AGM to Balqon LifePO4 battery upgrade

[autumnbreeze27]

Originally Posted by ranger42c

In another thread, I've been effectively talked out of Li for our own application, but if you don't mind saying, can you mention cost of your 400 Ah LiFePo4 house bank?

-Chris

I paid $2800 for the battery and some spare parts.
I figure I could have rolled my own for a little less, but it was worth it to me to have it done right the first time, and I have too many other irons in the fire right now.

I still have to make some kind of lid for the battery to protect it.

[ranger58sb]

Originally Posted by autumnbreeze27

I paid $2800 for the battery and some spare parts.
I figure I could have rolled my own for a little less, but it was worth it to me to have it done right the first time, and I have too many other irons in the fire right now.

I still have to make some kind of lid for the battery to protect it.

Thanks, useful info.

FWIW, Maine Sail makes some nifty boxes designed for Li batteries. You might check with him for info...

-Chris

[autumnbreeze27]

BTW, new plan for the battery switches:

Battery Selector HOUSE
1 = House Battery
2 = Emergency Battery
BOTH = Do not use

Battery Selector ENGINE
1 = Engine Battery
2 = Emergency Battery
BOTH = Both Engine & Emergency Batteries

[autumnbreeze27]

I installed the battery today, and curious what you think about these shore power charger settings:

I'm currently set to GEL2, which charges at 14.4v and floats at 13.8

The lifepo4 settings are 14.8/14.4, or 14.6/14.4.

She's been charging all night... she's only taking 9 amps now. When I powered it up for the first time it was at 13.2v. Now I'm at 14.

I reconfigured solar, it's now in absorption mode.

Regulation Voltage: 14.00 V (12V)
Temperature Compensation: Disabled
Absorption Time: 2:30:00 h:m:s
Absorption Ext. Voltage: disabled V
Float Voltage: 13.40 V (12V)
Float Timeout: 12:00:00 h:m:s
Float Cancel Voltage: disabled V
Equalize Voltage: disabled V
HV Disconnect: 14.50 V (12V)
HVD Reconnect: 13.20 V (12V)
Maximum Regulation Limit: 14.40 V (12V)
Maximum Battery Current: 60.00 A

[hellosailor]

Ignoring the question of what bulk charge voltage Balqon recommends for that battery, you do realize that NO float voltage at all should be used for lithium batteries?

[autumnbreeze27]

Originally Posted by hellosailor

Ignoring the question of what bulk charge voltage Balqon recommends for that battery, you do realize that NO float voltage at all should be used for lithium batteries?

I do, I don't understand why this charger that has a Lithium setting doesn't have a no float option, so I figured the GEL setting with the lower float value was safer.

We're only going to be in a marina for 5 more months, so I'm just trying to figure out a system so I don't damage my Li battery. I doubt once we cast off from shore power that we will have to worry about anything going in to float mode. If it means manually turning the charger off and on as needed, I'm ok with that, I'm not going to upgrade the charger since it won't be a primary source of power.

Balqon recommended 14.4 to charge.

The charger has a feature that once the battery is topped off, it will handle all the house loads. I wanted to see if it would go into that mode or not, but I may just chicken out and shut the charger down and see how the solar does.

[Maine Sail]

14.4 /13.8

If you are going to be at a a dock for five months discharge the LFP to 50-60%, isolate it, and run off your start battery & shore charger....

[autumnbreeze27]

Originally Posted by Maine Sail

14.4 /13.8

If you are going to be at a a dock for five months discharge the LFP to 50-60%, isolate it, and run off your start battery & shore charger....

What, do you subscribe to the Capt Ron philosophy of "If it's going to happen, it's going to happen out there!" LOL

I'll be evaluation the performance of our unit BEFORE we leave.

[hellosailor]

" so I'm just trying to figure out a system so I don't damage my Li battery."
The legal term might be "sales puffery" although some of us just call it "fraud". I suppose technically, the lithium setting on your charger IS a perfectly good lithium setting. It supplies the right voltage.
Sounds like the charger company just conveniently forgot to add "Oh, but you'll need a lithium battery management system (BMS) to properly use and disconnect the charger, unless you have staff to do that."


Maine's solution is one good way to deal with it. The other would be to run off your lithium bank, without charging it, and then periodically charge it. If you run the lithium bank down to 70% charge (30% discharge) before recharging it, perhaps daily or every second day? You'll barely be denting the lifetime of the battery. It seems that more and more claims are pointing to 3,000-10,000 cycles at that kind of discharge, which is pretty good, which ever claims are right.


With a little patience...I can't see that a proper lithium charging system, designed and matched to operate with a BMS, won't be on the market within a year or two. The opportunity, the need, is just way too obvious.

[autumnbreeze27]

I turned the shore power charger off yesterday, ran all night, the solar was able to bring the battery back up to 14v today.