Thanks so much Bob! Much appreciated and much respect to you old friend. I was probably rambling and got crossed up in the late hour on my last post.

Mr.Erv is getting good info that will help him along the way no doubt, enough to get him going apparently, and it is alot to take in at one time... and I'm always excited to help or encourage if I can... but I have to realize it's tough to take in several ways of going about things... The equations will come(and go as we get older) for people that are new to current technology, and when a few or more people are trying to help, it can get confusing.

I hope life's treating you well... and I'm sure we hope the best for Mr Erv... and thanks for your support. It's what this hobby is about buddy.

DGrant. I understand. I’m sure many have been in the same place, me included.

OP if you can find batteries with tabs attached use those. Much easier to make the packs. The ones I got did not have tabs so I soldered the packs. One reason for making a spot welder is to attach tabs to batteries. I’m still working on that project. Some success but not there yet.

Typically the cells in a pack are in series, to get the voltage one needs - that is pretty obvious. But, over time one or more cells charged over just the series connection may not charge up in the same amount of time, leading to an "unbalanced" pack. That cell when used then hits bottom before the others, potentially ruining it. So separate positive leads are also run from each cell, with a common negative, and plugged separately into the charger. Chargers will then monitor the voltage of each cell to ensure they are all at the same level before charging stops. Plain series charging can take a little less time. Balance monitored charging can get a few more mah replaced back into the battery.

Bummer - it seems like Sullivan doesn't offer the 6v any more. I would assume that using a 3S would be fine, although it may pump a bit slower than "normal". It's just a motor and a switch, so shouldn't be very sensitive.

One thing with buying battery packs you have to make sure you get the battery with the correct connector for your use. There are many different connectors In use. Store bought packs may have multiple power leads. Like a plug for your receiver, deans plug for charging and other uses and a balance lead and plug.

Here are some diagrams which will help in the wiring. The thick red and black leads would power your load. These would have the connector that you use. The thin leads are the balance leads which have the JST-XH balance connector. When you balance charge, you plug both leads to the charger. The charger measures the voltage and charges so each cell is close to the same voltage. Non-balance charging you would connect just the power lead. Balance leads have one more lead than the number of cells. So 3s has 4 leads.

JST-XH connector are inexpensive and can be purchased from Digi Key. Along with the pins. Batteries are running $6.55 for 2.5ah and $5.49 for 1.1ah. Minimum of 5 and I think you can mix them for the 5. These have no tabs. Stortronics.