New ,still in delivery box, .Victron AGM battery terminal voltage

T

tomboy352

Well-Known Member
Joined
14 Nov 2001
Messages
130
Location
nr.Ingleton
Visit site
Hi all,
I have just received my Tanya Victron AGM’s. The voltage is 12.65v as read with. Fluke technicians multimeter. There is evidence of an attempt to clean dust off the top.
I like to see 12.8v on a new battery which suggests to me that the AGMs have been self discharging for some time between manufacture (in Vietnam) and arriving onboard
They say that the AGM can handle this discharge without sulphating but should I be worried that I have bought old stock with reduced service life ?.
 
I think I’d give them a good charge and then monitor post-charge to make sure they’re retaining 12.8v. I recently had a delivery of the same batteries from BatteryMegastore, they were all > 12.8v on arrival.
 
I have emailed manufacture code and state of charge to Tanya Support asking for production date. When I get a reply I tell them that I will fully charge the batteries and monitor that they hold the charge.
But I expect that it would be capacity that suffered rather than ability to hold a charge
 
There is usually a label with a date code. A charged battery may well lose 0.1v per month sitting idle. Voltage is not a good indicator of battery health if you are worried. Fully charge them and the put a car headlight across them. Measure the amp draw (typically 4A) and monitor until the Voltage hits 12.1 (resting). That will give the approx 50% capacity (amp draw x no of hours discharging). If its close to the stated capacity then battery is probably fine.
 
My 2 90 amp AGMs were sent back to the manufacturer. When they left me they were showing 12.8V. When they arrived they were recorded at 12.91V. That could have been because a few days earlier they had dropped to 12.4 after 4 minutes use on my fresh water pump only & were slowly cimbing, plus a change in temperature. They had been disconnected since november & voltage had never dropped below 13 V which I checked monthly
The manufacturer says that they charged them to 13.2V & measured efficiency at 54% & 57%. So that shows that Voltage is NOT a fair measure of storage
They drained & re charged to 13.2 V again & claim that storage has climbed to 86% & 76% which THEY say is acceptable. :rolleyes:
I find that worrying as 76% of 90 amps is 68.4 amps & max I can take from that is 80% making 54.72 amps. That is from a professionally charged battery- not one partially charged from my engine- & showing 13.2 V
I regularly show just over 13 V after charge but as volts are not a proper measure one has to be wary of storage.
I am advised that a safe lowest limit is 11.4 volts. For this I can expect 600 discharges in its cycle. More if not allowed to go below 12 V
 
I eavesdropped a conversation in Halfords yesterday.
A guy returned an agm battery that he had bought for a jet-ski. When he checked the date code he found it was 6 years old, older than the one he was replacing.
I must be more diligent on checking age of batteries if bought from a shop.
 
We lived at anchor 4months p.a x 6 yrs plus some travelling . On solar panels, running fridge and tv etc.
On 3 x 70ah agms of unknown make. I am hoping that a 500 squid investment on a known brand will see us out. Although these days We will spend more time alongside
Old or damaged batteries have a higher resistance which drops the voltage when under load resulting in lower capacity
In the old days, Lucas used to recharge their unsold flooded battery stock on a timetable to keep them healthy
I wonder if Tanya will send me an accurate manufacture date or pull one out of a hat .
 
You must log in or register to reply here.

Share this page

Top