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Charger Size?

W

west

Jan 1, 1970
0
2 questions please.

1. Battery Chargers are rated in amps. How do you determine what size
charger you need for a 12V AGM battery?

2. To power my 100W transceiver in case of a blackout, should I use a 75
a/h or (2) 37a/h batteries in parallel? Perhaps someone can explain the pros
& cons of either arrangement. Thank you in advance.

Cordially,
west
 
C

Chris Hill

Jan 1, 1970
0
2 questions please.

1. Battery Chargers are rated in amps. How do you determine what size
charger you need for a 12V AGM battery?

For most battery types you look for a charger that can charge at 1/10
of the amp hour rate.
2. To power my 100W transceiver in case of a blackout, should I use a 75
a/h or (2) 37a/h batteries in parallel? Perhaps someone can explain the pros
& cons of either arrangement. Thank you in advance.

I wouldn't parallel batteries, one of the two inevitably ends up doing
more work and failing first.
 
C

clare at snyder.on.ca

Jan 1, 1970
0
2 questions please.

1. Battery Chargers are rated in amps. How do you determine what size
charger you need for a 12V AGM battery?

2. To power my 100W transceiver in case of a blackout, should I use a 75
a/h or (2) 37a/h batteries in parallel? Perhaps someone can explain the pros
& cons of either arrangement. Thank you in advance.

Cordially,
west
Genewrally, as a rule, one single larger battery is better than 2
smaller in parallel because of load sharing issues. If one cell on one
battery goes bad, it will drain both batteries. In thas case, having 2
does not give any redundancy - it just doubles the probability you
will have a problem, and makes the problem worse when it occurs.
 
S

Steve Spence

Jan 1, 1970
0
Chris said:
I wouldn't parallel batteries, one of the two inevitably ends up doing
more work and failing first.

Not usually. 3 strings of Trojans will last a decade with proper
maintenance. We run a 125 amp charger on our 1260 ah pack.
 
S

Steve Spence

Jan 1, 1970
0
west said:
2 questions please.

1. Battery Chargers are rated in amps. How do you determine what size
charger you need for a 12V AGM battery?

SS> A maximum of 10% of the ah rate. 75 ah of battery would need at
least 4 amps of charging, but not more than 8, unless you have a good 3
stage charger with battery temperature compensation. My charger lets me
dial in the ah rating of the pack, and has a temperature probe.
2. To power my 100W transceiver in case of a blackout, should I use a 75
a/h or (2) 37a/h batteries in parallel? Perhaps someone can explain the pros
& cons of either arrangement. Thank you in advance.

SS> Doesn't matter. Where it gets tricky is series/parallel strings. No
more than 3 is a good rule of thumb, but it's not concrete.
 
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