Quote:
Originally Posted by California98Civic
I had learned about the expanding problem during my own long conversations with the Odyssey techs, but this home-remedy never came up. Thanks for that. I have a smaller Odyssey battery I could adapt in this way.  |
In the end I decided on plywood for reinforcement rather than aluminium. Mainly because it is non-conductive - both thermally and electrically, but also because it is easier to work with and just as rigid, if a bit more bulky. (I did have to shave away some of the side pieces to accomodate the battery clamps and various protrusions in the battery compartment, and that involved a bit of trial and error, so I'm glad I didn't go for aluminium.)
It seems the only real issue with these batteries is longitudinal expansion, where the lead plates separate and the battery fails. So I've got two thick plywood end plates (18mm or 3/4 inch) and two side pieces of 5mm plywood, screwed and glued into the 'end grain' of the end plates. I used 'Cascamite' resin glue.
18mm ply is overkill in terms of stiffness, but putting screws into the edge of thinner ply is not so robust, so I used 18mm to get a good width for both screws and glue to hold well.
Anyway it seems to work just fine, and still fits in the car's battery tray. Mine is the PC1220 battery which is the standard 096 pattern and has a 'wedge-shaped' hold-down base that can be clamped down in the car, so a 5-sided box is not possible. The four-sided thing is fine though - just can't be removed. Well, if I ever do need to remove it I can cut through the glue joint on one side. I sprayed the battery casing lightly with silicone so the glue wouldn't bond to the plastic.
(But I have to say it was a disappointment to find that you can't use these batteries (these standard car-battery-shaped batteries, sold as car batteries!) at above 40 degrees C without mechanical restraint. That makes the batteries not really 'fit-for-purpose', as car engine bays will routinely get hotter than 40 degrees C, even on a cool day.)
But California98Civic, I'm still getting contradictory advice from Enersys tech people about the proper charging current for Odyssey batteries, and whether this minimum 0.4C charge they talk about is really necessary or not. What did you conclude about that?
I had one Enersys techie say, "Yes, you get more cycles with a >0.4C bulk charge, but no one really knows why," and another, equally confident Enersys techie said that as long as I make sure the battery really does get 100% recharged between discharges then I'll be fine, but that I must recognise that a FULL charge will need a 'float' charge of 6-8 hours AFTER the bulk/absorption charge has done all it is going to, and that 6-8 hours is 6-8 hours regardless of the charger's max power output, so if I can get the bulk/absorption charge down to two or three hours then there's a much better chance that an overnight charge will recharge the battery to 100% than if the bulk/absorption charge is itself taking ten hours.
I came across these guys today on a powered wheelchair forum. One recounts a conversation with the head bloke at Hawker (before Enersys bought them out) about their pure lead thin plate batteries and their charging requirements (scroll down a bit) ...
WheelchairDriver • View topic - Another battery from Enersys
...and this guy seems to have re-designed his wheelchairs for maximum performance and range. He rates Odyssey batteries, MK and Sonnenshein and advises against ever using anything else...
WheelchairDriver • View topic - AGM & GEL BATTERY INFO for POWERCHAIRS
...I reckon that if anyone is going to know about batteries it will be someone (with an engineering background!) who absolutely relies on batteries for their everyday personal mobility in a wheelchair. This guy seems to have re-designed his wheelchairs for maximum performance and range.