From:Dave Hennessey
Subject:RE: RE: RE: Gel cell power Date:Fri Sep 14 02:19:43 2012
Response to:17827
Bench charging batteries

A 1-amp battery charger will fully charge any battery - given enough time. This is the best rating for Hummer batteries, whether H-3 or small gel-cell.

Stronger chargers (like 10-amp) will do the job in 1/10th the time, but they will overheat a small battery, causing internal damage. 10-amp chargers are made for car-sized batteries, which can withstand more heat during charging.

Model 125/165 Generator Output

Harley does not explicitly specify the output of the generator. However, the Service Manual does provide a test to determine whether the generator is working acceptably:

"...remove the green wire from the F terminal of the regulator and touch it to engine base. If ammeter shows a charge of 5 amperes or more..."

If 5 amps is the minimum full-power output for an acceptable generator, we'll have to guess that a good generator will put out a maximum of something like 6-8 amps.

During normal operation, the voltage regulator will reduce the generator output to just enough to keep the original H-3 battery charged. At 25 mph with a fully charged battery, the ammeter should show something like 1-2 amps.

The 4.5 amp and 13 amp gel-cells are obviously not the same as the 7.4 amp H-3. But the regulator is a standard Delco-Remy unit designed to work in a number of applications, so it should keep all these gel-cells properly charged.


H-3 battery 7.4 amps


I spent some time looking for some kind of specs regarding Hummer/Model 165 generator output and had no luck. It looks like the Model 61 6V generator used on the 1936 - 1961 big Harley's is rated at 6 V / 15 Amp. For no really good reason, I would suspect that the lightweight bikes would not have output that high- maybe 10 Amp

I found several chargers for the SLA batteries - the recommendations are a 6V / 1Ah charger for batteries from 3.3 to 10Ah capacity or a 6V / 4Ah charger for batteries from 13.3 to 40Ah - figure that a 13Ah SLA needs close to the 4Ah rating to charge correctly.

The old H-2 battery was listed at 22Ah. I can't find specs for the H-3 battery, but it looks smaller so would be less, *maybe* somewhere around 15Ah.

Given the recommended chargers / charge rates on the SLA batteries, it seems possible that the generator with the standard regualtor setup might actually be charging too much for the SLA batteries... or I could be completely wrong...


Question is; Will the existing Harley generator actually replenish these gel cells? Or do you purchase a special charger or discard and replace when dead?

I found a 6v 4.5 ah gell cell at Tractor Supply for $9.99 they are so small you could probably install a couple and hook them up in parrallel to fill the battery box.