detrimental in others. The typical RV converter that does a 14.4-14.6V Bulk, 13.6-13.8V absorption and 13.2V float is great for LFP cycle life but bad for generator charging (takes longer)
LFP is essentially a drop-in for most lead-acid. The only criteria that determine if a charger is suitable is:
1) does it bulk/boost/absorb at 14.6V or lower?
2) does it float at 13.6V or lower?
If the answer to both is yes, it's generally fine. The only time one should replace a charger in-hand is if it fails to meet #1 and #2 above, or if it fails to operate as desired due to other system limitations.
The idea that special chargers are needed for LFP batteries is 80% marketing and 20% real.
Note how Battleborn does NOT indicate a LFP charger is needed:
Frequently Asked Questions
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