LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[bill good]

SVI
You are running the risk of getting "more bang for your buck".

Regards

[goboatingnow]

Originally Posted by roetter

Here is a link to a +/- 75A current sensor Pololu - ACS709 Current Sensor Carrier -75A to +75A. They have many more. I am planning to use smaller versions to monitor the consumption of my fridges with the Arduino.

Here I have it installed on a Blue Seas busbar that I cut up in the middle and added small bolts for the señor. Works great.

Note this board is really a 30A continuous rated one, this is too small

Dave

[diugo]

Personally, I prefer the through-hole type of Hall Effect current sensor. You simply stick the wire through it, insulation and all, with no direct connection whatsoever.

I am happy with the $8 IS-6 models I have ordered from devicecraft.com.

[T1 Terry]

The only real drawback with induction type sensing is the error factor between current going in and current coming out. If you have a clamp meter, try it over a cable one way around and then the other way around, 2 different readings, the average is usually close to the true reading, not precise enough for SOC measurement but it does give a close enough is good enough reading for determining basic loads.

T1 Terry

[SVI]

Originally Posted by goboatingnow

Note this board is really a 30A continuous rated one, this is too small

Dave

How is about this one (BB-HCSM)?

[SVI]

Open Energy Monitor - good example of what can be done, and complete systems for sale

[senormechanico]

We are waiting for delivery of 8 400 aH Lithium cells from Balqon for our home's backup solar array.

We ordered them in the last week of June, expecting a six week wait.
As we left for five weeks of vacation, we left with orders to ship upon our return.
Two checks were sent, one for up front, and the other to be cashed upon shipment.
The first was cashed, but not the second, and I can't get any phone response from them after multiple messages left on the answering machine.
Maybe they are waiting for delivery from the mfr, but a response by phone would be appreciated.

Hello?
Cruiser's Forum members are watching this thread...

Steve

[IceDog]

Hi Steve,
I hope your situation is resolved soon. Keep us informed. I was planning to order 4 700ah batteries from them but the shipping cost was going to be $900 to Florida. Then I looked at 8 400ah and the shipping was also high. However shipping for 4 400ah batteries was only around $100. I currently plan to order 4 400ah batteries from them for December timeframe...
Kevin
ps If you split your order in two you might get cheaper shipping? Assuming they get around to answering your calls...

[senormechanico]

I just got a call from Steven Perez at Balqon.
He apologized for the delay in responding as he was out of town.
He also said he's received notification from the factory that they are overwhelmed with orders and my cells should arrive in mid September.
He promised to keep me updated on the shipping progress.

I'm disappointed, but not surprised at the delay if it's because of the popularity of these cells. I wouldn't go back to lead acid even if they were new and cost nothing unless there was no alternative.

[deckofficer]

Steve,

It is good to see this increase in popularity for these cells. In the sport flying community there is now a couple of choices for electric planes. For the pilot that just wants to get in a couple of hours of flying per day and isn't fond of setting aside $12+ per hour for the expensive overhaul and the $30 and up per hour fuel costs, it is the way to go. Not only are they saving $40+ per hour but also no warm up, no worry of thermal shock when going from climb to idle, no plugs, oil, noise or vibration. Sailplanes that are self launch are also going electric. Even the FAA is considering raising the weight limit on LSA that are electric.

[hellosailor]

Steve, are you planning to use a BMS or balancing them manually?

[I.Grind]

I own a courier company, and have been asked to test some EV's. One of the ones I am testing has Valence LiFeMgPO4 batteries. Out of curiosity I went to the Valence website (Lithium Phosphate Battery Suppliers | Valence Technology) these things look pretty nifty. Smaller and lighter than LiFePO4 but more interesting is the claimed 7000 cycles at 100% dod.

I'm no electrical engineer, but these look pretty cool to me. I might be missing something, so no need to flame if I am not understanding something in the datasheets. I don't know the price either, and based on the MSRP of EV's, they could be quite expensive.

Just thought I'd share with the rest of you LiFePO4 "fanboys"

[Saltyhog]

Originally Posted by I.Grind

I own a courier company, and have been asked to test some EV's. One of the ones I am testing has Valence LiFeMgPO4 batteries. Out of curiosity I went to the Valence website (Lithium Phosphate Battery Suppliers | Valence Technology) these things look pretty nifty. Smaller and lighter than LiFePO4 but more interesting is the claimed 7000 cycles at 100% dod.

I'm no electrical engineer, but these look pretty cool to me. I might be missing something, so no need to flame if I am not understanding something in the datasheets. I don't know the price either, and based on the MSRP of EV's, they could be quite expensive.

Just thought I'd share with the rest of you LiFePO4 "fanboys"

Looks interesting, but wow... they sure are proud of their batteries. $3564 for a 138 AH Group 27 battery. Maybe they'll make it up in volume.

[I.Grind]

After you posted that I searched for price and found $1295.00. No bargain for sure.

[T1 Terry]

It looks like the bigger capacity is built up from paralleled small cylindrical cells, yet the cycle life is only at 0.5C rating, I couldn't find where they claimed the bigger capacity battery lasted more than 2500 cycles before the capacity had dropped below 80%, this seems to be the common cut off point for battery cycle life, if it was measured to 60% like lead acid the Winston and Sinopoly cells would have some very high numbers. Of course, these cycle life figures are calculated from data entered into a computer extrapolating total life from the level of capacity lost over what ever test period they use, they haven't been around long enough to have actually tested the 5,000 and 7,000 cycle life, a charge and discharge every day for 19 yrs to get 7,000 cycles.

T1 Terry