battery choice

full_mosey wrote:

westend wrote:

Note the charge specs limit the charge rate to 80A. You will need to dial your Magnum back and not use the full 125A when charging a pair. 80/400 = 20%

I thought that the "80A or smaller" in the table of the linked chart specifies the voltages to be attained, not the current acceptance. That is how I read it.

I don't see how you make the transition from Amps to Volts. I read 80A as the Amp limit at any point during the charge. Volts are managed by temperature so as to avoid gassing. Usually there is a formula/table for adjusting Volts up or down according to battery temperature.

In this case, I believe the 'Missing Amp Hours' rule does not apply. In contrast, I would be happy to use a 100A charger on my 100AH 800CCA AGM because I use temp comp chargers.

HTH;
John

In the specifications file you linked to there is a part labeled "Characteristics". Towards the bottom of that portion there is a heading in the left table called "Charging (constant voltage)". To the right it reads, "Cycle" and then "Initial charging current 80 amp or small (sic)". Next to that is a range of voltages ("7,25->7.45/77f (20C)"). To me that means that the voltages should be in that range with the current determined to be less than 80A. It does not specify a maximum current only that a typical constant voltage charger of less than 80 amps or smaller should attain those voltages at the temperatures listed. This is how I read the chart.

As mentioned, it's a non-issue for Pianotuna with his four batteries. I only wished to explain my understanding of the chart.