what battery may I / shall I use with PD Systems ?

in the following, please also click the provided links to get more information.

• All our systems (except a few battery based ignitions) may - technically seen - run without battery. We say technically seen, as there are a few legal and some technical aspects to observe.

• Any lead/acid battery, be it the oldfashioned liquid acid one or the more modern sealed gel or vlies battery. But please no car battery, with this there will be load problems. A motorcycle battery goes up to about 12 Ah.
  Do not use any other than a led acid battery! A motorcycle is some rough environment with changing voltage and also fast changing background frequencies in this voltage.
• No lithium, NICd, NiMH,NiZn, AgZn or whatever now exists! 
  Why not? 
  - First, we do not know whether those batteries may get damaged by our system and they are expensive
  - even more important we see possible dangers 
  Li-ion cannot accept overcharge, when fully charged the charge current must be cut off. This our systems do not. A continuous trickle charge (maintenance charge) would cause plating of metallic lithium, and this could compromise safety. The cathode material becomes an oxidizing agent, loses stability and produces carbon dioxide (CO2). The cell pressure rises and the cell might eventually vent with flame.
  Also those batteries can not take charge below 0°C (32°F)
• Never use a dry cell (non rechargable) battery. It might even explode and catch fire 

• We talk about replacement systems for vintage and classic motorcycles. So please stick to motorcycle batteries. Max capacity 12Ah. We offer for many years already vlies type lead/acid accus between 1,3 Ah and 7.2 Ah and had so far not seen any major problems with this. Do not use a car battery on those small motorcycle generators. The effect would be that they will not charge well (or only in very high revs) and the battery will be drained after a while. Additionally experience shows connections to  car batteries - invariably housed in sidecars - are problematic (bad contacts, risk of shortcircuits etc)

• this can have many reasons, both in battery itself, the charging system, the motorcycle wiring, oversized consumers...
  
  Even though the we are Powerdynamo, the small systems made for older motorcycles are not atomic power plants! Please if needed browse the lighting and battery matters section of our knowledgebase.
  
  Most  cases of batter charging problems tun out be be caused by dead batteries or broken/jammed wired.

• Also bear in mind that batteries need a certain amount of care and service and they do have a limited lifespan (which on some cheap makes can be more than limited!). All batteries discharge themselves, even whilst not in use. With vehicle batteries this can be per month  5–10 % (classic accu) resp. 2–5 % (gel/vlies types) capacity loss. Batteries kept unloaded over a longer period simply die.
• We offer for motorcycles which depend on optics which include the battery an empty battery housing into which a replacement battery may be hidden.