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Author Topic: Battery Bank  (Read 374 times)

KD9FRQ

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Battery Bank
« on: June 27, 2020, 06:31:10 AM »

I am need of some shack power help.

When I first started, I got a 45amp RV charger and linked it to two 100AH wet LA batteries.  They were linked in parallel.  One rig is on all the time but only drawing 1A in receive mode.  The batteries are now showing some age.

So, what 12v DC BMS do you use for your multi battery bank?
What charger are you using?
How many amps are you putting into your batteries all the time?
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K7AAT

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Re: Battery Bank
« Reply #1 on: June 27, 2020, 08:33:14 AM »


For the past 9 or more years I have run my entire station off two Power Sonic 55Ah AGM batteries.  I simply float charge them at 13.5VDC with an MFJ-4225MV power supply which has a reverse protection diode in its output.  This has worked flawlessly for me over these years.  I do believe their capacity has seriously diminished so will probably be in market for replacement AGM.  They sit under my ham desk.  Hate to get a single 100AH because of weight but 50Ah are getting harder to find and probably more expensive .  Cost is why I am not going with Lithium and their attendant special chargers.
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KB1GMX

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Re: Battery Bank
« Reply #2 on: June 27, 2020, 08:59:23 AM »

OK the questions...

What do you want to run?
For how long?

The RX load of 1A is pretty small so wht is the TX power/current.
That determines how big a battery. 

What I do.  I have two 33AH AGM usually in parallel for what I call
semiportable or remote station typically field day.  IF I want points
for non-engine power I bring 110W is solar to maintain them (FD).

For light weight portable under 10W (PEP SSB) I use either
8AH 12V gell cells or for the FT817 a Lithium pack 11AH in
size thats smaller [fits in pocket] and lighter than average
12V gell cell.

Home station is battery Solar and 150AH. This is both serious
and elaborate.   That makes the station completely independent
of the commmercial power.  That includes lights and computer!

If the battery is for emergency power back up then float it off a
suitable power supply with blocking diode.  The PS should be
adjusted to keep the battery at about 13.8V. 

The usual caveats for battery boxes, fusing and all is well advised.

Allison
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NA4IT

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Re: Battery Bank
« Reply #3 on: June 27, 2020, 04:56:41 PM »



Shack is powered with a 12V / 150AH UPS Battery, and a IOTA 30 amp supply / charger from Cascade Audio.
The IOTA supply is an Recreational Vehicle type supply / charger and have good RF shielding.
The DC voltage stays near 13.5V at all times, and when AC fails, there is NO loss of DC.
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KD9FRQ

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Re: Battery Bank
« Reply #4 on: June 28, 2020, 05:39:32 AM »

NA4IT,

What is the circuit card in the middle of the Positice lead?  My 45A RV charger looks almost the same.  I link the charger ground to the common station ground as well.

Ed, KD9FRQ
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K5LXP

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Re: Battery Bank
« Reply #5 on: June 30, 2020, 07:19:35 PM »

Just a few observations.  Wet cell batteries aren't the best for standby service.  AGM or gel are better suited plus can be kept indoors without worries of outgas or corrosion.

Fully charged batteries don't need much in the way of "current" all the time.  You float them at a specific voltage based on the make and model of the battery, and ambient temperature.  Generally the maintenance current for a hundred Ah setup will be well under an amp.

With proper care you can use a shack power supply as a float charger.  But if power is lost, the battery becomes discharged and power restored, the battery charge current can tax a station supply beyond it's rating.  Not always, depending, but it's something to check before you leave it go unattended.

12V equipment often poops out well above the lower limit of a lead battery discharge point, leaving battery capacity unusable.  My solution is to use a sine wave computer UPS.  Everything runs on 120V AC in the event of an outage as though nothing happened, and the UPS manages the battery charging.  I got my UPS's for free, IT folks get nervous about equipment not under warranty or service plan in the server room.  Been running the shack off UPS's for over a quarter century at this point, it checks all the boxes for me.

If all you're looking for is "standby" power vs always hot, leaving the battery offline on a maintainer and connecting it to the station equipment when needed (switch or plug) would be a simpler solution.

Mark K5LXP
Albuquerque, NM
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