Auxiliary Battery Problem?

[HammaMan]

- Requires the box be modified slightly with vibratory saw (got one on ebay for $50 delivered) - lid will snap on as you're accustomed to.
- Requires a ~3" 8ga extension to connect up the positive circuit breaker assembly to the positive terminal
- my 2 batts I got required ~30ma charging for several days to fully balance the cells (will eventually balance after 72hrs, I used lab bench power supply constant current, a resistor and standard batt charger may do it.

I'd call it an exact fit post mod, like exact fit

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[Snakebitten]

I'm in.

Just a bit smaller in all 3 dimensions.

And I didn't have anything for precision charging/balancing. Grabbed solely on reviews

I have tried to avoid/ignore this approach for as long as I could. But then you went and posted those amazing steady state static voltage logs. I have been looking at my logs for many months. I've never seen anything near that stable with the 3 vehicles I have loggers on.

U.N.C.L.E. ??

 

[HammaMan]

That's the "slim" model, I've linked it before I think

 

[PatchManager]

I've now replaced both batteries and am still having the same issue. I also disconnected the engine battery and charged it for an hour. I've made an appt. with the local Ford dealer since it's under warranty.

Did you get this issue corrected? If so, what was the fix?

 

[FaaWrenchBndr]

Just to mention it, this diagram is for the “NON Powerboost” model with the 2kW inverter ProPower. It does indeed have two auxiliary batteries

 

[FaaWrenchBndr]

Not that battery in particular. Battery issues of any kind just reminds that it has a battery that WILL malfunction and/or fail.

Resale is much less on Powerboosts also. Why is that? LOL. See. It precisely part of the fuckall equation. You're welcome.

Most folks who own Powerboosts want to be PROUD of them. Tell the good. Pretend there is no bad. lol. I'm realistic.

Seems like you need to sell the shit and go back to Dodge or Chevy

 

[ReverendQ]

- Requires the box be modified slightly with vibratory saw (got one on ebay for $50 delivered) - lid will snap on as you're accustomed to.
- Requires a ~3" 8ga extension to connect up the positive circuit breaker assembly to the positive terminal
- my 2 batts I got required ~30ma charging for several days to fully balance the cells (will eventually balance after 72hrs, I used lab bench power supply constant current, a resistor and standard batt charger may do it.

I'd call it an exact fit post mod, like exact fit

I'm In. Now to get rid of the gap on my version

 

[Mash150]

- Requires the box be modified slightly with vibratory saw (got one on ebay for $50 delivered) - lid will snap on as you're accustomed to.
- Requires a ~3" 8ga extension to connect up the positive circuit breaker assembly to the positive terminal
- my 2 batts I got required ~30ma charging for several days to fully balance the cells (will eventually balance after 72hrs, I used lab bench power supply constant current, a resistor and standard batt charger may do it.

I'd call it an exact fit post mod, like exact fit

Can these lithium batteries work in the truck under extended freezing conditions, as in days with the temperatures under -10 c and infrequent driving ?

 

[ReverendQ]

Can these lithium batteries work in the truck under extended freezing conditions, as in days with the temperatures under -10 c and infrequent driving ?

I don't believe these self-heat to assist with cold weather operations but may work for you. Check out the specifications here https://www.eco-worthy.com/products...ithium-battery-lifepo4?variant=36010575069349. I couldn't find these for the AGM in cab.

 

[HammaMan]

Can these lithium batteries work in the truck under extended freezing conditions, as in days with the temperatures under -10 c and infrequent driving ?

as I just posted in another lithium thread....

Lithium isn't a single chemistry. LFP isn't friendly to low temp charging, particularly sub freezing. W/out a smart BMS and heater in the batt, not advisable. Even w/ a heater in the batt, it can take up to an hr for the batt to reach safe charging temps. It will still discharge energy but can't take it back up. This could be hard on a traditional charging system lacking its transient buffer. Maybe the alternators can handle it, maybe they can't. Given it can discharge voltage won't dip low, but a cheap alternator might spike the voltage trying to recover or let go of sudden load like the ABS can hit the system with.

LTO and other lithium chemistries can do sub freezing temps. Most batts sold as house/starting batteries use LFP chemistry and they're just not good in cold temps where a battery can cold soak for 12+hrs (or worst case a day or two). That's a lot of mass to get up to temp and honest battery sellers will tell you the time it takes to warm it back up. It could take an hour to reach safe charging temp. Freezing isn't a magic number either, it's a gray zone where the C rate must be limited on either side of it up to around 40f.

Conditions like garage kept and driving frequency can impact this. If you overnight garage, the batt will charge before reaching a destination. Coming back it might not take any charge (not a big deal, they have loads of reserve capacity). Placing on a 15a charger is enough to feed its heaters, they're typically a 10a/120w heating element. Some may find it to be a small sacrifice for what it provides. Heat coming off of the engine in rewarming the batt is an unknown variable.
--------------
These little batts typically cannot heat and just use a hard charge cutoff at 32f (but can still let energy out) and can't receive engine heat. If the BMS doesn't use low temp protection, each charge below freezing can impact batt life 1-10x its normal span (typically measured in decades as is). They have 4-6000 charge cycles (full depth discharge) before reaching 80% capacity. I'm okay having that impact the few times a year mine may be charged below freezing as it's not a full charge that occurs. Lab testing is 100% DoC and reduces life by 90%. Essentially I count each freezing charge as if it's 10 normal charges, but it's also fractional recharges and there's no lab data for that.

What we have found is that lithium chemistries in general are lasting 40% longer than projections in EVs because people aren't performing full depth of discharge cycling. There's just no data on it. I'm 2 years into my LFP experiment and it's performing better than a new AGM so I'm still ahead by a lot.

 

[Mash150]

as I just posted in another lithium thread....

Lithium isn't a single chemistry. LFP isn't friendly to low temp charging, particularly sub freezing. W/out a smart BMS and heater in the batt, not advisable. Even w/ a heater in the batt, it can take up to an hr for the batt to reach safe charging temps. It will still discharge energy but can't take it back up. This could be hard on a traditional charging system lacking its transient buffer. Maybe the alternators can handle it, maybe they can't. Given it can discharge voltage won't dip low, but a cheap alternator might spike the voltage trying to recover or let go of sudden load like the ABS can hit the system with.

LTO and other lithium chemistries can do sub freezing temps. Most batts sold as house/starting batteries use LFP chemistry and they're just not good in cold temps where a battery can cold soak for 12+hrs (or worst case a day or two). That's a lot of mass to get up to temp and honest battery sellers will tell you the time it takes to warm it back up. It could take an hour to reach safe charging temp. Freezing isn't a magic number either, it's a gray zone where the C rate must be limited on either side of it up to around 40f.

Conditions like garage kept and driving frequency can impact this. If you overnight garage, the batt will charge before reaching a destination. Coming back it might not take any charge (not a big deal, they have loads of reserve capacity). Placing on a 15a charger is enough to feed its heaters, they're typically a 10a/120w heating element. Some may find it to be a small sacrifice for what it provides. Heat coming off of the engine in rewarming the batt is an unknown variable.
--------------
These little batts typically cannot heat and just use a hard charge cutoff at 32f (but can still let energy out) and can't receive engine heat. If the BMS doesn't use low temp protection, each charge below freezing can impact batt life 1-10x its normal span (typically measured in decades as is). They have 4-6000 charge cycles (full depth discharge) before reaching 80% capacity. I'm okay having that impact the few times a year mine may be charged below freezing as it's not a full charge that occurs. Lab testing is 100% DoC and reduces life by 90%. Essentially I count each freezing charge as if it's 10 normal charges, but it's also fractional recharges and there's no lab data for that.

What we have found is that lithium chemistries in general are lasting 40% longer than projections in EVs because people aren't performing full depth of discharge cycling. There's just no data on it. I'm 2 years into my LFP experiment and it's performing better than a new AGM so I'm still ahead by a lot.

Pretty much what I expected but I wanted to make sure that my understanding on low temperatures was somewhat not all that far off. And thank you for taking time for your in-depth reply.

 

[hatallica]

When adding a LiFePO4 (LFE) battery, I am curious if anyone is taking any steps to match the voltage to the AGM. Or are you just slapping it in and letting a slug of current equalize them?

I just built up a 12Ah LFE battery with BMS and noticed about a 1V difference from the Aux battery. To be extra safe, I connected 20 ohms between the positive terminals to bleed off a bit. Is that silly or prudent before connecting them in parallel?

 

[tsigwing]

When adding a LiFePO4 (LFE) battery, I am curious if anyone is taking any steps to match the voltage to the AGM. Or are you just slapping it in and letting a slug of current equalize them?

I just built up a 12Ah LFE battery with BMS and noticed about a 1V difference from the Aux battery. To be extra safe, I connected 20 ohms between the positive terminals to bleed off a bit. Is that silly or prudent before connecting them in parallel?

slap and go for me, no issues.

 

[hatallica]

slap and go for me, no issues.

Thanks. That is what I ended up doing.

Thankfully, I was not expecting a panacea. DC voltage (BECM Control Module V) was sitting at 14.9V for my entire commute this morning, so the LFE BMS rightfully refused any charge.

I may try an overnight float charge to add a few amp-hours back into the system. Starting from a healthier place can't hurt.

 

[Jmitchelltfo]

When adding a LiFePO4 (LFE) battery, I am curious if anyone is taking any steps to match the voltage to the AGM. Or are you just slapping it in and letting a slug of current equalize them?

I just built up a 12Ah LFE battery with BMS and noticed about a 1V difference from the Aux battery. To be extra safe, I connected 20 ohms between the positive terminals to bleed off a bit. Is that silly or prudent before connecting them in parallel?

Straight 4awg between my LFP and OEM AGM. Still works great after several months of cold weather. The X2 does limit the incoming charge to a max of 14.9 (up to 30 amps if discharged multiple times while under temp) I've seen 15.2v for both of my AGM's, which matches the max that I've seen on my DC/DC output.

Resting voltage of 13.0-13.2 has given me one less thing to worry about. I might even try to run the original battery under the hood until next winter which would put it over 1700 days, which is longer than most Ford H7's will probably last these days.

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