RE: [PSUBS-MAILIST] Lithium Iron Phosphate batteries

There is something missing as that shows 6 cells in the box and each cell is 3.3 volts and at least 10 AH. If they were all in parallel then they would be 2.8 -3.3 volts but 60-90 AH. Chinese web sites usually have incorrect wording as I believe is the case here.

If it is the latest in Cells then they are 20 AH cells and if it is 40 AH then they would be a 6-9 volt battery. I am using 15 AH cells but the latest are 20 AH but the cells are much larger.

There is a cautionary note with LFePO4 batteries and that is the battery management controls. They are up to Mk 4 in the controls so you need to be very careful on that issue.

IF they are not kept topped up they go bad. New tech is harder to manage and understand the pitfalls. Also quality in these is an issue. They are made in China. I found uncrimped wires, holes not tapped fully and loose connections. Hugh

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Jon Wallace
Sent: Saturday, 4 June 2011 1:43 a.m.
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Lithium Iron Phosphate batteries

Hi Alan,

The battery specs cite a 2.8v nominal voltage so I'm curious why the web site states 3.2v. Assuming 3.2v is correct, you would have to put 4 of these batteries in series to get a minimum of 12v at only 40 Ah. Another eight batteries would be required to get enough current capacity to equal a 120Ah lead-acid, for a cost of $720 not including the hardware to bind the batteries together. A lead-acid battery of the same specs is about $250.

Jon

On 6/3/2011 4:07 AM, Alan James wrote:

Hi,

Firstly, "Carsten don't eat the cucumbers".

Secondly, I was talking to a battery importer today, who is bringing in a load

of Chinese "Thunder Sky" Lithium Iron Phosphate batteries. I googled them & came up with this

Oakland, California based dealer & thought the prices were looking good.

http://www.electricmotorsport.com/store/ems_ev_parts_batteries_lpf_ts_40ah.php

These are 3.2 volt & can be linked together to form whatever voltage, using their accessories.

They seem almost good enough to compete with lead acid batteries for best bang for your buck.

Regards Alan

__________ Information from ESET NOD32 Antivirus, version of virus signature database 6175 (20110602) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com