LiFePO Batteries ???

[tpenfield]

My concern is that while the batteries are installed in the boat, it is supplying power (and small amounts of current) to the various systems throughout the boat. Mostly the inverter, but there is other stuff like CO detector and stereo keep-alive.

So, even though there is some loss within the battery itself (about 2% per month), more significantly will be the current draw within the boat.

Anyway, my go-forward plan will be to pull the LFP batteries during the off-season and keep them in a reasonably warm place . . . maybe put a charge to them now & then.

In other News, my new battery arrived. . .
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I've got it on the charger . . . the initial voltage was 2.54 volts . . . Which I think means the BMS was 'sleeping'. The LiTime charger kicked it over and the voltage immediately came up to the 11.3 volt range and continued to rise.

I will give the shipping dept. folks at LiTime a "D-" on their report card, as the battery was not packaged (in the outer box) very well . . . it looked like the UPS folks had to shore things up during shipment.

 

[airshot]

My plan as well is to remove the battery over the winter and store in my heated garage. Easy to monitor it over the winter. Based on all my radio control batteries ( lipos). They drop very little, some have not been charged in a year and still show storage charge...

 

[airshot]

I’m not sure if all LFP batteries are the same, but . . .

The cold protection in my batteries stops charging @ 32F, but the discharging keeps going until about 4F. So, with my boat, which has a lot of parasitic loads, the batteries run down.

I has some of those sneaky draws from my house battery. After replacing some wiring, cleaning up some questionable connections, and removing some long deleted switches, I have removed the parasitic draws. Also added a shutoff for future winter storage. I also monitor my batteries as my toys are stored in my pole barn where easy to acess. If my toys were locked up in some storage facility where I couldn't see or check on them......not sure I could sleep at night !!

 

[tpenfield]

I'd like to put my boat under cover for the winter, but it stands a little over 12 ft high on the trailer. Maybe something to think about in the future.

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I checked on the batteries after charging for about 2.5 hours (@ 20 amps) (13.48 volts). I'll have to see what the 'at rest' voltage comes out to be.

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I'll let it go for another hour or so, then let it sit overnight. Tomorrow's agenda might include installing the battery in the boat.

 

[alldodge]

I'd like to put my boat under cover for the winter, but it stands a little over 12 ft high on the trailer. Maybe something to think about in the future.

Always build your pole barns with a 14ft door

 

[bruceb58]

I know for a FACT that the BMS module does.. COULD.. draw power ALL the time. We use these batteries in Radio Controlled model airplane. SOME ...BMS systems HAVE ruined the battery by constantly drawing MONITORING POWER. You MUST have a full current rated switch to turn off ALL Parasitic currents. Some electronics STILL draw power even when turned off. Memory systems of radios can have that constant current draw when turned off.
The BMS should have a STANDBY mode of operation to prevent The BMS system from ruining the battery.
Why some of us still use Lead Acid batteries.

You are talking about an external BMS system. The internal BMS in these batteries have a standby current of 1mA.

 

[tpenfield]

Quick update . . .

Yesterday, I let the new battery come down to a resting voltage, which it did after a while. 13.24 volts. Checking it again in the AM it was 13.22 volts. So, about 70% charge per the voltage chart. I decided to give it a few more % of charge and hooked the charger up for about an hour.

When I came back to the battery, the charger had completed and the voltage was at about 12.9-12.8 volts . . . (weird). I disconnected the charger and it was still 12.8 volts all on its own . . . At that point I was not sure what was going on . . .So . . . I put the battery in the boat to let the solar charger have a go at it. I put the old/existing battery aside for the time being. After a short time, the (new) battery was at 13.34 volts. My thinking was that the charger (a LiTime brand charger at that) had done an over voltage thing at the end of the charging cycle and the battery went into protection mode. (maybe)

So as not to waste a moment, I had the old battery at 13.28 volts and the new battery at 13.34 volts (close enough!) So, I joined the two batteries into parallel matrimony and called it good.

 

[tpenfield]

It's raining so the solar charging is a bust for the rest of the day. I hooked up the AC power and ran the inverter charging. It went into bulk mode for a few minutes (20 amps), then went into absorption mode . . . was pulling 1-2 amps.

I'll see how things look in the AM.

 

[airshot]

Always build your pole barns with a 14ft door

Yep....realized it hat after building mine !! A 12' tall shot is be a minium....